JP7539140B2 - Method for producing acyloxysilane - Google Patents

Description

The present invention relates to an efficient method for producing acyloxysilane.

Acyloxysilanes are functional chemicals that are used as reagents or synthetic intermediates for the precision synthesis of pharmaceuticals, agricultural chemicals, electronic materials, etc., as well as raw materials for surface modifiers, sol-gel materials, nanomaterials, organic-inorganic hybrid materials, etc.
Methods using chlorosilanes as a raw material are known as methods for producing acyloxysilanes.Specifically, methods that have been investigated include (A) a method in which chlorosilane is reacted with a carboxylic acid directly or in the presence of a base (Patent Documents 1 and 2), (B) a method in which chlorosilane is reacted with a metal salt of a carboxylic acid (Patent Document 3), and (C) a method in which chlorosilane is reacted with a carboxylic anhydride (Patent Document 4).
On the other hand, as a method using a siloxane compound having a Si-O-Si bond as a raw material, a method has been reported in which (D) a disiloxane is reacted with a carboxylic acid anhydride in the presence of zinc(II) chloride (Non-Patent Document 1), or in the presence of trifluoromethanesulfonic acid or Amberlyst 15 (Patent Document 5). Also reported is an example of reacting a cyclic siloxane compound, octamethylcyclotetrasiloxane, with acetic anhydride in the presence of sulfuric acid (Patent Document 6), and an example of reacting in the presence of zinc(II) chloride or iron(III) chloride (Non-Patent Document 2).

However, the methods using chlorosilane as a raw material have problems such as: (1) handling of the raw material is difficult because chlorosilane, which generates corrosive hydrogen chloride upon hydrolysis, is used (Methods A and B); (2) when a base is not used in the reaction with a carboxylic acid, corrosive hydrogen chloride is by-produced (Method A); (3) when a base is used in the reaction with a carboxylic acid, a large amount of salt is by-produced (Method A); (4) a large amount of salt is also by-produced in the reaction with a metal carboxylate (Method B); and (5) when a reaction with a carboxylic anhydride is performed, acyl chlorides that are easily hydrolyzed and tend to generate corrosive hydrogen chloride are by-produced (Method C).
On the other hand, in the method (Method D) using a siloxane compound having a Si-O-Si bond as a raw material, there are no problems such as the generation of corrosive hydrogen chloride, and since the reaction has an atom utilization efficiency of 100%, there is no problem of unnecessary co-products. However, there are problems such as the low efficiency of conventional acidic compounds used as catalysts, which requires a large amount of acidic compound relative to the raw material (Non-Patent Document 1 uses 20 mol % zinc chloride relative to hexamethyldisiloxane; Patent Document 5 uses 10 mol % trifluoromethanesulfonic acid relative to hexamethyldisiloxane; Patent Document 5 uses 119 mass % Amberlyst 15 relative to hexamethyldisiloxane and 184 mass % relative to acetic anhydride, etc.), the need for a high reaction temperature of 130° C. or more (around 140° C. in Patent Document 6; 150° C. or 250° C. in Non-Patent Document 2), and the need for a long reaction time of several hours to 48 hours (Patent Documents 5 and 6, Non-Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 54-103500 European Patent Application No. 0837067 U.S. Pat. No. 4,379,766 German Patent No. 882401 European Patent Application No. 1378514 U.S. Pat. No. 2,910,496

Compt. Rend., 246, p.952-954 (1958) J. Organomet. Chem., 11, p.27-33 (1968)

The present invention was made in consideration of the above circumstances, and aims to provide a method for efficiently producing acyloxysilane from a siloxane compound having a Si-O-Si bond.

As a result of intensive research aimed at solving the above problems, the inventors discovered that the reaction between a siloxane compound having a Si-O-Si bond and a carboxylic acid anhydride proceeds smoothly in the presence of a specific catalyst, and acyloxysilane can be efficiently obtained, thus completing the present invention.

Ｘ^１Ｏ（ＳｉＲ^６Ｒ^７Ｏ）_ｎＸ^２ （ＩＣ）
（式（ＩＡ）～（ＩＣ）中、Ｒ^１～Ｒ^７は、それぞれ独立に炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよく；Ｘ^１およびＸ^２は、それぞれ独立にシリル基または水素原子であり；ｍおよびｎは、それぞれ独立に２以上１００００以下の整数である。）
＜６＞
前記カルボン酸無水物が、下記一般式（ＩＩＡ）または（ＩＩＢ）で表されるカルボン酸無水物である、＜１＞～＜４＞の何れかに記載のアシロキシシランの製造方法。
（Ｒ^８ＣＯ）_２Ｏ （ＩＩＡ）

（式（ＩＩＡ）中、Ｒ^８は、炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよい。式（ＩＩＢ）中、Ｒ^９は、炭素数２～２４の２価の炭化水素基であり、前記炭素数２～２４の２価の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよい。）
＜７＞
前記シロキサン化合物が、下記一般式（ＩＡ）で表されるシロキサン化合物であり、前記カルボン酸無水物が、下記一般式（ＩＩＡ）で表されるカルボン酸無水物であり、前記アシロキシシランが、下記一般式（ＩＩＩＡ）で表されるアシロキシシランである、＜１＞～＜４＞の何れかに記載のアシロキシシランの製造方法。
Ｒ^１Ｒ^２Ｒ^３Ｓｉ－Ｏ－ＳｉＲ^１Ｒ^２Ｒ^３ （ＩＡ）
（Ｒ^８ＣＯ）_２Ｏ （ＩＩＡ）
Ｒ^１Ｒ^２Ｒ^３Ｓｉ（ＯＣＯＲ^８） （ＩＩＩＡ）
（式（ＩＡ）中、Ｒ^１～Ｒ^３は、それぞれ独立に炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよい。
式（ＩＩＡ）中、Ｒ^８は、炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよい。
式（ＩＩＩＡ）中、Ｒ^１～Ｒ^３は、式（ＩＡ）中のＲ^１～Ｒ^３と同様に定義され、Ｒ^８は、式（ＩＩＡ）中のＲ^８と同様に定義される。）
＜８＞
前記シロキサン化合物が、下記一般式（ＩＢ）で表されるシロキサン化合物であり、前
記カルボン酸無水物が、前記一般式（ＩＩＡ）で表されるカルボン酸無水物であり、前記アシロキシシランが、下記一般式（ＩＩＩＢ）で表されるアシロキシシランである、＜１＞～＜４＞の何れかに記載のアシロキシシランの製造方法。

（Ｒ^８ＣＯ）_２Ｏ （ＩＩＡ）
Ｒ^８ＣＯ_２（ＳｉＲ^４Ｒ^５Ｏ）_ｐＣＯＲ^８ （ＩＩＩＢ）
（式（ＩＢ）中、Ｒ^４およびＲ^５は、それぞれ独立に炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよく；ｍは、２以上１００００以下の整数である。
式（ＩＩＡ）中、Ｒ^８は、炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよい。
式（ＩＩＩＢ）中、Ｒ^４およびＲ^５は、式（ＩＢ）中のＲ^４およびＲ^５と同様に定義され；Ｒ^８は、式（ＩＩＡ）中のＲ^８と同様に定義され；ｐは、１～１００の整数である。）
＜９＞
前記シロキサン化合物が、下記一般式（ＩＣ）で表されるシロキサン化合物であり、前記カルボン酸無水物が、前記一般式（ＩＩＡ）で表されるカルボン酸無水物であり、前記アシロキシシランが、下記一般式（ＩＩＩＣ）で表されるアシロキシシランである、＜１＞～＜４＞の何れかに記載のアシロキシシランの製造方法。
Ｘ^１Ｏ（ＳｉＲ^６Ｒ^７Ｏ）_ｎＸ^２ （ＩＣ）
（Ｒ^８ＣＯ）_２Ｏ （ＩＩＡ）
Ｒ^８ＣＯ_２（ＳｉＲ^６Ｒ^７Ｏ）_ｑＣＯＲ^８ （ＩＩＩＣ）
（式（ＩＣ）中、Ｒ^６およびＲ^７は、それぞれ独立に炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよく；Ｘ^１およびＸ^２は、それぞれ独立にシリル基または水素原子であり；ｎは、２以上１００００以下の整数である。
式（ＩＩＡ）中、Ｒ^８は、炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよい。
式（ＩＩＩＣ）中、Ｒ^６およびＲ^７は、式（ＩＣ）中の^６およびＲ^７と同様に定義され；Ｒ^８は、式（ＩＩＡ）中のＲ^８と同様に定義され；ｑは、１～１００の整数である。）＜１０＞
前記シロキサン化合物が、下記一般式（ＩＢ）で表されるシロキサン化合物であり、前記カルボン酸無水物が、下記一般式（ＩＩＢ）で表されるカルボン酸無水物であり、前記アシロキシシランが、下記一般式（ＩＩＩＤ）で表されるアシロキシシランである、＜１＞～＜４＞の何れかに記載のアシロキシシランの製造方法。

（式（ＩＢ）中、Ｒ^４およびＲ^５は、それぞれ独立に炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよく；ｍは、２以上１００００以下の整数である。
式（ＩＩＢ）中、Ｒ^９は、炭素数２～２４の２価の炭化水素基であり、前記炭素数２～２４の２価の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよい。
式（ＩＩＩＤ）中、Ｒ^４およびＲ^５は、式（ＩＢ）中のＲ^４およびＲ^５と同様に定義され；Ｒ^９は、式（ＩＩＢ）中のＲ^９と同様に定義され；ｒ１は、１～１００の整数であり；ｒ２は、１以上ｒ１以下の整数である。）
＜１１＞
前記シロキサン化合物が、下記一般式（ＩＣ）で表されるシロキサン化合物であり、前記カルボン酸無水物が、下記一般式（ＩＩＢ）で表されるカルボン酸無水物であり、前記アシロキシシランが、下記一般式（ＩＩＩＥ）で表されるアシロキシシランである、＜１＞～＜４＞の何れかに記載のアシロキシシランの製造方法。
Ｘ^１Ｏ（ＳｉＲ^６Ｒ^７Ｏ）_ｎＸ^２ （ＩＣ）

（式（ＩＣ）中、Ｒ^６およびＲ^７は、それぞれ独立に炭素数１～２４の炭化水素基または水素原子であり、前記炭素数１～２４の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよく；Ｘ^１およびＸ^２は、それぞれ独立にシリル基または水素原子であり；ｎは、２以上１００００以下の整数である。
式（ＩＩＢ）中、Ｒ^９は、炭素数２～２４の２価の炭化水素基であり、前記炭素数２～２４の２価の炭化水素基の炭素原子に結合した水素原子の一部または全部が反応に関与しない基で置換されていてもよい。
式（ＩＩＩＥ）中、Ｒ^６およびＲ^７は、式（ＩＣ）中の^６およびＲ^７と同様に定義され；Ｒ^９は、式（ＩＩＢ）中のＲ^９と同様に定義され；ｓ１は、１～１００の整数であり；ｓ２は、１以上ｓ１以下の整数である。）
＜１２＞
＜１＞～＜１１＞の何れかに記載の製造方法によりアシロキシシランを製造するアシロキシシラン製造工程、および
前記アシロキシシランに下記一般式（ＩＶ）で表されるアルコールを反応させ、前記アシロキシシランのアシロキシ基をアルコキシ基に変換する修飾工程
を含む、アルコキシシランの製造方法。
Ｒ^１０ＯＨ （ＩＶ）
（式中、Ｒ^１０は、炭素数１～６のアルキル基である。） That is, this application provides the following inventions.
<1>
A method for producing an acyloxysilane having a Si-OCO bond (OCO represents an oxycarbonyl group, O-C(=O)), comprising a reaction step of reacting a siloxane compound having a Si-O-Si bond with a carboxylic acid anhydride in the presence of an acid catalyst selected from the following (1) and (2):
(1) Perchlorate, trifluoromethanesulfonate, bis(trifluoromethanesulfonylimide) salt, hexafluoroantimonate, or thiocyanate of an element selected from the elements of Groups 3 to 15 of the periodic table; ruthenium chloride; gallium chloride; tin chloride; indium chloride; iron bromide; ruthenium bromide; tris(pentafluorophenyl)borane; trimethylsilyl trifluoromethanesulfonate; nonafluorobutanesulfonic acid; bis(perfluoroalkanesulfonyl)imide; bis(trifluoromethanesulfonyl)imide trimethylsilyl; perchloric acid; hexafluoroantimonate; or thiocyanic acid.
(2) Inorganic solid acid compounds.
＜2＞
The method for producing an acyloxysilane according to <1>, wherein the acid catalyst (1) is a compound selected from the group consisting of perchlorates, trifluoromethanesulfonates, bis(trifluoromethanesulfonylimide)salts, and hexafluoroantimonates of elements selected from the group consisting of elements of Groups 3, 8, and 13 to 15; ruthenium chloride; tris(pentafluorophenyl)borane; trimethylsilyl trifluoromethanesulfonate; nonafluorobutanesulfonic acid; bis(perfluoroalkanesulfonyl)imide; and bis(trifluoromethanesulfonyl)imide trimethylsilyl.
＜3＞
<4> The method for producing an acyloxysilane according to <2>, wherein the element selected from the group consisting of elements of Groups 3, 8, and 13 to 15 is an element selected from the group consisting of scandium, yttrium, samarium, yttrium, iron, ruthenium, copper, aluminum, gallium, indium, tin, and bismuth.
The method according to any one of <1> to <3>, wherein the acid catalyst (2) is at least one of zeolite and montmorillonite.
＜5＞
The method for producing an acyloxysilane according to any one of <1> to <4>, wherein the siloxane compound is a siloxane compound represented by the following general formula (IA), (IB), or (IC):
R ¹ R ² R ³ Si-O-SiR ¹ R ² R ³ (IA)

X ¹ O(SiR ⁶ R ⁷ O) _n X ² (IC)
(In formulas (IA) to (IC), R ¹ to R ⁷ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that do not participate in the reaction; X ¹ and X ² each independently represent a silyl group or a hydrogen atom; and m and n each independently represent an integer of 2 or more and 10,000 or less.)
＜6＞
The method for producing an acyloxysilane according to any one of <1> to <4>, wherein the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIA) or (IIB):
(R ⁸ CO) ₂ O (IIA)

(In formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with a group that does not participate in the reaction. In formula (IIB), R ⁹ is a divalent hydrocarbon group having 2 to 24 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the divalent hydrocarbon group having 2 to 24 carbon atoms may be substituted with a group that does not participate in the reaction.)
＜７＞
The method for producing an acyloxysilane according to any one of <1> to <4>, wherein the siloxane compound is a siloxane compound represented by the following general formula (IA), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIA), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIIA):
R ¹ R ² R ³ Si-O-SiR ¹ R ² R ³ (IA)
(R ⁸ CO) ₂ O (IIA)
R ¹ R ² R ³ Si (OCOR ⁸ ) (IIIA)
In formula (IA), R ¹ to R ³ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with a group that is not involved in the reaction.
In formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIIA), R ¹ to R ³ are defined in the same manner as R ¹ to R ³ in formula (IA), and R ⁸ is defined in the same manner as R ⁸ in formula (IIA).
＜8＞
The method for producing an acyloxysilane according to any one of <1> to <4>, wherein the siloxane compound is a siloxane compound represented by the following general formula (IB), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIA), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIIB):

(R ⁸ CO) ₂ O (IIA)
R ⁸ CO ₂ (SiR ⁴ R ⁵ O) _p COR ⁸ (IIIB)
(In formula (IB), R ⁴ and R ⁵ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction; and m represents an integer of 2 or more and 10,000 or less.
In formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIIB), R ⁴ and R ⁵ are defined as R ⁴ and R ⁵ in formula (IB); R ⁸ is defined as R ⁸ in formula (IIA); and p is an integer from 1 to 100.
＜9＞
The method for producing an acyloxysilane according to any one of <1> to <4>, wherein the siloxane compound is a siloxane compound represented by the following general formula (IC), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIA), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIIC):
X ¹ O(SiR ⁶ R ⁷ O) _n X ² (IC)
(R ⁸ CO) ₂ O (IIA)
R ⁸ CO ₂ (SiR ⁶ R ⁷ O) _q COR ⁸ (IIIC)
(In formula (IC), R ⁶ and R ⁷ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that do not participate in the reaction; X ¹ and X ² each independently represent a silyl group or a hydrogen atom; and n represents an integer of 2 or more and 10,000 or less.
In formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIIC), R ⁶ and R ⁷ are defined as ⁶ and R ⁷ in formula (IC); R ⁸ is defined as R ⁸ in formula (IIA); and q is an integer of 1 to 100.) <10>
The method for producing an acyloxysilane according to any one of <1> to <4>, wherein the siloxane compound is a siloxane compound represented by the following general formula (IB), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIB), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIID).

(In formula (IB), R ⁴ and R ⁵ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction; and m represents an integer of 2 or more and 10,000 or less.
In formula (IIB), R ⁹ is a divalent hydrocarbon group having 2 to 24 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the divalent hydrocarbon group having 2 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIID), R ⁴ and R ⁵ are defined as R ⁴ and R ⁵ in formula (IB); R ⁹ is defined as R ⁹ in formula (IIB); r1 is an integer of 1 to 100; and r2 is an integer of 1 or more and r1 or less.
<11>
The method for producing an acyloxysilane according to any one of <1> to <4>, wherein the siloxane compound is a siloxane compound represented by the following general formula (IC), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIB), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIIE):
X ¹ O(SiR ⁶ R ⁷ O) _n X ² (IC)

(In formula (IC), R ⁶ and R ⁷ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that do not participate in the reaction; X ¹ and X ² each independently represent a silyl group or a hydrogen atom; and n represents an integer of 2 or more and 10,000 or less.
In formula (IIB), R ⁹ is a divalent hydrocarbon group having 2 to 24 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the divalent hydrocarbon group having 2 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIIE), R ⁶ and R ⁷ are defined as R ⁶ and R ⁷ in formula (IC); R ⁹ is defined as R ⁹ in formula (IIB); s1 is an integer of 1 to 100; and s2 is an integer of 1 or more and s1 or less.
＜12＞
A method for producing an alkoxysilane, comprising: an acyloxysilane production step of producing an acyloxysilane by the production method according to any one of <1> to <11>; and a modification step of reacting the acyloxysilane with an alcohol represented by the following general formula (IV) to convert an acyloxy group of the acyloxysilane into an alkoxy group:
^R10OH (IV)
(In the formula, R ¹⁰ is an alkyl group having 1 to 6 carbon atoms.)

The manufacturing method of the present invention has the effect of making it possible to more efficiently manufacture acyloxysilanes using siloxane compounds having Si-O-Si bonds as raw materials, compared to conventional methods.

In particular, a preferred embodiment of the production method of the present invention has the following features.
(1) The raw materials and catalysts are easy to obtain, easy to handle, and highly safe.
(2) There are no problems such as the generation of corrosive hydrogen chloride.
(3) The reaction proceeds even under mild conditions of room temperature to about 90°C.
(4) Because of its high catalytic activity, the reaction proceeds even with a small amount of catalyst.
(5) In a reaction system that uses a solid catalyst, the catalyst can be easily separated and recovered.
(6) The reaction proceeds smoothly not only with low molecular weight disiloxanes, but also with polymers such as polysiloxanes.
That is, a preferred embodiment of the production method of the present invention enables a low-cost and highly efficient production process, and has great advantages over conventional techniques in terms of economy, environmental load, etc.

The present invention will be described in detail below. Unless otherwise specified, when a symbol in a formula in this specification is used in other formulas, the same symbol has the same meaning.
A method for producing an acyloxysilane according to one embodiment of the present invention is characterized by comprising a reaction step of reacting a siloxane compound having a Si-O-Si bond with a carboxylic acid anhydride in the presence of an acidic catalyst.

In the production method according to this embodiment, the siloxane compound having a Si—O—Si bond (hereinafter, simply referred to as a “siloxane compound”) used as a raw material is represented, for example, by the following general formulas (IA) to (IC).
R ¹ R ² R ³ Si-O-SiR ¹ R ² R ³ (IA)

X ¹ O(SiR ⁶ R ⁷ O) _n X ² (IC)
In these formulas (IA) to (IC), R ¹ to R ⁷ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and A part or all of the bonded hydrogen atoms may be substituted with groups that do not participate in the reaction. In this specification, "not participating in the reaction" means that the compound does not directly participate in the target reaction as a reactant. It also means that the reaction is neither inhibited nor promoted.
^X1 and ^X2 each independently represent a silyl group or a hydrogen atom.
Furthermore, m and n are each independently an integer of 2 or more and 10,000 or less.

When R ¹ to R ⁷ are each a hydrocarbon group having 1 to 24 carbon atoms, examples of the hydrocarbon group include an alkyl group, an aryl group, an aralkyl group, and an alkenyl group.

When the hydrocarbon group is an alkyl group, the number of carbon atoms in the alkyl group is preferably 1 to 20, more preferably 1 to 18, and even more preferably 1 to 10. In addition, some or all of the hydrogen atoms bonded to the carbon atoms of the alkyl group may be substituted with groups that are not involved in the reaction.

Examples of the group that does not participate in the reaction include an alkoxy group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 1 to 6 carbon atoms, a dialkylamino group having 1 to 6 carbon atoms, a cyano group, a nitro group, a halogen atom, etc. More specific examples of the alkoxy group, the alkoxycarbonyl group, the dialkylamino group, and the halogen atom include alkoxy groups such as a methoxy group, an ethoxy group, and a hexoxy group; alkoxycarbonyl groups such as a methoxycarbonyl group and a propoxycarbonyl group; dialkylamino groups such as a dimethylamino group and a diethylamino group; and halogen atoms such as a fluorine atom, a chlorine atom, and a bromine atom.
Specific examples of the alkyl group which may be substituted with a group which does not participate in the reaction include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a pentyl group, a hexyl group, a cyclohexyl group, an octyl group, a decyl group, a chloromethyl group, a 2-methoxyethyl group, a 3-ethoxypropyl group, a 2-methoxycarbonylethyl group, a 2-dimethylaminoethyl group, a 3-cyanopropyl group, a trifluoromethyl group, a 3-chloropropyl group, a 3,3,3-trifluoropropyl group, a 1H,1H,2H,2H-tridecafluorooctyl group, and a 1H,1H,2H,2H-heptadecafluorodecyl group.

In addition, when the hydrocarbon group is an aryl group, a monovalent aromatic organic group of a hydrocarbon ring system or a heterocyclic ring system can be used. In the case where the aryl group is a hydrocarbon ring system, the number of carbon atoms of the monovalent aromatic organic group of the hydrocarbon ring system is preferably 6 to 22, more preferably 6 to 14. Specific examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, a perylenyl group, and a pentacenyl group. In the case where the aryl group is a heterocyclic ring system, the heteroatom in the heterocyclic ring is a sulfur atom, an oxygen atom, or the like. In addition, the number of carbon atoms of the monovalent aromatic organic group of the heterocyclic ring system is preferably 4 to 12, more preferably 4 to 8. Specific examples of the aryl group include a thienyl group, a benzothienyl group, a dibenzothienyl group, a furyl group, a benzofuryl group, and a dibenzofuryl group.
A part or all of the hydrogen atoms bonded to the carbon atoms of the aryl group may be substituted with a group that does not participate in the reaction. Examples of the group that does not participate in the reaction include those shown in the case of the alkyl group above. Other groups that do not participate in the reaction include an oxyethylene group, an oxyethyleneoxy group, etc., which are divalent groups that bond two carbon atoms on a ring. Specific examples of aryl groups having such groups include a methylphenyl group, an ethylphenyl group, a hexylphenyl group, a methoxyphenyl group, an ethoxyphenyl group, a butoxyphenyl group, an octoxyphenyl group, a methyl(methoxy)phenyl group, a fluoro(methyl)phenyl group, a chloro(methoxy)phenyl group, a bromo(methoxy)phenyl group, a 2,3-dihydrobenzofuranyl group, and a 1,4-benzodioxanyl group.

Furthermore, when the hydrocarbon group is an aralkyl group, the number of carbon atoms in the aralkyl group is preferably 7 to 23, more preferably 7 to 16. In addition, some or all of the hydrogen atoms bonded to the carbon atoms of the aralkyl group may be substituted with groups that are not involved in the reaction.
Examples of the group that does not participate in the reaction include those mentioned above for the alkyl group.
Specific examples of the aralkyl group which may be substituted by a group which does not participate in the reaction include a benzyl group, a phenethyl group, a 2-naphthylmethyl group, a 9-anthrylmethyl group, a (4-chlorophenyl)methyl group, and a 1-(4-methoxyphenyl)ethyl group.

When the hydrocarbon group is an alkenyl group, the number of carbon atoms in the alkenyl group is preferably 2 to 23, more preferably 2 to 20, and even more preferably 2 to 10. Some or all of the hydrogen atoms bonded to the carbon atoms of the alkenyl group may be substituted with groups that are not involved in the reaction.
Examples of the group that does not participate in the reaction include those exemplified above for the alkyl group, as well as the aryl group and the like.
Specific examples of the alkenyl group which may be substituted by a group which does not participate in the reaction include a vinyl group, a 2-propenyl group, a 3-butenyl group, a 5-hexenyl group, a 9-decenyl group, a 2-phenylethenyl group, a 2-(methoxyphenyl)ethenyl group, a 2-naphthylethenyl group, and a 2-anthrylethenyl group.

When ^X1 and ^X2 are silyl groups, examples of the silyl group include a trialkylsilyl group, a dialkylsilyl group, an aryldialkylsilyl group, an alkenyldialkylsilyl group, a monoalkylsilyl group, a triarylsilyl group, a diarylsilyl group, a monoarylsilyl group, a trialalkylsilyl group, a diaralkylsilyl group, a monoaralkylsilyl group, a trialkenylsilyl group, a dialkenylsilyl group, a monoalkenylsilyl group, etc. Examples of the alkyl group, aryl group, aralkyl group, and alkenyl group in these silyl groups include those shown in the explanation of ^R1 to ^R7 .

m is preferably an integer of 3 or more and 1,000 or less, more preferably an integer of 3 or more and 200 or less, further preferably an integer of 3 or more and 50 or less, and particularly preferably an integer of 3 or more and 10 or less.
Further, n is preferably an integer of 3 or more and 5,000 or less, more preferably an integer of 3 or more and 3,000 or less, further preferably an integer of 3 or more and 1,000 or less, and particularly preferably an integer of 3 or more and 500 or less.

Therefore, specific examples of the siloxane compound having an Si-O-Si bond, which is a raw material having such a hydrocarbon group, include the following:
First, examples of the siloxane compounds represented by the general formula (IA) include hexamethyldisiloxane (Me ₃ SiOSiMe ₃ ), hexaethyldisiloxane (Et ₃ SiOSiEt ₃ ), 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane (Me ₂ PhSiOSiMe ₂ Ph), 1,3-dimethyl-1,1,3,3-tetraphenyldisiloxane (MePh ₂ SiOSiMePh ₂ ), 1,1,3,3-tetramethyl-1,3-divinyldisiloxane (Me ₂ ViSiOSiMe ₂ Vi), 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane ((ClCH ₂ )Me ₂ SiOSiMe ₂ (CH ₂ Cl), 1,3-bis(3-cyanopropyl)-1,1,3,3-tetramethyldisiloxane ([NC(CH ₂ ) ₃ ]Me ₂ SiOSiMe ₂ [(CH ₂ ) ₃ CN]), and the like.

Examples of the siloxane compound represented by general formula (IB) include hexamethylcyclotrisiloxane ((SiMe ₂ O) ₃ ), octamethylcyclotetrasiloxane ((SiMe ₂ O) ₄ ), 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane ((SiMeViO) ₄ ), and decamethylcyclopentasiloxane ((SiMe ₂ O) ₅ ).

Further, examples of the siloxane compound represented by general formula (IC) include poly(dimethylsiloxane) ( ^X1aO (SiMe2O) _pX2a ; X1a, ^{X2a = SiMe3 or H), poly(methylphenylsiloxane) (X1bO(SiMePhO)pX2b; X1b, X2b} ₌ ^SiMe3 _or ^{H )} _, and poly(dimethylsiloxane-co-diphenylsiloxane ₎ ( ^X1cO ( _SiMe2O ⁾ _q (SiPh2O ₎ ^rX2c ; ^X1c , ^X2c = _SiMe3 or H), ^each of ^which is independently terminated with a _{trimethylsiloxy} group or a hydroxy group.
As the poly(dimethylsiloxane) or poly(dimethylsiloxane-co-diphenylsiloxane) having a trimethylsilyl group at the end, for example, those commercially available as silicone oils under the names KF-968 or KF-54 (both manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

On the other hand, the carboxylic acid anhydride to be reacted with the alkoxysilane is represented, for example, by the following general formula (IIA) or (IIB).
(R ⁸ CO) ₂ O (IIA)

In general formulas (IIA) to (IIC), ^R8 is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with a group that does not participate in the reaction. ^R9 is a divalent hydrocarbon group having 2 to 24 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the divalent hydrocarbon group having 2 to 24 carbon atoms may be substituted with a group that does not participate in the reaction.

In general formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
Examples of the hydrocarbon group having 1 to 24 carbon atoms include an alkyl group, an aryl group, an aralkyl group, and an alkenyl group. Examples of the group that does not participate in the reaction include those described above in the description of R ¹ to R ⁷ in general formulas (IA) to (IC).
Regarding the number of carbon atoms in the hydrocarbon group, when the hydrocarbon group is an alkyl group, it is preferably 1 to 20, more preferably 1 to 18, and even more preferably 1 to 8; when the hydrocarbon group is an aryl group, it is preferably 4 to 20, more preferably 4 to 18, and even more preferably 6 to 12; when the hydrocarbon group is an aralkyl group, it is preferably 5 to 21, and more preferably 5 to 19; and when the hydrocarbon group is an alkenyl group, it is preferably 2 to 20, and more preferably 2 to 18.
Specific examples of these groups include those given in the explanation of R ¹ to R ⁷ in the above general formulae (IA) to (IC).

On the other hand, in general formula (IIB), R ⁹ is a divalent hydrocarbon group having 2 to 24 carbon atoms, and some or all of the hydrogen atoms of the divalent hydrocarbon group having 2 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
Examples of the divalent hydrocarbon group having 2 to 24 carbon atoms include an alkylene group, an arylene group, and an alkenylene group. Examples of the group that does not participate in the reaction include those described above in relation to R ¹ to R ⁷ in general formulas (IA) to (IC).
Regarding the number of carbon atoms in the hydrocarbon group, when the hydrocarbon group is an alkylene group, it is preferably 2 to 20, more preferably 2 to 18; when the hydrocarbon group is an arylene group, it is preferably 4 to 20, more preferably 4 to 18; and when the hydrocarbon group is an alkenylene group, it is preferably 2 to 20, more preferably 2 to 18.

Specific examples of the carboxylic anhydride (IIA) having such a hydrocarbon group include acetic anhydride (Ac ₂ O), propionic anhydride ((EtCO) ₂ O), butyric anhydride ((PrCO) ₂ O), isobutyric anhydride ((Me ₂ CHCO) ₂ O), valeric anhydride ((BuCO) ₂ O), isovaleric anhydride ((Me ₂ CHCH ₂ CO) ₂ O), pivalic anhydride ((tert-BuCO) ₂ O), hexanoic anhydride ((C ₅ H ₁₁ CO) ₂ O), heptanoic anhydride (C ₆ H ₁₃ CO) ₂ O), cyclohexanecarboxylic anhydride ((cyc-C ₆ H ₁₁ CO) ₂ O), octanoic anhydride ((C ₇ H ₁₅ CO) _{2 O} ), nonanoic anhydride ((C H ₁₇ CO) ₂ O), decanoic anhydride ((C ₉ H ₁₉ CO) O), lauric anhydride ((C ₁₁ H ₂₃ CO) ₂ O), myristic anhydride ((C ₁₃ H ₂₉ CO) ₂ O)), palmitic anhydride ((C ₁₅ H ₃₁ CO) ₂ O), stearic anhydride ((C ₁₇ H ₃₅ CO) ₂ O), difluoroacetic anhydride ((CF ₂ HCO) ₂ O)), trifluoroacetic anhydride ((CF ₃ CO) ₂ O), trichloroacetic anhydride ((CCl ₃ CO) ₂ O), chlorodifluoroacetic anhydride ((CClF ₂ CO) ₂ O), pentafluoropropionic anhydride ((C ₂ F ₅ CO) ₂ O), benzoic anhydride ((PhCO) ₂ O), toluic anhydride ((MeC ₆ H ₄ CO) ₂ O), naphthoic anhydride ((C ₁₀ H ₇ CO) ₂ O), phenylacetic anhydride ((PhCH ₂ CO) ₂ O), crotonic anhydride ((trans-MeCH═CHCO) ₂ O), isocrotonic anhydride ((cis-MeCH═CHCO) ₂ O), tiglic anhydride ((MeCH═CMeCO) ₂ O), oleic anhydride ([C ₈ H ₁₇ CH═CH(CH ₂ ) ₇ CO] ₂ O), and the like.

Specific examples of the carboxylic acid anhydride (IIB) include succinic anhydride ((CH ₂ ) ₂ (CO) ₂ O), glutaric anhydride ((CH ₂ ) ₃ (CO) ₂ O), octylsuccinic anhydride ((OctCHCH ₂ ) (CO) ₂ O), octadecylsuccinic anhydride ([(C ₁₈ H ₃₇ ) CHCH ₂ ] (CO) ₂ O), allylsuccinic anhydride ([(CH ₂ ═CHCH ₂ ) CHCH ₂ ] (CO) ₂ O), itaconic anhydride ([CH ₂ C(═CH ₂ )] (CO).
₂ O), 3,3-dimethylglutaric anhydride ((CH ₂ CMe ₂ CH ₂ )(CO) ₂ O), phthalic anhydride ((1,2-C ₆ H ₄ )(CO) ₂ O), and the like.

The molar ratio of the carboxylic acid anhydride to the raw material siloxane compound having Si-O-Si bonds can be selected arbitrarily, but taking into consideration the yield of acyloxysilane relative to the siloxane compound, it is usually 0.4 to 100, more preferably 0.5 to 50, even more preferably 0.5 to 20, and particularly preferably 0.5 to 10.

In the present embodiment, when the siloxane compound having a Si—O—Si bond is a siloxane compound represented by the general formula (IA) and the carboxylic acid anhydride is a carboxylic acid anhydride represented by the general formula (IIA), an acyloxysilane represented by the following general formula (IIIA) can be produced.
R ¹ R ² R ³ Si (OCOR ⁸ ) (IIIA)
In general formula (IIIA), R ¹ to R ³ are defined in the same manner as R ¹ to R ³ in formula (IA), and specific examples of R ¹ to R ³ include those shown in the description of R ¹ to R ³ in formula (IA), etc. R ⁸ is defined in the same manner as R ⁸ in formula (IIA), and specific examples of R ⁸ include those shown in the description of R ⁸ in formula (IIA), etc.

Therefore, specific examples of acyloxysilanes of general formula (IIIA) having these groups and the like include acetoxytrimethylsilane (Me ₃ SiOAc), acetoxytriethylsilane (Et ₃ SiOAc), acetoxydimethylphenylsilane (Me 2 PhSiOAc), acetoxymethyldiphenylsilane (MePh ₂ SiOAc), acetoxydimethylvinylsilane (Me ₂ ViSiOAc), acetoxy(chloromethyl)dimethylsilane ((ClCH ₂ )Me ₂ SiOAc), acetoxy(3-cyanopropyl)dimethylsilane ([NC(CH ₂ ) ₃ ]Me ₂ SiOAc), trimethyl(propionyloxy)silane (Me ₃ SiOCOEt), trimethyl(butanoyloxy)silane (Me ₃ SiOCOPr), (hexanoyloxy)trimethylsilane (Me ₃ SiOCOC) _, and the like. _5H11 ), (trifluoroacetyloxy) _{trimethylsilane} ( _Me3SiOCOCF3 ), ( _{pentafluoropropanoyloxy} )trimethylsilane ( _Me3SiOCOC2F5 ), ₍ benzoyloxy)trimethylsilane ( _Me3SiOCOPh ) _, and the like.

Furthermore, in this embodiment, when the siloxane compound having a Si—O—Si bond is a siloxane compound represented by general formula (IB) and the carboxylic acid anhydride is a carboxylic acid anhydride represented by general formula (IIA), an acyloxysilane represented by the following general formula (IIIB) can be produced.
(R ⁸ CO) O(SiR ⁴ R ⁵ O) _p (COR ⁸ ) (IIIB)
In general formula (IIIB), R ⁴ and R ⁵ are defined similarly to R ⁴ and R ⁵ in formula (IB), R ⁸ is defined similarly to R ⁸ in formula (IIA), and p is an integer of 1 to 100. Specific examples of R ⁴ and R ⁵ include those given in the description of R ⁴ and R ⁵ in formula (IB), and specific examples of R ⁸ include those given in the description of R ⁸ in formula (IIA).
Furthermore, p is preferably 1 to 80, more preferably 1 to 50, and further preferably 1 to 10.

Therefore, specific examples of acyloxysilanes represented by general formula (IIIB) having such groups include diacetoxydimethylsilane (AcO(SiMe ₂ O)Ac), 1,3-diacetoxy-1,1,3,3-tetramethyldisiloxane (AcO(SiMe ₂ O) ₂ Ac), 1,5-diacetoxy-1,1,3,3,5,5-hexamethyltrisiloxane (AcO(SiMe ₂ O) ₃ Ac), 1,7-diacetoxy-1,1,3,3,5,5
,7,7-octamethyltetrasiloxane (AcO(SiMe ₂ O) ₄ Ac), diacetoxydiphenylsilane (AcO(SiPh ₂ O)Ac), 1,3-diacetoxy-1,1,3,3-tetraphenyldisiloxane (AcO(SiPh ₂ O) ₂ Ac), 1,5-diacetoxy-1,1,3,3,5,5-hexaphenyltrisiloxane (AcO(SiPh ₂ O) ₃ Ac), 1,7-diacetoxy-1,1,3,3,5,5,7,7-octaphenyltetrasiloxane (AcO(SiPh ₂ O) ₄ Ac), 1,3-diacetoxy-1,1-dimethyl-3,3-diphenyldisiloxane (AcO(SiMe ₂ O)(SiPh ₂ O) Ac) and the like.

In this embodiment, when the siloxane compound having a Si—O—Si bond is a siloxane compound represented by general formula (IC) and the carboxylic acid anhydride is a carboxylic acid anhydride represented by general formula (IIA), an acyloxysilane represented by the following general formula (IIIC) can be produced.
(R ⁸ CO) O (SiR ⁶ R ⁷ O) _q (COR ⁸ ) (IIIC)
In general formula (IIIC), R ⁶ and R ⁷ are defined as R ⁶ and R ⁷ in formula (IC), R ⁸ is defined as R ⁸ in formula (IIA), and q is an integer of 1 to 100. Specific examples of R ⁶ and R ⁷ include those given in the description of R ⁶ and R ⁷ in formula (IC), and specific examples of R ⁸ include those given in the description of R ⁸ in formula (IIA).
Furthermore, q is preferably 1 to 80, more preferably 1 to 50, and further preferably 1 to 10.

Specific examples of acyloxysilanes represented by general formula (IIIC) include those shown in the description of acyloxysilanes represented by general formula (IIIB).

Furthermore, in this embodiment, when the siloxane compound having a Si-O-Si bond is a siloxane compound represented by general formula (IB) and the carboxylic acid anhydride is a carboxylic acid anhydride represented by general formula (IIB), an acyloxysilane represented by general formula (IIID) below can be produced. The acyloxysilane represented by general formula (IIID) below has a compound skeleton formed from r1 (SiR ⁴ R ⁵ -O) units derived from the siloxane compound and r2 (O-CO-R ⁹ -CO) units derived from the carboxylic acid anhydride, and one or more (SiR ⁴ R ⁵ -O) units are present on both sides of the (O-CO-R ⁹ -CO) unit.

In general formula (IIID), R ⁴ and R ⁵ are defined similarly to R ⁴ and R ⁵ in formula (IB), R ⁹ is defined similarly to R ⁹ in formula (IIB), r1 is an integer of 1 to 100, and r2 is an integer of 1 or more and r1 or less. Specific examples of R ⁴ and R ⁵ include those shown in the description of R ⁴ and R ⁵ in formula (IB), and specific examples of R ⁹ include those shown in the description of R ⁹ in formula (IIB).
Furthermore, r1 and r2 are preferably 1-80, more preferably 1-50, and further preferably 1-20.

Therefore, specific examples of acyloxysilanes represented by general formula (IIID) having such groups or the like include 1,1-dimethyl-2,8-dioxa-3,7-dioxo-1-silacyclooctane ((SiMe ₂ O)[CO(CH ₂ ) _{3CO 2} ]), 1,1,3,3-tetramethyl-2,4,10-trioxa-5,9-dioxo-1,3-disilacyclodecane ((SiMe ₂ O) ₂ [CO(CH ₂ ) _{3CO 2} ]), 1,1,3,3,5,5-hexamethyl-2,4,6,12-tetraoxa-7,11-dioxo-1,3,5-trisilacyclododecane ((SiMe ₂ O) ₃ [CO(CH ₂ ) _{3CO 2} ]), and ]), 1,1,3,3,5,5,7,7-octamethyl-2,4,6,8,14-pentaoxa-9,13-dioxo-1,3,5,7-trisilacyclotetradecane ((SiMe ₂ O) ₄ [CO(CH ₂ ) ₃ CO ₂ ]), 1,1,3,3,5,5,7,7,9,9-decamethyl-2,4,6,8,10,16-hexaoxa-11,13-dioxo-1,3,5,7,9-pentasilacyclohexadecane ((SiMe ₂ O) ₅ [CO(CH ₂ ) ₃ CO ₂ ]), 1,1,3,3,5,5,7,7,9,9,11,11-dodecamethyl-2,4,6,8,10,12,18-heptaoxa-13,17-dioxo-1,3,5,7,9,11-hexasilacyclooctadecane ((SiMe ₂ O) ₆ [CO(CH ₂ ) ₃ CO ₂ ]), and the like.

Furthermore, in this embodiment, when the siloxane compound having a Si-O-Si bond is a siloxane compound represented by general formula (IC) and the carboxylic acid anhydride is a carboxylic acid anhydride represented by general formula (IIB), an acyloxysilane represented by the following general formula (IIIE) can be produced. The acyloxysilane represented by the following general formula (IIIE) has a compound skeleton formed from s1 (SiR ⁶ R ⁷ -O) units derived from the siloxane compound and s2 (O-CO-R ⁹ -CO) units derived from the carboxylic acid anhydride, and one or more (SiR ⁶ R ⁷ -O) units are present on both sides of the (O-CO-R ⁹ -CO) unit.

In general formula (IIIE), R ⁶ and R ⁷ are defined in the same way as R ⁶ and R ⁷ in formula (IC). R ⁹ is defined in the same way as R ⁹ in formula (IIB). s1 is an integer of 1 to 100, and s2 is an integer of 1 or more and s1 or less. Specific examples of R ⁶ and R ⁷ include those shown in the description of R ⁴ and R ⁵ in formula (IB), and specific examples of R ⁹ include those shown in the description of R ⁹ in formula (IIB).
Additionally, s1 and s2 are preferably 1-80, more preferably 1-50, and further preferably 1-20.

Specific examples of acyloxysilanes represented by general formula (IIIE) include those shown in the description of acyloxysilanes represented by general formula (IIID).

In the reaction step in this embodiment, it is believed that the reaction proceeds by nucleophilic interaction between the carboxylic acid anhydride and the siloxane compound having a Si-O-Si bond.
Therefore, the reaction in this embodiment is a reaction in which a bond recombination occurs between the Si—O—Si bond of the siloxane compound and the CO—O—CO bond of the carboxylic acid anhydride. In the reaction step, for example, when the siloxane compound represented by the general formula (IA) is reacted with 1 equivalent of the carboxylic acid anhydride represented by the general formula (IIA), 2 equivalents of the acyloxysilane represented by the general formula (IIIA) are produced (Scheme 1).

スキーム１

Scheme 1

On the other hand, in the reaction of a cyclic or linear siloxane compound represented by the general formula (IB) or (IC), not only the acyloxylation of the Si-O-Si bond but also a disproportionation reaction between the products proceeds, so that when a carboxylic anhydride represented by the general formula (IIA) is reacted, an acyloxysilane represented by the general formula (IIIB) or (IIIC) having acyloxy groups at both ends is produced (Schemes 2 and 3).

スキーム２

Scheme 2

スキーム３

Scheme 3

The molecular weight distribution of the acyloxysilane in Schemes 2 and 3 varies depending on the reactivity of the raw material polysiloxane and carboxylic acid anhydride, and their feed ratio, but generally, the higher the feed ratio of the raw material carboxylic acid anhydride to the siloxane compound, the higher the proportion of low molecular weight compounds in the distribution.

In addition, the reaction of a cyclic or linear siloxane compound represented by the general formula (IB) or (IC) with a cyclic carboxylic acid anhydride represented by the general formula (IIB) also gives Si—O—
Not only the acyloxylation of the Si bond but also a disproportionation reaction between the products proceeds, so that a cyclic acyloxysilane having a carbonyloxy group in the ring and represented by the general formula (IIID) or (IIIE) is produced (Schemes 4 and 5).

スキーム４

Scheme 4

スキーム５

Scheme 5

In the reaction step of this embodiment, an acid catalyst selected from the following (1) and (2) is used to promote the reaction.
(1) Perchlorate, trifluoromethanesulfonate, bis(trifluoromethanesulfonylimide) salt, hexafluoroantimonate, or thiocyanate of an element selected from the elements of Groups 3 to 15 of the periodic table; ruthenium chloride; gallium chloride; tin chloride; indium chloride; iron bromide; ruthenium bromide; tris(pentafluorophenyl)borane; trimethylsilyl trifluoromethanesulfonate; nonafluorobutanesulfonic acid; bis(perfluoroalkanesulfonyl)imide; bis(trifluoromethanesulfonyl)imide trimethylsilyl; perchloric acid; hexafluoroantimonate; or thiocyanic acid.
(2) Inorganic solid acid compounds.

The Group 3 to Group 15 element in the acidic catalyst (1) is preferably a Group 3, Group 8, or Group 13 to 15 element, more preferably a Group 3, Group 8, Group 13, or Group 15 element, and even more preferably a Group 3, Group 8, or Group 13 element.
More specifically, the Group 3 to Group 15 elements are preferably scandium, yttrium, samarium, yttrium, iron, ruthenium, copper, aluminum, gallium, indium, tin, or bismuth, more preferably scandium, iron, ruthenium, aluminum, gallium, indium, tin, or bismuth, and even more preferably scandium, iron, ruthenium, aluminum, gallium, or indium.

Therefore, specific examples of perchlorates, trifluoromethanesulfonates, bis(trifluoromethanesulfonylimide) salts, hexafluoroantimonates, and thiocyanates of elements selected from Groups 3 to 15 include iron(III) perchlorate, silver perchlorate, hexafluoroantimonates, and specific examples of thiocyanates include scandium(III) trifluoromethanesulfonate, yttrium(III) trifluoromethanesulfonate, iron(III) trifluoromethanesulfonate, copper(II) trifluoromethanesulfonate, aluminum(III) trifluoromethanesulfonate, gallium(III) trifluoromethanesulfonate, indium(III) trifluoromethanesulfonate, and trifluoromethanesulfonic acid. Examples of the imidazole include tin(IV), bismuth(IV) trifluoromethanesulfonate, lanthanum(III) trifluoromethanesulfonate, praseodymium(IV) trifluoromethanesulfonate, neodymium(IV) trifluoromethanesulfonate, ytterbium(IV) trifluoromethanesulfonate, bis(trifluoromethanesulfonyl)imide scandium(III), bis(trifluoromethanesulfonyl)imide zinc(II), bis(trifluoromethanesulfonyl)imide indium(III), bis(trifluoromethanesulfonyl)imide tin(IV), iron(III) hexafluoroantimonate, indium(III) hexafluoroantimonate, iron(III) thiocyanate, and indium(III) thiocyanate.

As the acid catalyst of (1), ruthenium chloride, gallium chloride, tin chloride, indium chloride, iron bromide, or ruthenium bromide can also be used.
It is also a preferred method to add silver perchlorate, silver hexafluoroantimonate, or the like to the reaction system together with the chloride or bromide thereof and convert the chloride or bromide into a perchlorate, hexafluoroantimonate, or the like in the reaction system for use.

Furthermore, as the acid catalyst (1), tris(pentafluorophenyl)borane, trimethylsilyl trifluoromethanesulfonate, nonafluorobutanesulfonic acid, bis(perfluoroalkanesulfonyl)imide, bis(trifluoromethanesulfonyl)imide trimethylsilyl, perchloric acid, hexafluoroantimonic acid, or thiocyanic acid can also be used.

On the other hand, examples of the inorganic solid acid compounds of (2) above include solid inorganic substances such as metal salts and metal oxides. More specifically, examples include zeolites, mesoporous silica, montmorillonite, etc., which have protic hydrogen atoms or metal atoms (aluminum, titanium, gallium, iron, cerium, scandium, etc.), as well as inorganic solid acids supported by silica gel, heteropolyacids, carbon-based materials, etc.

Among these, in terms of catalytic activity or selectivity to products, inorganic solid acids having regular pores and/or layered structures such as zeolite, mesoporous silica, and montmorillonite are preferred, and solid acids such as zeolite and montmorillonite are more preferred. There are no particular limitations on the type of regular pores and/or layered structures of inorganic solid acids, but in consideration of the ease of diffusion of reacting molecules or generated molecules, the pore diameter of a solid acid catalyst having a pore structure is usually 0.2 to 20 nm, preferably 0.3 to 15 nm, and more preferably 0.3 to 10 nm. In addition, in a solid acid catalyst having a layered structure, the interlayer distance is usually 0.2 to 20 nm, preferably 0.3 to 15 nm, and more preferably 0.3 to 10 nm.

When zeolite is used as an inorganic solid acid catalyst having an ordered pore structure, examples of the type include various zeolites having a basic skeleton such as Y type, beta type, ZSM-5 type, mordenite type, SAPO type, etc. In addition, USY type (Ultrastable Y type), known as SUSY type (Super Ultrastable Y), VUSY type (Very Ultrastable Y), SDUSY type (Super dealuminated ultrastable Y), etc., which are obtained by secondary treatment of Y type zeolite (Na-Y), can be used.
Also preferably usable are those of USY type (for the USY type, see, for example, "Molecular Sieves", Advances in Chemistry, Volume 121, American Chemical Society, 1973, Chapter 19, etc.).

In terms of reaction rate, among these zeolites, USY type, beta type, Y type, ZSM-5 type, and mordenite type are preferred, USY type, beta type, and Y type are more preferred, and USY type and beta type are even more preferred.

Various types of zeolites can be used, such as Bronsted acid type zeolites having protic hydrogen atoms and Lewis acid type zeolites having metal cations. Among these, proton type zeolites having protic hydrogen atoms are represented by H-Y type, H-SDUSY type, H-SUSY type, H-beta type, H-mordenite type, H-ZSM-5 type, etc. In addition, ammonium type zeolites such as NH ₄ -Y type, NH ₄ -VUSY type, NH ₄ -beta type, NH ₄ -mordenite type, NH ₄ -ZSM-5 type, etc., which are calcined to convert them to proton type can also be used.
Furthermore, the silica/alumina ratio (ratio of substances) of the zeolite can be selected from various ratios depending on the reaction conditions, but is usually 3 to 1,000, preferably 3 to 800, more preferably 5 to 600, and even more preferably 5 to 400.

Various types of zeolites, including commercially available products, can be used. Specific examples of commercially available products include USY-type zeolites such as CBV760, CBV780, CBV720, CBV712, and CBV600, which are commercially available from Zeolite Co., Ltd. Examples of Y-type zeolites include HSZ-360HOA and HSZ-320HOA, which are commercially available from Tosoh Corporation. Examples of beta zeolites include CP811C, CP814N, CP7119, CP814E, CP7105, CP814CN, CP811TL, CP814T, CP814Q, CP811Q, CP811E-75, CP811E, CP811C-300, etc., available from Zeolist, Inc.; HSZ-930HOA, HSZ-940HOA, etc., available from Tosoh Corporation; and UOP-Beta, etc., available from UOP, Inc. Furthermore, examples of mordenite zeolites include CBV21A, CBV90A, etc., available from Zeolist, Inc.; and HSZ-660HOA, HSZ-620HOA, HSZ-690HOA, etc., available from Tosoh Corporation. Examples of ZSM-5 zeolites include CBV5524G, CBV8020, and CBV8014N, which are commercially available from Zeolite.

On the other hand, when montmorillonite is used as an inorganic solid acid having a layered structure, not only Bronsted acid having protons between layers, but also Lewis acid having cations of elements of groups 3 to 15 of the periodic table between layers can be used.
Examples of montmorillonite having Bronsted acidity include montmorillonite KSF, montmorillonite K10, and montmorillonite K30.
Examples of Lewis acidic materials include those having cations between layers, such as scandium (III), titanium (III), titanium (IV), zirconium (IV), manganese, iron (III), ruthenium (III), cobalt (II), nickel (II), copper (II), zinc (II), aluminum (III), gallium (III), indium (III), tin (IV), and bismuth (III) (in this specification, an n-valent cation of a metal M may be referred to as an M ⁿ⁺ ion).
The interlayer cations are preferably titanium (III), titanium (IV), zirconium (IV), iron (III), ruthenium (III), aluminum (III), gallium (III), indium (III), and tin (IV), more preferably titanium (III), titanium (IV), zirconium (IV), and tin (IV), and even more preferably titanium (III), titanium (IV), zirconium (IV), and tin (IV).
These cations are not limited to one type, and a mixture of a plurality of types may also be used.
The catalysts (1) and (2) may also be used in combination.

The amount of catalyst relative to the siloxane compound or carboxylic acid anhydride can be determined as desired, but the weight ratio is usually about 0.0001 to 20, preferably about 0.0001 to 10, more preferably about 0.001 to 8, and even more preferably about 0.001 to 6.

In this embodiment, the reaction in the reaction step can be carried out in a liquid phase or gas phase state depending on the reaction temperature or reaction pressure. The reaction can be carried out in various conventionally known reactor configurations, such as a batch type or a flow type.
The reaction temperature is usually -20°C or higher, preferably -10 to 300°C, more preferably -10 to 200°C, and further preferably 0 to 100°C.
Furthermore, the reaction pressure is usually from 0.1 to 100 atm, preferably from 0.1 to 50 atm, and more preferably from 0.1 to 10 atm.
The reaction time depends on the amount of the raw material, the amount of the catalyst, the reaction temperature, the shape of the reaction apparatus, etc., but in consideration of productivity and efficiency, it is usually about 1 to 1,200 minutes, preferably about 1 to 600 minutes, and more preferably about 1 to 300 minutes.

When the reaction is carried out in a liquid phase system, a solvent may be used or the reaction may be carried out without a solvent. When a solvent is used, various solvents that do not react with the raw materials, such as hydrocarbons such as toluene, decahydronaphthalene, and decane; halogenated hydrocarbons such as dichloromethane, chloroform, deuterated chloroform, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4-trichlorobenzene; and ethers such as tert-butyl methyl ether and dibutyl ether, can be used, and two or more of these can be mixed together. When the reaction is carried out in a gas phase, the reaction can be carried out by mixing an inert gas such as nitrogen.

The reaction step of this embodiment can also be carried out under microwave irradiation. In this reaction system, the dielectric loss coefficients of the raw materials, such as the carboxylic acid anhydride and acid catalyst, are relatively large and efficiently absorb microwaves. Therefore, under microwave irradiation, the carboxylic acid anhydride, catalyst, etc. are activated, allowing the reaction to be carried out more efficiently.

In microwave irradiation reactions, various commercially available devices equipped with contact or non-contact temperature sensors can be used. In addition, the microwave irradiation output, type of cavity (multi-mode, single mode), irradiation form (continuous, intermittent), etc. can be determined as desired depending on the scale and type of reaction. The microwave frequency is usually 0.3 to 30 GHz. Among these, the IMS frequency band allocated for use in the industrial, scientific, and medical fields is preferable, and even more preferable among these are the 2.45 GHz band, 5.8 GHz band, etc.

In addition, in microwave irradiation reactions, a heating material (susceptor) that absorbs microwaves and generates heat can be added to the reaction system in order to heat the reaction system more efficiently. As the type of heating material, various types of materials known in the art, such as activated carbon, graphite, silicon carbide, and titanium carbide, can be used. In addition, a molded catalyst can be used that is made by mixing the catalyst and heating material powder described above and calcining the mixture using an appropriate binder such as sepiolite or hormite.

The reaction step of this embodiment can proceed in a closed reaction apparatus. However, the reaction can also proceed more efficiently by using an open reaction apparatus and continuously removing the reaction product from the reaction system.

When a solid acid catalyst is used in the production method of this embodiment, the catalyst can be easily separated and recovered after the reaction step by a method such as filtration or centrifugation.
Furthermore, the acyloxysilane produced can be easily purified by means commonly used in organic chemistry, such as distillation, recrystallization, column chromatography, etc.

The acyloxysilane provided by the production method according to the present embodiment has a highly reactive acyloxy group, and therefore it is believed that reactions when used as a synthetic intermediate, a surface treatment agent, a sol-gel material, etc. can be efficiently carried out under mild conditions, making it highly useful as a functional chemical.
For example, the surface treatment agent can rapidly treat the surface of solid materials such as glass under mild conditions at room temperature for a few minutes, and the hydrophilicity or hydrophobicity of the solid material surface can be easily controlled depending on the type of acyloxysilane used.
The surface treatment agent is a composition containing the acyloxysilane produced by the above reaction, and not only isolated and purified acyloxysilane but also a mixed solution containing a plurality of acyloxysilanes can be used.
Furthermore, in the method for producing acyloxysilane according to this embodiment, various acyloxysilanes can be produced easily under mild conditions, so that the reaction solution containing acyloxysilane can be used directly for surface treatment.
When an acyloxysilane is used as the surface treatment agent, it can be diluted with an organic solvent that does not react with acyloxysilane, such as toluene or hexane, if necessary.
The surface treatment of the solid material can be carried out by various conventional methods such as a dipping method, a casting method, a spin coating method, a spray coating method, or the like.

In the production method according to the present embodiment, the resulting acyloxysilane has a reactive acyloxy group, and therefore the method may include a modification step in which the resulting acyloxysilane is reacted with a modifying agent to convert the acyloxy group into another functional group.
The modification step can be carried out not only with a purified siloxane compound, but also with an unpurified siloxane compound. That is, it is possible to convert the acyloxy group to another substituent in one pot by adding a modifying agent to a reaction solution containing acyloxysilane.

The modifying agent used in the modification step is not particularly limited as long as it reacts with an acyloxy group, and examples thereof include alcohol, water, etc. When an alcohol is used as the modifying agent, the acyloxy group can be converted into an alkoxy group, and when water is used as the modifying agent, the acyloxy group can be converted into a hydroxy group.
The alcohol may, for example, be an alcohol represented by the following general formula (IV), and the acyloxy group is converted to the corresponding alkoxy group (R ¹⁰ O group) by reaction with the alcohol.
^R10OH (IV)

In general formula (IV), R ¹⁰ is an alkyl group having 1 to 6 carbon atoms. The number of carbon atoms in the alkyl group is preferably 1 to 4, and more preferably 1 to 3. Specific examples of R ¹⁰ include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a pentyl group, and a hexyl group.
Specific examples of the alcohol of general formula (IV) having these groups include methanol (MeOH), ethanol (EtOH), isopropanol (iso-PrOH), tert-butanol (tert-BuOH), pentanol (PentOH), and hexanol (HexOH).
In addition, the alkoxy group (R ¹⁰
Specific examples of the aryloxy group include a methoxy group, an ethoxy group, an isopropoxy group, a tert-butoxy group, a pentyloxy group, and a hexyloxy group.

In the modification step, the reaction may be carried out in the presence of a basic compound or the like in order to promote the reaction. As the basic compound, an organic compound or an inorganic compound can be used. Specific examples of the organic compound include triethylamine, tripropylamine, diisopropylethylamine, dicyclohexylmethylamine, pyridine, and dimethylaniline. Specific examples of the inorganic compound include sodium carbonate, potassium carbonate, cesium carbonate, and potassium phosphate.
The basic compound may be used in a catalytic amount and may be the same as or different from those used in each reaction step. When used as a catalyst, an acyloxy group can be converted to a hydroxy group, an alkoxy group, or the like by adding a modifying agent such as water or an alcohol in a one-pot manner without adding a base.

The amount of the modifying agent can be selected arbitrarily, but the molar ratio to the acyloxysilane is usually 1 or more and 30 or less, preferably 1 or more and 20 or less, and more preferably 1 or more and 10 or less.
The modification step may be carried out in the presence or absence of a solvent, and the solvent may be the same as that used in the reaction step.
The reaction temperature can also be arbitrarily selected, but is usually −20° C. or higher, preferably −10 to 300° C., more preferably −10 to 200° C., and even more preferably 0 to 100° C. When an alcohol is used as a modifying agent, and the reaction is carried out at room temperature to control the reactivity of the alcohol, the room temperature range is usually 0 to 40° C., preferably 5 to 40° C., and more preferably 10 to 35° C.
The reaction time depends on the amount of acyloxy group-containing siloxane product, the amount of reaction accelerator, the reaction temperature, the shape of the reaction apparatus, etc., but taking into consideration productivity and efficiency, it is usually 1 minute to 72 hours, preferably 1 minute to 48 hours, more preferably 1 minute to 24 hours, and even more preferably about 1 minute to 10 hours.

The manufacturing method according to this embodiment can also be applied to polymers such as polysiloxane. For example, under mild conditions around room temperature, polysiloxane can be reacted with acetic anhydride to obtain diacetoxysilanes such as monomers and dimers in a short time of less than one hour. This reaction is a reaction system that can also be used for recycling and reusing waste silicone.

Next, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
The main analytical instruments used in the following examples are as follows:
Nuclear magnetic resonance spectroscopy (hereinafter sometimes referred to as NMR): Bruker AVANCE III HD 600MHz (with cryoprobe)
Gas chromatograph analysis (hereinafter sometimes referred to as GC): Shimadzu Corporation GC-2014
Gas chromatograph mass spectrometry (hereinafter sometimes referred to as GC-MS): Shimadzu Corporation GCMS-QP2010Plus
Short-path distillation: Kiriyama Seisakusho short-path distillation apparatus AB25F-1 or Shibata Scientific glass tube oven GTO-350RD (hereinafter, each may be referred to as short-path distillation apparatus A or B, respectively).

Example 1
Hexamethyldisiloxane (Me ₃ SiOSiMe ₃ ) 2 mmol, acetic anhydride (Ac
_2O ) 4mmol, iron(III) perchlorate _hexahydrate (Fe( _ClO4 ) _3.6H2O )
0.02 mmol was placed in a reaction vessel and stirred for 30 minutes at about 25° C. (room temperature). The product was analyzed by GC, GC-MS, and NMR, and the NMR analysis of the product showed that 1.88 mmol (yield 94%) of (acetoxy)trimethylsilane (Me ₃ SiOAc) was produced (see Table 1-1).

(Examples 2 to 215, Comparative Examples 1 to 3)
The reaction and analysis were carried out in the same manner as in Example 1, but the reaction conditions (raw materials, catalyst, temperature, time, etc.) were changed. The product yields were measured by NMR, and the results are shown in Tables 1-1 to 1-20.

The notes in Tables 1-1 to 1-20 (hereinafter sometimes simply referred to as "Table 1") are as follows.
1) _Me3SiOSiMe3 : _{Hexamethyldisiloxane
Et3SiOSiEt3} : _{Hexaethyldisiloxane
Me2PhSiOSiMe2Ph} : 1,1,3,3- _tetramethyl -1,3-diphenyldisiloxane
_{MePh2SiOSiMePh2} : 1,3-dimethyl-1,1,3,3 _- tetraphenyldisiloxane
_{Me2ViSiOSiMe2Vi} : 1,1,3,3 _- tetramethyl-1,3-divinyldisiloxane
( _ClCH2 ) _Me2SiOSiMe2 ( _CH2Cl ): 1,3-bis( _chloromethyl )-1,1,3,3-tetramethyldisiloxane
[NC( _CH2 ) ₃ ] _Me2SiOSiMe2 [( _CH2 ) _3CN ]: 1,3 _- bis(3-cyanopropyl)-1,1,3,3-tetramethyldisiloxane
( _SiMe2O ) ₄ : Octamethylcyclotetrasiloxane
( _SiMe2O ) ₅ : Decamethylcyclopentasiloxane
KF-968: Poly(dimethylsiloxane) (manufactured by Shin-Etsu Chemical Co., Ltd., Me ₃ SiO(SiMe ₂ O) _p SiMe ₃ , a polysiloxane having a methyl group and trimethylsilyl groups at both ends)
KF-54: Poly(dimethylsiloxane-co-diphenylsiloxane) (Shin-Etsu Chemical Co., Ltd., _Me3SiO ( _SiMe2O ) _q ( _SiPh2O ) _rSiMe3 , q:r=approximately 73:27, _polysiloxane having methyl and phenyl groups as substituents and both ends terminated with trimethylsilyl groups)
When the siloxane compound is a polymer, the number of moles used indicates the number of moles per repeating structural unit. The molecular weight of the repeating structural unit was 74.2 for KF-968 and 107.7 for KF-54. The number average molecular weight (polystyrene standard) of KF-968 and KF-54 measured by gel permeation chromatography (toluene eluent) was 6000 and 1300, respectively, so the values of p for KF-968 and q+r for KF-54 were estimated to be about 79 and 11, respectively.

2) _Ac2O : acetic anhydride,
(EtCO) _2O : Propionic anhydride
( _C5H11CO ) _2O : _Hexanoic anhydride
( _CF3CO ) _2O : Trifluoroacetic anhydride
( _C2F5CO ) _2O : _{Pentafluoropropionic} anhydride
( _CH2 ) ₃ (CO) _2O : glutaric anhydride
(PhCO) _2O : Benzoic anhydride

3) Fe( _ClO4 ) _3.6H2O : Iron(III) _perchlorate hexahydrate
_FeBr3 : Iron(III) bromide
_RuCl3 : Ruthenium(III) chloride
_RuCl3 · _H2O : Ruthenium(III) chloride hydrate
_InCl3 : Indium(III) chloride
_SnCl4 : Tin(IV) chloride
_AgClO4 : Silver perchlorate
_AgSbF6 : Silver hexafluoroantimonate
Sc(OTf) ₃ : Scandium(III) trifluoromethanesulfonate
Yb(OTf) ₃ : Ytterbium(III) trifluoromethanesulfonate
Fe(OTf) ₃ : Iron(III) trifluoromethanesulfonate
Cu(OTf) ₂ : Copper(II) trifluoromethanesulfonate
Al(OTf) ₃ : Aluminum trifluoromethanesulfonate(III)
Ga(OTf) ₃ : Gallium(III) trifluoromethanesulfonate
In(OTf) ₃ : Indium(III) trifluoromethanesulfonate
Sn(OTf) ₃ : Tin(IV) trifluoromethanesulfonate
Bi(OTf) ₄ : Bismuth(IV) trifluoromethanesulfonate
La(OTf) ₃ : Lanthanum(III) trifluoromethanesulfonate
Pr(OTf) ₄ : Praseodymium(IV) trifluoromethanesulfonate
Nd(OTf) ₄ : Neodymium(IV) trifluoromethanesulfonate
Yb(OTf) ₄ : ytterbium(IV) trifluoromethanesulfonate
Me ₃ SiOTf: Trimethylsilyl trifluoromethanesulfonate
_{C4F9SO3H : Nonafluorobutanesulfonic} acid
Sc( _NTf2 ) ₃ : Bis(trifluoromethanesulfonyl)imidoscandium(III)
Zn( _NTf2 ) ₂ : Bis(trifluoromethanesulfonyl)imide zinc(II)
In( _NTf2 ) ₃ : Bis(trifluoromethanesulfonyl)imide indium(III)
Sn( _NTf2 ) ₄ : Bis(trifluoromethanesulfonyl)imide tin(IV)
_{Me3SiNTf2 :} Bis(trifluoromethanesulfonyl)imide trimethylsilyl
Tf ₂ NH: Bis(trifluoromethanesulfonyl)imide
( _{C4F9SO2 ) 2NH} : Bis( _{nonafluorobutanesulfonyl} )imide
B(C ₆ F ₅ ) ₃ : Tris(pentafluorophenyl)borane
_ZnCl2 : Zinc chloride (II)
TfOH: Trifluoromethanesulfonic acid
CBV780: USY zeolite CBV780 (manufactured by Zeolist)
Ti3 ⁺ -mont: Montmorillonite containing Ti3 ⁺ ions
Ti4 ⁺ -mont: Montmorillonite containing Ti4 ⁺ ions
Zr4 ⁺ -mont: Montmorillonite containing Zr4 ⁺ ions
Fe3 ⁺ -mont: Montmorillonite containing Fe3 ⁺ ions
Ru3 ⁺ -mont: Ru3 ⁺ ion-containing montmorillonite
Cu2 ⁺ -mont: Montmorillonite containing Cu2 ⁺ ions
Zn2 ⁺ -mont: Zn2 ⁺ ion-containing montmorillonite
Al3 ⁺ -mont: Al3 ⁺ ion-containing montmorillonite
Ga3 ⁺ -mont: Montmorillonite containing Ga3 ⁺ ions
In3 ⁺ -mont: Montmorillonite containing ^In3+ ions
Sn4 ⁺ -mont: Sn4 ⁺ ion-containing montmorillonite
Amberlyst 15: H ⁺ type cation exchange resin Amberlyst 15 (manufactured by The Dow Chemical Company)
The ^Mn+ ion-containing montmorillonite containing the cations of element M described above was prepared by adding a nitrate or chloride of element M to Na ⁺ montmorillonite in water to exchange the Na ⁺ ions for Mn ⁺ ions.

4) Numbers in parentheses are in mmol, numbers in square brackets are in mg.
5) DCB: 1,2-dichlorobenzene
PhMe: Toluene
_CHCl3 : Chloroform
_CH2Cl2 : _{Dichloromethane}
6) 25°C indicates the reaction temperature at room temperature. For reactions at temperatures higher than room temperature, an oil bath (Riko Kagaku MH-5D) was used.

7) Me ₃ SiOAc: Acetoxytrimethylsilane
_Et3SiOAc : Acetoxytriethylsilane
_Me2PhSiOAc : Acetoxydimethylphenylsilane
_MePh2SiOAc : Acetoxymethyldiphenylsilane
_Me2ViSiOAc : Acetoxydimethylvinylsilane
( _ClCH2 ) _Me2SiOAc : Acetoxy(chloromethyl)dimethylsilane
[NC( _CH2 ) ₃ ] _Me2SiOAc : Acetoxy(3-cyanopropyl)dimethylsilane
Me ₃ SiOCOEt: Trimethyl(propionyloxy)silane
Me ₃ SiOCOC ₅ H ₁₁ : (Hexanoyloxy)trimethylsilane
Me ₃ SiOCOCF ₃ : (Trifluoroacetyloxy)trimethylsilane
Me ₃ SiOCOC ₂ F ₅ : (Pentafluoropropanoyloxy)trimethylsilane
_Me3SiOCO ( _CH2 ) _{3CO2SiMe3 :} 1,3- _bis (trimethylsiloxycarbonyl)propane
Me ₃ SiOCOPh: (benzoyloxy)trimethylsilane
( _SiMe2O )[CO( _CH2 ) _3CO2 ]: 1,1-dimethyl-2,8-dioxa-3,7-dioxo-1 _- silacyclooctane
( _SiMe2O ) ₂ [CO( _CH2 ) _3CO2 ]: 1,1,3,3-tetramethyl-2,4,10-trioxa-5,9-dioxo-1,3 _- disilacyclodecane
( _SiMe2O ) ₃ [CO( _CH2 ) _3CO2 ]: 1,1,3,3,5,5-hexamethyl-2,4,6,12 _- tetraoxa-7,11-
Dioxo-1,3,5-trisilacyclododecane
( _SiMe2O ) ₄ [CO( _CH2 ) _3CO2 ]: 1,1,3,3,5,5,7,7-octamethyl-2,4,6,8,14-pentaoxa-9,13-dioxo-1,3,5,7 _- trisilacyclotetradecane
( _SiMe2O ) ₅ [CO( _CH2 ) _3CO2 ]: 1,1,3,3,5,5,7,7,9,9-decamethyl-2,4,6,8,10,16-hexaoxa-11,13 _- dioxo-1,3,5,7,9-pentasilacyclohexadecane
( _SiMe2O ) ₆ [CO( _CH2 ) _3CO2 ]: 1,1,3,3,5,5,7,7,9,9,11,11-dodecamethyl-2,4,6,8,10,12,18-heptaoxa-13,17 _- dioxo-1,3,5,7,9,11-hexasilacyclooctadecane
AcO( _SiMe2O )Ac: Diacetoxydiphenylsilane
AcO( _SiMe2O ) _2Ac : 1,3-diacetoxy-1,1,3,3-tetramethyldisiloxane
AcO( _SiMe2O ) _3Ac : 1,5-diacetoxy-1,1,3,3,5,5-hexamethyltrisiloxane
AcO( _SiMe2O ) _4Ac : 1,7-diacetoxy-1,1,3,3,5,5,7,7-octamethyltetrasiloxane
AcO( _SiPh2O )Ac: Diacetoxydiphenylsilane
AcO( _SiPh2O ) _2Ac : 1,3-diacetoxy-1,1,3,3-tetraphenyldisiloxane
AcO( _SiPh2O ) _3Ac : 1,5-diacetoxy-1,1,3,3,5,5-hexaphenyltrisiloxane
AcO( _SiPh2O ) _4Ac : 1,7-diacetoxy-1,1,3,3,5,5,7,7-octaphenyltetrasiloxane
AcO( _SiMe2O )( _SiPh2O )Ac: 1,3-diacetoxy-1,1-dimethyl-3,3-diphenyldisiloxane

8) Yield by NMR (Acyloxysilane Yield to Siloxane Compound)
9) Yield of siloxane product relative to carboxylic acid anhydride
10) A mixture of compounds with two acetoxy groups, AcO( _SiMe2O ) _tAc (t = 1, 2, 3, 4, 5, ≧6). The numbers in brackets indicate the ratio of the compounds. The yield indicates the total yield.
11) A mixture of compounds having two acetoxy groups _{, Me2CHCO2} ( _SiMe2O ) _uCOCHMe2 (u = 1, 2, 3, 4, ≧5). The numbers in brackets indicate _the ratio of the compounds. The yield indicates the total yield.
12) Compounds with a carbonyloxy group in the ring (SiMe ₂ O) _v1 [CO(CH ₂ ) ₃ CO ₂ ] _v2 (v2 = 1 and v1
A mixture of three compounds (P1 to P3) with v = 1, 2, and 3, and another compound (P4) with v = 1, v ≥ 4, and v ≥ 2, v ≥ 2. The numbers in the brackets indicate the ratio of compounds P1 to P4. The yield indicates the total yield.
13) Me ₃ SiOAc and the compound AcO(SiMe ₂ O) _w Ac (w = 1, 2, 3, 4,
≧5). The numbers in brackets indicate the ratio of the compounds. The yield indicates the total yield.
14) A mixture of acyloxysilane containing Me ₃ Si group, Me ₃ SiO(SiMe ₂ O) _w1 [CO(CH ₂ ) ₃ CO ₂ ] _w2 SiMe ₃ (w1 ≧ 0, w2 ≧ 1) (Q1) and a compound having a carbonyloxy group in the ring, (SiMe ₂ O) _w3 [CO(CH ₂ ) ₃ CO ₂ ] _w4 (three compounds (Q2 to Q4) where w4 = 1 and w3 = 1, 2, and 3, and other compounds (Q5) where w4 = 1 and w3 ≧ 4 and w4 ≧ 2 and w3 ≧ 2). The figures in square brackets show the ratio of compounds Q1 to Q5. The yield shows the total yield.
15) Me ₃ SiOAc and the compound with two acetoxy groups, AcO(SiMe ₂ O) _x Ac (x = 1, 2
), AcO( _SiPh2O ) _yAc (y = 1, 2), AcO( _SiMe2O )( _SiPh2O )Ac, and a mixture of AcO( _SiR2 ) _zOAc (R = Me, Ph; z ≧ 3) (oligosiloxane compounds with 3 or more silicon atoms, with acetoxy groups at both ends and methyl or phenyl groups as substituents on the other silicon atoms). The figures in square brackets show the ratio of these compounds. The yield shows the total yield.

From the results shown in Table 1, it is clear that the production method of the present invention has high catalytic activity and the reaction proceeds easily even at around room temperature, making it possible to produce acyloxysilane more efficiently than with conventionally known catalysts.
For example, when iron(III) perchlorate hexahydrate, ruthenium(III) chloride hydrate, bis(trifluoromethanesulfonyl)imide scandium(III), bis(trifluoromethanesulfonyl)imide indium(III), bis(trifluoromethanesulfonyl)imide trimethylsilyl, bis(trifluoromethanesulfonyl)imide, and bis(nonafluorobutanesulfonyl)imide were used as catalysts in the reaction of hexamethyldisiloxane with acetic anhydride (Examples 1, 9, 52, 56, 59, 61, and 63), acyloxysilanes could be obtained in high yields of 94%, 93%, 98%, 98%, 96%, 98%, and 98%, respectively, under conditions of stirring at 25° C. for 0.5 hours.
On the other hand, when zinc chloride or trifluoromethanesulfonic acid, which are conventionally known catalysts, were used (Comparative Examples 1 and 2), the yield of acyloxysilane was 1% or 20%, respectively, at 25°C for 0.5 hours, which were lower than the yields in Examples 1, 9, 52, 56, 59, 61, and 63.

Furthermore, even when a solid acid catalyst was used, for example, when Sn ^ion- containing montmorillonite was used as the catalyst in the reaction of hexamethyldisiloxane with acetic anhydride (Example 106), acyloxysilane was obtained in a yield of 56% when stirred at 25° C. for 0.5 hours.
In contrast, when the conventionally known Amberlyst 15 was used (Comparative Example 3), the yield of acyloxysilane was 15% under conditions of 25° C. for 0.5 hour, which was lower than the yield in Example 106.
These results show that by using an acidic catalyst selected from (1) and (2), acyloxysilane can be produced more efficiently than when a conventional catalyst is used.

The acyloxysilane obtained by the above reaction can be converted into other substituents such as alkoxy groups by reacting it with an appropriate modifying agent such as alcohol, as shown in the examples below.

(Example 216)
0.03 mL of the reaction solution containing about 0.074 mmol (per silicon atom) of AcO(SiMe ₂ O) _t Ac (t=1-5, ≧6; their composition ratio is 1:10:13:13:11:49) obtained in Example 144 in Table 1 was dissolved in 0.45 mL of deuterated chloroform, and 0.22 mmol of methanol and 0.22 mmol of triethylamine were added and allowed to stand at room temperature for about 5 hours. As a result of analyzing the product by NMR, it was found that about 0.073 mmol (moles per silicon atom, yield ≧95%) of MeO(SiMe ₂ O) _t Me (t=1-5, ≧6; their composition ratio is 2:11:13:13:12:48) was produced (see Table 2).

(Examples 217 to 221)
The reaction and analysis were carried out in the same manner as in Example 216, but the reaction conditions (raw materials, catalyst, temperature, time, etc.) were changed. The product yields were measured by NMR, and the results are shown in Table 2.

The notes in Table 2 are as follows:
1) In Examples 216 to 221, the reaction solutions obtained in Examples 144, 145, 146, 173, 173, and 212 were used to react with the modifier. The amounts (mL) of the reaction solutions used were 0.03, 0.05, 0.08, 0.09, 0.09, and 0.02, respectively, and the number of moles is the number of moles per silicon atom. The values in square brackets indicate the ratio of the acyloxysilane compounds.
2) MeOH: Methanol
EtOH: ethanol.
3) _Et3N : Triethylamine.
4) _CDCl3 : deuterated chloroform.
5) 25℃ indicates the reaction at room temperature.

6) MeO( _SiMe2O )Me: Dimethyldimethoxysilane
MeO( _SiMe2O ) _2Me : 1,1,3,3-tetramethyl-1,3-dimethoxydisiloxane
MeO( _SiMe2O ) _3Me : 1,1,3,3,5,5-hexamethyl-1,5-dimethoxytrisiloxane
MeO( _SiMe2O ) _4Me : 1,1,3,3,5,5,7,7-octamethyl-1,7-dimethoxytetrasiloxane
MeO( _SiMe2O ) _5Me : 1,1,3,3,5,5,7,7,9,9-decamethyl-1,9-dimethoxypentasiloxane
_Me3SiOMe : Trimethylmethoxysilane
_Me3SiOEt : Ethoxytrimethylsilane
EtO( _SiMe2O )Et: Diethoxydimethylsilane
EtO( _SiMe2O ) _2Et : 1,3-diethoxy-1,1,3,3-tetramethyldisiloxane
EtO( _SiMe2O ) _3Et : 1,5-diethoxy-1,1,3,3,5,5-hexamethyltrisiloxane
EtO( _SiMe2O ) _4Et : 1,7-diethoxy-1,1,3,3,5,5,7,7-octamethyltetrasiloxane
MeO( _SiPh2O )Me: Dimethoxydiphenylsilane
MeO( _SiMe2O )( _SiPh2O )Me: 1,1-dimethyl-1,3-dimethoxy-3,3-diphenyldisiloxane
MeO(SiPh ₂ O) ₂ Me: 1,3-dimethoxy-1,1,3,3-tetraphenyldisiloxane The figures in the brackets indicate the ratio of the modified compounds produced, and the yield indicates the total yield.
7) Yield by NMR (relative to acyloxysilane)

^{The 29} Si-NMR and GC-MS measurement data of the acyloxysilanes and modified compounds thereof obtained in the Examples in Tables 1 and 2 above are shown in Tables 3-1 to 3-5.

The notes in Tables 3-1 to 3-5 are as follows:
1) The names of each product are listed in Table 1, Note 7 and Table 2, Note 6.
2) Chemical shift value of ^29Si NMR. _CDCl3 was used as the NMR solvent. Measured with the addition of relaxation agent Cr(acac) ₃ (chromium(III) acetylacetonate). The figures in parentheses indicate the number of silicon atoms or their ratio based on the integral ratio of peak areas. Note that * indicates an estimate of the number of silicon atoms or their ratio in the compound, since it is believed that signals from multiple compounds overlap at the same position.
3) GC-MS: Gas chromatograph mass spectrometry, EI method: Electron impact ionization method (70 eV).
4) _{C6D6 was} used as the NMR solvent.

As shown in the following examples, when a solid acid catalyst is used, it has been confirmed that the acyloxysilane obtained by the manufacturing method of the present invention can be easily isolated and purified by procedures such as distillation and recrystallization after separating the catalyst by centrifugation, filtration, etc. Furthermore, when a homogeneous catalyst is used, it has been confirmed that the acyloxysilane can be easily isolated and purified by procedures such as distillation and recrystallization without separating the catalyst when the amount of catalyst is small.

(Example 222)
25.6 mmol of hexamethyldisiloxane (Me ₃ SiOSiMe ₃ ), 26.9 mmol of propionic anhydride ((EtCO) ₂ O), and 400 mg of Sn ⁴⁺ -Mont catalyst (prepared by reacting Kunipia F (Na-type montmorillonite, Na ⁺ -Mont) manufactured by Kunipia Corporation with tin(IV) chloride pentahydrate in water) were placed in a reaction vessel and stirred at 90° C. for 45 minutes. The catalyst solid was separated by centrifugation, and the supernatant was separated, after which the catalyst was washed with hexane (1 mL twice). The supernatant and the washings were combined and concentrated under reduced pressure, and the product was distilled using a short-path distillation apparatus A, resulting in 23.0 mmol (yield 90%) of trimethyl(propionyloxy)silane (Me ₃ SiOCOEt).

The physical properties and spectral data of the product obtained were as follows:
Boiling point: 135-140℃ (short path distillation temperature)
¹ H-NMR (CDCl ₃ ): δ 0.28 (s, 9H, SiCH ₃ ), 1.10 (t, J = 7.5 Hz, 3H, COCCH ₃ ), 2.32
(q, J = 7.5 Hz, 2H, _COCH2 )
^13C -NMR (CDCl ₃ ): δ -0.3, 9.1, 29.1, 175.1
^29Si -NMR( _CDCl3 ): δ 23.0

(Example 223)
6.4 mmol of hexamethyldisiloxane (Me ₃ SiOSiMe ₃ ), 6.7 mmol of hexanoic anhydride ((C ₅ H ₁₁ CO) ₂ O), and 100 mg of Sn ⁴⁺ -Mont catalyst (prepared by reacting Kunipia F (Na-type montmorillonite, Na ⁺ -Mont) manufactured by Kunipia Corporation with tin(IV) chloride pentahydrate in water) were placed in a reaction vessel and stirred at 90° C. for 45 minutes. The catalyst solid was separated by centrifugation, and the supernatant was separated, after which the catalyst was washed with hexane (1 mL twice). The supernatant and the washings were combined and concentrated under reduced pressure, and the product was distilled using a short-path distillation apparatus B, resulting in 4.5 mmol (yield 70%) of (hexoyloxy)trimethylsilane (Me ₃ SiOCOC ₅ H ₁₁ ).

The physical properties and spectral data of the product obtained were as follows:
Boiling point: 90-95℃/48mmHg (short path distillation temperature)
¹ H-NMR (CDCl ₃ ): δ 0.27 (s, 9H, SiCH ₃ ), 0.89 (t, J = 7.2 Hz, 3H, CCH ₃ ), 1.26-1.34 (m, 4H, CH ₂ ), 1.59 (quint, J = 7.4 Hz, 2H, COCCH ₂ ), 2.28 (t, J = 7 .4Hz, 2H,
COCH ₂ )
^13C -NMR (CDCl ₃ ): δ -0.3, 13.9, 22.3, 24.7, 31.3, 35.9, 174.6
^29Si -NMR( _CDCl3 ): δ 23.0

(Example 224)
8 mmol of 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane (Me ₂ PhSiOSiMe ₂ Ph), 6.7 mmol of acetic anhydride (Ac ₂ O), and 180 mg of Sn ⁴⁺ -Mont catalyst (prepared by reacting Kunipia F (Na-type montmorillonite, Na ⁺ -Mont) manufactured by Kunipia Corporation with tin(IV) chloride pentahydrate in water) were placed in a reaction vessel and stirred at 90°C for 45 minutes. The catalyst solid was separated by centrifugation, and the supernatant was separated, after which the catalyst was washed with toluene (1 mL twice). The supernatant and the washings were combined and concentrated under reduced pressure, and the product was distilled using a short-path distillation apparatus B, resulting in 5 mmol of acetoxydimethylphenylsilane (Me ₂ PhSiOAc) (yield 63%).

The physical properties and spectral data of the product obtained were as follows:
Boiling point: 100-110℃/3.5mmHg (short path distillation temperature)
¹ H-NMR (CDCl ₃ ): δ 0.58 (s, 6H, SiCH ₃ ), 2.09 (s, 3H, COCH ₃ ), 7.37-7.46 and 7.62-7.67 (each m, 5H, C ₆ H ₅ )
^13C -NMR (CDCl ₃ ): δ -1.6, 22.9, 127.9, 130.2, 133.6, 135.7, 171.6
^29Si -NMR( _CDCl3 ): δ 11.7

(Example 225)
24 mmol of hexamethyldisiloxane (Me ₃ SiOSiMe ₃ ), 36 mmol of trifluoroacetic anhydride ((CF ₃ CO) ₂ O), and 350 mg of Sn ⁴⁺ -Mont catalyst (prepared by reacting Kunipia F (Na-type montmorillonite, Na ⁺ -Mont) manufactured by Kunipia Corporation with tin(IV) chloride pentahydrate in water) were placed in a reaction vessel and stirred at 90° C. for 45 minutes. The catalyst solid was separated by centrifugation, and the supernatant was separated, after which the catalyst was washed with pentane (twice with 1 mL). The supernatant and the washings were combined and concentrated under reduced pressure, and the product was distilled using short-path distillation apparatus A, resulting in 19.7 mmol (yield 82%) of (trifluoroacetyloxy)trimethylsilane (Me ₃ SiOCOCF ₃ ).

The physical properties and spectral data of the product obtained were as follows:
Boiling point: 86-88℃ (short path distillation temperature)
^1H -NMR (CDCl ₃ ): δ 0.40 (s, 9H, SiCH ₃ )
^13C -NMR (CDCl ₃ ): δ -0.7, 114.5 (q, J = 286 Hz), 156.7 (q, J = 42 Hz)
^29Si -NMR ( _CDCl3 ): δ 33.5

(Example 226)
25 mmol of _{hexamethyldisiloxane} ( _Me3SiOSiMe3 ), 37.5 mol of propionic anhydride ((EtCO) _2O ), and 0.016 mmol of bis(trifluoromethanesulfonyl)imide indium(III) were placed in a reaction vessel and stirred for 30 minutes at 90° C. The product was distilled using a short-path distillation apparatus A, and 23.8 mmol of trimethyl(propionyloxy)silane ( _Me3SiOCOEt ) was obtained (yield 95%).
The physical properties and spectral data of the product obtained were consistent with those obtained in Example 222.

According to the production method of the present invention, acyloxysilanes, which are useful as functional chemical products, can be efficiently and safely produced by reacting a siloxane compound having a Si—O—Si bond with a carboxylic acid anhydride, and therefore the utility value of the present invention is high and its industrial significance is great.

Claims (11)

A method for producing an acyloxysilane having a Si-OCO bond (OCO represents an oxycarbonyl group, O-C(=O)), comprising a reaction step of reacting a siloxane compound having a Si-O-Si bond with a carboxylic acid anhydride in the presence of an acid catalyst selected from the following (1) and (2):
(1) Perchlorates, trifluoromethanesulfonates (excluding iron trifluoromethanesulfonate), bis(trifluoromethanesulfonylimide )salts, hexafluoroantimonates, or thiocyanates of elements selected from Groups 3 to 15 of the periodic table; ruthenium chloride; gallium chloride; tin chloride; indium chloride; iron bromide; ruthenium bromide; tris(pentafluorophenyl)borane; trimethylsilyl trifluoromethanesulfonate; nonafluorobutanesulfonic acid; bis(perfluoroalkanesulfonyl)imide; bis(trifluoromethanesulfonyl)imide trimethylsilyl; perchloric acid; hexafluoroantimonate; or thiocyanic acid.
(2) At least one of zeolite and montmorillonite. 2. The method for producing acyloxysilane according to claim 1, wherein the acid catalyst (1) is a compound selected from the group consisting of perchlorates, trifluoromethanesulfonates (excluding iron trifluoromethanesulfonate) , bis(trifluoromethanesulfonylimide)salts, and hexafluoroantimonates of elements selected from the group consisting of elements of Groups 3, 8, and 13 to 15; ruthenium chloride; tris(pentafluorophenyl)borane; trimethylsilyl trifluoromethanesulfonate; nonafluorobutanesulfonic acid; bis(perfluoroalkanesulfonyl)imide; and bis(trifluoromethanesulfonyl)imide trimethylsilyl. 3. The method for producing an acyloxysilane according to claim 2, wherein the element selected from the group consisting of elements of Groups 3, 8, and 13 to 15 is an element selected from the group consisting of scandium, yttrium, samarium, ytterbium , iron, ruthenium, copper, aluminum, gallium, indium, tin, and bismuth . The method for producing an acyloxysilane according to any one of claims 1 to 3 , wherein the siloxane compound is a siloxane compound represented by the following general formula (IA), (IB), or (IC):
R ¹ R ² R ³ Si-O-SiR ¹ R ² R ³ (IA)

X ¹ O(SiR ⁶ R ⁷ O) _n X ² (IC)
(In formulas (IA) to (IC), R ¹ to R ⁷ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that do not participate in the reaction; X ¹ and X ² each independently represent a silyl group or a hydrogen atom; and m and n each independently represent an integer of 2 or more and 10,000 or less.) The method for producing an acyloxysilane according to any one of claims 1 to 3 , wherein the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIA) or (IIB):
(R ⁸ CO) ₂ O (IIA)

(In formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with a group that does not participate in the reaction. In formula (IIB), R ⁹ is a divalent hydrocarbon group having 2 to 24 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the divalent hydrocarbon group having 2 to 24 carbon atoms may be substituted with a group that does not participate in the reaction.) The method for producing an acyloxysilane according to any one of claims 1 to 3, wherein the siloxane compound is a siloxane compound represented by the following general formula (IA), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIA), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIIA):
R ¹ R ² R ³ Si-O-SiR ¹ R ² R ³ (IA)
(R ⁸ CO) ₂ O (IIA)
R ¹ R ² R ³ Si (OCOR ⁸ ) (IIIA)
In formula (IA), R ¹ to R ³ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with a group that does not participate in the reaction.
In formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIIA), R ¹ to R ³ are defined in the same manner as R ¹ to R ³ in formula (IA), and R ⁸ is defined in the same manner as R ⁸ in formula (IIA). The method for producing an acyloxysilane according to any one of claims 1 to 3, wherein the siloxane compound is a siloxane compound represented by the following general formula (IB), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIA), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIIB):

(R ⁸ CO) ₂ O (IIA)
R ⁸ CO ₂ (SiR ⁴ R ⁵ O) _p COR ⁸ (IIIB)
(In formula (IB), R ⁴ and R ⁵ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction; and m represents an integer of 2 or more and 10,000 or less.
In formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIIB), R ⁴ and R ⁵ are defined as R ⁴ and R ⁵ in formula (IB); R ⁸ is defined as R ⁸ in formula (IIA); and p is an integer from 1 to 100. The method for producing an acyloxysilane according to any one of claims 1 to 3, wherein the siloxane compound is a siloxane compound represented by the following general formula (IC), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIA), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIIC):
X ¹ O(SiR ⁶ R ⁷ O) _n X ² (IC)
(R ⁸ CO) ₂ O (IIA)
R ⁸ CO ₂ (SiR ⁶ R ⁷ O) _q COR ⁸ (IIIC)
(In formula (IC), R ⁶ and R ⁷ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that do not participate in the reaction; X ¹ and X ² each independently represent a silyl group or a hydrogen atom; and n represents an integer of 2 or more and 10,000 or less.
In formula (IIA), R ⁸ is a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIIC), R ⁶ and R ⁷ are defined as ⁶ and R ⁷ in formula (IC); R ⁸ is defined as R ⁸ in formula (IIA); and q is an integer from 1 to 100. The method for producing an acyloxysilane according to any one of claims 1 to 3, wherein the siloxane compound is a siloxane compound represented by the following general formula (IB), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIB), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIID).

(In formula (IB), R ⁴ and R ⁵ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that are not involved in the reaction; and m represents an integer of 2 or more and 10,000 or less.
In formula (IIB), R ⁹ is a divalent hydrocarbon group having 2 to 24 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the divalent hydrocarbon group having 2 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIID), R ⁴ and R ⁵ are defined as R ⁴ and R ⁵ in formula (IB); R ⁹ is defined as R ⁹ in formula (IIB); r1 is an integer of 1 to 100; and r2 is an integer of 1 or more and r1 or less. The method for producing an acyloxysilane according to any one of claims 1 to 3, wherein the siloxane compound is a siloxane compound represented by the following general formula (IC), the carboxylic acid anhydride is a carboxylic acid anhydride represented by the following general formula (IIB), and the acyloxysilane is an acyloxysilane represented by the following general formula (IIIE):
X ¹ O(SiR ⁶ R ⁷ O) _n X ² (IC)

(In formula (IC), R ⁶ and R ⁷ each independently represent a hydrocarbon group having 1 to 24 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group having 1 to 24 carbon atoms may be substituted with groups that do not participate in the reaction; X ¹ and X ² each independently represent a silyl group or a hydrogen atom; and n represents an integer of 2 or more and 10,000 or less.
In formula (IIB), R ⁹ is a divalent hydrocarbon group having 2 to 24 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the divalent hydrocarbon group having 2 to 24 carbon atoms may be substituted with groups that are not involved in the reaction.
In formula (IIIE), R ⁶ and R ⁷ are defined as R ⁶ and R ⁷ in formula (IC); R ⁹ is defined as R ⁹ in formula (IIB); s1 is an integer of 1 to 100; and s2 is an integer of 1 or more and s1 or less. A method for producing an alkoxysilane, comprising: an acyloxysilane production step of producing an acyloxysilane by the production method according to any one of claims 1 to 10 ; and a modification step of reacting the acyloxysilane with an alcohol represented by the following general formula (IV) to convert an acyloxy group of the acyloxysilane into an alkoxy group.
^R10OH (IV)
(In the formula, R ¹⁰ is an alkyl group having 1 to 6 carbon atoms.)