JP2947137B2 - Acrylic silane distillation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Spontaneous polymerization of acrylsilane produced when chlorosilane or acetoxysilane having methacryloxy group or acryloxy group (hereinafter referred to as "acrylsilane") is produced, in particular, acrylsilane produced inside a distillation column. The present invention relates to a distillation method for suppressing spontaneous polymerization of water.

[0002]

2. Description of the Related Art Acrylic silane is a silane coupling agent, a raw material of a silane coupling agent, a raw material of a polysiloxane, a terminating agent in the production of polysiloxane, a surface treatment agent for various base materials, a modified material of various resins, and the like. Effective for a wide range of applications. Generally, such highly useful acrylic silane is obtained by performing a hydrosilylation reaction between an acrylate or methacrylate having an unsaturated site and a hydrosilane compound in the presence of a transition metal catalyst such as platinum, and further reacting the reaction solution. By distillation under reduced pressure.

[0003] Such a production example is disclosed in Japanese Patent Publication No. 6-51707.
JP-A-2003-157, which discloses a method for producing 3-methacryloxypropyldimethylchlorosilane by reacting allyl methacrylate and methyldichlorosilane in the presence of a platinum catalyst, and then performing distillation under reduced pressure. .

However, acrylic silane can be a raw material for producing various functional materials due to its high polymerizability. However, acrylic silane can be used as a raw material in the synthesis reaction process, distillation purification process, storage process, and transport process of acrylic silane. However, it has a drawback that it is easily thermally spontaneously polymerized. Therefore, in the case of heating at room temperature or higher in the acrylic silane synthesis reaction step and the distillation purification step after the synthesis reaction, it is most important how to prevent spontaneous polymerization of acryl silane. Usually, in order to prevent such spontaneous polymerization of acrylic silane, a polymerization inhibitor is added to a raw material or a reaction liquid of acrylic silane (hereinafter, referred to as an acrylic silane solution) to carry out a synthesis reaction and distillation purification. doing.

[0005] Certainly, the spontaneous polymerization of acrylsilane in the acrylsilane solution can be suppressed by this method. However, in this method, spontaneous polymerization that occurs when acrylsilane vaporized in the distillation purification step passes through the inside of the distillation column cannot be suppressed. Basically, the distillation purification device is composed of a distillation still for heating and decompressing the acrylsilane solution obtained in the synthesis reaction step to vaporize and a distillation column for distilling the vaporized acrylsilane. Is effective in suppressing the spontaneous polymerization of the acrylsilane solution in the distillation still, but has no effect of suppressing the spontaneous polymerization of acrylsilane vapor or droplets (hereinafter, referred to as acrylsilane vapor) in the distillation column. It is. This is because the polymerization inhibitor added to the acrylic silane solution is not vaporized in the still, so that no polymerization inhibitor exists inside the distillation column.

As a method for suppressing spontaneous polymerization inside the distillation column, there is a method using a polymerization inhibitor having a boiling point equal to or slightly lower than that of acrylic silane. However, this method has a disadvantage that a large amount of a polymerization inhibitor is mixed into the product after distillation, thereby deteriorating the quality of the product, and a disadvantage that the type of the polymerization inhibitor must be appropriately selected according to the boiling point of the acrylic silane. Had. Although there is a method using oxygen or laughing gas, spontaneous polymerization cannot be sufficiently prevented by oxygen or laughing gas alone.

[0007]

The inventors of the present invention have conducted intensive studies on the above-mentioned problems, and as a result, it has been found that acrylsilane having a specific structure can be obtained in the presence of at least one of a hindered phenol compound and an amine compound. Then, it was found that when performing purification by distillation while supplying an N-nitrosophenylhydroxylamine salt mixed solution from the upper portion of the distillation column, it was possible to effectively suppress spontaneous polymerization of acrylsilane inside the distillation column, and completed the present invention. .

[0008]

The present invention has the following constitutions (1) to (3). (1) The acrylsilane represented by the general formula (I) is purified by distillation using a hindered phenol compound or N, N'-
Diphenyl-p-phenylenediamine or / and
A method for distilling acrylic silane, wherein the method is carried out while supplying an N-nitrosophenylhydroxylamine salt mixture from the top of a distillation column in the presence of at least one of an amine compound which is enothiazine . CH ₂ ＣＲCR ¹ COO (X) _m SiR ² _n R ³ _3-n (I) wherein R ¹ is hydrogen, an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms And X is CH ₂ C
H ₂ O or CH ₂ or a combination of these two groups, m is 1 to 12, R ² is a hydrolyzable group, R ³ is an alkyl group having 1 to 12 carbon atoms, alkenyl And n is 1-3. (2) An N-nitrosophenylhydroxylamine salt represented by the general formula (II): (R ⁴ N (NO) O) _p Y _q (II) wherein R ⁴ is an aryl group having 6 to 10 carbon atoms. And
p is 1-4, q is 1-4, and Y is a cation atom or molecule. The method for distilling acrylsilane according to the above (1), which is a compound represented by the following formula (1): (3) In the above item (1) or (2), the hindered phenol compound is a compound in which at least one substituent that gives steric hindrance near the hydroxyl group of the aromatic ring is bonded. A method for distilling acrylic silane as described above.

Hereinafter, the present invention will be described in detail. The present invention provides a method for purifying an acrylic silane having a specific structure by distillation using a hindered phenol compound or N, N'-diphenyl.
Ru-p-phenylenediamine and / or phenothia
Amine compounds that are gin (“amine
Compound ”is“ N, N′- ”unless specifically mentioned.
Diphenyl-p-phenylenediamine or / and
Amine compounds that are enothiazines ". This is a distillation method in which an N-nitrosophenylhydroxylamine salt mixture is supplied from the upper part of the distillation column in the presence of at least one of the above.

The distillation method of the present invention is effective for suppressing the spontaneous polymerization of the acrylsilane represented by the general formula (I). The acrylic silane is highly useful, but is liable to cause spontaneous polymerization. CH ₂ = CR in ^{_{1 COO (X) m SiR 2}} n R 3 3 _over n ... (I) [wherein, R ¹ is hydrogen, aryl alkyl group or the carbon number of 1 to 8 carbon atoms is 6 to 10 And X is CH ₂ C
H ₂ O or CH ₂ or a combination of these two groups, m is 1 to 12, R ² is a hydrolyzable group, R ³ is an alkyl group having 1 to 12 carbon atoms, alkenyl A group or an aryl group, and n is 1 to 3. ]

The present invention provides, among others, the compounds represented by the general formula (I)
² is —OC (＝ O) R ⁵ [wherein R ⁵ has 1 to 8 carbon atoms.
An alkenyl group having 1 to 8 carbon atoms, an alkynyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 10 carbon atoms. ], Preferably -OC (= O) CR ⁶
ＣＨCH _{2 wherein} R ⁶ is an alkyl group having 1 to 2 carbon atoms or hydrogen. Or halogen elements, particularly preferably those having a structure of —OC (＝ O) CH ₃ or a chlorine atom.

More specifically, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropylmethyldichlorosilane, 3-methacryloxypropyldimethylchlorosilane, 3-acryloxypropyltrichlorosilane, 3-acryloxypropylmethyldichlorosilane, 3-acryloxypropyldimethylchlorosilane,
Examples thereof include 3-methacryloxypropyldimethylacetoxysilane, 3-methacryloxypropyldimethylmethacryloxysilane, 3-acryloxypropyldimethylacetoxysilane, and 3-acryloxypropyldimethylacryloxysilane.

In the present invention, spontaneous polymerization inside the distillation column can be effectively suppressed by continuously supplying a liquid in which a polymerization inhibitor for suppressing spontaneous polymerization is dispersed or dissolved from the upper portion of the distillation column. . The supply method is not particularly limited, and any of a dropping method and a spraying method may be used. However, a polymerization inhibitor having a boiling point higher than that of acrylsilane to be purified by distillation or having no boiling point must be used. If the boiling point is close to that of acrylic silane, a large amount will be mixed into the product and the quality will be deteriorated. As the polymerization inhibitor used in the present invention, N-nitrosophenylhydroxylamine salt is suitable.

The N-nitrosophenylhydroxylamine salt used in the present invention can be represented by the compound of the above general formula (II). (R ⁴ N (NO) O) _p Y _q (II) wherein R ⁴ is an aryl group having 6 to 10 carbon atoms;
p is 1-4, q is 1-4, and Y is a cation atom or molecule. Specific examples thereof include N-nitrosophenylhydroxylamine ammonium salt, N-nitrosophenylhydroxylamine sodium salt, N-nitrosophenylhydroxylamine potassium salt, and N-nitrosophenylhydroxylamine aluminum salt. These may be used alone or in combination of two or more.

The supply amount of the N-nitrosophenylhydroxylamine salt used in the present invention depends on the shape of the distillation column, but is 0.1 to 1 per hour based on the amount of acrylsilane.
0000 ppm (weight conversion) is appropriate,
In particular, it is preferably from 1 to 100 ppm (in terms of weight).

Further, N-nitrosophenylhydroxyl
The amine salt mixture is N-nitrosophenylhydroxyl
Mixing the amine salt with a solvent that disperses or dissolves it
Therefore, it is prepared. The solvent used at this time is not particularly limited, but does not react with acrylic silane or the polymerization inhibitor,
Further, those which do not mix with the distilled and purified acrylic silane are preferable, and in particular, the acrylic silane itself to be distilled and purified and a liquid having a higher boiling point than the acrylic silane are preferable.

In the present invention, the acrylic silane solution to be purified by distillation must contain at least one of a hindered phenol compound and an amine compound. This is because spontaneous polymerization easily occurs inside the still.

Specific examples of the hindered phenol compound used in the present invention include 2,6-di-tert-butyl-4-methylphenol and 2,6-di-tert-butyl-4-dimethylaminomethylphenol.
Specific examples of the amine compound used in the present invention include N,
N'-diphenyl-p-phenylenediamine, phenothiazine and the like can be exemplified.

The amount of the hindered phenol compound or amine compound used in the present invention is preferably from 1 to 100,000 ppm (in terms of weight), more preferably from 10 to 5,000 ppm (in terms of weight), based on the acrylsilane solution. In the present invention, a hindered phenol compound or an amine compound may be used alone, or at least one or more hindered phenol compounds and one or more amine compounds may be used in combination.

Specific methods of use include a method of adding immediately before the synthesis reaction of acrylic silane, a method of pre-mixing to the raw material of acrylic silane, and a method of adding to the acrylic silane solution immediately before purification by distillation. Can be exemplified.

In the distillation method of the present invention, a gas or air obtained by diluting molecular oxygen with an inert gas may be introduced into the apparatus.

An example of a distillation apparatus that can be used in the present invention will be described with reference to the accompanying drawings. The distillation method of the present invention is most preferably performed using the distillation apparatus shown in FIG. 1, but is not limited to the distillation apparatus unless departing from the technical idea of the present invention. The acrylic silane solution obtained by the synthesis reaction is charged into the distillation still 1 and heated and decompressed to vaporize the acrylic silane. Decompression is
The heating is carried out by a vacuum pump 6 and the heating is carried out by circulating a heating medium through a jacket 7 provided around the distillation still 1. The vaporized acrylic silane is led to the distillation tower 2, goes up the distillation tower 2, is discharged from the upper part of the distillation tower 2, and is led to the aggregator 4. On the other hand, an N-nitrosophenylhydroxylamine salt mixture is charged into the top feed liquid tank 3, and the mixture is supplied to the inside of the distillation column 2 while adjusting the flow rate by the flow rate control valve 8.
The acrylic silane is liquefied by the aggregator 4 and stored in the distillate tank 5. In some cases, it is led to the upper part of the distillation column 2 and distillation purification is performed again.

[0023]

The present invention will be described below in detail with reference to Examples, Comparative Examples and Reference Examples. Note that the present embodiment does not limit the present invention at all.

Example 1 An acrylsilane solution containing 3-methacryloxypropyldimethylchlorosilane as a main component was synthesized from allyl methacrylate and dimethylchlorosilane in the presence of a platinum catalyst by a known method. About 5 kg of this acrylic silane solution was added to 2,6-di-tert-butyl-4.
-0.5 g of dimethylaminomethylphenol,
It was put into the distillation still 1 and heated and depressurized. First, the pressure inside the apparatus was reduced to 30 kPa, and the top temperature of the distillation column 2 was set to 60 to 60 kPa.
At 85 ° C., after distilling off low-boiling components containing allyl methacrylate as a main component, the pressure was reduced to 15 kPa, and
At 75 ° C., a fraction of 3-methacryloxypropyldimethylchlorosilane was obtained. During that time, a liquid obtained by dissolving N-nitrosophenylhydroxylamine aluminum salt in 3-methacryloxypropyldimethylchlorosilane at a weight ratio of 2% is supplied from the top of the distillation column 2 having an inner diameter of about 50 cm filled with a helipak. did. After the distillation was completed, the inside of the distillation column 2 was inspected, but no spontaneous polymerization product of acrylic silane was found.

(Example 2) Instead of a solution in which N-nitrosophenylhydroxylamine aluminum salt was dissolved in 3-methacryloxypropyldimethylchlorosilane at a weight ratio of 2%, N-nitrosophenylhydroxylamine aluminum salt was used. Distillation was carried out in accordance with Example 1 except that a liquid obtained by dissolving mineral oil (manufactured by Soken Chemical Co., Ltd .: NeoSK-OIL330) at a weight ratio of 2% was added from the top of the distillation column 2. Done. After the distillation was completed, the inside of the distillation column 2 was inspected, but no spontaneous polymerization product of acrylic silane was found.

Comparative Example 1 The procedure of Example 1 was repeated except that a solution prepared by dissolving N-nitrosophenylhydroxylamine aluminum salt in 3-methacryloxypropyldimethylchlorosilane at a weight ratio of 2% was not supplied. Distillation was performed. The pressure was reduced to 15 kPa, and the top temperature was 30 to 6
After distilling off the low-boiling component mainly composed of allyl methacrylate at 9 ° C., a spontaneous polymer of acrylsilane is formed inside the distillation column 2, and the distillation operation becomes impossible because the product blocked the distillation column. Was.

(Comparative Example 2) Instead of a solution in which N-nitrosophenylhydroxylamine aluminum salt was dissolved in 3-methacryloxypropyldimethylchlorosilane at a weight ratio of 2%, 2,6-di-tert-butyl-4- Distillation was carried out in the same manner as in Example 1, except that a liquid in which methylphenol was dissolved in 3-methacryloxypropyldimethylchlorosilane at a weight ratio of 2% was added from the top of the distillation column 2. While the pressure was reduced to 15 kPa and a low-boiling component mainly composed of allyl methacrylate was distilled off at a tower top temperature of 30 to 69 ° C., a spontaneous polymerization product of acrylsilane was formed inside the distillation column 2, Distillation operation was disabled because the material blocked the distillation column.

(Comparative Example 3) Phenothiazine was replaced with 3-methacryloxypropyldimethylchlorosilane in place of a solution prepared by dissolving N-nitrosophenylhydroxylamine aluminum salt in 3-methacryloxypropyldimethylchlorosilane at a weight ratio of 2%. The distillation was carried out in the same manner as in Example 1, except that a liquid dissolved at a weight ratio of 2% was added from the top of the distillation column 2. The pressure was reduced to 15 kPa and the distillation column 2 was distilled at a tower top temperature of 30 to 69 ° C. while distilling off low-boiling components mainly composed of allyl methacrylate.
A spontaneous polymerization product of acrylic silane was formed inside the column, and the product clogged the distillation column, making the distillation operation impossible.

[0029]

As is clear from the examples and comparative examples, when the N-nitrosophenylhydroxylamine salt mixture is supplied from the upper part of the distillation column, the spontaneous polymerization of acrylsilane in the distillation column can be suppressed very effectively. I understand. Further, since the N-nitrosophenylhydroxylamine salt mixture is hardly mixed into the distilled and purified acrylic silane, that is, the product, the quality of the product is extremely good.

[Brief description of the drawings]

FIG. 1 is a diagram of a flow sheet of a distillation apparatus.

[Explanation of symbols]

 1. Distillation still 2. Distillation column 3. 3. Top feed liquid tank Condenser 5. Distillate tank 6. Decompression pump 7. Jacket 8. Flow control valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07F 7/00-7/21 CA (STN) REGISTRY (STN) WPI (DIALOG)

Claims (3)

(57) [Claims] 1. A method for purifying an acrylic silane represented by the general formula (I) by distillation using a hindered phenol compound or
N, N′-diphenyl-p-phenylenediamine or
And / or a phenothiazine amine compound in the presence of an amine compound while supplying the N-nitrosophenylhydroxylamine salt mixture from the top of the distillation column. CH ₂ ＣＲCR ¹ COO (X) _m SiR ² _n R ³ _3-n (I) wherein R ¹ is hydrogen, an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms And X is CH ₂ C
H ₂ O or CH ₂ or a combination of these two groups, m is 1 to 12, R ² is a hydrolyzable group, R ³ is an alkyl group having 1 to 12 carbon atoms, alkenyl And n is 1-3. ] 2. An N-nitrosophenylhydroxylamine salt represented by the general formula (II) (R ⁴ N (NO) O) _p Y _q ... (II) wherein R ⁴ is an aryl having 6 to 10 carbon atoms. Group,
p is 1-4, q is 1-4, and Y is a cation atom or molecule. The method for distilling acrylsilane according to claim 1, wherein the compound is represented by the following formula: 3. The hindered phenol compound is a compound in which at least one substituent which gives steric hindrance near a hydroxyl group of an aromatic ring is bonded. 3. The method for distilling acrylic silane according to 1.).