JP7647063B2 - 4-Ammoniopiperidinium salts and uses thereof - Google Patents

Description

This disclosure relates to novel 4-ammoniopiperidinium salts and their uses.

4-Ammoniopiperidinium salt compounds have been reported as structure directing agents for the production of zeolites (e.g., Patent Documents 1 and 2, Non-Patent Documents 1 to 3). The 4-ammoniopiperidinium salt compounds in these known documents are disclosed as structure directing agents for the production of ITQ-39 and MFI-type zeolites. However, these 4-ammoniopiperidinium salt compounds were not able to produce small pore zeolites.

US Patent Publication No. 2015/0275099 International Publication No. 2013/175014

The Journal of Physical Chemistry, 2015, Vol. 119, pp. 7711-7720 Journal of the American Chemical Society, 2012, Vol. 134, pp. 6473-6478 Journal of the American Chemical Society, 2011, Vol. 133, pp. 9497-9505

The objective of this disclosure is to provide at least one of a novel 4-ammoniopiperidinium salt that can be used as a structure directing agent for producing small pore zeolites and a method for producing the same, as well as an organic structure directing agent for producing zeolites that contains the same and a method for producing small pore zeolites using the same.

The inventors discovered that 4-ammoniopiperidinium salt represented by general formula (1) can solve the above problems, and thus completed the invention disclosed herein.

That is, the present invention is as set forth in the claims, and the gist of the present disclosure is as follows.
[1] A 4-ammoniopiperidinium salt represented by general formula (1):

(In the formula, R ¹ , R ² , R ³ , R ⁴ , and R ⁵ each independently represent a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms (each of these groups may be independently substituted with one or more selected from the group consisting of a halogen group, a hydroxy group, an alkoxy group represented by -OR (R represents a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms), an amino group, and a phenyl group). R ¹ , R ² , and R ³ are not mutually bonded. Y ^- may be the same or different and represents any anion.)
[2] The 4-ammoniopiperidinium salt according to the above [1], wherein in the formula (1), R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are each independently a methyl group or an ethyl group (which may be substituted with one or more selected from the group consisting of a halogen group, a hydroxy group, an alkoxy group represented by -OR (R represents a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms), an amino group, and a phenyl group).
[3] The 4-ammoniopiperidinium salt according to the above [1], wherein in the formula (1), R ¹ , R ² , R ³ , R ⁴ and R ⁵ are methyl groups.
[4] The 4-ammoniopiperidinium salt according to any one of [1] to [3], wherein _in the formula ⁽ 1), Y ⁻ is Cl ⁻ (chloride ion), Br ⁻ (bromide ion), I ⁻ (iodide ion), _{C 6} H ₅ SO _{2 O} ⁻ (benzenesulfonate ion), p-CH ₃ C ₆ H 4 SO ₂ O ⁻ (p-toluenesulfonate ion), CH ₃ SO ₂ O ⁻ (methanesulfonate ion), CF 3 SO 2 O − (trifluoromethanesulfonate ion), or OH ⁻ (hydroxide ion).
[5] A method for producing a zeolite, comprising: a crystallization step of crystallizing a composition containing an organic structure directing agent source containing the 4-ammoniopiperidinium salt according to any one of [1] to [4] above, a silica source, an alumina source, an alkali source, and water.

The present disclosure provides at least one of a novel 4-ammoniopiperidinium salt and a method for producing the same, an organic structure directing agent for producing zeolites containing the same, and a method for producing small pore zeolites using the same.

XRD pattern of CHA type zeolite of Example 2-3 SEM observation diagram of CHA type zeolite of Example 2-3

The following describes this disclosure by showing an example of an embodiment.

First, the definitions of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and Y ⁻ in general formula (1) will be explained in detail.

R ¹ , R ² , R ³ , R ⁴ , and R ⁵ each independently represent a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms (each of these groups may be independently substituted with one or more selected from the group consisting of a halogen group, a hydroxy group, an alkoxy group represented by -OR (R represents a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms), an amino group, and a phenyl group).

The linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms represented by R ¹ , R ² , R ³ , R ⁴ , and R ⁵ is not particularly limited, and examples thereof include a propyl group, an isopropyl group, a butyl group, a 1-methylpropyl group, a 2-methylpropyl group, a cyclopropyl group, a tert-butyl group, and a cyclobutyl group.

The methyl group, ethyl group, or linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms represented by R ¹ , R ² , R ³ , R ⁴ , and R ⁵ may each be independently substituted with one or more groups selected from the group consisting of a halogen group, a hydroxy group, an alkoxy group represented by -OR (R represents a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms), an amino group, and a phenyl group, as described above.

The linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms in R is synonymous with the linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms represented by R ¹ , R ² , R ³ , R ⁴ , and R ⁵ .

The alkoxy group represented by -OR is not particularly limited, but examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a 2-methylpropoxy group, a cyclopropoxy group, a tert-butoxy group, and a cyclobutoxy group.

R ¹ , R ² , R ³ , R ⁴ and R The group represented by ⁵ is not particularly limited, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclopropyl group, a butyl group, an isobutyl group, a tertiary butyl group, a cyclobutyl group, a trifluoromethyl group, a difluoromethyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a 2,2,3,3-tetrafluoropropyl group, a 3,3,3-trifluoropropyl group, a 1,1-difluoropropyl group, a perfluoro(1-methylpropyl) group, a 2,2,2-trifluoro-1-(trifluoromethyl)ethyl group, a perfluorocyclopropyl group, a 2,2,3,3-tetrafluorocyclopropyl group, a perfluorobutyl group, a 2,2,3,3,4,4,4-heptafluorobutyl group, a 3,3,4,4,4-pentafluorobutyl group, a 4,4,4-trifluoropropyl group, a 5,5-trifluoropropyl group, a 6,6-trifluoropropyl group, a 7,7-trifluoropropyl group, a 8,8-trifluoropropyl group, a 9,9-trifluoropropyl group, a 10,1-trifluoropropyl group, a 11,1-trifluoropropyl group, a 12,1-trifluoropropyl group, a 13,1-trifluoropropyl group, a 14,1-trifluoropropyl group, a 15,1-trifluoropropyl group, a 16,1-trifluoropropyl group, a 17,1-trifluoropropyl group, a 18,1-trifluoropropyl group, a 19,1-trifluoropropyl group, a 21,1-trifluoropropyl group, a 22,1-trifluoropropyl group, a 23,1-trifluoropropyl group, a Examples of the alkyl group include a fluorobutyl group, a 1,2,2,3,3,3-hexafluoro-1-(trifluoromethyl)propyl group, a 1-(trifluoromethyl)propyl group, a 1-methyl-3,3,3-trifluoropropyl group, a perfluorocyclobutyl group, a 2,2,3,3,4,4-hexafluorocyclobutyl group, a chloromethyl group, a bromomethyl group, an iodomethyl group, a 2-chloroethyl group, a 3-bromopropyl group, a hydroxymethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 4-hydroxybutyl group, a methoxymethyl group, a 2-methoxyethyl group, a 2-methoxypropyl group, a 3-methoxypropyl group, a 4-methoxybutyl group, an ethoxymethyl group, an ethoxyethyl group, a 2-ethoxypropyl group, a 3-ethoxypropyl group, a 4-ethoxybutyl group, an aminomethyl group, a 2-aminoethyl group, a 2-aminopropyl group, a 3-aminopropyl group, a 4-aminobutyl group, a benzyl group, and a phenethyl group.

From the viewpoint of excellent zeolite yield, R ¹ , R ² , R ³ , R ⁴ and R ⁵ are preferably each independently a methyl group or an ethyl group (which may be substituted with one or more selected from the group consisting of a halogen group, a hydroxy group, an alkoxy group represented by -OR (R represents a methyl group, an ethyl group, or a linear, branched or cyclic alkyl group having 3 to 4 carbon atoms), an amino group, and a phenyl group), more preferably each independently a methyl group or an ethyl group (which may be substituted with one or more selected from the group consisting of a halogen group, a hydroxy group, a methoxy group, an amino group, and a phenyl group), more preferably each independently a methyl group or an ethyl group, and more preferably a methyl group.

It should be noted that R ¹ , R ² , and R ³ are not mutually bonded. For example, if R ¹ =R ² =ethyl groups and the ethyl groups are bonded to each other, a pyrrolidine ring is formed together with the nitrogen atom carrying R ¹ and R ² , but the present invention does not include such a structure.

Y ^{1 -} may be the same or different and represents any anion.

The arbitrary anion is not particularly limited, but may include, for example, a halide ion, a sulfonate compound ion, a carboxylate ion, or a hydroxide ion (OH ⁻ ).

The halide ion is not particularly limited, but examples thereof include fluoride ion, chloride ion, bromide ion, and iodide ion.

The sulfonate compound ion is not particularly limited, and examples thereof include sulfonate compound ions represented by R ⁶ SO ₂ O ^- (R ⁶ represents a hydrogen atom, a methyl group, an ethyl group, an alkyl group having 3 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, or a 4-methylphenyl group), such as a sulfonate ion, a methylsulfonate ion, an ethylsulfonate ion, a trifluoromethanesulfonate ion, a benzenesulfonate ion, a p-toluenesulfonate ion, a fluorosulfonate ion, a methylsulfate ion, an ethylsulfate ion, and a phenylsulfate ion.

The carboxylate ion is not particularly limited, and examples thereof include carboxylate ions represented by R ⁷ COO ⁻ (R ⁷ represents a hydrogen atom, a methyl group, an ethyl group, a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a phenyl group (the phenyl group may be substituted with a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms)), such as a formate ion, an acetate ion, a propionate ion, a trifluoroacetate ion, a benzoate ion, or a 4-methylbenzoate ion.

The linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms in Y ^- (R ⁶ and R ⁷ ) has the same meaning as the linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms in R ¹ , R ² , R ³ , R ⁴ , and R ⁵ .

The fluoroalkyl group having 1 to 4 carbon atoms in ^R7 may be any of linear, branched, and cyclic fluoroalkyl groups, and is not particularly limited. Examples of such fluoroalkyl groups include trifluoromethyl, difluoromethyl, perfluoroethyl, 2,2,2-trifluoroethyl, 1,1-difluoroethyl, 2,2-difluoroethyl, perfluoropropyl, 2,2,3,3,3-pentafluoropropyl, 2,2,3,3-tetrafluoropropyl, 3,3,3-trifluoropropyl, 1,1-difluoropropyl, perfluoro(1-methylpropyl) group, 2,2,2- Examples include a trifluoro-1-(trifluoromethyl)ethyl group, a perfluorocyclopropyl group, a 2,2,3,3-tetrafluorocyclopropyl group, a perfluorobutyl group, a 2,2,3,3,4,4,4-heptafluorobutyl group, a 3,3,4,4,4-pentafluorobutyl group, a 4,4,4-trifluorobutyl group, a 1,2,2,3,3,3-hexafluoro-1-(trifluoromethyl)propyl group, a 1-(trifluoromethyl)propyl group, a 1-methyl-3,3,3-trifluoropropyl group, a perfluorocyclobutyl group, and a 2,2,3,3,4,4-hexafluorocyclobutyl group.

The alkoxy group having 1 to 4 carbon atoms for ^R6 may be any of linear, branched, and cyclic alkoxy groups, and is not particularly limited. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a 2-methylpropoxy group, a cyclopropoxy group, a tert-butoxy group, and a cyclobutoxy group.

In addition, Y ⁻ is preferably each independently Cl ⁻ (chloride ion), Br ⁻ (bromide ion), I ⁻ (iodide ion), C ₆ H ₅ SO ₂ O ⁻ (benzenesulfonate ion), p-CH ₃ C ₆ H ₄ SO ₂ O ⁻ (p-toluenesulfonate ion), CH ₃ SO ₂ O ⁻ (methanesulfonate ion), CF ₃ SO ₂ O ⁻ (trifluoromethanesulfonate ion), or OH ⁻ (hydroxide ion), and more preferably Br ⁻ (bromide ion), Cl ⁻ (chloride ion), or OH ⁻ (hydroxide ion), in terms of excellent zeolite yield.

Specific examples of the 4-ammoniopiperidinium salt (1) of this embodiment include the following (1-1) to (1-120), but this embodiment is not limited to these.

In this specification, Me represents a methyl group, Et represents an ethyl group, Ph represents a phenyl group, TsO 4 ^-- represents a p-toluenesulfonate ion, and TfO 4 ^-- represents a trifluoromethanesulfonate ion.

Among the compounds represented by (1-1) to (1-120), the 4-ammoniopiperidinium salt of this embodiment is preferably one or more compounds selected from the group consisting of 1-4, 1-7, 1-8, 1-9, 1-39, 1-40, 1-44, 1-45, 1-111, 1-112, 1-116, and 1-117, in view of ease of synthesis.

Next, the method for producing the 4-ammoniopiperidinium salt (1) of this embodiment will be described.

<First embodiment of manufacturing method>
An example of a method for producing a 4-ammoniopiperidinium salt (1) of the present embodiment is a method for producing a 4-ammoniopiperidinium salt represented by general formula (1a) (hereinafter also referred to as "Production Method 1"), which includes a step of reacting a compound represented by general formula (2) with a compound represented by general formula (3) (hereinafter also referred to as a "reaction step").

(In the formula, R ⁸ and R ⁹ may be the same or different and each independently represent a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms (each of these groups may be independently substituted with one or more selected from the group consisting of a halogen group, a hydroxy group, an alkoxy group represented by -OR (R represents a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms), an amino group, and a phenyl group).
The definitions and preferred ranges of the groups in ^R8 and ^R9 are the same as the definitions and preferred ranges of the groups in ^R1 , ^R2 , ^R3 , ^R4 , and ^R5 .

(In the formula, R ¹⁰ represents a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms (these groups may be substituted with one or more selected from the group consisting of a halogen group, a hydroxy group, an alkoxy group represented by -OR (R represents a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms), an amino group, and a phenyl group), and Ya represents a halogen atom, or an organic sulfonyloxy group represented by R ⁶ SO ₂ O-.)
The definitions and preferred ranges of the groups in R ¹⁰ are the same as the definitions and preferred ranges of the groups in R ¹ , R ² , R ³ , R ⁴ and R ⁵ .

R ⁶ has the same meaning as R ⁶ in the above Y ^{1 -} , and the preferred range is also the same.

(In the formula, R ⁸ and R ⁹ are the same as R ⁸ and R ⁹ in general formula (2). R ¹⁰ is the same as R ¹⁰ in general formula (3). ^{Ya -} represents a halide ion or a sulfonate ion represented by R ⁶ SO ₂ O ^- . R ⁶ is the same as R ⁶ in general formula (3).)
The substituents represented by R ⁸ , R ⁹ and R ¹⁰ have the same definitions as those of the substituents represented by R ¹ , R ² , R ³ , R ⁴ and R ⁵ , and the preferred ranges are also the same.

In the first embodiment of the manufacturing method, the compound represented by the general formula (2) may be a commercially available product as is, or may be synthesized by alkylating commercially available 4-aminopiperidine by a publicly known method.

In the manufacturing method 1, a commercially available compound represented by general formula (3) can be used.

In the reaction of the manufacturing method 1, the amount of the compound represented by the general formula (3) relative to the compound represented by the general formula (2) is preferably 2 to 100 moles, and more preferably 2 to 10 moles, relative to 1 mole of the compound represented by the general formula (2) in terms of excellent reaction yield.

In the reaction of Production Method 1, it is preferable to react the compound represented by General Formula (2) with the compound represented by General Formula (3) in a solvent. There are no limitations on the solvent as long as it does not inhibit the reaction, and examples of the solvent include aromatic hydrocarbon solvents, ether solvents, ester solvents, halogen solvents, amide solvents, urea solvents, ketone solvents, nitrile solvents, sulfoxide solvents, alcohol solvents, and water.

Specific examples of these solvents include toluene and xylene as aromatic hydrocarbon solvents, tetrahydrofuran, 1,2-dimethoxyethane, and 1,4-dioxane as ether solvents, ethyl acetate or butyl acetate as ester solvents, chloroform, carbon tetrachloride, and chlorobenzene as halogen solvents, N,N-dimethylformamide or N,N-dimethylacetamide as amide solvents, 1,3-dimethyl-2-imidazolidinone or 1,3-dimethyl-3,4,5,6-tetrahydropyrimidin-2(1H)-one as urea solvents, acetone or methyl ethyl ketone as ketone solvents, acetonitrile, propionitrile, and benzonitrile as nitrile solvents, dimethyl sulfoxide as sulfoxide solvent, and methanol, ethanol, and propanol as alcohol solvents.

The solvent is preferably at least one selected from the group consisting of halogen-based solvents and alcohol-based solvents, and more preferably at least one selected from the group consisting of dichloromethane, ethanol, and methanol.

In the manufacturing method 1, the reaction temperature is preferably any temperature between 0°C and 200°C, more preferably between 20°C and 80°C. The reaction time is preferably between 1 hour and 100 hours.

In addition to the reaction step, Production Method 1 may include a step of isolating the 4-ammoniopiperidinium salt represented by general formula (1a) obtained in the reaction step (hereinafter also referred to as the "isolation step"), and may further include a step of ion-exchanging the 4-ammoniopiperidinium salt isolated in the isolation step (hereinafter also referred to as the "ion exchange step"), if necessary.

In the isolation step, any isolation method can be used as long as the 4-ammoniopiperidinium salt (1a) can be isolated from the reaction mixture. As the isolation method, any purification method commonly used by those skilled in the art can be applied, and examples of the isolation method include, but are not limited to, solvent extraction, column chromatography, preparative thin layer chromatography, preparative liquid chromatography, and recrystallization.

The ion exchange step is a step of ion-exchanging the 4-ammoniopiperidinium salt (1a) isolated in the isolation step. The ion exchange step can produce a 4-ammoniopiperidinium salt represented by general formula (1b).

(In the formula, R ⁸ , R ⁹ and R ¹⁰ are defined as R ⁸ , R ⁹ and R ¹⁰ in general formula (1a), and Yb ⁻ represents a halide ion or a hydroxide ion.)

The ion exchange method can be a general method used by those skilled in the art for ion exchange of quaternary ammonium salts, for example, by contacting 4-ammoniopiperidinium salt (1a) with an ion exchange resin. The ion exchange resin may be any ion exchange resin having an exchange group ^Yb- , for example, Diaion SA10A, Diaion SA12A, or Diaion SA11A, and preferably Diaion SA10A.

The ion exchange may be carried out in a solvent that does not inhibit the ion exchange. The solvent may be one or more selected from the group consisting of ether solvents, ester solvents, ketone solvents, nitrile solvents, alcohol solvents, and water. Specific examples of the solvents are the same as those exemplified in the explanation of Production Method 1 above.

<Method for producing 4-dialkylaminopiperidine represented by formula (2)>
An example of an embodiment of the method for producing 4-dialkylaminopiperidine (2) to be subjected to Production Method 1 includes a method for producing 4-dialkylaminopiperidine (2) (hereinafter also referred to as "Starting Material Production Method 1"), which is characterized by having a step of reacting 4-aminopiperidine represented by general formula (4), a reducing agent, and one or more compounds selected from carbonyl compounds represented by general formula (5).

(In the formula, R ⁹ has the same meaning as R ⁹ in general formula (2), and the preferred range is also the same.)

(In the formula, X may be the same or different and represents a hydrogen atom, a methyl group, an ethyl group, or a linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms.)

The linear, branched, or cyclic alkyl group having 3 to 4 carbon atoms is not particularly limited, and examples thereof include the same linear, branched, or cyclic alkyl groups having 3 to 4 carbon atoms as exemplified in the explanation of R ¹ , R ² , R ³ , R ⁴ , and R ^5. Each X is preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom.

The reducing agent is not particularly limited as long as it can reduce the iminium cation compound, which is the intermediate product of Raw Material Production Method 1. For example, formic acid, ammonium formate, sodium triacetoxyborohydride, pyridine borane, 2-picoline borane, or 5-ethyl-2-methylpyridine borane can be used.

In the raw material preparation method 1, the amount of reducing agent added relative to 4-aminopiperidine (4) is preferably 2 to 50 molar equivalents, and more preferably 4 to 10 molar equivalents.

In the raw material preparation method 1, the amount of carbonyl compound (5) added relative to 4-aminopiperidine (4) is preferably 2 to 50 molar equivalents, and more preferably 4 to 10 molar equivalents.

In the raw material preparation method 1, 4-aminopiperidine (4), a reducing agent, and a carbonyl compound (5) are reacted in a solvent. The solvent may be any solvent that does not inhibit the reaction, and examples of the solvent include aromatic hydrocarbon solvents such as benzene, toluene, and xylene, ether solvents such as tetrahydrofuran, diethyl ether, and diisopropyl ether, and alcohol solvents such as methanol, ethanol, and isopropyl alcohol, and water. Preferred examples of the solvent include alcohol solvents and water, and more preferred examples of the solvent include methanol and water.

In the raw material production method 1, the preferred reaction temperature is any temperature between 20°C and 150°C, the more preferred reaction temperature is between 40°C and 120°C, and the preferred reaction time is between 1 hour and 100 hours.

In addition, in the raw material production method 1, a catalyst for promoting the reaction may be added. The catalyst is not particularly limited, but examples thereof include a ruthenium complex, a rhodium complex, and an iridium complex.

The starting material production method 1 may include a step of isolating the 4-aminopiperidine (4) obtained by the above reaction.
The isolation method and other conditions may be the same as those in the isolation step of Production Method 1.

<Method of manufacturing small pore zeolite>
The 4-ammoniopiperidinium salt (1) of this embodiment can be used for known applications of ammonium salts, but can also be used as at least one of a ligand for a transition metal catalyst and an organic structure directing agent (hereinafter also referred to as "SDA") for the production of zeolites, and further as an SDA for the production of zeolites. The 4-ammoniopiperidinium salt (1) of this embodiment can be used particularly as an SDA for the production of small pore zeolites, and further as an SDA for directing CHA-type zeolites.

The method for producing zeolite in this embodiment is characterized by having a crystallization step of crystallizing a composition containing an organic structure directing agent source including a 4-ammoniopiperidinium salt represented by general formula (1), a silica source, an alumina source, an alkali source, and water.

Below, we will explain the method for producing zeolite using the 4-ammoniopiperidinium salt (1) of this embodiment as an SDA, taking as an example the method for producing CHA-type zeolite, which is a small pore zeolite.

The method for producing CHA-type zeolite in this embodiment is characterized by having a crystallization step of crystallizing a composition (hereinafter also referred to as the "raw material composition") that contains an organic structure directing agent source containing 4-ammoniopiperidinium salt represented by general formula (1), a silica source, an alumina source, an alkali source, and water.

An "aluminosilicate" is a complex oxide with a structure consisting of a repeating network of aluminum (Al) and silicon (Si) via oxygen (O). Among aluminosilicates, those that have a crystalline XRD peak in their powder X-ray diffraction (hereinafter also referred to as "XRD") pattern are "crystalline aluminosilicates", and those that do not have a crystalline XRD peak are "amorphous aluminosilicates".

In this embodiment, the XRD pattern is measured using CuKα radiation as a radiation source, and the measurement conditions include the following conditions.
Radiation source: CuKα radiation (λ=1.5406Å)
Measurement mode: Step scan Scan speed: 4.0° per minute
Measurement range: 2θ=3.0° to 50.0°

A crystalline XRD peak is a peak that is detected by identifying the 2θ of the peak top in the analysis of an XRD pattern using general analysis software (e.g., SmartLab Studio II, manufactured by Rigaku Corporation). Although not particularly limited, the half-width (full width at half maximum) of the XRD peak can be, for example, 2θ = 0.50° or less.

"Zeolite" is a compound in which the skeleton atoms (hereinafter also referred to as "T atoms") have a regular structure with oxygen (O) interposed therebetween, and the T atoms are metal atoms. Zeolite may contain two or more metal atoms as T atoms. In this embodiment, the concept of metal atoms includes both atoms of metal elements and atoms of metalloid elements.

A "zeolite-like substance" is a compound having a regular structure in which T atoms are oxygen-mediated, and which contains at least an atom other than a metal (hereinafter also referred to as a "non-metal atom") as the T atom. As an example, a zeolite-like substance contains a metal atom and a non-metal atom as the T atom. Specific examples of zeolite-like substances include complex phosphorus compounds containing phosphorus (P) as the T atom, such as aluminophosphate (AlPO) and silicoaluminophosphate (SAPO). The zeolite in this embodiment preferably does not contain phosphorus as a T atom, and more preferably does not contain phosphorus.

The "regular structure" (hereinafter also referred to as "zeolite structure") in zeolites and zeolite-like substances is a skeletal structure specified by a structure code (hereinafter also referred to as "structure code") defined by the Structure Commission of the International Zeolite Association. For example, the CHA structure is specified by the structure code "CHA", and the FAU structure is specified by the structure code "FAU". The zeolite structure can be identified by comparing with the XRD pattern (hereinafter also referred to as "reference pattern") of each structure described in Collection of Simulated XRD Powder Patterns for Zeolites, Fifth Revised Edition (2007). With respect to zeolite structure, the framework structure, crystal structure, and crystal phase are used synonymously.

An "analogous structure" is a structure formed by linking structural units (building units) contained in a zeolite structure, and is a structure that cannot be identified as a zeolite structure when compared with a reference pattern.

In this embodiment, "type zeolite", such as "CHA type zeolite" or "FAU type zeolite", means a zeolite having a zeolite structure of the corresponding structure code, and preferably means a crystalline aluminosilicate having a zeolite structure of the corresponding structure code.

The silica source is silica (SiO ₂ ) or a silicon compound that is a precursor thereof, and examples thereof include one or more selected from the group consisting of colloidal silica, amorphous silica, sodium silicate, tetraethyl orthosilicate, precipitated silica, fumed silica, crystalline aluminosilicate, and aluminosilicate gel, and is preferably at least one of crystalline aluminosilicate, aluminosilicate gel, and sodium silicate.

The alumina source is alumina (Al ₂ O ₃ ) or an aluminum compound that is a precursor thereof, and examples thereof include one or more selected from the group consisting of aluminum sulfate, sodium aluminate, aluminum hydroxide, aluminum chloride, aluminosilicate gel, crystalline aluminosilicate, and metallic aluminum, and is preferably at least one of crystalline aluminosilicate and aluminosilicate gel.

The organic structure directing agent source contains a 4-ammoniopiperidinium salt represented by the general formula (1). The 4-aminopiperidinium cation contained in the 4-ammoniopiperidinium salt functions as an SDA that directs the small pore zeolite. The anion contained in the 4-ammoniopiperidinium salt is preferably at least one selected from the group consisting of chloride ions, bromide ions, iodide ions, and hydroxide ions, at least one selected from the group consisting of bromide ions, iodide ions, and hydroxide ions, or at least one selected from the group consisting of iodide ions and hydroxide ions.

The organic structure directing agent source may contain a known SDA or other ammonium salt that directs CHA-type zeolite. For example, known SDAs that direct CHA-type zeolite include one or more selected from the group consisting of trialkyladamantan ammonium cation, trialkylcyclohexyl ammonium cation, and quinuclidine cation.

The alkali source may be a compound containing an alkali metal element, and may be at least one of an alkali metal hydroxide and an alkali metal halide. The alkali metal is preferably at least one selected from the group consisting of sodium, potassium, rubidium, and cesium, at least one of sodium and potassium, sodium and potassium, or sodium.

In this embodiment, the raw material composition preferably has any combination of the following compositions.
_SiO2 / _Al2O3 : 5 or more, or 10 or more _and
OH/SiO ₂ : 0.10 or more, 0.20 or more, or 0.30 or more; and
M/ _SiO2 : 0.06 or more, 0.10 or more, or 0.15 or more; and
SDA/SiO ₂ : 0.01 or more, 0.02 or more, or 0.03 or more, and
2.0 or less, 0.50 or less, or 0.30 or less; H ₂ O/SiO ₂ : 5 or more, 8 or more, or 10 or more; and
60 or less, 40 or less, or 30 or less

In the above composition, _SiO2 / _Al2O3 is the molar ratio of silica to alumina in the raw material composition, and OH/ _SiO2 , _M / _SiO2 , SDA/ _SiO2 and _H2O / _SiO2 are the molar ratios of hydroxide ions, alkali metal, SDA or water to silica in the raw material composition, respectively. M is an alkali metal, and when the alkali metal is sodium or when the alkali metals are sodium and potassium, M/ _SiO2 is Na/ _SiO2 or (Na+K)/ _SiO2 , respectively.

In the present embodiment, the raw material composition may contain seed crystals. When the raw material composition contains seed crystals, the content of the seed crystals in the raw material composition is, for example, 0 mass% or more, 0.5 mass% or more, and 10.0 mass% or less, 5.0 mass% or less, or 3.5 mass% or less, expressed as a mass ratio of silicon in the seed crystals converted into silica (SiO ₂ ) relative to the mass of silicon in the raw material composition (not including the seed crystals) converted into silica (SiO 2 ).

The seed crystals may be any zeolite that does not contain odd-numbered rings in the crystal structure, and are preferably zeolite having a structure selected from the group consisting of FAU, CHA, AEI, LEV, AFX, ERI, OFF, LTL, and GME, more preferably zeolite having a structure selected from the group consisting of CHA, AEI, LEV, AFX, and ERI, and even more preferably CHA-type zeolite.

In the present embodiment, the raw material composition is crystallized in the crystallization step, and the raw material composition may be crystallized by hydrothermal treatment. The hydrothermal treatment may be performed by placing the raw material composition in a sealed pressure-resistant container and heating it. The hydrothermal treatment conditions may include the following.
Treatment temperature: 80°C or higher or 140°C or higher and 190°C or lower or 180°C or lower Treatment time: 2 hours or more and 500 hours or less Treatment pressure: Autogenous pressure

The state of the raw material composition during crystallization is arbitrary, and may be either static or stirred, but stirring is preferred.

The zeolite production method of this embodiment may include post-treatment steps such as a washing step, a drying step, an SDA removal step, or an ammonium treatment step.

In the washing step, the zeolite is washed. Any washing method can be used, but an example is to bring the zeolite into contact with a sufficient amount of pure water.

The drying process removes moisture from the zeolite. Any drying method can be used, but an example is treating the zeolite in air at 100°C or higher and 150°C or lower for 2 hours or more.

The SDA removal process removes any SDA remaining in the zeolite. One method for removing SDA is to treat it in air at 400°C to 700°C for 1 to 2 hours.

The ammonium treatment step removes alkali metals from the zeolite and changes the cation type to ammonium type (hereinafter referred to as "NH ₄ ⁺ type"). The ammonium treatment method includes contacting the zeolite with an aqueous solution containing ammonium ions. The NH ₄ ⁺ type zeolite may be heat-treated to change the cation type to proton type (hereinafter referred to as "H ⁺ type"). Specific heat treatment conditions include, for example, in air at 500°C for 1 to 2 hours.

The zeolite obtained by the manufacturing method of this embodiment (hereinafter also referred to as "the zeolite of this embodiment") may be any type, but is preferably a small pore zeolite.

An example of the zeolite of this embodiment is CHA-type zeolite. CHA-type zeolite has a _SiO2 / _Al2O3 ratio of 5 _or more or 8 or more and 50 or less, 30 or less, or 15 or less, and an average crystal grain size of 0.05 μm or more or 0.1 μm or more and 0.8 μm or less, 0.5 μm or less, or 0.35 μm or less.

The zeolite obtained by the zeolite manufacturing method of this embodiment can be used in known zeolite applications, such as an adsorbent, catalyst, adsorbent carrier, or catalyst carrier. It can also be used as a nitrogen oxide reduction catalyst, an SCR catalyst, or a carrier for these.

Next, examples of the present embodiment will be described, but the present embodiment is not limited to these.
(H ¹ -NMR and C ¹³ -NMR)
The H ¹ -NMR and C ¹³ -NMR spectra of the samples were measured using a JEOL ECZ400 (400 MHz, manufactured by JEOL Ltd.). The H ¹ -NMR spectra of the samples were measured using deuterated chloroform (CDCl ₃ ) or heavy water (D ₂ O) as the measurement solvent and tetramethylsilane (TMS) as the internal standard. The measurement data are listed in the order of chemical shift, multiplicity, coupling constant (Hz), and integral value.

(Powder X-ray Diffraction)
The XRD of the sample was measured using a general X-ray diffraction device (device name: Ultima IV, manufactured by RIGAKU Corporation). The measurement conditions were as follows.
Radiation source: CuKα radiation (λ=1.5405Å)
Measurement mode: Step scan
Scan width: 0.02°
Divergence slit: 1.00 deg
Scattering slit: open
Receiving slit: Open
Measurement time: 1.0 min
Measurement range: 2θ=3.0° to 43.0°
The zeolite structure of the sample was identified by comparing the XRD pattern obtained from the sample with a reference pattern.
(Composition analysis, quantitative determination of silicon and aluminum)
A typical inductively coupled plasma emission spectrometer (OPTIMA3300DV, manufactured by PERKIN ELMER) was used to perform composition analysis of the samples. The samples were dissolved in a mixed solution of hydrofluoric acid and nitric acid to prepare a measurement solution. The obtained measurement solution was put into the device to analyze the composition of the samples. _SiO2 / _Al2O3 was calculated from the obtained _molar concentrations of silicon (Si) and aluminum (Al).

Synthesis example 1

Formaldehyde (38% aqueous solution, 45 g, 0.55 mol) was ice-cooled to 0°C, 1-methyl-4-aminopiperidine (Tokyo Chemical Industry Co., Ltd., 25 g, 0.22 mol) was added dropwise over 30 minutes, and formic acid (98% aqueous solution, 55 g, 1.2 mol) was added dropwise over 30 minutes. After the addition, the temperature was raised to 60°C and the mixture was stirred for 24 hours. During this time, carbon dioxide foaming was observed. The resulting reaction solution was cooled using an ice bath, and then 2.0 M hydrochloric acid (250 g, 0.50 mol) was added dropwise over 30 minutes. After that, excess formic acid and formaldehyde were removed by steam distillation. 50 g of pure water was added to the remaining pale orange solid to dissolve it, and the mixture was cooled using an ice bath. A 48% aqueous NaOH solution was added until the pH of the aqueous solution reached 11. After extraction with tetrahydrofuran and ethyl acetate, anhydrous sodium sulfate was added to the extract, which was then stirred and the solids were filtered off to obtain a liquid composition. Tetrahydrofuran and ethyl acetate were removed from the liquid composition using a rotary evaporator, and the remaining pale yellow oil was distilled under reduced pressure to obtain 1-methyl-4-dimethylaminopiperidine as a colorless, transparent oil (24.8 g, yield 79%).

NMR spectrum of 1,1-dimethyl-4-trimethylammoniopiperidinium diiodide: ^1H -NMR (400 MHz, _D2O , 20°C): δ 2.59 (brd, J = 12.0 Hz, 2H), 1.94 (m, 1H), 1.93 (s, 6H), 1.91 (s, 3H), 1.74 (brt, J = 12.0 Hz, 2H), 1.58 (brd, J = 12.0 Hz, 2H), 1.13 (ddd, J = 12.0 Hz, J = 12.0 Hz, J = 2.8 Hz, 2H). ¹³ C{ ¹ H}-NMR (100 MHz, D ₂ O): δ60.65 (1C), 53.81 (2C), 44.44 (1C), 40.29 (2C), 26.97 (2C).

(Synthesis of 4-ammoniopiperidinium salt)
Example 1-1

An ethanol solution (200 mL) of 1-methyl-4-dimethylaminopiperidine (24.8 g, 0.174 mol) obtained in Synthesis Example 1 was ice-cooled to 0°C, and iodomethane (150 g, 1.05 mol) was added dropwise over 30 minutes. After the addition, the temperature was raised to 50°C and stirred for 24 hours. The resulting reaction solution was then cooled using an ice bath, and the white solid precipitated in the reaction solution was filtered off. The filtered product was washed with ethanol to obtain 1,1-dimethyl-4-trimethylammoniopiperidinium diiodide (66.4 g, yield 89.5%) in the form of a white solid.

NMR spectrum of 1,1-dimethyl-4-trimethylammoniopiperidinium diiodide: ^1H -NMR (400 MHz, _D2O , 20°C): δ 3.87 (tt, J = 12.4 Hz, J = 3.6 Hz, 1H), 3.80 (ddd, J = 12.8 Hz, J = 2.4 Hz, J = 2.4 Hz, 2H), 3.59 (ddd, J = 13.2 Hz, J = 13.2 Hz, J = 2.4 Hz, 2H), 3.30 (s, 3H), 3.25 (s, 3H), 3.24 (s, 9H), 2.51 (m, 2H), 2.36 (m, 2H). ¹³ C{ ¹ H}-NMR (100 MHz, D ₂ O, 20° C.): δ68.21 (1 C), 60.98 (2 C), 56.38 (1 C), 51.83 (3 C), 47.88 (1 C), 20.96 (2 C).

Example 1-2

An anion exchange resin (Mitsubishi Chemical Corporation, Diaion (registered trademark) SA10A, OH-type, 400 cm 3 ) was added to an aqueous solution (100 mL) of 1,1-dimethyl ^{- 4} -trimethylammoniopiperidinium diiodide (25 g, 58.7 mmol) obtained in Example 1-1 above, and the mixture was allowed to stand for 12 hours. After separating the anion exchange resin by filtration, the aqueous solution was concentrated with a rotary evaporator until the total weight of the aqueous solution became 50 g, thereby obtaining 1,1-dimethyl-4-trimethylammoniopiperidinium dihydroxide as a 24% aqueous solution (yield 96%).

NMR spectrum of 1,1-dimethyl-4-trimethylammoniopiperidinium dihydroxide: ¹³ C{ ¹ H}-NMR (100 MHz, H ₂ O, 20° C.): δ 68.25 (1C), 60.82 (2C), 56.15 (1C), 51.36 (3C), 47.29 (1C), 20.63 (2C).

(Synthesis of CHA-type zeolite)
Example 2-1
1,1-Dimethyl-4-trimethylammoniopiperidinium dihydroxide (hereinafter also referred to as "DMTMAPOH") obtained in Example 1-2, zeolite Y ( _SiO2 / _Al2O3 =11), 29% sodium silicate, 48% sodium hydroxide and water were mixed to obtain a raw material composition having _the following molar composition.

SiO ₂ /Al ₂ O ₃ = 14.7
SDA/ _SiO2 = 0.125
Na/ _SiO2 = 0.35
OH/ _SiO2 = 0.60
_H2O / _SiO2 = 10
CHA type zeolite was added to the raw material composition so that the seed crystal content was 2.0 mass%, and thoroughly mixed and stirred. After mixing and stirring, the raw material composition was sealed in a stainless steel autoclave, and the autoclave was heated at 140°C for 84 hours while rotating to obtain a product. The obtained product was filtered, washed, and dried overnight at 110°C in air to obtain the zeolite of this example. _The zeolite of this example was a single phase CHA type zeolite, with _SiO2 / _Al2O3 of 10.2, Na/Al of 0.22, and an average crystal grain size of 0.18 μm.

Example 2-2
The zeolite of this example was obtained in the same manner as in Example 2-1, except that a raw material composition having the following molar composition was obtained.

SiO ₂ /Al ₂ O ₃ = 16.3
SDA/ _SiO2 = 0.125
Na/ _SiO2 = 0.35
OH/ _SiO2 = 0.60
_H2O / _SiO2 = 10
The zeolite of this example was a single phase CHA type zeolite, with a SiO ₂ /Al ₂ O ₃ ratio of 11.3, a Na/Al ratio of 0.16, and an average crystal grain size of 0.13 μm.

Example 2-3
The zeolite of this example was obtained in the same manner as in Example 2-1, except that a raw material composition having the following molar composition was used by mixing the DMTMAPOH obtained in Example 1-2, 48% sodium hydroxide, zeolite Y, and water.

SiO ₂ /Al ₂ O ₃ = 14.4
OH/ _SiO2 = 0.55
Na/ _SiO2 = 0.35
SDA/ _SiO2 = 0.10
_H2O / _SiO2 = 10
The zeolite of this example was a single phase CHA type zeolite, with SiO ₂ /Al ₂ O ₃ of 10.0, Na/Al of 0.28, and an average particle size of 0.24 μm.

The XRD pattern of the CHA-type zeolite of this example is shown in Figure 1, and the SEM image is shown in Figure 2.

Example 2-4
The zeolite of this example was obtained in the same manner as in Example 2-1, except that the DMTMAPOH obtained in Example 1-2, zeolite Y (SiO ₂ /Al ₂ O ₃ = 11, 48% sodium hydroxide, and water were mixed to obtain a raw material composition having the following molar composition.

SiO ₂ /Al ₂ O ₃ = 11.1
SDA/ _SiO2 = 0.1
Na/ _SiO2 = 0.3
OH/ _SiO2 = 0.5
_H2O / _SiO2 = 10
The zeolite of this example contained a trace amount of impurities but was a CHA type zeolite, had a SiO ₂ /Al ₂ O ₃ ratio of 9.1, a Na/Al ratio of 0.42, and an average particle size of 0.30 μm.

Example 2-5
The zeolite of this example was obtained in the same manner as in Example 2-1, except that the DMTMAPOH obtained in Example 1-2, zeolite Y (SiO ₂ /Al ₂ O ₃ = 11, 48% sodium hydroxide, and water were mixed to obtain a raw material composition having the following molar composition.

SiO ₂ /Al ₂ O ₃ = 11.1
SDA/ _SiO2 = 0.15
Na/ _SiO2 = 0.3
OH/ _SiO2 = 0.6
_H2O / _SiO2 = 10
The zeolite of this example was a single phase CHA type zeolite, with SiO ₂ /Al ₂ O ₃ of 10.2, Na/Al of 0.40, and an average particle size of 0.34 μm.

Claims (4)

A 4-ammoniopiperidinium salt represented by the general formula (1):
(In the formula, R ¹ , R ² , R ³ , R ⁴ , and R ⁵ represent methyl groups . Note that R ¹ , R ² , and R ³ are not mutually bonded. Y ^- represents OH ^- (hydroxide ion) .) A method for producing a small pore zeolite, comprising: a crystallization step of crystallizing a composition comprising a source of an organic structure directing agent containing the 4- ammoniopiperidinium salt according to any one of claims 1, a silica source, an alumina source, an alkali source, and water. 3. The method for producing a small pore zeolite according to claim 2, wherein the small pore zeolite is a CHA type zeolite. The SiO of the CHA type zeolite ₂ /Al ₂ O ₃ The method for producing a small pore zeolite according to claim 3, wherein the ratio is 5 or more and 50 or less.