JPH0768255B2 - Method for producing silyl unsaturated carboxylate - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a silyl unsaturated carboxylate. More specifically, it relates to a method for producing a silyl unsaturated carboxylate with a high yield by reacting an unsaturated carboxylic acid with hydrosilane.

[Technical background of the invention and its problems]

As a method for producing a silyl unsaturated carboxylate, a method of reacting a metal salt of an unsaturated carboxylic acid with chlorosilane is known (DNAndreev. Et al. CA No. 55 1533).
2). However, this reaction has a drawback that the reaction yield is low, chlorosilane remains, and the purity of the target product is lowered.

There is also a method in which an unsaturated carboxylic acid and chlorosilane are reacted in the presence of a hydrochloric acid scavenger such as triethylamine to obtain the desired product. However, in this reaction, the by-produced hydrochloride must be removed, the process becomes complicated, and the target product is adsorbed to hydrochloric acid during the filtration process, resulting in a significant decrease in yield. When it is purified by distillation, there is a drawback that the hydrochloride is easily sublimated and distilled, and the purity of the target product is lowered.

On the other hand, a method for producing a silylcarboxylate by reacting a carboxylic acid and hydrosilane in the presence of Pd, Ni, Rh catalyst is known (LHSommer, JELyons, J.Am.Chem.S.
oc., 91 7061 (1969)).

However, when this reaction is carried out using an unsaturated carboxylic acid, a large amount of saturated carboxylic acid silyl ester is simultaneously produced.
Especially when the Rh catalyst is used, an addition reaction to the carboxy group also occurs. On the other hand, when a Pt catalyst is used as the catalyst, an addition reaction of the unsaturated carboxylic acid to the double bond also occurs. Especially when the unsaturated carboxylic acid is (meth) acrylic acid, since the boiling points of these by-products are close to the boiling point of the target product,
Purification by distillation was difficult, and it was difficult to obtain high-purity silyl (meth) acrylate.

In view of such drawbacks of the prior art, the present inventors have proposed a method of reacting an unsaturated carboxylic acid and hydrosilane in the presence of a palladium catalyst and an aprotic polar solvent (patent dated on the same date as this application). Wish (1)). According to this method, a silyl unsaturated carboxylate can be efficiently obtained with high purity without a reduction reaction of the unsaturated group of the unsaturated carboxylic acid. However, since the aprotic polar solvent is intrinsically extremely hygroscopic, when it is used as the main solvent, the corresponding silanol and its hydrolyzate are likely to be produced, and it is necessary to strictly control the water content. .

[Object of the Invention]

The present invention, without the production of undesired by-products,
It is intended to provide a method for producing a silyl unsaturated carboxylate with high yield.

[Structure of Invention]

As a result of earnest studies to achieve such an object, the present inventors have found that when an unsaturated carboxylic acid and hydrosilane are reacted in the presence of a palladium catalyst and a ligand, the unsaturated group of the unsaturated carboxylic acid is reacted. The present inventors have found that a silyl unsaturated carboxylate can be produced with high purity and high yield without involving the reduction reaction of 1.

That is, the present invention has the general formula (Wherein R ¹ , R ² , and R ³ represent a hydrogen atom, a halogen atom, or a substituted or unsubstituted monovalent hydrocarbon group), and an unsaturated carboxylic acid represented by the general formula (Wherein R ⁴ , R ⁵ , and R ⁶ represent an alkoxy group or a substituted or unsubstituted monovalent hydrocarbon group), and react with hydrosilane in the presence of a palladium catalyst and a ligand. The general formula, characterized by (In the formula, R ^{1 to} R ⁶ are as described above) The present invention relates to a method for producing a silyl unsaturated carboxylate.

In the unsaturated carboxylic acid (1) used in the present invention,
R ¹ , R ² and R ³ represent a hydrogen atom, a halogen atom or a substituted or unsubstituted monovalent hydrocarbon group. For example, R ¹ is a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group or a dodecyl group; a cyclopentyl group, Cycloalkyl group such as cyclohexyl group; aralkyl group such as 2-phenylethyl group and 2-phenylpropyl group; aryl group such as phenyl group and tolyl group; carboxyl group and carbon atom of these monovalent hydrocarbon groups Chloromethyl group, chlorophenyl group, 3,3,3 in which the hydrogen atom bonded to is partially substituted with halogen atom, amino group, cyano group, alkoxy group, hydroxyl group, etc.
Substituted hydrocarbon groups such as -trifluoropropyl group, aminoethyl group, cyanoethyl group, 0-methoxyphenyl group, 0-hydroxyphenyl group are exemplified.

Among these, because of easy availability of raw materials and synthesis,
A hydrogen atom, an alkyl group, an aralkyl group and an aryl group are preferable, and a hydrogen atom and an alkyl group are particularly preferable. Examples of R ² are the same substituents and hydrogen atoms as R ¹ , hydrogen atoms, alkyl groups, aralkyl groups and aryl groups are also preferable, and hydrogen atoms and alkyl groups are particularly preferable. Examples of R ³ are the same substituents and hydrogen atoms as those of R ¹ , hydrogen atoms, alkyl groups, aralkyl groups and aryl groups are also preferable, and hydrogen atoms and alkyl groups are particularly preferable.

Such unsaturated carboxylic acids include acrylic acid, methacrylic acid, 2-ethylacrylic acid, crotonic acid, isocrotonic acid, 2-ethylcrotonic acid, angelic acid, 2
-Chloroacrylic acid, 3-chloroacrylic acid, cinnamic acid, α-methylcinnamic acid, β-methylcinnamic acid, o-methoxycinnamic acid, maleic acid, fumaric acid, etc. are exemplified, but they are also available. Acrylic acid and methacrylic acid are preferred because they are easily produced.

In the hydrosilane (2) used in the present invention, R ⁴ , R ⁵ and R ⁶ represent an alkoxy group or a substituted or unsubstituted monovalent hydrocarbon group. For example, R ⁴ is an alkoxy group such as methoxy group, ethoxy group, butoxy group, phenoxy group; methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group. Group, alkyl group such as dodecyl group; cycloalkyl group such as cyclopentyl group and cyclohexyl group; aralkyl group such as 2-phenylethyl group and 2-phenylpropyl group; aryl group such as phenyl group and tolyl group, and A chloromethyl group, a chlorophenyl group, 3,3,3-, in which a hydrogen atom bonded to a carbon atom of these monovalent hydrocarbon groups is partially substituted with a halogen atom, an amino group, a cyano group, an alkoxy group, a hydroxyl group or the like. Trifluoropropyl group, aminoethyl group, cyanoethyl group, o
Substituted hydrocarbon groups such as -methoxyphenyl group and o-hydroxyphenyl group are exemplified. Among these, an alkyl group and an aryl group are preferable, and a methyl group, an ethyl group, a butyl group, and a phenyl group are particularly preferable because the raw materials are easily available and can be synthesized. Examples of R ⁵ include the same substituents as R ^4, and similarly, an alkyl group and an aryl group are preferable, and a methyl group, an ethyl group, a butyl group and a phenyl group are particularly preferable. Examples of R ⁶ include the same substituents as R ^4, and similarly, an alkyl group and an aryl group are preferable, and a methyl group, an ethyl group, a butyl group and a phenyl group are particularly preferable.

Such hydrosilanes include trimethylsilane, triethylsilane, tributylsilane, triphenylsilane, methyldiethylsilane, dimethylethylsilane, methyldibutylsilane, dimethylbutylsilane, ethyldibutylsilane, diethylbutylsilane, methyldiphenylsilane, dimethyl. Examples include phenylsilane, ethyldiphenylsilane, diethylphenylsilane, butyldiphenylsilane, dibutylphenylsilane, methylethylbutylsilane, methylethylphenylsilane, methylbutylphenylsilane, ethylbutylphenylsilane, methyldiethoxysilane, and dimethylethoxysilane. However, among these, trimethylsilane, triethylsilane, tributylsilane, and triphenesilane are easy to obtain and to synthesize. Rushiran is preferable.

Examples of the palladium catalyst used in the present invention include coordination compounds of palladium metal, palladium metal powder, palladium metal supported on carbon and palladium salts, and the palladium in the coordination compound has any valence. May be. These catalysts include PdCl ₂ ,
Examples include homogeneous catalysts such as PdCl ₂ (PPh ₃ ) ₂ , Pd (OCOCH ₃ ) ₂ and PdCl ₂ (PhCN) ₂ and heterogeneous catalysts such as Pd-C. Among these, recovery is also possible. Pd-C is preferable because it can be regenerated.

The amount of the palladium catalyst used is not particularly limited and can be changed in consideration of the type of raw material, reaction, temperature, reaction time, etc., but from the viewpoint of reactivity and economy, it is 100 to 300 ppm relative to hydrosilane. Is preferred.

The ligand used in the present invention generally includes a ligand capable of forming a complex compound with a transition metal or the like, and examples thereof include an alkylphosphine such as tributylphosphine and an arylphosphine such as triphenylphosphine. Examples of the phosphine compound, benzonitrile, octadiene, and the like are preferable, and among these, a phosphine compound is preferable, and triphenylphosphine is particularly preferable, because it exhibits a relatively excellent effect. The amount of the ligand used is not particularly limited and can be changed depending on the type of the ligand, the type of the palladium catalyst and the like, but from the viewpoint of effect and economy, 0.5 to 1.5 equivalents relative to the palladium atom are preferable.

In the present invention, it is preferable to use an aprotic polar solvent, and by combining with the above-mentioned palladium catalyst, excellent effects are exhibited. As the aprotic polar solvent, dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), hexamethylphosphoramide (HMP
A), nitromethane, N-methylpyrrolidone, acetonitrile, acetone and the like are exemplified, and some of them may be mixed and used. Among these, N, N-dimethylformamide, dimethylsulfoxide, and hexamethylphosphoramide are preferable because they exhibit excellent effects.

In order to control the reaction temperature and dissolve the raw materials, it is possible to use another solvent in combination as a reaction solvent. Examples of such a solvent include benzene, toluene, xylene, n-hexane and cyclohexane. The reaction solvent preferably contains 1% by weight or more of an aprotic polar solvent, and particularly preferably 10% by weight or more.

The reaction temperature is in the range of 40 to 160 ° C, preferably 80 to 120 ° C. Within this temperature range, the unsaturated carboxylic acid is preferably equivalent equivalent (mol) or more and 2 times equivalent (mol) or less, more preferably 1.3 times equivalent (mol) or more and 1.8 times equivalent (mol) or less with respect to the hydrosilane. By the reaction, the generation of by-products can be suppressed and the desired product can be produced in good yield. From the reaction product, a highly pure target product can be obtained by a conventional purification method such as distillation.

Further, in the production method of the present invention, a polymerization inhibitor such as oxygen, hydroquinone, or P-methoxyphenol is added in order to prevent the polymerization of the unsaturated carboxylic acid as a raw material or the unsaturated carboxylate of the product. Is preferred.

〔The invention's effect〕

According to the production method of the present invention, the desired silyl unsaturated carboxylate can be produced without generating an undesirable by-product such as HCl. In addition, the step of filtering the by-product is not necessary, the process is simplified, and when a heterogeneous catalyst is used, it can be recovered and regenerated, and a catalyst with a high yield can be used. Also, instead of chlorosilane, which is highly hydrolyzable, it is possible to use hydridosilane, which reduces the influence of water,
Since the raw materials can be easily handled and the reaction process can be easily controlled, and the generation of silanol and its hydrolyzate derived from the raw material silane can be suppressed, the desired product can be produced in good yield.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the examples,% means% by weight.

Example 1 A flask equipped with a thermometer and a reflux condenser was charged with toluene.
700 g, N, N-dimethylformamide (DMF) 170 g, Pd-C catalyst 40 g containing 0.5% by weight of palladium, and triphenylphosphine 0.5 g were added and heated to 110 ° C. with stirring. Then 560 g of methacrylic acid and 1000 of tributylsilane
g, a mixture of 2 g of P-methoxyphenol was added. During the reaction, hydrogen is generated and heat generation is observed.
The mixture was kept at 0 ° C to 120 ° C and stirred for 4 hours.

After the generation of hydrogen stopped and the reaction was completed, it was cooled to room temperature and the Pd-C catalyst was filtered off. Then, 1210 g of a fraction of 115 to 117 ° C./3 Torr was obtained by vacuum distillation. When this fraction was subjected to GC-Mass, NMR, and IR analysis, it was found that tributylsilyl methacrylate was present at 92% and tributylsilylisobutanoate, which is a reduction product of the unsaturated bond, was present at 6%. The isolated yield of tributylsilyl methacrylate was 85%.

Comparative Example 1 The reaction was performed in the same manner as in Example 1 except that the triphenylphosphine used in Example 1 was not used as the ligand. After the reaction was completed, the reaction mixture was analyzed by GC, and the peak of the starting material tributylsilane disappeared, and the silylated product was obtained in a yield of 90% .However, tributylsilyl methacrylate and its reduced product tributylsilyl were obtained. It was found that isobutanoate was produced at a ratio of about 2: 1.

Example 2 A flask equipped with a thermometer and a reflux condenser was charged with toluene.
700g, DMF170g, Pd-C containing 0.5% by weight of palladium
40 g of catalyst and 0.5 g of triphenylphosphine were added, and the mixture was heated to 110 ° C. with stirring. Then methacrylic acid 560
A mixture of g, 990 g of diphenylmethylsilane and 2 g of P-methoxyphenol was added. During the reaction, hydrogen is generated and an exotherm is observed, so keep the reaction temperature at 110 ° C-120 ° C. 4.
Stir for 5 hours.

After the generation of hydrogen stopped and the reaction was completed, it was cooled to room temperature and the Pd-C catalyst was filtered off. Then, it was distilled under reduced pressure to obtain 1128 g of a fraction at 140 to 150 ° C./2 Torr. GC-Mass, NMR and IR analyzes of this fraction revealed that 94% of diphenylmethylsilylmethacrylate and 4% of diphenylmethylsilylisobutanoate, which is a reduction product of its unsaturated bond, were present. It was The isolated yield of diphenylmethylsilyl methacrylate was 80%.

Claims (5)

[Claims] 1. A general formula (Wherein R ¹ , R ² , and R ³ represent a hydrogen atom, a halogen atom, or a substituted or unsubstituted monovalent hydrocarbon group), and an unsaturated carboxylic acid represented by the general formula (Wherein R ⁴ , R ⁵ , and R ⁶ represent an alkoxy group or a substituted or unsubstituted monovalent hydrocarbon group), and are reacted with each other in the presence of a palladium catalyst and a ligand. The general formula, characterized by (In the formula, R ^{1 to} R ⁶ are as described above). 2. The method for producing a silyl unsaturated carboxylate according to claim 1, wherein the ligand is a phosphine compound. 3. The method for producing a silyl unsaturated carboxylate according to claim 1, wherein the unsaturated carboxylic acid is acrylic acid or methacrylic acid. 4. The method for producing a silyl unsaturated carboxylate according to claim 1, wherein the hydrosilane is tributylsilane. 5. The method for producing a silyl unsaturated carboxylate according to claim 1, wherein the palladium catalyst is Pd—C.