JPS63188689A - Production of gamma-methacryloxypropylsilanes - Google Patents

Abstract

PURPOSE:To prevent a polymerization of allyl methacrylate and obtain the titled silanes useful as coupling agents, etc., in good yield, by reacting the allyl methacrylate with a specific silane compound in the presence of a hindered phenol. CONSTITUTION:(A) Allyl methacrylate is reacted with (B) a silane compound expressed by formula I (n is 0 or 1; R<1> is 1-6C alkyl or phenyl; X is hydrolyzable group) in the presence of a hindered phenol expressed by formula II (R<2> is >=1C alkyl; R<3> and R<4> are H or >=1C alkyl) to afford the aimed silanes expressed by formula III, e.g. gamma-methacryloxypropylmethoxysilane, etc. The amount of the component (C) is preferably 0.1ppm-10wt.% based on the component (A).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses γ-methacryloxypropylsilanes, which are widely used as silane coupling agents, that is, γ-methacryloxypropylsilanes,
- It relates to a method for producing methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltrichlorosilane, etc. (hereinafter simply referred to as γ-methacryloxypropylsilanes).

More specifically, in the hydrosilylation reaction for synthesizing γ-methacryloxypropylsilanes, which are silane coupling agents, the yield of γ-methacrylic acid allyl ester is improved by preventing the polymerization reaction of methacrylic acid allyl ester, which is a raw material for the synthesis. - It relates to a method for producing methacryloxypropylsilanes.

Technical background of the invention and its problems A silane coupling agent is a compound that has an organic functional group and a hydrolyzable group that reacts with an inorganic substance in its molecule.

Since such silane coupling agents have the above-mentioned functional groups, they can chemically bond organic polymers and inorganic substances such as silica, dramatically improving the mechanical strength of organic polymers. Therefore, demand is expected to increase as it is essential for the development of advanced composite materials.

Now, when trying to synthesize γ-methacryloxypropylsilanes, which are one of the main silane coupling agents, by a hydrosilylation reaction, the raw material, allyl methacrylate, polymerizes just by heating. occurs, resulting in gelation. Therefore, it is known that when no polymerization inhibitor is present in the reaction system, the yield of γ-methacryloxypropylsilanes is extremely low (see Japanese Patent Publication No. 3379969). ``In order to prevent polymerization of allyl methacrylate in this hydrosilylation reaction, the following polymerization inhibitors have conventionally been used, but they have the following problems.

(1) Hydroquinone or 2, which is a general polymerization inhibitor as disclosed in JP-A No. 60-4191,
, 5-di-t-butylhydroquinone, γ
- When purifying methacryloxypropylsilanes by distillation, there is a problem that γ-methacryloxypropylsilanes gel.

(2) As disclosed in JP-A No. 60-239491@, when 2,5-di-t-butylbenzoquinone is used as a polymerization inhibitor, γ-methacryloxypropylsilanes gel during the distillation. However, these 2.5
-Di-t-butylbenzoquinone is expensive and highly irritating, which poses a problem in terms of ease of handling.

Note that the method for producing γ-methacryloxypropyltrimethoxysilane from allyl methacrylate and trimethoxysilane has only been previously reported in Japanese Patent Publication No. 38-2136, and details such as yield are not available. is unknown.

1. The present invention was made to solve the problems associated with the above-mentioned conventional technology. To provide a method for producing γ-methacryloxypropylsilanes, which prevents polymerization and also prevents gelation of γ-methacryloxypropylsilanes during the distillation, thereby significantly increasing the yield thereof. The purpose is to

Summary of the Invention The present invention involves adding a hindered phenol, represented by 2,6-di-t-butylhydroxytoluene, to a hydrosilylation reaction system as a polymerization inhibitor for allyl methacrylate to inhibit the main silane cup. This is a method for producing γ-methacryloxypropylsilanes that makes it possible to obtain γ-methacryloxypropylsilanes, which is one of the ring agents, in high yield.

The method for producing γ-methacryloxypropylsilanes according to the present invention involves the reaction of methacrylic acid allyl ester with a silane compound represented by the following general formula (I>), which is represented by the following general formula (II). H3IRnX3-
n (In the formula, n is O or 1, R1 is an alkyl group having 1 to 6 carbon atoms or a phenyl group, and X is a hydrolyzable group.) (In the formula, R2 is an alkyl group having 1 or more carbon atoms. is a group, and R3
J: and R4 are hydrogen or an alkyl group having 1 or more carbon atoms. ) General formula (III) (In the formula, n is O or 1, R1 is an alkyl group having 1 to 6 carbon atoms or a phenyl group, and X is a hydrolyzable group.) Specific explanation of the defense is as follows: The method for producing γ-methacryloxypropylsilanes according to the invention will be specifically explained.

In the method for producing γ-methacryloxypropylsilanes according to the present invention, methacrylic acid allyl ester and the above-mentioned silane compound are mixed in the presence of t-hindered phenol. Specifically, the following compounds may be mentioned.

(1) 2.6-di-t-butyl p-hydroxytoluene (BHT) 0M (2> 2.6-di-t-butylphenol H (3) 2-methyl-6-t-butyl-p-cresol (
MBPC> H H3 (4) 2,2°-medylene-bis(4-methyl-6-
(t-butylphenol) (5) Bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane (8HPB> (6) (mono, di, tri) α-methylbenzylphenol R These polymerization inhibitors The amount added is O.lpm to 20% by weight, preferably ioppm to 5% by weight, based on the allyl methacrylate ester.

Further, one of the silane compounds that reacts with the above allyl methacrylate has the general formula +s+uglyX3-1. n is O or 1, R1 is an alkyl group having 1 to 6 carbon atoms or a phenyl group, and X is a hydrolyzable group. Here, X is, for example, a halogen, an alkoxy group, an acetoxy group, an isocyanate group, or an azide group, and among these, a halogen or an alkoxy group is preferred.

In the present invention, the catalyst (hydrosilylation catalyst) used when producing γ-methacryloxypropylsilanes is a chloride or a complex of a platinum metal element and rhenium (Re), which have been conventionally used for the above reaction. (The concentration of the catalyst is about 10-8 to 10-3 mol of metal ions per 1 mol of methacrylic acid), but platinum chloride developed by the present inventors as described below can be used. It is particularly preferred to use a new catalyst that has been subjected to certain treatments on mH2Ptcle.6H20.

Note that as catalysts for promoting the hydrosilylation reaction for synthesizing a silane coupling agent by the hydrosilylation reaction, those shown in conventional methods (1) to (4) are known, but all of them are described below. There were some problems.

(1) Isopropanol solution of chloroplatinic acid 1-12PtC1.6H20 (J, Amer, Chem, Soc,
VOL, 82°3602 (1960)) This catalyst requires a fairly long period of time (commonly called the induction period) before it exhibits steady catalytic activity; There is a problem in that it must be pretreated with some of the reaction reagents.

(2) Platinum β-diketone forceps (Special Publication Publication February 19, 1989)
(See Publication No. 47) Using this catalyst, as described in the above publication, hydrosilylated products can be produced from allyl chloride and trichlorosilane in a relatively high yield, but the reaction temperature at this time is There are problems in that the catalyst is expensive, the reaction time is long, and preparation of the catalyst is time-consuming.

(3) A method using a chloroplatinic acid catalyst in the presence of phenothiazine, diphenylamine, etc. (Japanese Patent Publication No. 56-2987
Publication No. 3) When this method is adopted, the catalyst induction period is shortened, and the reaction temperature can be kept low, or the yield of the desired hydrosilylated product is low.

(4) Reaction product of chloroplatinic acid and cyclohexanone (Japanese Patent Publication No. 53-41132) When this catalyst is used, the desired hydrosilylated product can be obtained in a relatively high yield. There is a problem that it reacts with silane compounds.

Therefore, as a hydrosilylation catalyst, (1) the catalyst is easy to prepare, (2) the induction period can be significantly shortened, and (2)
Unlike cyclohexanone, the catalyst (or auxiliary catalyst) is not consumed by reacting in the reaction system; (1) the reaction proceeds under mild reaction conditions; and 1q of silane coupling agent is produced in high yield. It is necessary to meet the conditions.

Therefore, the inventors dissolved chloroplatinic acid in ethers or esters having 3 or more carbon atoms, and dissolved the resulting solution at 30%
'C or higher, preferably maintained at 50 to 120'C, and used as a hydrosilylation catalyst.

Next, the raw materials and manufacturing method of this hydrosilylation catalyst will be described in detail.

(''a) Ethers ethyl ether, butyl ether, phenyl ether,
Chain or cyclic ethers having three or more carbon atoms, such as anisole, tetrahydrofuran, furan, tetrahydrofuran, and dioxane, are used, and these needles do not contain aliphatic multiple bonds.

Of these, tetrahydrofuran is particularly suitable.

The amount of these ethers used is usually 1 mol or more, particularly preferably 100 to 200 mol, per 1 mol of platinum chloride.
0 mol, and there is no particular upper limit.

Ethers may be used as a solvent for the hydrosilylation reaction when producing a silane coupling agent.

(b) Esters methyl acetate, amyl acetate, methyl propionate, edyl benzoate, dimethyl phthalate, γ-butyrolactone, δ
-3 carbon atoms such as valerolactone, ε-caprolactone, etc.
The above chain or cyclic esters are used, but these esters preferably do not contain aliphatic multiple bonds.

Among these, γ-butyrolactone is particularly suitable.

The amount of esters to be used is the same as in the case of ether.

(C) Method for producing a hydrosilylation catalyst To produce this hydrosilylation catalyst (reaction product of chloroplatinic acid and an ether or ester), chloroplatinic acid is dissolved in the ether or ester, preferably under nitrogen. Under atmosphere, usually 5 minutes or more, preferably 30 minutes or more
Heat for 2 hours. The heating temperature is 30°C or higher, preferably 50 to 120°C, but when the boiling point of the selected ether or ester is lower than this temperature range, it is heated to a temperature below the boiling point of the ether or ester. .

The reaction product of chloroplatinic acid and ethers or esters thus obtained is usually treated with anhydrous 6A, if necessary.
A desiccant such as sodium M, anhydrous sodium carbonate, or sodium carbonate is added and dried to obtain a hydrosilylation catalyst.

When a small amount of this hydrosilylation catalyst is added to, for example, an equimolar mixture of trichlorosilane and allyl chloride, a significant exothermic reaction immediately occurs. Such heat generation does not occur when only chloroplatinic acid is added. Using the hydrosilylation catalyst prepared in this way, the induction period of the silylation reaction is significantly short.

Next, the reaction temperature when producing the γ-methacryloxypropyl-1 to realkoxysilanes according to the present invention will be described. The reaction temperature is not particularly limited, but is usually room temperature to 1.
The temperature is about 00'C, preferably 40 to 70C.

In addition, even in the distillation step after the completion of hydrosilylation, the addition of the polymerization inhibitor used in the present invention is effective in preventing gelation of the product γ-methacryloxypropylsilane.

Effects of the Invention According to the method for producing γ-methacrylic[1-xypropylsilanes according to the present invention, the polymerization of hindered phenol represented by BHT or allyl methacrylate ester is prevented, and these allyl methacrylate esters are Since gelation does not occur, the target γ-methacryloxypropylsilanes can be obtained in high yield, and the product T-methacryloxypropylsilanes can be obtained in the distillation residue manufacturing process after the reaction is completed. does not gel. Also B
HT is also recognized as a food additive and is a highly safe substance.

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 One gram of chloroplatinic (IV) acid was placed in a three-bottle flask equipped with a reflux condenser, a stirring rod, and a temperature of 81, and 200 d of tetrahydrofuran was added to a colander, and the reflux temperature of tetrahydrofuran was adjusted to about 65° under a nitrogen atmosphere. C. for 1 hour and the resulting solution was dried over anhydrous sodium sulfate to prepare the hydrosilylation catalyst. (Catalyst A) Next, in a three-bottle flask equipped with a reflux condenser, a punching rod, and a thermometer, 50 ml of toluene and 3 g of BHTo were added as a solvent.
, methacrylic acid allyl ester 12.6y (0.1 mol), catalyst A obtained as above as a catalyst, 1
trd;! (equivalent to 10 −5 mol as platinum), and 13.47 (0.11 mol) of trimethoxysilane was added dropwise from the dropping funnel over 1 hour. Reaction temperature is 50℃
The reaction was continued for an additional 30 minutes. Gas chromatography analysis revealed that γ-methacryloxypropyltrimethoxysilane was obtained in a yield of 86% (based on allyl methacrylate ester).

Example 2 In a three-bottle flask equipped with a reflux condenser, a punching rod, and a thermometer, 50 ni of toluene as a solvent and 2 as a polymerization inhibitor were added.
, 6-di-t-butylhydroxytoluene (BHT)0
13g, allyl methacrylate 12. el (0
, 1 mol), chloroplatinic acid as catalyst < t-12P
Add an isopropyl alcohol solution of L CI s ・61-120> in an amount equivalent to 10-6 moles of platinum,
13.4!17 (0.11 mol) of trimethoxysilane was added to the solution via the dropping funnel (over 1 hour). The reaction temperature is 5
The temperature was maintained at 0°C and the reaction was continued for an additional 30 minutes. Gas chromatography analysis revealed that γ-methacryloxypropyltrimethoxysilane was obtained in a yield of 86% (based on allyl methacrylate ester).

Examples 3 to 4 The reaction was carried out in the same manner as in Example 2, except that the polymerization inhibitor listed in Table 1 was used instead of 2,6-di-t-butylhydroxytoluene (BHT) in Example 2. Ta. The results are shown in Table 1.

Reference Example 1 In Example 2, except that the anti-handling agent was not used,
The reaction was carried out in the same manner as in Example 2. The results are shown in Table 1.

Comparative Examples 1 to 3 The reaction was carried out in the same manner as in Example 2, except that the polymerization inhibitor listed in Table 1 was used instead of 2,6-di[-butylhydroxy 1-luene. . The results are shown in Table 1.

K' = *γ-methacryloxypropyltrimethoxysilane (based on allyl methacrylate ester) 8H'T-: 2,6-di-t-butyl-p-hydroxytoluene MBPC: 2-methyl-6-t-butyl-p −
Cresol 8HPB: Bis(2-methyl-4-hydroxy-5-t-butyl-phenyl)butane DPPD: N,N'-diphenyl-p-phenylenediamine MEHQ: Hydroquinone monomethyl ether catechol: 4-[-butylcatechol Example 5 2,6-G-t-budgie of Example 2. 2,2-methylene-bis(4-methyl-hydroxy-5-t-butylphenol was used instead of hydroxytoluene, and trichlorosilane 14,9tj(
The reaction was carried out in the same manner as in Example 2, except that 0.11 mol) was used. Gas Chromatography Reference Example 2 When the reaction was carried out in the same manner as in Example 5 except that no polymerization inhibitor was added, gelation occurred and the desired product could not be obtained.

Example 6 A mixture containing the product of Example 2 was further added with BHTo.
2 g was added and distilled under reduced pressure.

Boiling point 93-94°C 10.3 ant-1g as product
γ-methacryloxypropyltrimethoxysilane is 2
0.39 was obtained. This was a yield of 81.6% based on allyl methacrylate.

Agent: Patent Attorney Shun Meki Partial Procedural Amendment (April 30, 1985) Commissioner of the Patent Office Kuro 1) Akio Yu -51, Display of Case 1988 Patent Application No. 20173 2, Name of Invention γ-Metacrylic Method for producing roxypropylsilanes
Name: Toa Fuel Industry Co., Ltd.';! , 4 7. Contents of the amendment 1) On page 15, lines 11-12 of the specification, the phrase "γ-methacryloxypropyltrialkoxysilanes" is amended to read "γ-methacryloxypropylsilanes". .

2) In lines 2-3 of page 21 of the specification, r2,2'-
methylene-bis(4-methyl-hydroxy-5-t-butylphenol)," is replaced with "r2,2'-methylene-bis(4-methyl-hydroxy-5-t-butylphenol)," to correct.

Claims (2)

[Claims] (1) Methacrylic acid allyl ester and the following general formula (
The reaction with a silane compound represented by the following general formula (III) is carried out in the presence of a hindered phenol having a structure represented by the following general formula (II).
) Method for producing γ-methacryloxypropylsilanes represented by general formula (I) HSiR^1_nX_3_-_n (wherein, n is 0 or 1, R^1 is an alkyl group having 1 to 6 carbon atoms or It is a phenyl group, and X is a hydrolyzable group.) General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^2 is an alkyl group having 1 or more carbon atoms, and R
^3 and R^4 are hydrogen or an alkyl group having 1 or more carbon atoms. ) General formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, n is 0 or 1, and R^1 is the number of carbon atoms 1 to 6
is an alkyl group or a phenyl group, and X is a hydrolyzable group. ) (2) The method for producing γ-methacryloxypropylsilanes according to claim 1, wherein the amount of hindered phenol used is 0.1 ppm to 10% by weight based on allyl methacrylate.