JPH0739427B2 - Method for producing monoalkoxysilane compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is useful as a method for producing a monoalkoxysilane compound, particularly as a terminal group of various siloxane polymers by the reaction of a dialkoxysilane compound with a Grignard reagent. The present invention relates to a method for producing a monoalkoxysilane compound.

(Prior Art) A method for producing a monoalkoxysilane compound is a method in which dimethylchlorosilane [(CH ₃ ) ₂ HSiCl] is subjected to an addition reaction with a compound having an olefin group at a molecular chain end, and then a dehydrochlorination reaction with an alcohol (the following formula) However, the cost of dimethylchlorosilane is high, and the addition reaction is slow and the yield is poor, so the resulting monoalkoxysilane compound is very expensive. There are drawbacks.

For the production of this monoalkoxysilane compound, a method of reacting a dichlorosilane compound with a Grignard reagent and then performing dehydrochlorination reaction using alcohol (the following formula) It is also known that the yield of this Grignard reaction is poor, and this reaction involves the reaction of the Grignard reaction product with the Grignard reagent as shown in the following formula. When a disubstituted by-product is produced and the amount of the disubstituted produced is 1 mol of the Grignard reagent dropped into 1 mol of the dichlorosilane compound and reacted, the raw material: the monosubstituted: the disubstituted:
Since it is 1: 2.5: 1, it is difficult to selectively obtain only the desired monosubstituted compound.

(Structure of the Invention) The present invention relates to a method for producing a monoalkoxysilane compound, which solves such disadvantages. (Here, A is a hydrogen atom, a halogen atom, a vinyl group, a perfluoroalkyl group, a nitrile group, an N, N-dialkylamino group, a chain or cyclic oxyalkyl group, and a P-chlorophenyl group having them as a substituent. An atom or a group selected from substituted phenylene groups, R ¹ is an alkyl group, n is an integer of 0 to 20, provided that when n = 0, the above A is a hydrogen atom, a vinyl group, a perfluoroalkyl group and a substituent group thereof. To a dialkoxysilane compound represented by a substituted phenylene group and a P-chlorophenyl group.) In an organic solvent represented by the formula R ² MgX (where R ² is a monovalent hydrocarbon group and X is a halogen atom). The Grignard reagent was reacted dropwise to give the formula (Wherein A, R ¹ , R ² and n are the same as described above) to obtain a monoalkoxysilane compound.

That is, the present inventor conducted various studies on a method for producing a monoalkoxysilane compound capable of solving the disadvantages in the conventional method, and the dialkoxysilane compound represented by the above formula was used as a starting material, and a Grignard reagent was reacted therewith. The disubstituted silane by-product, which is found in the Grignard reaction of the dichlorosilane compound, is scarcely produced, and therefore the desired monoalkoxysilane compound is obtained with high selectivity and high yield, and without dehydrochlorination. The present invention was completed by advancing research into the type of dialkoxysilane compound used here and the reaction conditions.

The dialkoxysilane compound as a starting agent used in the method of the present invention has the formula , A is a hydrogen atom, a halogen atom such as chlorine, fluorine or bromine, a vinyl group, a perfluoroalkyl group, a nitrile group, an N, N-dialkylamino group, a chain-like or cyclic oxyalkyl group and those substituted A substituted phenylene group having a group, R ¹ is a methyl group, an ethyl group, a propyl group,
An alkyl group such as a butyl group, n is an integer of 0 to 20, and when n = 0, the above A is a hydrogen atom, a vinyl group, a perfluoroalkyl group and a substituted phenylene group having them as a substituent and P- A chlorophenyl group, which includes dimethyldimethoxysilane, chloropropylmethyldimethoxysilane, β-cyanoethylmethyldiethoxysilane, vinylmethyldiethoxysilane, octadecylmethyldimethoxysilane, and 3,3,3-trifluoropropylmethyldimethoxysilane. Silane, N, N-dimethyl-
Examples of γ-aminopropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, p-chlorophenylmethyldimethoxysilane and the like,
All of these may be industrially produced.

The Grignard reagent used in the method of the present invention has the formula
R ² MgX, R ² is a monovalent hydrocarbon group selected from alkyl groups such as methyl group and ethyl group, alkenyl groups such as vinyl group and allyl group, aryl groups such as phenyl group and tolyl group, X Is a halogen atom such as chlorine or bromine, which is conventionally known, and examples thereof include methyl magnesium chloride, ethyl magnesium bromide and phenyl magnesium bromide.

The reaction between the dialkoxysilane compound and the Grignard reagent is carried out in an organic solvent. Examples of the organic solvent include ether solvents such as diethyl ether and tetrahydrofuran, and hydrocarbon solvents such as hexane, benzene and toluene. Etc., and these may be used as a mixed solvent of two or more thereof.

The method of the present invention may be carried out by mixing the dialkoxysilane compound described above with the above-mentioned organic solvent and then dropwise adding a Grignard reagent to the reaction.
C., preferably in the temperature range of 20 to 100.degree. However, when oxygen is present in this reaction system, the Grignard reagent reacts with oxygen in the reaction stage to reduce the yield of the monoalkoxysilane compound, so this is preferably performed in an atmosphere of an inert gas such as nitrogen or argon.

The reaction between this dialkoxysilane compound and the Grignard reagent is However, if the reaction rate coefficients in equations (1) and (2) are k ₁ and k ₂ , then there is a relationship of K ₁ > k ₂ , and k ₁ is overwhelmed in comparison with k _2. Since the amount of the disubstituted product obtained by the sequential reaction is extremely small, a monoalkoxysilane compound as the monosubstituted product can be selectively obtained. For example, a Grignard reagent can be used with respect to 1 mol of the dialkoxysilane compound. It is possible to obtain a monoalkoxysilane in a surprisingly high yield of starting material: mono-substituted product: di-substituted product = 1.0: 98.0: 1.0 when 1 mol of is added, and the molar ratio of this dialkoxysilane compound and the Grignard reagent is If the ratio is 1 or more, the production ratio of the disubstituted product increases, and if it is 1 or less, the ratio of the raw materials in the reaction product increases. Therefore, this molar ratio is preferably in the range of 0.8 to 1.3 mol.

The monoalkoxysilane compound obtained by this method, for example, γ-chloropropyldimethylmethoxysilane, is said to be useful as a terminal group of organopolysiloxane, and this terminal group is further a γ-mercaptopropyl group,
Since it can be converted into an N-β-aminoethyl-γ-aminopropyl group and the like, it can be used for the production of various organopolysiloxanes, but this is also used as a surface treatment agent requiring a monomolecular film. Is also useful.

Next, examples of the present invention will be given.

Example 1 182.5 g (1 of γ-chloropropylmethyldimethoxysilane
Hexane (300 mol) and 300 ml of hexane are heated to 40 ° C, and while stirring, 60.6 g (1.2 mol) of methyl chloride is blown into a mixture of 24.3 g (1 mol) of magnesium metal and 300 ml of tetrahydrofuran. 1 mol of the methylmagnesium chloride-tetrahydrofuran solution prepared in step 1 was added dropwise under a nitrogen gas atmosphere to react, and the internal temperature was raised to 50 ° C and stirring was continued for 1 hour after the addition was completed. , The liquid was concentrated and distilled under reduced pressure.
153.2 g (yield 92%) of γ-chloropropyldimethylmethoxysilane with 169.5 ° C / 751 mmHg was obtained. The reaction composition of this reaction solution was as follows: raw material: γ-chloropropyldimethylmethoxysilane: γ-chloromethyltrimethylsilane = 1.
It was 0: 98.0: 1.0.

Example 2 The same treatment as in Example 1 was carried out except that γ-chloropropylmethyldimethoxysilane in Example 1 was changed to 187 g (1 mol) of β-cyanoethylmethyldiethoxysilane, and the boiling point was 57 ° C./4 mmHg. 139.7 g (yield 89%) of a certain β-cyanoethyldimethylethoxysilane was obtained.

Example 3 202 g 3,3,3-trifluoropropyldimethoxysilane
(1 mol) was mixed with 300 ml of toluene and heated to 40 ° C,
26.7g (1.1mol) of magnesium metal with stirring
Phenylmagnesium bromide-tetrahydrofuran solution prepared by adding 172.7 g (1.1 mol) of phenylbromide to a mixture of benzene and 300 ml of tetrahydrofuran.
1.1 mol was added dropwise under a nitrogen gas atmosphere to react, and after the addition was completed, the internal temperature was raised to 50 ° C. and stirring was continued for 1 hour. The obtained reaction liquid was passed, the liquid was concentrated and distilled under reduced pressure. However, 211 g (yield 85%) of 3,3,3-trifluoropropylmethylphenylmethoxysilane having a boiling point of 110 ° C / 1 mmHg was obtained, and the composition of this reaction solution was as follows: Raw material: 3,3,3-trifluoro Propylmethylphenylmethoxysilane: 3,3,3-trifluoropropylmethyldiphenylsilane = 0: 97: 3.

Example 4 191 g (1.0 mol) of γ-N, N-dimethylaminopropylmethyldimethoxysilane was mixed with 300 ml of benzene and heated to 40 ° C., and while stirring, 24.3 g of metallic magnesium.
1 mol of a vinylmagnesium chloride-tetrahydrofuran solution prepared by blowing 68.8 g (1.1 mol) of vinyl chloride gas into a mixture of (1 mol) and 300 ml of tetrahydrofuran was added dropwise under a nitrogen gas atmosphere to cause reaction, and then added dropwise. After the completion, the internal temperature was raised to 50 ° C and stirring was continued for 1 hour. The obtained reaction solution was passed through, and the solution was concentrated and distilled under reduced pressure. Γ-N, N with a boiling point of 76 ° C / 1mmHg 155.2 g (83% yield) of dimethylaminopropylmethylvinylmethoxysilane were obtained.

Example 5 The same treatment as in Example 1 was carried out except that γ-chloropropylmethyldimethoxysilane in Example 1 was changed to the dialkoxysilane compound shown in Table 1.
The products shown in the table could be obtained.

Claims (1)

[Claims] 1. A formula (Here, A is selected from a hydrogen atom, a halogen atom, a vinyl group, a perfluoroalkyl group, a nitrile group, an N, N-dialkylamino group, a chain or cyclic oxyalkyl group and a substituted phenylene group having them as a substituent. Atom or group, R ¹ is an alkyl group, n is an integer of 0 to 20, provided that when n = 0, A is a hydrogen atom, a vinyl group, a perfluoroalkyl group and a substituted phenylene group having them as a substituent, P-chlorophenyl group.) To a dialkoxysilane compound represented by the formula R ² MgX in an organic solvent.
(Wherein R ² is a monovalent hydrocarbon group, and X is a halogen atom), the Grignard reagent represented by (Wherein A, R ¹ , R ² and n are the same as described above) to obtain a monoalkoxysilane compound.