JPS606357B2 - Method for producing monohydrodiene organopolysiloxane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a monohydrogenorganopolysiloxane having a hydrogen atom directly bonded to an elementary atom.

Conventionally, a method for producing mono/hydrogenorganopolysiloxane involves, for example, subjecting a polysiloxane having a methylhydrogensiloxane unit in its molecule to an equilibration reaction with hexamethyldisiloxane in the presence of an acid catalyst. Although this method is known, it has various disadvantages that are undesirable from an industrial standpoint, such as a low yield of 10 to 25% of the target product and the production of a large amount of by-products, making purification difficult. .

Furthermore, as a method for producing this type of siloxane, a method is known in which a chlorosilane having a hydrogen atom and a silanol are subjected to a dehydrochloric acid reaction (see U.S. Pat. No. 3,462,386); The speed is small,
Therefore, it takes a long time to obtain the desired product, and the yield is extremely low because the condensation reaction of silanol occurs due to the action of the hydrochloric acid produced.

On the other hand, in the method of reacting chlorosilane having a hydrogen atom with sila/-ols, a method using a dehydrochlorination agent has been attempted in order to obtain the target product in high yield, but this method requires a large amount of The problem was that the use of a reaction solvent of

The present invention aims to provide a method for producing monohydrodiene organopolysiloxane that solves the conventional problems as described above, and this invention is based on the general formula HSiR (OR2>r...-(1) where RI is a substituted or unsubstituted monovalent hydrocarbon group, R
2 represents an alkyl group having 1 to 4 carbon atoms, n is 1,
2 or 3) and a triorganosilanol represented by the general formula , catalytic amounts of tin, zinc, potassium carboxylates, carbonates or ha.

This method is characterized by the reaction being carried out in the presence of a gene compound, and according to this method, the general formula
・ HSiRkin-n (OSi Shigeru)...(m) (in the formula, R1
, R3 and n have the same meanings as above) can be obtained with high purity and high yield, and therefore have the effect of extremely high pot yield.

Next, to explain the present invention in more detail, first, the organoalkoxysilane used as a starting material in the present invention is represented by the above general formula (1), and is represented by RI in the formula. Examples of substituted or unsubstituted monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, butyl, aryl groups such as phenyl, alkenyl groups such as vinyl and allyl groups, or monovalent groups such as these. Examples include groups in which some or all of the hydrogen atoms of a valent carbon group are substituted with halogen atoms, etc., and examples of the alkyl group having 1 to 4 carbon atoms represented by R2 include methyl group, ethyl group, and propyl group. Illustrated.

Specifically, such organoalkoxysilanes include dimethylmethoxysilane, dimethylethoxysilane, dimethylisopropoxysilane, methyldimethoxysilane, methyldiethoxysilane, methyldiisopropoxysilane, trimethoxysilane, triethoxysilane,
Examples include triisopropoxysilane, phenylditoxysilane, and diphenylmethoxysilane.

Further, in the present invention, the triorganosilanol used as a starting material in combination with the organoalkoxysilane is represented by the above general formula (0), in which R3 is a substituted or unsubstituted monovalent It represents a hydrocarbon group, and examples of R3 include the same groups as R2 described above. Examples of such triorganosilanol include trimethylsilanol, phenyldimethylsilanol, diphenylmethylsilanol, and triphenylsilanol. Furthermore, ``the catalyst used in the present invention is selected from tin, zinc, potassium carboxylates, carbonates, or halides, including dibutyltin diacetate, dibutyltin dioctenoate, monobutyl trioctenoate. Examples include tin, dibutyltin dilaurate, tin octenoate, zinc stearate, zinc acetate, zinc acetylacetone, potassium acetate, zinc carbonate, potassium carbonate, charcoal tin, and zinc chloride.

In the method of the present invention, an organoalkoxysilane represented by the general formula (1) described above and a triorganosilanol represented by the general formula (D) are reacted according to the following reaction formula (dealcoholization reaction) in the presence of the catalyst described above. ) and by removing the alcohol by-produced from the system, the desired monohydrogenorganopolysiloxane can be easily obtained.

HSiRki-n(OR2)n10 cabin SiOH→HSiR
The usage ratio of the above organoalkoxysilane and triorganosilanol is (
The amount of silanol of formula (0) is preferably 1 mole per alkoxy group of formula (1), and the catalyst is used in an amount of 0.0005 to 5% by weight, preferably 0.005% by weight based on the starting material. It is desirable to set it as the range of -0.5 weight%.

In addition, although the reaction proceeds in a wide temperature range (10 to 20
The reaction is preferably carried out at a temperature range of 0 qo), preferably 50 to 120 qo. After the reaction is complete, some unreacted substances are present in the system, but these can be completely decomposed by hydrolyzing them with hydrochloric acid water, and the by-product alcohol can be completely decomposed. can be reliably removed by washing with water.

Next, examples of the present invention will be described.

Example 1 Internal volume 5 with stirrer, thermometer and reflux condenser
00' flask, add trimethylsilanol 189.
4 (2.1 mol), methyldiethoxysilane 134.
3 (1.00 mol) and dibutyltin octenoate 0
．． After 16 hours of reaction was carried out at the reflux temperature of ether/alcohol (80°C), 130 hours of 5% hydrochloric acid was added and a hydrolysis reaction was carried out at room temperature for 1 hour.

The mixture was then washed with water until neutral and distilled, yielding 211 siloxanes represented by the formula (yield: 95*%).
Comparative Example 1 The same siloxane as that obtained in Example 1 was obtained when the treatment was carried out in the same manner as in Example 1 above, except that dibutyltin dioctenate was not used at all. The yield was 7%.

Comparative Example 2 Dimethyljethoxysilane was used instead of methyljethoxysilane, and the amount of dibutyltin dioctenate was reduced to 3.
．． Although the reaction was carried out for 2 hours in the same manner as in Example 1, except for 2 nights, no product was obtained.

Example 2 The treatment was carried out in substantially the same manner as in Example 1 using the types of organo/alkoxysilanes, triorganosilanols and catalysts shown in the table below, resulting in organopolysiloxanes of the types shown in the table. was gotten.

Table Comparative Example 3 Into the same flask as used in Example 1, 8.32 g (0.0723 mol) of methyldichlorosilane.

31.7 moles (0.148 moles) of diphenylmethylsilanol and 0.02 moles of dibutyltin dioctenate were charged, the reaction was carried out in the same manner, and then the treatment was carried out.
18.4 ta of siloxane represented by the formula was obtained (yield: 5
3%).

Claims (1)

[Claims] 1 General formula HSiR^1_3_-_n(OR^2)_n (in the formula, R
^1 represents a substituted or unsubstituted monovalent hydrocarbon group, R^2 represents an alkyl group having 1 to 4 carbon atoms, and n is 1, 2 or 3);
A triorganosilanol represented by the general formula R^3_3SiOH (wherein R^3 represents a substituted or unsubstituted monovalent hydrocarbon group) is mixed with a catalytic amount of tin, zinc, potassium carboxylate, carbonate, etc. General formula HSiR^1_3_-_n(OSiR^3_3)_n(, characterized by reacting in the presence of a salt or a halide)
A method for producing a monohydrodiene organoborisiloxane represented by the formula (wherein R^1, R^3 and n have the same meanings as above).