JPH04164088A - Production of siloxane having si-si bond - Google Patents

Abstract

PURPOSE:To obtain the subject compound from a high-boiling fraction which has hitherto been of no utilization value in synthesizing chlorosilane according to simple treatment by reacting a specific disilane mixture with a cyclotrisiloxane. CONSTITUTION:A disilane mixture containing at least one disilane, expressed by formula I (n is 6-0) and having >=2 chlorine atoms bound to one silicon atom is reacted with a cyclotrisiloxane expressed by formula II (R is H or monofunctional hydrocarbon) to introduce -(OSiR2)3- between the >=2 Si-Cl bonds of the disilane in which the >=2 chlorine atoms are bound to the aforementioned one silicon atom by leaving one Si-Cl bond among the above-mentioned Si-Cl bonds. Thereby, the objective compound is obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing siloxane having 5i-3i bonds from a disilane mixture, and in particular, relates to a method for producing siloxane having a 5i-3i bond from a disilane mixture, and in particular, the present invention relates to a method for producing siloxane having a 5i-3i bond from a disilane mixture. Converting disilanes to siloxanes having 5i-5i bonds,
The present invention relates to a method for producing the above-mentioned siloxane that can be effectively employed for isolation.

[Prior Art and Problems to be Solved by the Invention] In the silicone industry, the production of chlorosilane by the direct method is a very important route, and now a large amount of chlorosilane is produced annually by the direct method.

However, in this case, a high-boiling point fraction can be obtained by collecting chlorosilane by distillation, but this high-boiling point fraction contains disilanes with close boiling points that are difficult to separate by distillation. It has been difficult to effectively utilize the boiling point fraction.

That is, focusing on disilane, a high-boiling fraction during the production of chlorosilane by the direct method, and classifying it based on boiling point, it can be divided into the following three fractions.

Low boiling seafood: C, H, Si, CsH, 5CQSi
2. C4H1, CQ, Siz medium boiling point seafood, H, CQ
3Si2. C2H6CQSSi2 High boiling point: C, H,
C bird Si2. Also, in this case, even if expressed by the same compositional formula, for example, C4H,, CQ, and Si are 1,2
-chloride (Me2CQSj-5iCQMe2), 1
．． Structural isomers such as 1-chloride (MeCflt, Si51-5i,) (Me represents a methyl group. The same applies hereinafter.

), and furthermore Contains substances other than disilane such as.

In fact, when high-boiling point distillation and gas chromatography analysis shows a very complicated pattern as shown in Table 1 below, the high-boiling point fraction is S i −S i
Although it contains an industrially useful compound with a bond as its main component, there is no effective separation method for the structural isomers of chloro and methyl because their boiling points are close, and there are problems in terms of effective utilization. Ta.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a method for producing siloxane that can be effectively employed to obtain siloxane having a 5i-8i bond from a high-boiling fraction produced during chlorosilane synthesis. do.

In order to achieve the above object, the present inventors have made extensive studies and found that it is effective to react a disilane mixture with cyclotrisiloxane.

That is, the present inventors first investigated the reactivity of chlorosilanes and cyclotrisiloxane, and found that when chlorosilanes and an excess molar amount of cyclotrisiloxane are reacted at low temperature in a polar solvent that does not have a proton, Silanes that do not have one chlorine atom on Si do not react with cyclotrisiloxane at all, but silanes that have two or more chlorine atoms on one Si react by inserting cyclotrisiloxane between 5i-C0. However, it was found that the reaction continued until Si having two or more chlorine atoms was used up (see the reaction formula below).

represents hexamethylphosphoryltriamide) Furthermore,
The present inventors applied the above reaction to disilanes, and found that, for example, when cyclotrisiloxane was reacted with the structural isomers of C4H4 and Cl22Si, only one chloro atom was bonded to each Si. Not done1,2-
The dichlor form does not react at all, but the 1,1-dichlor form reacts with cyclotrisiloxane to obtain, for example, compound (1) of the following formula, and this compound (1) is 1,2-
It has been found that the boiling point is significantly different from that of the dichlor compound and that they can be separated from each other, and in this case, the obtained compound (1) becomes a mixture of the following formulas (2) and (3) upon hydrolysis.

Compound (1) -! In this case, Me4CQ2S i□ is Me3CQ3S
Even if i□ is mixed, the compound of formula (4) can be obtained by the following reaction, and further
By hydrolyzing the compound of
The present inventors have found that these compounds can also be easily separated, leading to the present invention.

Therefore, the present invention provides the following compositional formula CI) (CH,). It is represented by Si, C-1...[l] (where n is an integer from 6 to 0), and contains at least one type of disilane in which two or more chlorine atoms are bonded to one silicon atom. The disilane mixture is reacted with cyclotrisiloxane represented by the following formula (U) (wherein R represents a hydrogen atom or a monovalent hydrocarbon group of the same or different types) to produce the above 1.
Of the two or more 5i-CQ bonds of disilane in which two or more chloro atoms are bonded to one silicon atom, one 5i
-CQ bond and between other 5i-CQ bonds (OS i
Provided is a method for producing a siloxane having a 5i-Si bond, which is characterized by introducing Rz h (wherein R has the same meaning as above).

The present invention will be explained in more detail below.

In the method for producing siloxane having a 5i-Si bond of the present invention, the starting material has the following compositional formula [13M and Sit C
L -n is a disilane mixture represented by [I], and this mixture contains disilanes in which two or more chlorine atoms are bonded to one silicon atom, such as MeCQ2SiSiMe3゜MeCfl, SiSi(1
1Mall, CD, 5iSiCQ, etc. (all of them must contain at least one kind.) As such a disilane mixture, a high boiling point fraction produced in the production of chlorosilane by a direct method is preferably used.

On the other hand, the cyclotrisiloxane to be reacted with this disilane mixture is represented by the following formula (II). In this case, R is a hydrogen atom or a monovalent group of the same or different types. The hydrocarbon group preferably has 1 to 10 carbon atoms, such as methyl, phenyl, trifluoropropyl, vinyl groups, etc. Among these, hexamethylcyclotrisiloxane is particularly preferred. used.

The amount of the above chloromethyldisilane mixture and cyclotrisiloxane to be used is selected as appropriate, and the number of silicon atoms having two or more chlorine atoms in the mixture and whether two or three chlorine atoms are bonded to silicon atoms are determined. Although it varies depending on whether the
-330 parts by weight.

The reaction between the chloromethyldisilane mixture and cyclotrisiloxane is preferably carried out using a polar solvent without protons, such as hexamethylphosphoryltriamide (HMPA), dimethylsulfoxide (DMSO), dimethylformamide (DMF), etc. . Among these, HMPA is particularly preferred. The amount used is 0.1 to 10% by weight based on cyclotrisiloxane,
Particularly suitable is 0.5 to 3% by weight. If it is less than 0.1%, the reaction rate may be slow, and if it exceeds 10%, there is a risk that the monochlorosilane reaction will start to occur.

The reaction conditions are also selected appropriately, but the reaction temperature is 30°C or less,
In particular, the temperature is preferably 0 to 30°C, and if the temperature exceeds 30°C, silicon atoms having only one chloro atom may also start to react with cyclotrisiloxane. In addition, 0℃
Although the reaction is possible even at a lower temperature, the reaction rate decreases if the temperature is too low. Moreover, the reaction time is usually 1 to 5 hours.

In addition, in this reaction, CQ2 in the disilane mixture
It is preferable to concentrate the Me4S i2 component by pre-distillation or the like.

Therefore, in the present invention, in this reaction, cyclotrisiloxane acts on disilane in which two or more chloro atoms are bonded to one silicon atom in the disilane mixture, and out of the two or more 5i-CQ bonds, All but one 5i-C
By introducing (○S i Rzh) between the Q bonds, for example, the following siloxanes (i) and (n) are obtained.

The siloxane thus obtained can be easily separated by distillation due to the difference in boiling point, and if the obtained siloxane is hydrolyzed by a conventional method, the hydrolyzate can be further easily separated by distillation. I can do it.

According to the method for producing siloxane according to the present invention,
Siloxane, which can be easily separated by distillation, can be produced from the high-boiling fraction produced during chlorosilane synthesis by the direct method, and the high-boiling fraction, which has little utility value, can be effectively utilized.

In addition, the siloxane obtained in the present invention can be copolymerized with cyclic siloxanes in the presence of an alkali or acid catalyst to give a polymer having trimethylsilyl groups etc. in the side chain, and it can be made into a useful polymer. can[
M., Ishikawa et al.

J, Polymn, Sci, Polymn, Le
tter, 21.657 (1983)) [Effects of the Invention] According to the invention, it is possible to easily and reliably obtain a siloxane having a 5i-8i bond which is easily separable from a disilane mixture and which is difficult to obtain by other methods. It can be advantageously employed to produce siloxanes having 5i-Si bonds by simple processing from high-boiling fractions during chlorosilane synthesis, which have not been of any use up to now.

Hereinafter, the present invention will be specifically explained with reference to Examples.

〔Example〕

1 kg of the high-boiling fraction during the production of chlorosilane was subjected to simple distillation, and 5
0 to b were collected. When this fraction was analyzed by gas chromatography, it was found that this fraction contained Me, S, as shown in Table 1.
iSiMe, 14.3%, Me, SiSiMe
, C124,8%, Mg2Si, Cl2211, 1
% of disilanes, and also various silanes with boiling points close to each other.

Table 1 Peak Time Concentration Compound N00 (%) 1 0.988 0.0059 2 0.995 0.003 3 1.887 0.0251 4 1.162 0.5073 5 1.36 1.3623 6 1 .435 0.9847 9 1.745 4.723710 1.8
85 1.3464 11 1.875 4.3369 12 1.95 3.6504 13 2.843 5.1433 1G 2,275 1.852717 2.3
97 9.1671 20 2.96 2.8702 21 3.813 0.2535 22 3.262 0.0339 23 3.318 0.030324 3
．． 498 0.007925 3.632
0.017726 3.733 0.021
727 3.3 0.009928 3
．． 958 0.010229 4.827
0.009430 4.13 0.0059
31 4.688 0.004332 4
．． 8 0.004933 4.878
0.004334 4.968 0.0046
35 5.515 0.004536 5
．． 615 0.001937 5.733
0.013338 6.158 0.016
939 6.313 0.010340
6.453 0.053841 6.675
0.003942 7.822 0.00
8 Next, 400 g of hexamethylcyclotrisiloxane and 4 g of hexamethylphosphoryltriamide were added to 400 g of the above fraction, and the mixture was stirred at 0° C. for 1 hour. During this time, solid hexamethylcyclotrisiloxane gradually reacts and dissolves.
After 1 hour, the solution became completely homogeneous.

This solution was heated to 70°C with 2wn+Hg to remove unreacted hexamethylcyclotrisiloxane and chlorosilanes, and then passed through a short distillation column and distilled under reduced pressure.
b was collected.

This fraction was subjected to "HNMR", "S i NMR".

As a result of analysis by IR and GC-MASS, the following formula (1
). In addition, this compound (1) is shown in the drawing.
) also shows the infrared absorption spectrum of this compound (
The n25°C of 1) was 1.4139.

[Reference example]

Next, the above compound (1) was dissolved in 190 g of diethyl ether, and this was added to water for hydrolysis. The hydrolyzate was washed with water, dried, stripped, and distilled to isolate fraction 75-b. This was subjected to 1H-NMR and IR.

Analyzed by GC-MASS, UV absorption was measured in cyclohexane and 5i-5i was determined by absorption at 213 nm.
As a result of confirming the existence of the bond, it was found that it was a mixture of (2) and (3) below (at a ratio of 1:2).

[Brief explanation of drawings]

The drawing shows an infrared absorption spectrum of compound (1) obtained by the method of the present invention. Applicant Shin-Etsu Chemical Co., Ltd. Agent Patent Attorney Takashi Kojima

Claims (1)

[Claims] 1. The following compositional formula [I] (CH_3)_nSi_2Cl_6_-_n...[
I] (where n is an integer from 6 to 0), and contains at least one type of disilane in which two or more chlorine atoms are bonded to one silicon atom, is represented by the following formula [II] ▲Math. , chemical formulas, tables, etc. ▼...[II] (However, R represents a hydrogen atom or a monovalent hydrocarbon group of the same or different types.) By reacting with cyclotrisiloxane shown in 1 above,
Of the two or more Si-Cl bonds of disilane in which two or more chlorine atoms are bonded to one silicon atom, one Si
Si-Si is characterized by leaving the -Cl bond and introducing ▲mathematical formula, chemical formula, table, etc.▼ (however, R indicates the same meaning as above) between other Si-Cl bonds.
A method for producing a siloxane having a bond.