JPH04187690A - Preparation of straight-chain silicone - Google Patents

Abstract

PURPOSE:To massively prepare the subject silicone homogeneously containing siloxane units and having a constant chain length by reacting a specific cyclic silicone with a tri-substituted halogeno silane and water in the presence of an inorganic solid compound. CONSTITUTION:A cyclic silicone of formula I (R<1>, R<2> are H, alkyl, alkenyl, aryl, halogenoalkyl; n is 3-10) (e.g. octamethylcyclosiloxane) is reacted with a tri-substituted halogeno silane of formula II (R<3>-R<5> are alkyl, alkenyl, aryl, halogenated alkyl; X is halogen) (e.g. trichlorosilane) and water in the presence of an inorganic solid compound (preferably silica gel), if necessary, a hydrocarbon solvent such as pentane or benzene usually at a room temperature for 1-20hr to prepare the objective compound of formula III.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing linear silicone, more specifically,
This invention relates to a method for producing linear silicone having no distribution of siloxane units and a constant siloxane chain length.

[Prior Art] Volatile licorice oil is widely used in cosmetics and other applications. Most of the demand for volatile silicone oils is occupied by cyclic silicones such as octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, but from the viewpoint of volatility control for a wide variety of products, For example, there are cases where a silicone with a volatility intermediate or lower than these is required. In such cases, a linear silicone having a specific siloxane chain length is appropriately selected and used depending on its volatility. Therefore, most of the volatility control can be achieved with cyclic silicones and linear silicones.

[Problems to be Solved by the Invention] However, volatile linear silicones are generally produced by fractional distillation of the low boiling point of the equilibrated polymerization product of octamethylcyclotetrasiloxane and tetramethyldisiloxane. Therefore, it is difficult to obtain a large amount of a specific linear silicone. Furthermore, a method for partially hydrolyzing trimethylchlorosilane and dimethylchlorosilane [J.

Am, Chem, Soc, 68.358 (19
46)) is also known, but this method also yields only a mixture of linear silicones with different siloxane chain lengths.

Therefore, an object of the present invention is to provide a method that can produce a large amount of linear silicone having a specific siloxane chain length without any distribution of siloxane units.

[Means for Solving the Problems] Under these circumstances, the present inventors conducted intensive research and found that the above problems could be solved by a method of reacting a cyclic silicone, a trisubstituted halogenosilane, and water in the presence of an inorganic solid compound. The inventors have discovered that the problem can be solved, and have completed the present invention.

The present invention is shown by the following reaction formula.

(Margin below) R” R” 1 ] (SIO),, + R' Si X
10 H20R2R5 (1) (n) 1l R6R2R5 (III) (wherein, R1 and R2 may be the same or different, and represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, or a halogenated alkyl group, RB, R' and R5 may be the same or different and represent an alkyl group, an alkenyl group, an aryl group, or a halogenated alkyl group, X represents a halogen atom, and n represents an integer of 3 to 10. (2), a linear silicone (In
).

Cyclic silicone (I) is the starting material used in this reaction.
) Specific examples include hexamethylcyclotrisiloxane, hexaethylcyclotrisiloxane, hexaphenylcyclotrisiloxane, hexaethylcyclotrisiloxane, trimethyltrivinylcyclotrisiloxane,
Trimethyltriphenylcyclotrisiloxane, octamethylcyclotetrasiloxane, octaethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetra(trifluoropropyl)tetramethylcyclo Examples include tetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and the like.

Further, specific examples of the tri-substituted halogenosilane (n) which is the other raw material include trimethylchlorosilane, triethylchlorosilane, triphenylchlorosilane, dimethylethylchlorosilane and the like.

Further, the inorganic solid compound used in the production method of the present invention is preferably one that is insoluble in the reaction solution, and furthermore, one that is uniformly dispersed in the reaction solution. Specifically, silica gel,
Examples include titanium dioxide, silica/alumina, and silica gel is particularly preferred.

The silica gel in the present invention refers to an amorphous silicic acid polymer, and any type of silica gel can be used, but it is preferable to use one with a small particle size because a high reaction rate can be obtained with a small amount.

Here, the amount of trisubstituted halogenosilane (II) used in the reaction is 2 to
It is preferably about 10 times the mole, particularly about 2 to 4 times the mole, and even more preferably about 3 times the mole. The amount of the inorganic solid compound to be used is selected depending on the reactivity of the cyclic silicone (I) and the trisubstituted halogenosilane (II).
A range of 50% by weight is preferred. Water is used in principle in a stoichiometric excess, i.e. 1
It is preferable to use it in a range of 500 to 500 times the mole, particularly 5 to 20 times the mole.

In addition, a reaction solvent may or may not be used, but for example, when using hexamethylcyclotrisiloxane, which is solid at room temperature, as the cyclic silicone (I), it may be used to make the reaction proceed smoothly. Good too. Examples of the reaction solvent include pentane, hexane, heptane, benzene,
Hydrocarbon solvents that are immiscible with water, such as toluene, are preferred.

The production method of the present invention is carried out, for example, by adding trisubstituted halogenosilane (II) to a mixed solution of cyclic silicone (I), an inorganic solid compound, and water. The reaction is
Although it depends on the reactivity of the cyclic silicone (I), it usually takes 1 to 20 hours to complete at room temperature.

The obtained linear silicone (m) can be easily separated from unreacted cyclic silicone (I) and trisubstituted halogenosilane (II) by distillation under normal pressure or reduced pressure, preferably under reduced pressure. . The recovered cyclic silicone (I) and tri-substituted halogenosilane (II)
can be used again in the reaction.

[Examples] Hereinafter, the present invention will be explained in more detail by giving examples, but the present invention is not limited thereto.

Example 1 In a 500 ml flask equipped with a dropping funnel, 100 g of octamethylcyclotetrasiloxane, 60.6 g of water, and silica gel (Merck Kieselgel 60.250-4) were placed in a 500 ml flask equipped with a dropping funnel.
00 mesh) 10.1 g was charged. While stirring thoroughly, add 109.9 g of trimethylchlorosilane to 1
It dripped over time. After 10 hours, stirring was stopped and the silica gel was filtered. After distilling off excess trimethylchlorosilane from the obtained filtrate, it was transferred to a separating funnel to separate the aqueous layer, and the oil layer was washed twice with 50 ml of water, once with 50 ml of saturated aqueous sodium bicarbonate solution, and then further Washed twice with 50 ml of water. The resulting solution was distilled under reduced pressure to obtain 63.5 g of tetradecamethylhexasiloxane. 468g of raw material octamethylcyclotetrasiloxane was recovered. The yield calculated based on the reacted octamethylcyclotetrasiloxane was 78%.

Example 2 In a 500 ml flask equipped with a dropping funnel, 150 g of decamethylcyclopentasiloxane, 732 g of water, and silica gel (Merck Kieselgel 60.250-400) were added.
12.2 g of mesh was charged. While sufficiently stirring, 132 g of trimethylchlororane was added dropwise over 1 hour. After 11 hours, stirring was stopped and the silica gel was filtered. After distilling off excess trimethylchlorosilane from the obtained filtrate, it was transferred to a separating funnel to separate the aqueous layer.
The oil layer was washed twice with 50 ml of water, once with 50 ml of saturated aqueous sodium bicarbonate solution, and twice with 50 ml of water.

The resulting solution was distilled under reduced pressure to obtain 788 g of hexadecamethylheptasiloxane. 830g of the raw material decamethylcyclopentasiloxane was recovered. The yield calculated based on the reacted decamethylcyclopentasiloxane is 6
It was 7.1%.

[Effects of the Invention] As described above, according to the method for producing a linear silicone of the present invention, a linear silicone having a specific siloxane chain length and having no distribution of siloxane units can be produced in large quantities.

that's all

Claims (2)

[Claims] (1) The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R^1 and R^2 may be the same or different,
It represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, or a halogenated alkyl group, and n represents an integer of 3 to 10. ) Cyclic silicone represented by the following general formula (II) ▲ Numerical formula, chemical formula, table, etc. ▼ (II) (In the formula, R^3, R^4 and R^5 may be the same or different, represents an alkyl group, an alkenyl group, an aryl group, or a halogenated alkyl group, and X represents a halogen atom) and water are reacted in the presence of an inorganic solid compound. General formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) (In the formula, R^1, R^2, R^3, R^4, R^5 and n have the same meanings as above. A method for producing linear silicone represented by (2) The method for producing a linear silicone according to claim 1, wherein the inorganic solid compound is silica gel.