JP2805393B2 - Method for producing linear silicone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a method for producing a linear silicone, and more particularly, to a method for producing a linear silicone having a constant sikirose chain length without a distribution of siloxane units. Related to manufacturing method.

[Prior Art] Volatile silicone oils are widely used in cosmetics applications and the like. Most of the demand for such volatile silicone oils is occupied by cyclic silicones such as octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. In some cases, a silicone having a volatility intermediate or lower than these is required. In such a case, a linear silicone having a specific siloxane chain length is appropriately selected and used according to its volatility. Thus, the majority of volatility control can be accommodated by cyclic and linear silicones.

[Problems to be Solved by the Invention] However, volatile linear silicones are generally produced by fractional distillation of a low boiling portion of an equilibrium polymerization product of octamethylcyclotetrasiloxane and tetramethyldisiloxane. Therefore, it is difficult to obtain only a specific linear silicone in a large amount. A method of partially hydrolyzing trimethylchlorosilane and dimethylchlorosilane [J. Am. Chem. Soc., 68, 358 (1946)] is also known. Only a mixture of

Accordingly, an object of the present invention is to provide a method capable of producing a large amount of only a linear silicone having a specific siloxane chain length without distribution of siloxane units.

[Means for Solving the Problems] Under such circumstances, the present inventors have conducted intensive studies and as a result, have found that the above-mentioned problems have been solved by a method of reacting cyclic silicone, trisubstituted halogenosilane and water with the presence of an inorganic solid compound. Were solved, and the present invention was completed.

 The present invention is represented by the following reaction formula.

(Wherein, R ¹ and R ² may be the same or different, and a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a halogenated alkyl group; R ³ , R ⁴ and R ⁵ may be the same or different , An alkyl group, an alkenyl group, an aryl group or a halogenated alkyl group, X represents a halogen atom, and n represents 3 to 10
Indicates an integer. That is, the present invention provides a linear silicone (II) comprising reacting a cyclic silicone (I), a trisubstituted halogen silane (II) and water in the presence of an inorganic fixing compound.
The present invention provides the production method of I).

Specific examples of the cyclic silicone (I) which is a starting material used in this reaction include hexamethylcyclotrisiloxane, hexaethylcyclotrisiloxane, hexaphenylcyclotrisiloxane, hexaethylcyclotrisiloxane, and trimethyltrivinylcyclotrisiloxane. , Trimethyltriphenylcyclotrisiloxane, octamethylcyclotetrasiloxane, octaethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetra (trifluoropropyl) tetramethyl Examples include cyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and the like.

The other raw material is a tri-substituted halogenosilane (II)
Specific examples include trimethylchlorosilane, triethylchlorosilane, triphenylchlorosilane, dimethylethylchlorosilane and the like.

Further, as the inorganic solid compound used in the production method of the present invention, those which are insoluble in the reaction solution and which are uniformly dispersed in the reaction solution are preferable. Specific examples include silica gel, titanium dioxide, silica / alumina and the like, and silica gel is particularly preferred. The silica gel in the present invention refers to an amorphous silicic acid polymer, and any type can be used. However, a silica gel having a small particle size is preferable in that a small amount and a high reaction rate can be obtained.

Here, the amount of the tri-substituted halogenosilane (II) used in the reaction is 2 to 2 with respect to the cyclic silicone (I).
The molar amount is preferably about 10 times, particularly about 2 to 4 times, and more preferably about 3 times. The amount of the inorganic fixing 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 in principle in stoichiometric excess, i.e. 1 to 50 relative to cyclic silicone (I).
It is preferably used in a molar amount of 0-fold, particularly 5 to 20-fold. Also, the reaction solvent may or may not be used,
For example, when hexamethylcyclotrisiloxane or the like which is solid at room temperature is used as the cyclic silicone (I), it may be used for smoothly proceeding the reaction. As the reaction solvent, a hydrocarbon solvent that does not mix with water, such as pentane, hexane, heptane, benzene, and toluene, is preferable.

The production method of the present invention includes, for example, cyclic silicone (I),
It is carried out by adding a tri-substituted halogenosilane (II) to a mixture of an inorganic solid compound and water. The reaction is
Although it depends on the reactivity of the cyclic silicone (I), it is usually completed in 1 to 20 hours at room temperature.

The obtained linear silicone (III) is distilled under normal pressure or reduced pressure, preferably under reduced pressure, to obtain unreacted cyclic silicone (I) and tri-substituted halogenosilane (II).
And can be easily separated. Here, the recovered cyclic silicone (I) and trisubstituted halogenosilane (II)
Can be used again for the reaction.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Tetradecamethylhexasiloxane (in the general formula (I),
Synthesis of R ¹ = R ² = R ³ = R ⁴ = R ⁵ = CH ₃ , n = 4) In a 500 ml flask equipped with a dropping funnel, 100 g of octamethylcyclotetrasiloxane, 60.6 g of water and silica gel (manufactured by Merck) Kieselgel 60,250-400 mesh) 10.1g
Was charged. While sufficiently stirring, 109.9 g of trimethylchlorosilane was added dropwise over 1 hour. After 10 hours, the stirring was stopped and the silica gel was filtered. After excess trimethylchlorosilane was distilled off from the resulting filtration, the mixture was transferred to a separating funnel to separate the aqueous layer, and the oil layer was washed twice with 50 ml of water twice.
Was washed once with a saturated aqueous solution of sodium hydrogencarbonate and then twice with 50 ml of water. The resulting solution was distilled under reduced pressure to obtain 63.5 g of tetradecamethylhexasiloxane. 46.8 g of octamethylcyclotetrasiloxane as a raw material was recovered. The yield calculated based on the reacted octamethylcyclotetrasiloxane was 78%.

Example 2 Hexadecamethylheptasiloxane (in the general formula (I),
Synthesis of R ¹ = R ² = R ³ = R ⁴ = R ⁵ = CH ₃ , n = 5): In a 500 ml flask equipped with a dropping funnel, 150 g of decamethylcyclopentasiloxane, 73.2 g of water and silica gel (manufactured by Merck) Kieselgel 60,250-400 mesh) 12.2g
Was charged. With sufficient stirring, 132 g of trimethylchlorosilane 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, the mixture 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 a saturated sodium hydrogen carbonate aqueous solution, and further with 50 ml. Of water twice. The obtained solution was distilled under reduced pressure to obtain 78.8 g of hexadecamethylheptasiloxane. 83.0 g of decamethylcyclopentasiloxane as a raw material was recovered. The yield calculated based on the reacted decamethylcyclopentasiloxane was 67.1%.

[Effects of the Invention] As described above, according to the method for producing a linear silicone of the present invention, a large amount of linear silicone having a specific siloxane chain length without distribution of siloxane units can be produced.

Continued on the front page (58) Fields investigated (Int. Cl. ⁶ , DB name) C07F 7/08 C08G 77/06 G08G 77/38 CA (STN) REGISTRY (STN) WPIDS (STN) BEILSTEIN (STN)

Claims (2)

(57) [Claims] 1. The following general formula (I) (In the formula, R ¹ and R ² may be the same or different and each represent 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 and the following general formula (II) (In the formula, R ³ , R ⁴ and R ⁵ may be the same or different and each represents an alkyl group, an alkenyl group, an aryl group or a halogenated alkyl group, and X represents a halogen atom.) The following general formula (III) characterized in that silane and water are reacted in the presence of an inorganic solid compound. (Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and n have the same meanings as described above). 2. The process according to claim 1, wherein the inorganic solid compound is silica gel.