SU446509A1 - The method of producing hexa-organo-cyclotrisiloxanes with perfluoroalkylaryl substituents at the silicon atom - Google Patents

Description

one

This invention relates to a process for the preparation of hexa-organocyclotrisiloxanes with aryl substituents at the silicon atom, which can be used in the synthesis of benzo-oil-resistant siloxane rubbers.

A known method for producing cyclosiloxanes with perfluoroalkylaryl substituents at the silicon atom is hydrolyzed in the ester of the corresponding diorganodichlorosilanes, followed by distillation of the cyclic products. During hydrolysis, along with cyclosiloxanes, a significant amount of polymer products is formed, and the content of a trimer in a mixture of cyclosiloxanes does not exceed 15–20%. In addition, the use of toxic and explosive ether in industrial production is associated with great difficulties.

The purpose of the invention is to increase the yield of perfluoroalkylaryl containing hexa-organo-cyclotrisiloxanes.

According to the invention, the reaction between diorganodichlorosilane with a perfluoroalkylaryl substituent at the silicon atom with an amide is carried out in a ketone solution.

A method for the preparation of these compounds by the interaction of an organic amide, for example formamide, acetamide, with dioorganodichlorosilanes, i.a. (trifluoromethyl) -phenylcichlorosilane, bis- (l {-trifluorotolyl) -dichlorosilane in a ketone-type solvent, for example acetone, methyl ethyl ketope, at room temperature for 24-48 hours. The molar ratio of diorganodichlorosilane and o 1 mg of the organic amide and a diorganodichlorosilane / solvent volume ratio of 1: 3-5. After completion of the process, cyclotrisiloxane is isolated by distillation or crystallization.

The yield of hexa-organo-cyclotrisiloxanes with perfluoroalkylaryl groups at the silicon atom is 5Q-70%.

Example 1. To a solution of 16.7 g (0.64 mol) of methyl- (g-trifluorotolyl) dichlorosilane in 75 ml of acetone, 14.4 g (3.2 mol) of formamide was added over 45 minutes. The reaction is exothermic. When the formamide is added, the reaction mixture is left under stirring at room temperature for 30 hours. Then ammonium chloride is filtered off from the reaction products and 75 ml of water is added to the filtrate. The lower siloxane layer is separated, which is washed several times with water and dried with calcium chloride. During the distillation of the siloxane oil, 8.8 g (yield 68%) of 1,3,5-trimethyltri - (W-trifluorotolyl) - cycl trisiloxane, m.p. 204–206 ° C (1–, 5., 20 ,,,, -., 20 1.3218, mol. Weight was found. Hg. ST.), P D 1.4710, and 4,607, calculated 612. OSPK Literary data: 1.4698, d 4 Example 2. To a solution of 78.4 g (0.3 mol) of methyl- (W-trifluortolyl) -dichlorosilane in 390 ml of acetone, 94.5 g are added with stirring over 1 hour ( 2.1 mol) formamide. The reaction mixture was left at room temperature for 48 hours and then treated in the same manner as in Example 1. 43.78 g (yield 76%) of 1,3,5-trimethyl-1, 3.5 - (W-trifluorotholyl) were obtained. - cyclotrisiloxane. Example 3. To a solution of 16.2 g (0.0045 mol) of methyl- (W-heptafluoropropylphenyl) - dichlorosilane in 80 ml of acetone, 13.5 g (0.3 mol) of formamide are added with stirring. The reaction mixture is left at room temperature for 48 hours and then is treated as in Example 1. After distillation, 5.8 g (yield 66%) of 1,3,5-trimethyl-1,3,5-tri- (l- heptafluoropropylphenyl) - cyclotrisiloxane, t. Kip. 200–201 ° C (0.5 mmHg), p 1.4280, 1.4673. Found,%: C 39.8, 39.9; H 3.0, 2.8; F 43.51, 43.40; Si 8.8, 8.9. Calculated,%: C 39.49; H 2.32; F 43.73; Si 9.23. Mol weight found 905; calculated 913.68. Subject of the Invention The method of producing hexaorgano-cyclotrisiloxanes with perfluoroalkylaryl substituents at the silicon atom based on diorganodichlorosilane with a perfluoroalkyl substituent at the silicon atom, characterized in that, in order to increase the yield of the target product, the subject, a subject, is at solvent ketone type, for example acetone.