Method for preparing hydroxyalkyl disiloxane

Abstract

The invention relates to a method for preparing hydroxyalkyl disiloxane. The method includes the following steps: (1) mixing carboxylic acid unsaturated ester with dimethylchlorosilane in an organic solvent, introducing inert gas, adding hydrosilyation catalyst and stirring for 2 to 12 hours; (2) dropwising a mixed liquid of acidic aqueous solution and the organic solvent to the hydrosilylation reaction product and hydrolyzing for 1 to 6 hours; (3) regulating the hydrolysis product pH to be neutral, extracting organic layers three times with extraction agent, washing three times, drying for 24 hours and removing the extraction agent by rotary evaporating to obtain the finished product. The method has the advantages of simple operation, simple steps, mild reaction conditions, pure product and high yield, and the yield of the hydrosilylation reaction product can reach 83.2% and the yield of the hydrolysis product can reach 89.5%.

Description

technical field [0001] The invention relates to a method for preparing hydroxyhydrocarbyl disiloxane, which belongs to the technical field of synthesis of organic silicon compounds. Background technique [0002] Hydroxyhydrocarbyl-terminated polysiloxane oligomer is one of the main raw materials for the preparation of silicone block polymers, which has very important value. When synthesizing hydroxyhydrocarbyl-terminated polysiloxane oligomer, hydroxyhydrocarbyl disiloxane is a necessary raw material. [0003] At present, the existing domestic methods for preparing hydroxyalkyl disiloxanes are mainly hydrosilylation and organometallic synthesis. Chai Zibin, Wu Qingzhou, etc. used tetraethoxysilane and allyl alcohol as raw materials, carried out transesterification under the catalysis of sodium ethoxide, and obtained the monobasic transesterification product allyloxytriethoxysilane by controlling the conditions, and then It reacts with 1,1,3,3-tetramethyldisiloxane under th...

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Problems solved by technology

However, the organometallic synthesis method has higher requirements for operation and more by-products, which is not suitable for industrial production.

In 2003, Scheurich in Canada prepared 1,3-bis(γ-hydroxypropyl)tetramethyldisiloxane with 3-acetoxypropyl dimethylsilane. The method first used anisyl alcohol and bromopropyl Alkynes react to generate 1-methoxy-4-[(2-propyn-1-oxy)methyl]-benzene (1-methoxy-4-[(2-propyn-1-yloxy)methyl]-benzene), Utilize the first step product to react with 3-acetoxypropyl dimethyl silane to generate [3-[[3-(acetoxy) propyl] dimethylsilyl]]-2-propynol (3 -[[3-(acetyloxy)propyl]dimethylsilyl]-2-propyn-1-ol), then drop hydrazine hydrate into the methanol solution of propynyl alcohol at room temperature, stir for seven days, and then extract and purify with dichloromethane to obtain 1,3-bis(γ-hydroxypropyl)tetramethyldisiloxane (Scheurich, Rene P.Sel.Org.React.Database (SORD), 2003, (20121004)), but the method steps are very complicated , it is difficult to use industrially

In 2016, the organosilicon research group of Shandong University synthesized 1,3-bis(γ-hydroxypropyl)tetramethyldisiloxane by alcoholysis-hydrosilylation-hydrolysis of dimethylhydrochlorosilane. The reaction discharges hydrogen chloride by using an allyl alcohol-sodium allyl alcohol mixed solution, an organic solvent with little solubility of hydrogen chloride, or an acidic absorbent, and improves the hydrosilylation yield by using a hydrosilylation catalyst to obtain disiloxane, but The purity of the product obtained by this method is slightly poor, and the purification is slightly difficult (Zhang Yuhan. A preparation method for hydroxypropyl (butyl) disiloxane, CN105037735A[P].)

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