METHOD OF PRODUCING POLY(ORGANO)(HYDROXY)SILOXANES WITH A GIVEN DEGREE OF POLYCONDENSATION Russian patent published in 2019 - IPC C08G77/06 C08G77/08 C08G77/16 

FIELD: chemistry.

SUBSTANCE: invention relates to chemistry and technology of producing poly(organo)(hydroxy)siloxanes with given degrees of polycondensation. Disclosed is a method of producing poly(organo)(hydroxy)siloxanes of general formula {[R¹R²SiO]_a[R³SiO_3/2]_b[O_1/2H]_c} with a given degree of condensation of "n" organo-trialkoxysilane, where a=0.3–0.8 is molar number of difunctional links; b=0.1–0.2 – molar amount of trifunctional links, c=0.1–0.132 – molar amount of OH groups, including acidohydrolytic copolycondensation of individual organotrialkoxysilanes or mixtures thereof of general formula R¹Si(OR²)₃ with one or mixture of diorganocyclosiloxanes of general formula [R³R⁴SiO]_m, where m=3–6, where R²=CH₃, C₂H₅; R³=CH₃; R¹=R⁴=CH₃, C₂H₃, C₃H₄F₃, C₆H₅, in molar ratio of reagents R¹Si(OR²)₃ : R³R⁴SiO-link=1:2÷5, glacial acetic acid taken in an amount required to provide an "n" condensation degree on organo-trialkoxysilane not greater than 0.833, in the presence of catalytic amounts of concentrated sulfuric acid from 1.7 to 3.1 wt%, wherein the process is carried out at temperature of 85÷100 °C for 2–3 hours with subsequent stepwise increase of temperature of mixture to 120 °C with distillation of alcohol and its acetate to achieve a given organo(trialkoxy)silane condensation, returning the distilled products to the cooled reaction mass, adding demineralized water in an amount calculated by the equation m=yƒ-2x, (where m, y, x is molar quantity of water, alkoxysilane and acetic acid respectively, ƒ – functionality of alkoxysilane), required for complete hydrolysis of alkoxy groups, followed by neutralization of reaction mass, filtration of mixture and removal of volatile substances, wherein output of poly(organo)(hydroxy)siloxanes is not less than 97.8 wt%.

EFFECT: disclosed method is easy to implement and environmentally friendly, and the obtained poly(organo)(hydroxy)siloxanes are used for processing molds to simplify extraction of articles from seats in the bus and polymer industry.

4 cl, 8 ex