ИСТИНА

Method of obtaining oligo(organosiloxanes) comprizing hydrolytic polycondensation of chlorosilanes or their mixts. in a water-​free active medium, boiling of the reaction mass and distg. off the solvent, in which chlorosilanes used are compds. having formula Y3-​nSiCln, (n = 1-​3, Y is monovalent hydrocarbon substituents -​CH3, -​C2H5, -​C3H7; -​C4H9, -​CH=CH2, -​C6H5)​, or -​H, reactive medium is a mixt. of urea with 1,​3-​diketone selected from acetylacetone, acetoacetate, malonate in aprotic solvents, condensation is carried out at boiling temp. during 1-​5 h, after cooling Schiff base hydrochloride ppt. and target product is sepd. from soln. by known methods. Thus, polysiloxane oligomer with mol. mass 6200 was obtained in 89​% yield by copolycondensation of phenyltrichlorosilane, methyltrichlorosilane, methyl(phenyl)​dichlorosilane and dimethyl(vinyl)​dichlorosilane carried out at molar ratio SiCl​/urea​/acetylacetone=1.0:1.0:1.0 in hexane.