摘要:
In the preparation of a cyclic diphenylsiloxane of the formula ##STR1## WHEREIN N IS 3 OR 4, BY HYDROLYSIS OF A DIPHENYLDIHALOGENOSILANE, THE IMPROVEMENT WHICH COMPRISES ADDING THE DIPHENYLDIHALOGENOSILANE, IN THE PRESENCE OF AN ORGANIC, APROTIC SOLVENT TO AN AQUEOUS BASIC SOLUTION, THE BASE BEING EMPLOYED IN AN AMOUNT WHICH IS AT LEAST STOICHIOMETRICALLY EQUIVALENT TO THE HALOGEN CONTENT, WHEREBY THE CYCLIC DIPHENYLSILOXANE IS OBTAINED IN HIGH YIELD AND PURITY. The base is preferably lithium hydroxide, potassium hydroxide or sodium hydroxide and is used in the form of an at least 5 molar solution, about 2.1 to 2.5 equivalents being used per mole of diphenyldihalogenosilane.
摘要:
A process for the preparation of an organopolysiloxanol comprising contacting at least one organochlorosilane of the formula(CH.sub.3).sub.a (C.sub.2 H.sub.5).sub.b (CH.sub.2 = CH --).sub.c SiCl.sub.4-a-b-cWhereina, b and c is 0, 1, 2 or 3And wherein2 .ltoreq. a+b+c .ltoreq. 3At a temperature of about -10.degree. to 90.degree.C with water containing NH.sub.4 Cl in an amount from 1 to 100 percent of its saturation concentration, the pH value of the aqueous solution being adjusted to between about 7.5 and 11.6 by introduction of NH.sub.3, separating the hydrolyzate from the aqueous solution immediately after hydrolysis, and flushing the hydrolyzate with an inert gas, to remove NH.sub.3 therefrom.
摘要:
A process for making cold-setting, non-shrinkable polyurethane foam resins using a mixture of silicon compounds of the formula:A.sub.x B.sub.x+2whereinx=2-25, preferably 2-5A is the group R' Si O.sub.3/2B is the group (R).sub.3 Si O.sub.1/2R represents an alkyl group having from 1 to 3 carbon atomsR' represents an aryl group having from 6 to 14 carbon atoms, with the proviso that the mixture contains at least one compound wherein x is greater than 3.