A process can be used for increasing the molecular weight of low molecular weight α,ω-polysiloxanediols. The process involves heating the low molecular weight α,ω-polysiloxanediols in the presence of acetic anhydride at temperatures of 80° C. to 220° C., preferably at temperatures of 100 to 200° C., and particularly preferably at temperatures of 120-180° C., for 1 h to 24 h, preferably for 2 h to 16 h, and particularly preferably for 3 h to 12 h. The molar amount of the silanol groups used is greater than that of the acetic anhydride used.

The present invention relates to a process for producing and for regenerating siloxane hydrogen carrier compounds.

SiOC-linked, linear polydimethylsiloxane-polyoxyalkylene block copolymers of formula (I) C—B-(AB).sub.a—C1 are produced by reaction of end-equilibrated α,ω-diacetoxypolydimethylsiloxanes with a mixture including at least one polyether polyol, preferably a polyether diol, and at least one polyether monool or at least one monohydric alcohol.

SiOC-linked, linear polydimethylsiloxane-polyoxyalkylene block copolymers of formula (I) C—B-(AB).sub.a—C1 are produced by reaction of end-equilibrated α,ω-diacetoxypolydimethylsiloxanes with a mixture including at least one polyether polyol, preferably a polyether diol, and at least one polyether monool or at least one monohydric alcohol.

Processes are described for purifying acidic, preferably superacidic, in particular trifluoromethanesulfonic acid-acidified, end-equilibrated acetoxysiloxanes, wherein the acidic, preferably superacidic, in particular trifluoromethanesulfonic acid-acidified, acetic anhydride-containing and optionally acetic acid-containing equilibrated, preferably end-equilibrated acetoxysiloxane, which is optionally dissolved in an inert solvent, is contacted with a base, the precipitate is filtered off thereafter and then the filtrate obtained is optionally purified by distillation.

Processes are described for purifying acidic, preferably superacidic, in particular trifluoromethanesulfonic acid-acidified, end-equilibrated acetoxysiloxanes, wherein the acidic, preferably superacidic, in particular trifluoromethanesulfonic acid-acidified, acetic anhydride-containing and optionally acetic acid-containing equilibrated, preferably end-equilibrated acetoxysiloxane, which is optionally dissolved in an inert solvent, is contacted with a base, the precipitate is filtered off thereafter and then the filtrate obtained is optionally purified by distillation.

Organofunctional organopolysiloxanes resins are prepared by reaction of a reactive silicone resin with a symmetrically substituted disiloxane in the presence of a heterogeneous activated silicate catalyst.

Organofunctional organopolysiloxanes resins are prepared by reaction of a reactive silicone resin with a symmetrically substituted disiloxane in the presence of a heterogeneous activated silicate catalyst.

By incorporating an additional TCS and/or DCS redistribution reactor in the TCS recycle loop and/or DCS recycle loop, respectively, of a process and system for silane manufacture, efficiencies in the production of silane are realized. Further improvements in efficiencies may be realized by directing a portion of the product from a redistribution reactor into a distillation column, and specifically into the distillation column that formed the feedstock that went into the redistribution reactor.

The present disclosure relates to a method for preparing polyorganosiloxanes, comprising the following steps: a) reacting together a hydroxyl-terminated polysiloxane and a dialkoxysilane or an oligomer thereof in the presence of Catalyst 1, and b) reacting the product of Step a) with an endcapper in the presence of Catalyst 2 to form the polyorganosiloxane. According to this method, poly-organosiloxanes with an appropriate degree of the polymerization and viscosity are prepared by the polycondensation and equilibration reactions sequentially, and can significantly reduce the viscosity, and improve the flowability and thermal conductivity of the resulting silicone compositions, compared with other polysiloxanes at the same high thermally conductive filler loading.