A method for making long chain hydroxyl terminated polydiorganosiloxanes with low cyclics content via condensation polymerization employs a selective catalyst. The catalyst includes a salt-anion complex and a free acid.

Spherical polysilsesquioxane particles in which, in a first step, trialkoxysilane of formula (I)

RSi(OR.sup.1).sub.3   (I),

in which R represents a C.sub.1-16 hydrocarbon radical whose carbon chain may be interrupted by nonadjacent —O— groups, and R.sup.l represents a C.sub.1-4 alkyl radical, is reacted with acidified water having a pH of not more than 6 with commixing to afford a hydrolyzate, in a second step the hydrolyzate is mixed with a solution of a base in water or C.sub.1-4 alkanol, in a third step the mixture is stored for 30 minutes to 6 hours, in a fourth step the mixture is mixed with a further solution of a base in water or C.sub.1-4 alkanol, in a fifth step the mixture is agitated for at least 5 minutes, and in a sixth step the polysilsesquioxane particles are isolated.

Spherical polysilsesquioxane particles in which, in a first step, trialkoxysilane of formula (I)

RSi(OR.sup.1).sub.3   (I),

in which R represents a C.sub.1-16 hydrocarbon radical whose carbon chain may be interrupted by nonadjacent —O— groups, and R.sup.l represents a C.sub.1-4 alkyl radical, is reacted with acidified water having a pH of not more than 6 with commixing to afford a hydrolyzate, in a second step the hydrolyzate is mixed with a solution of a base in water or C.sub.1-4 alkanol, in a third step the mixture is stored for 30 minutes to 6 hours, in a fourth step the mixture is mixed with a further solution of a base in water or C.sub.1-4 alkanol, in a fifth step the mixture is agitated for at least 5 minutes, and in a sixth step the polysilsesquioxane particles are isolated.

Equilibrated trifluoromethanesulfonic acid-acidified α,ω-diacetoxypolydimethylsiloxanes, processes for the production thereof and SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA and a process for the production thereof are described, wherein the production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA is effected by reacting trifluoromethanesulfonic acid-acidified acetoxysiloxane with polyetherols optionally in the presence of buffer mixtures and optionally an additional condensation catalyst and optionally in the presence of an inert solvent.

Equilibrated trifluoromethanesulfonic acid-acidified α,ω-diacetoxypolydimethylsiloxanes, processes for the production thereof and SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA and a process for the production thereof are described, wherein the production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA is effected by reacting trifluoromethanesulfonic acid-acidified acetoxysiloxane with polyetherols optionally in the presence of buffer mixtures and optionally an additional condensation catalyst and optionally in the presence of an inert solvent.

Equilibrated trifluoromethanesulfonic acid-acidified α,ω-diacetoxypolydimethylsiloxanes, processes for the production thereof and SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA and a process for the production thereof are described, wherein the production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA is effected by reacting trifluoromethanesulfonic acid-acidified acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.

Equilibrated trifluoromethanesulfonic acid-acidified α,ω-diacetoxypolydimethylsiloxanes, processes for the production thereof and SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA and a process for the production thereof are described, wherein the production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA is effected by reacting trifluoromethanesulfonic acid-acidified acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.

A method for making long chain hydroxyl terminated polydiorganosiloxanes with low cyclics content via condensation polymerization employs a trifluoromethane sulfonate compound catalyst. The trifluoromethane sulfonate may be complexed with a multidentate ligand.

A method for making long chain hydroxyl terminated polydiorganosiloxanes with low cyclics content via condensation polymerization employs a trifluoromethane sulfonate compound catalyst. The trifluoromethane sulfonate may be complexed with a multidentate ligand.

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.