Abstract: Process for producing PU foams by reacting at least one polyol component with at least one isocyanate component in the presence of one or more catalysts that catalyse the isocyanate-polyol and/or isocyanate-water reactions and/or isocyanate trimerization, and optionally one or more chemical or physical blowing agents, with use of SiOC-bonded polyether siloxanes having branching in the siloxane moiety, prepared from branched siloxanes bearing acetoxy groups, wherein a sufficient amount of the SiOC-bonded polyether siloxane having branching in the siloxane moiety is added that the proportion by mass of this polyether siloxane (e) based on the finished PU foam is from 0.0001% to 10% by weight.

Abstract: Upcycling process for producing acidic, end-equilibrated siloxanes bearing acetoxy groups and having chain lengths of greater than 3 silicon atoms from end-of-life silicones by thermal digestion in an acidic reaction medium comprising acetic anhydride, acetic acid and at least one further Brønsted acid having a pKa of <4, the digestion taking place in a reactor having a volume of at least 1 liter.

Abstract: Described is a process for producing preferably trifluoromethanesulfonic acid-acidified, end-equilibrated, acetoxy-bearing siloxanes which comprises reacting cyclic siloxanes, in particular comprising D4 and/or D5, and/or cyclic branched siloxanes of the D/T type with acetic anhydride using preferably trifluoromethanesulfonic acid as catalyst and with addition of acetic acid, wherein the cyclic branched siloxanes of the D/T type are mixtures of cyclic branched siloxanes of the D/T type which contain not only siloxanes comprising D and T units but also siloxanes comprising Q units.

Abstract: A process for the recycling of silicones, especially silicone rubber and/or silicone oils, by the chemical transformation thereof to silanes and/or siloxanes having acetoxy groups is described, wherein silicone rubber and/or silicone oils are subjected to a heat treatment in digestion systems comprising acetic anhydride and/or acetoxysiloxane, and at least one Brønsted acid, with addition of acetic acid.

Abstract: Branched SiOC-linked polyethersiloxanes have the following formula (I) where R1 is an alkyl radical having 1 to 4 carbon atoms or a phenyl radical, but preferably 90% of the radicals R1 are methyl radicals; b has a value of from 1 to 10; a has a value of from 1 to 200, preferably 10 to 100, a value of from 3 to 70 when b is ?1 and ?4, or a value of from 3 to 30 when b is >4; and R2 denotes identical or different polyether radicals, but at least one radical R2 is a structural element radical of formula (II): where p=at least 2, preferably p=2-6, particularly preferably p=3.

Abstract: SiOC-based polyethersiloxanes are prepared based on linear ?,?-hydroxy group-bearing siloxanes. In a first step, ?,?-acetoxy group-bearing linear polysiloxanes are prepared. In a second step, the ?,?-acetoxy group-bearing linear polysiloxanes are converted into the desired organosiloxane units, preferably shorter organosiloxane units, wherein the thus converted organosiloxane units have ?,?-acetoxy groups. In a third step, the ?,?-acetoxy group-bearing linear polysiloxanes from step 2 react with polyetherols to give SiOC-based polyethersiloxanes.

Abstract: The invention describes (i) reaction systems for the production of siloxanes bearing acetoxy functions, comprising a) silanes and/or siloxanes bearing alkoxy groups and/or b) silanes and/or siloxanes bearing acetoxy groups, c) silanes and/or siloxanes bearing hydroxy groups, d) optionally simple siloxane cycles and/or DT cycles, e) a reaction medium, comprising acetic anhydride, perfluoroalkanesulfonic acid and preferably acetic acid, (ii) a process for producing linear or branched siloxanes bearing acetoxy functions and also the use of same for producing polyethersiloxanes.

Abstract: Described is a process for producing SiOC-bonded polyether siloxanes branched in the siloxane portion from cyclic branched siloxanes of the D/T type, wherein said process comprises in a first step reacting the mixtures of cyclic branched siloxanes of the D/T type with acetic anhydride optionally in admixture with simple siloxane cycles under acid catalysis to afford acetoxy-bearing branched siloxanes, in a second step performing the equilibration of the acetoxy-modified branched siloxane with superacid, preferably with addition of acetic acid and in a third step reacting the superacid-treated acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.

Abstract: Described is a process for producing acidified, preferably superacid-acidified, in particular trifluoromethanesulfonic acid-acidified, end-equilibrated linear ?,?-acetoxy-bearing siloxanes, wherein linear ?,?-hydroxy-bearing siloxanes, using acid, preferably superacid, particularly preferably perfluoroalkanesulfonic acid, especially preferably trifluoromethanesulfonic acid, as catalyst, are reacted with acetic anhydride and with addition of acetic acid.

Abstract: The method for the physical reutilization of sheet-like siliconized structures comprises treating the sheet-like siliconized structure in a liquid digestion system comprising acetic anhydride and/or an acetoxysiloxane, and at least one Brøonsted acid, optionally solvent, preferably with addition of acetic acid, and removing the desiliconized sheet-like structure from the liquid phase.

Abstract: Process for producing SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers comprising repeating (AB) units, comprising pretreating acidified, end-equilibrated ?,?-diacetoxypolydimethylsiloxanes with a base and reacting the ?,?-diacetoxypolydimethylsiloxanes resulting therefrom with polyether diols in the presence of a solid, liquid or gaseous base, optionally using inert solvents.

Abstract: Process for producing PU foams by reacting at least one polyol component with at least one isocyanate component in the presence of one or more catalysts that catalyze the isocyanate-polyol and/or isocyanate-water and/or isocyanate trimerization reactions, and optionally one or more chemical or physical blowing agents, with use of SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers having repeat (AB) units, obtainable through the reaction of polyether diols with equilibrated ?,?-diacetoxypolydialkylsiloxanes, wherein a sufficient amount of the SiOC-linked, linear polydialkylsiloxane-polyoxyalkylene block copolymers having repeat (AB) units is added such that the proportion by mass of said component based on the finished PU foam is from 0.0001% to 10% by weight, preferably 0.01% to 6% by weight, especially 0.05% to 5% by weight.

Abstract: Described is a process for producing preferably trifluoromethanesulfonic acid-acidified, end-equilibrated, acetoxy-bearing siloxanes which comprises reacting cyclic siloxanes, in particular comprising D4 and/or D5, and/or cyclic branched siloxanes of the D/T type with acetic anhydride using preferably trifluoromethanesulfonic acid as catalyst and with addition of acetic acid, wherein the cyclic branched siloxanes of the D/T type are mixtures of cyclic branched siloxanes of the D/T type which may contain not only siloxanes comprising D and T units but also siloxanes comprising Q units.

Abstract: Equilibrated trifluoromethanesulfonic acid-acidified ?,?-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.

Abstract: Equilibrated trifluoromethanesulfonic acid-acidified ?,?-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.

Abstract: Described is a process for producing trifluoromethanesulfonic acid-acidified, end-equilibrated, acetoxy-bearing siloxanes which comprises reacting cyclic siloxanes, in particular comprising D4 and/or D5, and/or cyclic branched siloxanes of the D/T type with acetic anhydride using trifluoromethanesulfonic acid as catalyst and with addition of acetic acid.

Abstract: The production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers comprising repeating (AB) units by reaction of polyether diols with trifluoromethanesulfonic acid-acidified, equilibrated ?,?-diacetoxypolydimethylsiloxanes is described, wherein the reaction is undertaken by adding a solid, liquid or gaseous base, optionally using inert solvents.

Abstract: The production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers comprising repeating (AB) units by reaction of polyether diols with trifluoromethanesulfonic acid-acidified, equilibrated ?,?-diacetoxypolydimethylsiloxanes is described, wherein the reaction is undertaken by adding a solid, liquid or gaseous base, optionally using inert solvents.

Abstract: Reaction system for preparing acetoxy function-bearing siloxanes having chain lengths of more than 3 silicon atoms, comprising silanes and/or siloxanes bearing alkoxy groups, silanes and/or siloxanes bearing acetoxy groups, silanes and/or siloxanes bearing hydroxy groups and/or simple siloxane cycles and/or DT cycles, and also a reaction medium comprising acetic anhydride, Brønsted acid and acetic acid, wherein Brønsted acids having a pKa ??1.30 are used, and wherein the acetic acid is present in the reaction system in amounts of 0.4 to 15.0 percent by weight, based on the reaction system, wherein the molar ratio of Brønsted acid used to acetic acid is in a defined range, with the proviso that either the sole use of trifluoromethanesulfonic acid and also of trifluoromethanesulfonic acid and acetic acid is excluded, and/or that the Brønsted acid used at least in part has a pKa between ?1.3 and >?13.5.

Abstract: SiOC-linked, linear polydimethylsiloxane-polyoxyalkylene block copolymers of formula (I) C—B-(AB)a—C1 are produced by reaction of end-equilibrated ?,?-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.