Process for preparing organically modified polyorganosiloxanes

1. A process for the dehydrogenative condensation of alcohols and siloxanes which have at least one hydrogen atom bound to a silicon atom in the molecule, wherein at least one quaternary ammonium hydroxide is used as a catalyst for the process.

2. The process as claimed in claim 1 , wherein at least one quaternary ammonium hydroxide is a compound of the general formula (I)

where

R 1 , R 2 , R 3 and R 4 are, independently of one another, substituted or unsubstituted branched or unbranched hydrocarbon radicals which have from 1 to 20 carbon atoms and may contain heteroatoms and may contain further functional groups; and two radicals R 1 to R 4 together can form a five- or six-membered ring which may contain heteroatoms, may be substituted and may contain multiple bonds.

3. The process as claimed in claim 1 , wherein the quaternary ammonium hydroxide is selected from the group consisting of:

tetramethylammonium hydroxide,

tetraethylammonium hydroxide,

tetrapropylammonium hydroxide,

tetraisopropylammonium hydroxide,

tetrabutylammonium hydroxide,

tetraisobutylammonium hydroxide,

tetra-tert-butylammonium hydroxide,

tetrapentylammonium hydroxide,

tetrahexylammonium hydroxide,

tetraheptylammonium hydroxide,

tetraoctylammonium hydroxide,

benzyltrimethylammonium hydroxide,

diethyldimethylammonium hydroxide,

methyltripropylammonium hydroxide,

N,N,N,N′,N′,N′-hexabutylhexamethylenediammonium hydroxide,

tetrakis(2-hydroxyethyl)ammonium hydroxide,

tributylmethylammonium hydroxide,

triethylmethylammonium hydroxide,

trimethylphenylammonium hydroxide,

(2-hydroxyethyl)trimethylammonium hydroxide,

(2-hydroxyethyl)triethylammonium hydroxide,

(2-hydroxyethyl)tripropylammonium hydroxide,

(2-hydroxyethyl)tributylammonium hydroxide,

hexamethonium hydroxide,

dimethyldiethanolammonium hydroxide; and

mixtures thereof,

in each case as an anhydrous solid, as a solid in various degrees of hydration, as a solution in aqueous or nonaqueous solvents or mixtures of solvents, adsorbed or covalently bound to support substances or as a dispersion, are used as effective catalysts, optionally in admixture with further catalysts which is not a quaternary ammonium hydroxide.

4. The process as claimed in claim 1 , wherein after completion of dehydrogenative condensation the quaternary ammonium hydroxide compounds are decomposed up to 90% based on the total weight of the catalyst within 10 hours of heating at temperatures up to 200° C. optionally under >5 mbar reduced pressure.

5. The process as claimed in claim 1 , wherein the siloxanes are compounds of the general formula (II)

where the radicals

R are one or more identical or different radicals selected from among linear or branched, saturated, monounsaturated or multiply unsaturated alkyl, aryl, alkylaryl or arylalkyl radicals having from 1 to 40 carbon atoms, haloalkyl groups having from 1 to 20 carbon atoms, siloxy groups and triorganosiloxy groups,

R′ and R″ are each, independently of one another, H or R,

x is an integer from 0 to 600,

y is an integer from 0 to 100,

with the proviso that at least one hydrogen atom bound to a silicon atom is present in the molecule,

are used as siloxanes which have at least one hydrogen atom bound to a silicon atom in the molecule.

6. The process of claim 5 , wherein:

x is an integer from 0 to 200,

y is an integer from 0 to 50.

7. The process of claim 6 , wherein:

y is an integer <40.

8. The process as claimed in claim 1 , wherein the alcohols are at least one compound selected from the group consisting of linear or branched, saturated, monounsaturated or polyunsaturated, aromatic, fluorinated or perfluorinated, mono(meth)acrylated or poly(meth)acrylated, aliphatic-aromatic, optionally further functionalized monoalcohols or polyalcohols, polyether monoalcohols or polyalcohols, amino alcohols, primary amino alcohols, N-alkyl alcohols, arylamino-(C 2 H 4 O) n alcohols, arylamino-(C 2 H 4 O) n alcohols in which n and m are each from 1 to 50, N-alkylamino or arylamino alcohols, polyether alcohols bearing amino groups, hydroxyalkylpiperazines, hydroxyalkylpiperidines and hydroxyalkylpyrrolidines, trialkylalkanolammonium salts, dialkyldialkanolammonium salts, dialkylbis[hydroxy(oligoalkoxy)]ammonium salts, mercapto alcohols, S-alkyl, arylthio ethylene oxide, propylene oxide alcohols, S-alkyl alcohols or arylthio alcohols, hydroxyalkylphosphonium salts, and hydroxyarylphosphonium salts.

9. The process as claimed in claim 1 , wherein the alcohols are selected from the group consisting of:

methanol, ethanol, fatty alcohols having from 6 to 22 carbon atoms, polyether alcohols comprising styrene oxide and/or butylene oxide which have been functionalized with propylene oxide or ethylene oxide, polyether alcohols bearing amino groups, polyether alcohols containing styrene oxide and/or butylene oxide, amino alcohols and mixtures thereof.

10. The process as claimed in claim 1 , wherein the catalyst is used as a homogeneous or heterogeneous catalyst or the reaction is carried out as a homogenized heterogeneous or heterogenized homogeneous catalysis.

11. The process as claimed in claim 1 , wherein the molar ratio of SiH groups to alcohol groups is in the range from 1:0.1 to 1:0.99 molar equivalent.

12. The process as claimed in claim 1 , wherein the alcohol is used in a 10% molar excess, based on SiH groups.

13. The process as claimed in claim 5 , wherein polyorganosiloxanes selected from the group consisting of comb-like, α-monosubstituted, α,ω-disubstituted and mixed polydimethylhydrogensiloxanes of the general formula (II) are used.

14. The process as claimed in claim 1 , wherein the polyorganosiloxanes are selected from the group consisting of compounds of the general formula (III):

M-O-D x -D′ y -M  (III)

where

M is trialkylsilyl or trimethylsilyl,

D x is (dialkylsilyloxy) x , or (dimethylsilyloxy) x , and

D′ y is

x is an integer from 0 to 600,

y is an integer from 0 to 100.

15. The process as claimed in claim 1 , wherein the polyorganosiloxanes are selected from the group consisting of compounds of the general formula (IV):

M′-O-D x -M′  (IV)

where

M′ is dialkyl(hydrogen)silyl, or dimethylhydrogensilyl, and

D x is (dialkylsilyloxy) x , or (dimethylsilyloxy) x , and

x is an integer from 0 to 600.

16. The process as claimed in claim 1 , wherein polyorganosiloxanes selected from the group consisting of compounds of the general formula (V):

M′-O-D x -D′ y -M′  (V)

where

M′ is dialkyl(hydrogen)silyl, or dimethylhydrogensilyl,

D x is (dialkylsilyloxy) x , or (dimethylsilyloxy) x , and

D′ y is

x is an integer from 0 to 600,

y is an integer from 0 to 100, are used.

17. The process as claimed in claim 1 , wherein the process is carried out in the absence of solvents.

18. The process of claim 3 , wherein the alcohols are selected from the group consisting of:

methanol, ethanol, fatty alcohols having from 6 to 22 carbon atoms, polyether alcohols comprising styrene oxide and/or butylene oxide which have been functionalized with propylene oxide or ethylene oxide, polyether alcohols bearing amino groups, polyether alcohols containing styrene oxide and/or butylene oxide, amino alcohols and mixtures thereof;

the molar ratio of SiH groups to alcohol groups is in the range from 1:0.1 to 1:0.99 molar equivalent;

the reaction is carried out in the absence of solvents.

19. The process as claimed in claim 18 , wherein the polyorganosiloxanes are selected from the group consisting of compounds of the general formula (III):

M-O-D x -D′ y -M  (III)

where

M is trialkylsilyl, or trimethylsilyl,

D x is (dialkylsilyloxy) x , or (dimethylsilyloxy) x , and

D′ y is

x is an integer from 0 to 600,

y is an integer from 0 to 100.

20. The process as claimed in claim 18 , wherein the polyorganosiloxanes are selected from the group consisting of compounds of the general formula (IV):

M′-O-D x -M′  (IV)

where

M′ is dialkyl(hydrogen)silyl, or dimethylhydrogensilyl, and

D x is (dialkylsilyloxy) x , or (dimethylsilyloxy) x , and

x is an integer from 0 to 600.