Process for preparing (mercaptoorganyl)alkoxysilanes

1. A process for the preparation of (mercaptoorganyl)alkoxysilanes, comprising reacting alkali-metal hydrogensulfide with a mixture of (haloorganyl)alkoxysilane and (haloorganyl)halosilane in an alcohol with the exclusion of air and under elevated pressure.

2. The process of claim 1 , wherein said (mercaptoorganyl)alkoxysilane compound produced is of the general formula I:

wherein the substituents R are identical or different and are selected from the group consisting of: C 1 –C 8 alkyl; C 2 –C 12 alkenyl; C 6 –C 10 aryl; C 7 –C 16 aralkyl; or OR′, wherein the substituents R′ are identical or different and are selected from the group consisting of: a C 1 –C 24 branched or unbranched monovalent alkyl or alkenyl group; an aryl group; and an aralkyl group;

R″ is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C 1 –C 30 hydrocarbon group which is optionally substituted by F, Cl, Br, I, NH 2 or NHR′; and

x is 1–3.

3. The process of claim 1 , wherein said (haloorganyl)alkoxysilane compounds are of the general formula II:

wherein the substituents R are identical or different and are selected from the group consisting of: C 1 –C 8 alkyl; C 2 –C 12 alkenyl; C 6 –C 10 aryl; C 7 –C 16 aralkyl; or OR′, wherein the substituents R′ are identical or different and are selected from the group consisting of: a C 1 –C 24 branched or unbranched monovalent alkyl or alkenyl group; an aryl group; and an aralkyl group;

R″ is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C 1 –C 30 hydrocarbon group which is optionally substituted by F, Cl, Br, I, NH 2 or NHR′;

x is 1–3; and

Hal is chlorine, bromine, fluorine or iodine.

4. The process of claim 1 , wherein said (haloorganyl)halosilane compounds are of the general formula III:

wherein R″ is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C 1 –C 30 hydrocarbon group which is optionally substituted by F, Cl, Br, I, NH 2 , or NHR′ wherein the substituent R′ is selected from the group consisting of: a C 1 –C 24 branched or unbranched monovalent alkyl or alkenyl group; an aryl group and an aralkyl group;

x is 1–3; and

Hal is chlorine, bromine, fluorine or iodine; and

the substituents R′″ are identical or different and are selected from the group consisting of: F; Cl; Br; I; C 1 –C 8 alkyl; C 2 –C 12 alkenyl; C 6 –C 10 aryl; C 7 –C 16 aralkyl; and OR′, wherein the substituent R′ is selected from the group consisting of: a C 1 –C 24 branched or unbranched monovalent alkyl or alkenyl group; an aryl group; and an aralkyl group.

5. The process of claim 1 , wherein said alkali-metal hydrogen sulfide is selected from the group consisting of: lithium hydrogen sulfide (LiSH), sodium hydrogen sulfide (NaSH), caesium hydrogen sulfide (CsSH) or potassium hydrogensulfide (KSH).

6. The process of claim 1 , further comprising the addition of polar, protic, aprotic, basic or acidic additives to the reaction mixture at the beginning of the reaction and/or during the reaction and/or at the end of the reaction.

7. The process of claim 1 , wherein the molar ratio of (haloorganyl)alkyoxysilane to (haloorganyl)halosilane is 1:0.00001 to 1:0.8.

8. The process of claim 1 , wherein the quantity of hydrolysable Si halide in said mixture of (haloorganyl)alkyoxysilane and (haloorganyl)halosilane is between 10 mg/kg and 800 000 mg/kg.

9. The process of claim 1 , wherein the molar quantity of said alkali-metal hydrogen-sulfide used in said process exceeds the sum of the molar quantities of said (haloorganyl)alkoxysilane and of said (haloorganyl)halosilane by 1% to 50%.

10. The process of claim 1 , wherein said alcohol is a primary, secondary, tertiary alcohol having from 1 to 24 carbon atoms.