Process for the preparation of organosilanes

1. Process for the preparation of an organosilane of the formula I,

in which

R are identical or different and are a C 1 -C 8 -alkyl group, C 1 -C 8 -alkenyl, C 1 -C 8 -aryl or C 1 -C 8 -aralkyl group or an OR′ group, R′ are identical or different and are a branched or straight-chain monovalent C 1 -C 24 -alkyl or -alkenyl group, an aryl group, an aralkyl group, a hydrogen (—H), an alkyl ether group O—(CR 111 2 ) —O-Alk or 0-(CR III 2 ) y —O-Alk or an alkyl polyether group 0-(CR III 20)y-Alk or 0-(CR 111 2 − CR III 2 -0)y-Alk, where y=2-20, R III , independently of one another, are H or an alkyl group, and Alk is a branched or straight-chain, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic monovalent C 1 -C 20 -hydrocarbon group,

R″ is a branched or straight-chain, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C 1 -C30-hydrocarbon group which is optionally substituted by F, C 1 , Br, I, HS, NH 2 or NHR′,

X=S if n=2 and m is an average sulphur chain length of from 1.5 to 4.5, and

x=SH if n=1 and m=1,

by reacting a (haloorganyl)alkoxysilane of the formula 11

in which R, R′ and R″ have the above-mentioned meanings and Hal is chlorine, bromine, fluorine or iodine,

in a reaction with a sulphurization reagent selected from the group consisting of alkali metal hydrogen sulphide, metal sulphide Me 2 S, metal polysulphide Me 2 Sg and any desired combinations thereof, where Me=alkali metal, NH 4 or (alkaline earth metal) 1/2 , and g=1.5-8.0, and optionally additionally with sulphur and/or with H 2 S in alcohol, characterized in that the Me 2 S or Me 2 S g contains more than 10% by weight of water and the alkali metal hydrogen sulphide contains more than 3% by weight of water.

2. Process for the preparation of an organosilane according to claim 1 , further comprising adding an additive before, during or after the reaction.

3. Process for the preparation of an organosilane wherein according to claim 2 , the additive is a non-alcoholic solvent, polar, protic, aprotic, basic or acidic additive.

4. Process for the preparation of an organosilane according to claim 1 , further comprising removing a solvent/water mixture from crude product suspension and separating off the resulting organosilane of the formula I from solid.

5. Process for the preparation of an organosilane according to claim 3 , further comprising removing a solvent/water mixture from crude product suspension and separating off the resulting organosilane of the formula I from solid.

6. Process for the preparation of an organosilane according to claim 1 , further comprising removing solvent from a crude product suspension, mixing the resulting mixture containing the organosilane of the formula I and solid Me(Hal) with water containing at least one buffer, and separating phases that form thereby.

7. Process for the preparation of an organosilane according to claim 1 , wherein an alkali metal hydrogen sulphide is used as the water-containing sulphurization reagent in the case of organosilanes of the formula I where X=SH, m=1 and n=1.

8. Process for the preparation of an organosilane according to claim 1 , wherein Me 2 S and sulphur are used as the water-containing sulphurization reagent in the case of organosilanes of the formula I where X=S and m=3.5-4.5.

9. Process for the preparation of an organosilane according to claim 1 , wherein alkali metal hydrogen sulphides, Me 2 S, Me 2 S g . and any desired combinations thereof, and optionally additionally sulphur and/or H 2 S, are used as water-containing sulphurization reagents in the case of.organosilanes of the formula I where X=S and m=1.5-4.5, and wherein the reaction is carried out in a closed vessel in the absence of air.