Process for preparing urea-containing mercaptosilanes

1. A process for preparing a urea-containing mercaptosilane of formula I

where each R 1 is independently selected from the group consisting of a C1-C10 alkoxy group, a C2-C10 cyclic dialkoxy group, a phenoxy group, a C4-C10 cycloalkoxy group, a C6-C20 aryl group, a C1-C10 alkyl group, a C2-C20 alkenyl group, a C7-C20 aralkyl group or a halogen, and each R is independently a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon group, the process comprising reacting a halosilane of formula II

where Hal is F, Cl, Br or I

with NaSH in a C2-C8 alcohol.

2. The process of claim 1 , wherein the alcohol is ethanol.

3. The process of claim 1 , wherein the urea-containing mercaptosilane is

(EtO) 3 Si—CH 2 —NH—CO—NH—CH 2 —SH,

(EtO) 3 Si—CH 2 CH 2 —NH—CO—NH—CH 2 —SH,

(EtO)3Si—CH2-NH—CO—NH—CH2CH2-SH,

(EtO)3Si—CH2CH2-NH—CO—NH—CH2CH2-SH,

(EtO)3Si—CH2CH2CH2-NH—CO—NH—CH2-SH,

(EtO)3Si—CH2CH2CH2-NH—CO—NH—CH2CH2-SH,

(EtO)3Si—CH2-NH—CO—NH—CH2CH2CH2-SH,

(EtO)3Si—CH2CH2-NH—CO—NH—CH2CH2CH2-SH,

(EtO)3Si—CH2CH2CH2-NH—CO—NH—CH2CH2CH2-SH,

(MeO)3Si—CH2-NH—CO—NH—CH2-SH,

(MeO)3Si—CH2CH2-NH—CO—NH—CH2-SH,

(MeO)3Si—CH2-NH—CO—NH—CH2CH2-SH,

(MeO)3Si—CH2CH2-NH—CO—NH—CH2CH2-SH,

(MeO)3Si—CH2CH2CH2-NH—CO—NH—CH2-SH,

(MeO)3Si—CH2CH2CH2-NH—CO—NH—CH2CH2-SH,

(MeO)3Si—CH2-NH—CO—NH—CH2CH2CH2-SH,

(MeO)3Si—CH2CH2-NH—CO—NH—CH2CH2CH2-SH or

(MeO) 3 Si—CH 2 CH 2 CH 2 —NH—CO—NH—CH 2 CH 2 CH 2 —SH.

4. The process of claim 1 , wherein the reaction is conducted without additional organic solvent.

5. The process of claim 1 , wherein the reaction is conducted at a temperature between 0° C. and +150° C.

6. The process of claim 1 , wherein the halosilane of formula II, prior to reaction with NaSH, is prepared from a hydrochloride salt of an amine of formula III

and an isocyanatosilane of formula IV

by addition of a base.

7. The process of claim 6 , wherein the base is NaOEt.

8. The process of claim 6 , wherein the base is added until a pH between 7 and 14 is established.

9. The process of claim 1 , wherein the halosilane of formula II, prior to reaction with NaSH, is prepared from an isocyanate-halogen compound of formula V

and an aminosilane of formula VI

10. The process of claim 1 , further comprising filtering the reaction mixture and distilling off the alcohol.

11. The process of claim 10 , further comprising drying a product formed from the reaction.