Cleavage of cyclic organosilanes in the preparation of aminofunctional organoalkoxysilanes

An aminofunctional organoalkoxysilane of formula Iwherein the R groups bonded to nitrogen are identical or different and each individual R group is hydrogen, an alkyl radical having from 1 to 4 carbon atoms, an aryl radical or an arylalkyl radical,R is an alkyl radical having from 1 to 8 carbon atoms or an aryl radical,R is an alkyl radical having from 1 to 8 carbon atoms or an aryl radical,y is 2, 3 or 4 and n is 0, 1 or 2, is prepared by a process comprising:reacting a chlorofunctional organoalkoxysilane of formula IIwherein R , R , y and n are as defined above, with ammonia or an organic amine of formula IIIwherein the two R groups are identical or different and each is defined as described above;separating organic amine hydrochloride or ammonium chloride by-product which is formed in the reaction;distilling the resulting crude product, thereby preparing an aminofunctional organoalkoxysilane or the product fraction of an aminofunctional organoalkoxysilane; andtreating the aminofunctional organoalkoxysilane or the product fraction of an aminofunctional organoalkoxysilane with an alcohol.