Synthesis of [(Trialkoxysilyl)propyl]imides

Abstract

Imidization reactions between anhydrides and (alkoxysilyl)propylamines containing alkorysilane groups result in hydrolysis and condensation of the alkoxysilane groups and formation of SiOSi bonds. As a result, the direct reaction of various anhydrides with (γ-aminopropyl)trialkoxysi- lanes did not afford [(trialkoxysilyl)propyl]imides but instead resulted in insoluble crosslinked materials. A successful two-step synthesis of [(trialkoxysilyl)propyl]imides is reported. In the first step, an inter- mediate imide was prepared by reaction of an anhydride with 2-aminopy- ridine. Following removal of the water of imidization, addition of an (γ-aminopropyl)trialkoxysilane resulted in a transimidization equilibri- um which favored displacement of 2-aminopyridine and formation of a [(trialkoxysilyl)propyl]imide in high yield. Synthesis of a moisture- curable polyimide containing alkoxysilane endcaps is briefly described