Silylation of Non-Terminal Double Bonds of Natural Oils

摘要

Silylation of non-terminal double bonds of unsaturated fatty acids with reactive organosilicons was successfully accomplished using the 'Ene' reaction route. The 'Ene' reaction, which is a subset of the famous Diels Alder reaction, enables grafting of vinyl silanes onto unsaturated organic molecules irrespective of the position of the double bond. This procedure was used to graft vinyltrialkoxysilanes onto unsaturated fatty acids of various triglyceride oils. Methyl oleate and methyl stearate were used as model compounds to investigate this reaction. H-1 NMR and TGA were used to characterize the structure of the silylation products and to determine the extent of grafting as a function of reaction conditions. It was found that this grafting reaction follows a second order kinetics. Under extreme conditions a silyl-ester redistribution reaction can also occur where an alkoxy group attached to the silicon atom is exchanged with an alkoxy group of the organic ester. Grafting vinyltrimethoxysilane onto natural oils such as soybean, canola and Abyssinian oils leads to a convenient one-component, moisture activated cure system of these natural oils.