Silane Coupling Agent Crosile® 189 is a colorless clear liquid with light typical odor and easily soluble in ethyl alcohol, acetone, benzene, toluene etc. Insoluble in water. 3-Mercaptopropyltrimethoxysilane is a bifunctional organosilane possessing a reactive organic mercapto and a hydrolyzable inorganic methoxysilyl group.