Silane hydrolysis with rare earth metal catalysts

摘要

A process for silane hydrolysis, having a good degree of control of reaction rate and presenting mild conditions, comprises reacting together a silane having at least one hydrolysable group with water in the presence of a catalyst comprising a rare earth metal salt with a non-nucleophilic ligand. The ligand is selected from trifluoromethanesulfonate, perchlorate, oxalate, acetate and other alkanoate having a chain length of from 2 to 10 carbon atoms, hexafluoroacetylacetonate and acetylacetonate, with triflate as the preferred ligand. The rare earth metal is preferably a lanthanide, especially lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, thulium or ytterbium. The hydrolysis product may be used in surface treatments of materials having a superficial oxide or hydroxide layer; in one aspect the hydrolysis is carried out in the presence of the surface to be treated. The process is also useful in the production of silicon-based gels such as solvogels and alcogels.