Two strategies to improve the catalytic activity of Ti-MCM-41 materials in the epoxidation of olefins are described; the first approach involves silylation of the surface of Ti-MCM-41 which produces a very hydrophobic catalyst whereas the second approach is based on removal of water from the reaction media; the increase in activity is not due to a change in the intrinsic activity of the Ti sites, but rather to a decrease of the catalyst deactivation by reducing the formation of diols produced by ring opening of the epoxide.