The use of ultra wide pore silica as a catalyst for the hydrogenation of polystyrene to give poly(cyclohexylethylene) (PCHE) has facilitated the development of a dramatically improved process with much milder conditions. The large pores allow rapid diffusion into and out of-the catalyst, so that the interior surfaces are also available for reaction. The mild conditions give rise to high-quality PCHE, whose structure is shown in the Figure.