Titanium-based solid catalysts for transesterification of methyl-methacrylate by 1-butanol: the homogeneous catalysis contribution Original Research Article

Titanium-based solid catalysts were prepared according to two different procedures. In order to improve the stability of the Sisingle bondOsingle bondTi bond in the titanium grafted silica catalysts, the surface remaining hydroxyl groups were passivated to prevent the titanium leaching by Sisingle bondOsingle bondTi bond solvolysis. This was performed by grafting trimethoxy-silane groups on isolated silanols of silica, after or before metal grafting. The synthesised materials were characterised by FT-IR spectroscopy, and their catalytic properties evaluated in the reaction of transesterification of methyl-methacrylate (MMA) with 1-butanol (BuOH) in liquid phase to produce butyl-methacrylate (BuMA). An important titanium leaching (18–35%) was always detected with all the solid catalysts.Investigation of the behaviour of Ti(OBu)4 as homogeneous catalyst for very small concentrations of titanium was carried out in order to evaluate the catalytic contribution of the active dissolved species. We demonstrate here that the catalytic activity is mainly due to the homogeneous catalysis.