Catalytic transfer hydrogenation of 2-butanone on MgO. New active surface sites generated by treatment with chloroform

In the course of heterogeneous catalytic transfer hydrogenation (CTH) of ca rbonyl compounds with alcohols on MgO, the catalyst is continuously poisone d, which leads to a complete loss of activity. The main result of the prese nt work is that deactivation may be prevented by treatment with chloroform and the initial activity of MgO is retained for as long as 65 h. Detailed i nvestigations were carried out (activations of MgO, TG, DSC, chloroform tre atment, FT-IR spectroscopy, CDCl3 adsorption) in order to identify both typ es of active centers responsible for poisoning and CTH. Based on our own ex perimental results as well as on data in the literature, the prerequisites of CTH on MgO appear to be basic (O2-) site and adjacent surface hydroxyl s ite pairs. Lewis acid centers responsible for poisoning are blocked and act ive surface hydroxyl groups of weakly acidic character are simultaneously g enerated by chloroform treatment.