Investigation on organocalcium catalysis is just unfolding during the past decade. Beside conventional Ca salts with strong electron-withdrawing counter anions that may serve as Lewis acid catalysts, many Ca complexes have also been designed recently and found to be good catalysts in activation of element-H(EAH) bonds like transition metal catalysts. These findings are interesting and may attract the interest of the chemists. Due to the great abundance, non-toxicity, and biocompatible features of Ca element,Ca-catalyzed reactions can be of great significance from the viewpoint of industry. This short review summarizes the recent advances on Ca-catalyzed reactions of EAH bonds. We hope that it may provide a useful guide for interested readers from both the academy and industry.
PtSnNa/γ-Al_2 O_3 catalyst is widely used in the dehydrogenation of light alkane. This paper reports a new fabrication method of the catalyst. In the work, γ-Al_2 O_3, SnCl_4 and NaCl were ball milled to upload Sn and Na^+ onto the support instead of the conventionally used immersion method. The subsequent baking procedures frimly fixed Sn onto the support, which could disperse Pt introduced by immersion. The effects of Sn and Na^+ additives on the catalytic performance of PtSnNa/γ-Al_2 O_3 catalyst were investigated. It was found that the appropriate molar ratio of Sn/Pt was 6:1 while the favorable weight percentage of Na^+was 0.90%. Compared with the reaction catalyzed by the industrially employed PtSnNa/γ-Al_2 O_3 catalyst, the conversion of propane and the selectivity of propylene had been greatly improved,which were 26.97% and 99.18% respectively after 12 h reaction.
A unique Pd&Cu@Al catalyst was easily fabricated just by immersing commercial aluminum foil in a mixed xylene solution of PdCl_2 and CuCl_2. The catalyst fabrication process led to aluminum oxide coatings in situ, which supported the metal nanoparticles and enhanced their catalytic activities for the phosphine-free Heck reaction of aryl halides and styrenes with high turnover number(TON) up to 3.9×10~5. The reaction can be scaled up to at least 100 mmol and has been applied in modification of drug Lapatinib's intermediate with low metal residue. This novel catalyst is of good application potential in industrial production because it was extremely easy to be recycled, in regardless of the generation of the insoluble impurities or tars during the reaction processes.
