Kenneth O’Connor (Marshall University, USA)
Catalytic hydrogenation is one of the most often employed methods for the conversion of alkenes to alkanes. Typically these reactions are conducted in solution using either a homogeneous or heterogeneous transition metal catalyst. The green hydrogenation of methyl trans-cinnamate and dimethyl fumarate currently performed in our organic chemistry laboratory classes will be presented. This experiment uses 2% Pd nanoparticles entrapped in an aluminum oxy-hydroxide matrix (Pd/Al(O)OH) as the transition metal catalyst; the hydrogenation is essentially quantitative within 45 minutes and student yields are in the 70-95% range. The catalyst is recycled, the solvent used to separate the product from the catalyst is recovered and coupled with the fact that no waste is generated in this experiment, this experiment is an excellent example of a green chemical reaction. Students use TLC to determine if the reaction has gone to completion and NMR and IR to obtain spectroscopic data of the reactants and products.