UC San Diego

This dissertation describes investigations and findings in our efforts to improve an iridium catalyst system for formic acid disproportionation to generate methanol. First we studied whether or not a catalyst that was effective for thermal formic acid disproportionation catalysis could be used as an electrocatalyst for formic acid reduction. It was found that, under the conditions studied, this was not a viable option.

We then studied the electronic effects of various ligand substituents, both electron-donating and electron-withdrawing, on the iridium complex for thermal formic acid disproportionation. It was found that the complex containing the unsubstituted ligand was the most selective and active for methanol generation.

Our final investigation with this iridium complex was to study the effects of various Lewis acids as additives for the catalytic reaction. We found that the addition of Zn2+ to reaction mixtures resulted in both increased rate of methanol formation and increased selectivity for methanol.

The last work described in this dissertation focuses on the measurement and application of hydricity, a vital thermodynamic property for hydrogenation catalysts. We described efforts to measure the hydricity values of iridium complexes in acetonitrile, as well as an attempt to apply a nickel complex with a hydricity value predicted to be effective for formic acid disproportionation.