Catalysis research at the nanoscale relies on the ability to design and characterize relevant structures with an unprecedented degree of precision. An important application in the energy industry is the conversion of an alcohol, oxygen and carbon monoxide to the corresponding dialkyl carbonate, along with other potentially useful partial oxidation products. We are studying the particular case of ethanol conversion to diethyl carbonate (DEC). Dimethyl carbonate (DMC) has been investigated for its potential as a fuel oxygenate; however, DEC has several advantages (higher heating value, higher gasoline/water distribution coefficient, benign decomposition products) over DMC in this regard.

Recent studies have provided evidence for the catalytic activity of CuCl2 and PdCl2, supported on activated carbon (AC). In our investigation of CuCl2/PdCl2/AC catalysts at ambient reaction pressure, we have observed DEC synthesis rates up to 0.0004 mol DEC/mol Cu-sec, with selectivities from ethanol to DEC up to 60%. At higher reaction pressures, 100% selectivity to DEC can be reached.

To identify the factors that facilitate DEC synthesis on CuCl2/PdCl2/AC, we have carried out x-ray absorption and x-ray diffraction experiments to characterize the state of Cu and Pd under reaction conditions. Insights from these studies will be useful to infer other catalyst modifications that might lead us to a catalyst that is increasingly active and stable towards the synthesis of diethyl carbonate.