Ultrafast excited state proton transfer in the condensed phase and nanoconfinement

A safe one-pot catalytic process for directly producing tertiary butyl alcohol (TBA) from liquid-phase isobutane oxidation with oxygen is demonstrated. This is achieved by operating outside the vapor phase flammability envelope and catalytically decomposing tertiary butyl hydroperoxide (TBHP), the main product of homogeneous isobutane oxidation, at 125 °C and 35 bar. Among a dozen heterogeneous metal-based catalysts tested, amorphous MnO2 (AMO) was found to be roughly an order of magnitude more active than supported Pd, Co, Au, and Nb-based catalysts for TBHP decomposition to TBA. As a result, high TBA/TBHP (up to 20.4) selectivity was achieved during isobutane oxidation in the presence of the AMO catalyst. The yield of gas phase C1 products was <1% and only a minor amount of acetone was produced as a β-scission byproduct. The use of n-hydroxy phthalimide (NHPI) as an initiator was found to enhance the TBA yield. This process provides a possible low energy pathway for making isobutylene from isobutane, avoiding the energy-intensive dehydrogenation and isobutane/isobutylene separation steps. 

David Ben Spry

Papers

Ultrafast excited state proton transfer in the condensed phase and nanoconfinement

Direct Tertiary Butyl Alcohol Formation via Catalytic Liquid Phase Isobutane Oxidation with Molecular Oxygen