Photocatalytic C-C coupling of acetonitrile into succinonitrile over hydrophobic TiO2 in a flow reactor

A radical C-C-coupling reaction of acetonitrile into succinonitrile over hydrophobic TiO2 photocatalyst with enhanced catalytic activity was developed. In addition, the usage of a flow reactor further improved the photon utilization efficiency for succinonitrile synthesis at room temperature. The space time yield of succinonitrile reached 55.59 μmol·gcat.-1·h-1 over hydrophobic TiO2 catalyst, which was much higher than that of pristine TiO2 (4.23 μmol·gcat.-1·h-1). Mechanistic studies revealed that the hydrophobic modification of TiO2 promoted the separation and transfer of photogenerated carriers, as well as suppressed their recombination. Hydrophobic TiO2 also enhanced the adsorption of -CH3 of acetonitrile, thus facilitating the activation of C-H bond and the utilization efficiency of photocarriers.