On the dual role of the reactant during aqueous phase hydrodechlorination of trichloroethylene (HDC of TCE) using Pd supported on swellable organically modified silica (SOMS)

Herein, the dual role of trichloroethylene (TCE) in liquid-phase hydrodechlorination with Pd catalysts supported on swellable organically modified silica (SOMS), is investigated. Batch experiments TCE-soaked Pd/SOMS showed 45% higher conversion after 4 h than dry Pd/SOMS, suggesting that TCE acts as a reactant and swelling-agent. Flow performed without ethanol (external swelling-agent) exhibited similar steady-state activities, confirming itself can cause swelling. Moreover, flow experiments, regardless whether SOMS-supported were pre-reduced or not, yielded conversions, Pd(2+) rapidly reduced by H2 dissolved water during approach to steady-state. In-situ characterization under reaction conditions using time-resolved X-ray absorption spectroscopy confirmed reduction species Pd(0) H2. Overall, this study shows economic viability eliminating need for an external swelling-agent well catalyst pre-reduction step.