Heterogeneous catalysis in supercritical water

Fluids at temperatures and pressures near their thermodynamic critical poin ts are attracting attention as media for heterogeneous catalytic reactions. Several factors have motivated this interest in catalytic reactions in sup ercritical fluids (SCFs), but the paradigm of pollution prevention is one o f the most important. The increased awareness of environmental sustainabili ty and the trend toward pollution prevention has led to a consideration of environmentally benign solvents such as supercritical water for chemical pr ocesses. This article provides an overview of the types of heterogeneous ca talytic reactions that have been accomplished in supercritical water. Addit ionally, we provide new experimental results for the heterogeneous catalyti c oxidation of phenol in supercritical water over bulk TiO2 and compare the performance of different transition metal oxide catalysts for this reactio n. (C) 2000 Elsevier Science B.V. All rights reserved.