Experimental measurements of benzene oxidation in supercritical water

Oxidation and hydrolysis reactions of benzene in supercritical water were i nvestigated thoroughly using experimental measurements Little to no reactio n occurred without oxygen at temperatures between 530 and 625 degreesC for residence times up to 6 s. Oxidation reactions were studied at temperatures ranging from 479 to 587 degreesC, pressures of 139 to 278 bar, reactor res idence times from 3 to 7 s, and with varying initial benzene concentrations from 0.4 to 1.2 mmol/L and oxygen concentrations from 40% of oxygen demand to 100% excess oxygen. To a 95% level of statistical confidence, the oxida tion rate was found to be of 0.4 +/- 0.07 order in benzene, 0.17 +/- 0.05 o rder in oxygen, and 1.4 +/- 0.1 order in water, with an activation energy o f 270 +/- 10 kJ/mol. The primary oxidation product at all reaction conditio ns studied was carbon dioxide. Other important oxidation products were carb on monoxide, phenol, and methane. Trace levels of additional light hydrocar bon gases and single- and multi-ringed aromatic species were also detected under some conditions.