CHEMICAL-REACTIONS IN SUPERCRITICAL WATER .1. PYROLYSIS OF TERT-BUTYLBENZENE

Supercritical water is a powerful solvent and a favourable reaction me dium for oxidation of organic material. The role of supercritical wate r in these processes is not fully understood. The influence of supercr itical water on the pyrolysis of tert.-butylbenzene as a model compoun d was investigated. Experiments were carried out in a flow reactor at pressures between 5 and 25 MPa, at temperatures between 505 and 540 de grees C and residence times between 15 and 55 s. Water, nitrogen, and water-nitrogen mixtures, respectively, were used as reaction media; no significant differences in the product formation rates and distributi ons were detected. In an experiment with D2O, instead of H2O, it was p roved, that deuterium is incorporated in all the product substances in various amounts. Interpretating the results with a reaction model bas ed on a radical mechanism it was made probable that H-D exchange react ions occur with radical intermediates.