(403d) Hydrocarbon Products from Supercritical Water Partial Oxidation of Benzene Between 375 to 440 °C

Supercritical water is a highly energetic partial oxidation medium for a wide variety of chemical processes ranging from jet fuel reformation to gasification of lignocellousic materials.  Supercritical water can also be used to partially oxidize benzene with several studies evaluating the reaction kinetics and mechanisms of benzene partial oxidation ultimately leading to gasification.   Notable intermediates of the partial oxidation of benzene include commodity chemicals such as phenol.  This study focuses on optimizing the conversion of the supercritical water partial oxidation of benzene to phenol and other non-gaseous species near water’s critical temperature.  The effects of reaction time, temperature, and benzene proportion were evaluated with an agitated 500 mL Hastelloy C276 batch reactor with 30 wt-% hydrogen peroxide as the oxidant.  In a factorial experimental design varying temperature between 390 and 420 °C, reaction time from 15 to 23 minutes, and benzene from 5 to 10 wt-%, it was found that conversion of phenol is favored at shorter reaction times, lower weight fractions of benzene, and higher temperature.  In a separate study, the reaction time was varied from 0 to 30 minutes and temperature from 375 to 440 °C.  In addition to unreacted benzene, the principal non-gaseous hydrocarbon products were phenol, benzoic acid, and biphenyl with lesser amounts of acetophenone, xanthone, and dibenzofuran.   The optimal process conditions and potential reactions for the principal products will be discussed.