Ci oxidative coupling via bromine activation and tandem catalytic condensation and neutralization over CaO/zeolite composites II. Product distribution variation and full bromine confinement

Abstract

We describe a three-step bromine-mediated process for oxidative coupling of methane using O2 as oxidant. In the first step, a supported metal bromide solid is treated with O2 to generate Br2 and supported metal oxide. The Br2 thus formed reacts with excess CH 4, giving a mixture of CH4, bromomethanes, and HBr. This mixture is passed over a CaO/zeolite composite which condenses bromocarbons with 100% conversion to products, and neutralizes HBr to reform the metal bromide. The resulting product contains higher hydrocarbons, excess CH4, and water. Once the HBr neutralizing capacity of the CaO is spent, the supported CaBr2/ZSM-5 may also serve as catalyst for methyl bromide coupling. The effect of temperature, pressure, and reaction time on the intermediate methane bromination as well as on the overall partial oxidation product distribution is discussed. Incorporation of this scheme into a reactor into which only methane and O2 are fed is described. © 2004 Elsevier B.V. All rights reserved.