Molten salts in a bubble column reactor as catalysts for the oxidative coupling of methane

Liq. Li2CO3 is a catalyst for the oxidative coupling of methane, and the catalysis is promoted by addn. of solid MgO particles

A mechanistic study on the oxidative coupling of methane over lithium doped magnesium oxide catalysts

To elucidate the importance of various reaction steps in the oxidative convers ion of methane, experiments were carried out with three reaction products: ethane, ethylene and carbon monoxide. These products were studied seperately, in oxidation experiments with and without a catalyst. Moreover , the effect of admixing them to a methane/oxygen feed was investigated. All experiments were carried out in a micro flow tubular quartz reactor, which was empty or filled with catalyst. The temperature was 800 C. The ethane and ethylene experiments have learnt that: - ethane to ethylene convers ion is much more rapid than ethane combustion, irrespective of the presence of a catalyst. The main path of combustion leads via ethylene -ethane is converted much more rapid than methane. This imposes serious constraints to maximum attainable yields. - The principal combustion product in absence of a catalyst is CO. With a catalyst C02 is dominating. This agrees well with the rapid catalytic oxidation observed with CO/02 feeds. The conclusions can be summarized in a simplified overall reaction scheme

Highly efficient solvolysis of epoxy resin using poly(ethylene glycol)/NaOH systems

Highly efficient recycling of methyl tetrahydrophthalic anhydride-cured epoxy resin is feasible using a poly(ethylene glycol) (PEG)/NaOH catalytic system, which can completely solubilise the epoxy resin at 180 degrees C in 50 min under atmospheric pressure. The structure of the solvolysis products has been characterized by FTIR, H-1 NMR, C-13 NMR, GPC and ESI-MS, indicating the decomposition of the curing bond through ester hydrolysis accompanied by transetherification as the plausible solvolysis mechanism. The process possesses high decomposition efficiency without requiring additional organic solvents or pressure, stressing the potential of this method for recycling of other anhydride-cured thermosetting resins. (C) 2012 Elsevier Ltd. All rights reserve

Dechlorination of poly(vinyl chloride) by 1-butyl-3-methylimidazoliumhydroxide

Highly efficient dechlorination of PVC has been realized at 180 degrees C and at atmospheric pressure, using 1-butyl-3-methylimidazoliumhydroxide ([Bmim]OH) as an environment-friendly reaction medium: in the absence of an external base or solvent the dechlorination efficiency is as high as 91.2%, while it is only 38.1% for PVC without ionic liquids. The dechlorination process follows first-order kinetics with apparent activation energy of 44 kJ mol(-1). Mechanistic analysis provides evidence for the equilibrium presence of carbene species, together with the hydroxide ions in [Bmim]OH, thus enhancing the dechlorination of PVC via a combined elimination and substitution mechanism. (C) 2011 Elsevier Ltd. All rights reserve