Steam cracking is a well-established commercial technology for ethylene production. Despite decades of optimization efforts, the process is, nevertheless, highly energy and carbon intensive. This review covers the recent advances in alternative approaches that hold promise in the intensification of ethylene production from hydrocarbon feedstocks ranging from methane to naphtha. Oxidative as well as nonoxidative approaches using conventional, chemical looping, membrane, electrochemical, and plasma-assisted systems are discussed. We note that catalysts, electrocatalysts, and/or redox catalysts play critical roles in the performance of these alternative ethylene production technologies. Meanwhile, the complexity in producing polymer-grade ethylene also requires comprehensive considerations of not only (catalytic) reactions for ethylene formation but also feedstock preparation (e.g., air separation for oxidative conversion) and product separations. Although these alternative technologies have yet to be commercially implemented, a number of oxidative approaches have shown promise for close to order-of-magnitude reduction in energy consumption and CO2 emissions in comparison to steam cracking. Given the substantial progress in these research areas and the significant increase in C1 and C2 supplies resulting from the US shale gas revolution, we are excited by the enormous opportunities and potential impacts in the advancement and eventual implementation of significantly intensified ethylene production technologies.

The protonic ceramic electrochemical cell (PCEC) is an emerging and attractive technology that converts energy between power and hydrogen using solid oxide proton conductors at intermediate temperatures. To achieve efficient electrochemical hydrogen and power production with stable operation, highly robust and durable electrodes are urgently desired to facilitate water oxidation and oxygen reduction reactions, which are the critical steps for both electrolysis and fuel cell operation, especially at reduced temperatures. In this study, a triple conducting oxide of PrNi 0.5 Co 0.5 O 3-δ perovskite is developed as an oxygen electrode, presenting superior electrochemical performance at 400~600°C. More importantly, the selfsustainable and reversible operation is successfully demonstrated by converting the generated hydrogen in electrolysis mode to electricity without any hydrogen addition. The excellent electrocatalytic activity is attributed to the considerable proton conduction, as confirmed by hydrogen permeation experiment, remarkable hydration behavior and computations.

Qinghaosu and derivatives were easily reduced by ferrous sulfate in aqueous acetonitrile to give results different from those reported for other reducing systems. The unstable epoxide 7, a compound that was postulated earlier as a species responsible for the antimalarial activity, now has been isolated and characterized. The earlier speculative secondary C-4 radical has also been trapped with 2-methyl-2-nitrosopropane and thus provides the very first direct evidence for the involvement of radicals in the in vitro cleavage of QHS-type compounds. A unified mechanism featuring interchangeable radical anions and reversible intramolecular radical reactions is proposed for the ferrous ion induced cleavage of the 1,2,4-trioxanes (i.e., QHS and the like). On the basis of this framework, together with consideration of counterion and solvent effects, a large body of divergent experimental outcomes can be satisfactorily rationalized, not only the formation of the main products but also the product ratios as well as their deviation from those obtained under other reaction conditions.