CO_2氧化低碳烷烃脱氢制低碳烯烃

对近年来国内外关于CO2氧化低碳烷烃脱氢制低碳烯烃的研究成果进行了综述。CO2作为温和的氧化剂应用于低碳烷烃氧化脱氢可提高反应的平衡转化率,抑制催化剂失活,是一个有应用前景的新工艺。用于此类反应的催化体系主要有Cr系和Ga系,但这两类催化剂的稳定性较差,通过调变催化剂载体表面的性质来改变活性组分与载体间的相互作用,可以提高催化剂的稳定性。不同催化体系中CO2的作用机制不同,Cr系催化剂上主要为氧化还原机理,而Ga系催化剂上则为异裂机理。为进一步提高反应效率,探索和研究同时具有脱氢与活化CO2能力的新催化体系是发展方向。

Oxidative Dehydrogenation of Light Alkanes with CO2 to Olefins

CO2 can be utilized as a mild oxidant in dehydrogenation of alkanes to olefins.Equilibrium conversion of the dehydrogenation can be increased and deactivations of the catalysts can be suppressed by adding CO2.Dehydrogenation of light alkanes to their corresponding olefins in the presence of CO2 has been reviewed,including the recent advances in development of the catalysts for the dehydrogenation,especially chromium-based and gallium-based catalysts.The main problems are that stability of these catalysts is still rather poor and their activity declined dramatically with reaction time,which are fatal for their industrial application.Improvements for the stability have been made recently by changing interaction between active species and support.The role of CO2 and related mechanisms in the dehydrogenation were also discussed.The dehydrogenation has been suggested to follow a redox mechanism over chromium and iron oxides,while proceeds through a heterolytic dissociation pathway on gallium and zinc oxides.It is recommended that future research should be foused on devolepment of efficient catalyst systems which can activate CO2 in relatively low temperature.