甲烷直接转化的新进展

NEW DEVELOPMENT ON DIRECT CONVERSION OF METHANE

本文扼要介绍甲烷直接转化 3个方面的新进展 :过渡金属盐及其配位络合物 ;化学模拟甲烷氧化酶 (MMO) ;在异相体系中CH4 直接与CO2 进行羧基化反应。Hg(II) /H2 SO4 和Pt(Ⅱ )配位络合物/H2 SO4 这两个均相催化体系的实验室研究结果表明 ,CH4 转化率超过 90 % ,生成CH3 OH的选择性超过80 % ,硫酸甲酯的单程产率达到 70 %以上。但在工程开发前 ,必须解决这两个体系在动力学上的局限性。Rh(Ⅱ )配位络合物 /光催化和化学模拟酶MMO这两个体系尚处于探索阶段。但由于在这两个体系中 ,CH4 的直接转化可在常温、常压下进行 ,其潜在的工业价值甚大。CH4 与CO2 反应直接制取醋酸的研究也仅刚刚开始 ,但除经济效益外 。

Three new developments for direct conversion of CH 4 are briefly introd uced in this article: (1) homogeneous catalysis of transit metals and their coor dinative complexes; (2) chemically mimic enzymes of methane monoxygenase (MMO) a nd (3) CH 4 directive reacting with CO 2 to produce acetic acid in heterogeneo us c atalytic system. Laboratory study for the two homogeneous systems of Hg (Ⅱ)/H 2S O 4 and Pt(Ⅱ) coordinative complex / H 2SO 4 shows that the CH 4 conversion >90% a t selectivity >80% and an over 70% one-pass yield of an ester of methanol is re ached. But the obstacle of kinetics in these two systems must be overcome before engineering development. Both Rh(Ⅱ) coordinative complex/ photocatalysis and c hemically mimic MMO systems are in exploratory stage. Since the direct conversio n of CH 4 in these two systems can be conducted in ambient temperature and pres su re, their potentially industrial benefit will be great. The study of CH 4 react in g with CO 2 directly to acetic acid is also in early stage, but the important v al ue of this reaction for environmental protection must be emphasized besides its economic profit.