合成气直接制备多碳醇的研究进展

Research Progress on Higher Alcohols Synthesis From Syngas

将煤炭资源通过合成气转化为多碳醇可有效提升现有煤基产品的附加值,实现煤炭资源清洁利用,并降低多碳醇对石油合成路径的依赖。合成气直接制备多碳醇技术受催化剂性能的制约。详细总结了合成气制备多碳醇的催化反应机理:甲醇同系化机理、烯烃水合机理、缩合机理、插入机理,并对铑基催化剂、钼基催化剂、改性甲醇合成催化剂和改性费-托合成催化剂4种合成气制多碳醇催化剂的研究进展进行了详述。合成气制备多碳醇在Rh单金属催化剂上遵循CO插入机理;在钼基催化剂上添加碱金属可促进CO的插入从而促进多碳醇的形成;在改性甲醇合成催化剂中添加碱金属可中和催化剂表面的酸性、抑制副反应的发生,促进多碳醇的生成;醇类合成催化剂与费-托合成催化剂组合可促进合成气制备多碳醇反应。合成气直接制备多碳醇的机理分析可为设计催化活性高、多碳醇选择性高的催化剂提供理论基础依据。

Converting syngas into higher alcohols can effectively enhance the added-value of coal based products,achieve the clean utilization of coal resources,and reduce the dependence of higher alcohol synthesis on petroleum pathways.The direct preparation of higher alcohols from syngas is constrained by catalyst performance.The catalytic reaction mechanisms for higher alcohol synthesis from syngas are comprehensively summarized,including methanol homologation mechanism,olefin hydration mechanism,condensation mechanism,and insertion mechanism.In addition,the research progress in four types of catalysts for higher alcohols synthesis,i.e.,rhodium-based catalysts,molybdenum-based catalysts,modified methanol synthesis catalysts,and modified Fischer-Tropsch synthesis catalysts,is elaborated.The preparation of higher alcohols from syngas follows the CO insertion mechanism on Rh catalysts.The addition of alkali metals on molybdenum-based catalysts can facilitate CO insertion,thereby promoting polyalcohol formation.Moreover,adding alkali metals to the modified methanol synthesis catalysts can neutralize the acidity on the catalyst surface,suppress undesired reactions,and enhance higher alcohol production.Additionally,the combination of alcohol synthesis catalysts and Fischer-Tropsch synthesis catalysts can promote syngas conversion to higher alcohols.The reaction mechanism analysis provides a theoretical foundation for designing catalysts with high catalytic activity and high selectivity for higher alcohol synthesis.