Abstract:

The development of biodiesel is of great scientific significance for achieving carbon emission reduction and energy substitution. The high-value green conversion of biodiesel by-product glycerol are conducive to the development and extension of the biodiesel industry chain. 1,3-Propanediol produced by catalytic hydrogenation of glycerol has become a research hotspot, and the design of catalysts with high activity and selectivity is the key. The dehydration-hydrogenation mechanism, direct hydrogenation mechanism and redox mechanism of glycerol to 1,3-propanediol on Pt-WO _x supported catalysts are elaborated. Pt dispersion, WO _x state and Pt-WO _x interface contact behavior in Pt-WO _x catalysts are further analyzed as they are the main influence factors on the catalytic performance. Pt dispersion affects the activation of H₂ and the further hydrogenation of intermediates. The WO _x state not only promotes the dispersion of Pt, but also closely relates with the Brönsted acid site of the catalyst. The Pt-WO _x interface affects the hydrogen overflow on the catalyst surfaces and the in-situ formation of the Brönsted acid site. Finally, it is proposed that Pt-WO _x catalysts should be rational designed from these three aspects, and the influence of each component and their interactions on the direct catalytic hydrogenation of glycerol should be deeply explored. Reaction mechanism and the influence of the different hydrogenation mode on the selective hydrogenation of glycerol should be investigated in order to promote the large-scale development and application of the hydrogenation of glycerol to 1,3-propanediol.

Key words: glycerol, hydrogenolysis, 1,3-propanediol, Pt-WO _x catalysts, reaction mechanism

摘要：

生物柴油的发展对实现碳减排、推进能源替补具有重要科学意义，将生物柴油副产粗甘油进行绿色处理及高值转化，有利于促进生物柴油产业链的延伸发展。甘油氢解制备1,3-丙二醇已成为目前粗甘油高值化利用的研究热点，设计开发高活性、高选择性的催化剂是该过程的关键。本文首先阐述了Pt-WO _x 系催化剂上甘油氢解制备1,3-丙二醇的脱水加氢机理、直接氢解机理以及氧化还原机理，明确了Pt-WO _x 系催化剂中Pt分散度、WO _x 状态和Pt-WO _x 界面接触等是影响催化性能的主要因素，并对其进行综述；进一步分析Pt分散度、WO _x 状态和Pt-WO _x 界面接触的影响机制。Pt分散度会影响H₂的活化及反应中间体的氢化；WO _x 状态与催化剂Brönsted酸性位点密不可分，还可促进活性金属的分散；Pt-WO _x 界面则影响催化剂氢溢流以及原位Brönsted酸的生成。最后，提出今后应从这三方面构筑新型Pt-WO _x 系催化剂；探究各活性组分对甘油氢解反应的影响规律及组分间相互作用的本质特征，完善反应机理；考察加氢方式对甘油选择性氢解的影响机制，以促进甘油选择性氢解制1,3-丙二醇技术路线的规模化发展。

关键词: 甘油, 氢解, 1,3-丙二醇, Pt-WO _x 催化剂, 反应机理