Inorganic Chemistry and Catalysis, Utrecht University, Sorbonnelaan 16, Utrecht, CA, 3584 (The Netherlands).
ChemSusChem. 2013 Sep;6(9):1576-94. doi: 10.1002/cssc.201300370. Epub 2013 Aug 1.
Vegetable oil-based feeds are regarded as an alternative source for the production of fuels and chemicals. Paraffins and olefins can be produced from these feeds through catalytic deoxygenation. The fundamentals of this process are mostly studied by using model compounds such as fatty acids, fatty acid esters, and specific triglycerides because of their structural similarity to vegetable oils. In this Review we discuss the impact of feedstock, reaction conditions, and nature of the catalyst on the reaction pathways of the deoxygenation of vegetable oils and its derivatives. As such, we conclude on the suitability of model compounds for this reaction. It is shown that the type of catalyst has a significant effect on the deoxygenation pathway, that is, group 10 metal catalysts are active in decarbonylation/decarboxylation whereas metal sulfide catalysts are more selective to hydrodeoxygenation. Deoxygenation studies performed under H2 showed similar pathways for fatty acids, fatty acid esters, triglycerides, and vegetable oils, as mostly deoxygenation occurs indirectly via the formation of fatty acids. Deoxygenation in the absence of H2 results in significant differences in reaction pathways and selectivities depending on the feedstock. Additionally, using unsaturated feedstocks under inert gas results in a high selectivity to undesired reactions such as cracking and the formation of heavies. Therefore, addition of H2 is proposed to be essential for the catalytic deoxygenation of vegetable oil feeds.
植物油基饲料被认为是生产燃料和化学品的替代来源。通过催化脱氧，可以从这些饲料中生产石蜡和烯烃。由于与植物油具有相似的结构，因此该过程的基础主要通过使用脂肪酸、脂肪酸酯和特定的三酸甘油酯等模型化合物进行研究。在这篇综述中，我们讨论了原料、反应条件和催化剂性质对植物油及其衍生物脱氧反应途径的影响。因此，我们对模型化合物在该反应中的适用性进行了总结。结果表明，催化剂的类型对脱氧途径有显著影响，即第 10 族金属催化剂在脱羰/脱羧反应中具有活性，而金属硫化物催化剂对加氢脱氧反应更具选择性。在 H2 下进行的脱氧研究表明，脂肪酸、脂肪酸酯、三酸甘油酯和植物油的反应途径相似，因为脱氧主要通过形成脂肪酸间接进行。在没有 H2 的情况下进行脱氧会根据原料的不同导致反应途径和选择性有显著差异。此外，在惰性气体存在下使用不饱和原料会导致高选择性的不期望反应，如裂化和重质物的形成。因此，提出添加 H2 对于催化植物油脱氧是必不可少的。
