Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706 (USA).
Angew Chem Int Ed Engl. 2014 Nov 17;53(47):12718-22. doi: 10.1002/anie.201407615. Epub 2014 Sep 4.
It is shown that microenvironments formed around catalytically active sites mitigate catalyst deactivation by biogenic impurities that are present during the production of biorenewable chemicals from biologically derived species. Palladium and ruthenium catalysts are inhibited by the presence of sulfur-containing amino acids; however, these supported metal catalysts are stabilized by overcoating with poly(vinyl alcohol) (PVA), which creates a microenvironment unfavorable for biogenic impurities. Moreover, deactivation of Pd catalysts by carbon deposition from the decomposition of highly reactive species is suppressed by the formation of bimetallic PdAu nanoparticles. Thus, a PVA-overcoated PdAu catalyst was an order of magnitude more stable than a simple Pd catalyst in the hydrogenation of triacetic acid lactone, which is the first step in the production of biobased sorbic acid. A PVA-overcoated Ru catalyst showed a similar improvement in stability during lactic acid hydrogenation to propylene glycol in the presence of methionine.
研究表明，在生物衍生物种生产生物可再生化学品的过程中，存在生物杂质，这些杂质会导致催化剂失活。催化活性位点周围形成的微环境可以减轻这种失活，钯和钌催化剂会被含硫氨基酸抑制，但这些负载金属催化剂可以通过用聚乙烯醇（PVA）进行过度包覆来稳定，这会形成一种不利于生物杂质的微环境。此外，通过形成双金属 PdAu 纳米粒子，从高反应性物种分解产生的碳沉积导致的 Pd 催化剂失活也得到了抑制。因此，在三乙酸内酯的加氢反应中，与简单的 Pd 催化剂相比，PVA 包覆的 PdAu 催化剂的稳定性要高出一个数量级，三乙酸内酯加氢是生产生物基山梨酸的第一步。在甲硫氨酸存在下，PVA 包覆的 Ru 催化剂在乳酸加氢生成丙二醇的反应中也表现出类似的稳定性提高。
