Highly selective/enantioselective Pt-ReOx/C catalyst for hydrogenation of L-malic acid at mild conditions

• 来源期刊: 能源化学
• 年，卷（期）: 2018,（3）
• 页码范围: 903-912
• 页数: 10页
• 语种: 英文

摘要

The catalyst preparation strategy was based on a strict introduction sequence of rhenium and platinum precursors and their strong interaction with carbon support resulted in the formation of 0.5 nm Pt-ReOx species of atomic dispersion,where platinum is metallic,while monolayer rhenium is partially oxidized (Re2+).The reaction kinetics was studied taking into account the process of L-malic acid association leading to the formation of inactive cyclic oligomeric species.High TOFs (ca.50 h-1),selectivities (ca.99％)and stability of Pt-ReOx/C catalysts in aqueous-phase hydrogenation of L-malic acid,which are close to those of the homogeneous pincer type complexes,were revealed at mild conditions (T=90-130℃).Taking into account that (i) hydrogenation reaction occurred 2-3 orders of magnitude faster than its racemization and (ii) association of L-malic acid dominates at low temperatures and in a concentrated solution,special reaction conditions that allow obtaining chemically and optically (ee ＞ 99％) pure (5)-3-hydroxy-γ-butyrolactone and (5)-1,2,4-butanetriol were found.Basing on HAADF-STEM,EDX,XPS,and knetic studies,the structure of active species and basic reaction pathways are proposed.