| 宁晓玉,豆叶帆,伊思静,王金昭,李婧婧.化学通报,2023,86(11):1395-1401. |
| 铁苯基膦配合物均相催化乙酰丙酸乙酯与甲酸反应转化为γ-戊内酯的分子机制 |
| Theoretical Investigation of the Mechanism for the Conversion of Ethyl Levulinate and Formic Acid into γ-Valerolactone Promoted by Homogenous Iron Catalyst |
| 投稿时间：2023-04-28 修订日期：2023-05-26 |
| DOI： |
| 中文关键词: 乙酰丙酸(酯) γ-戊内酯 反应机理 密度泛函理论 |
| 英文关键词:Levulinic acid/Levulinate ester γ-Valerolactone Reaction mechanism Density functional theory (DFT) |
| 基金项目:国家自然科学基金项目(22002077)和山西省基础研究项目(20210302124125)资助 |
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| 中文摘要: |
| 本文基于密度泛函理论，计算了Fe(CF3SO3)2/PP3催化乙酰丙酸乙酯与甲酸反应转化为γ-戊内酯的反应机理。分析了单重态和三重态反应路径的热力学和动力学性质，结果表明除了预催化剂活化出现势能面交叉外，反应主要在三重态势能面上进行，包括以下几个步骤：甲酸盐配位方式重置，β-H消除得到活性催化剂[FeH(PP3)]+，接着乙酰丙酸乙酯的羰基碳和羰基氧接连被质子化得到中间体4-羟基戊酸乙酯，最后质子化的反离子CF3SO3H作为氢转移梭子协助分子内脱醇—关环生成目标产物γ-戊内酯。进一步探讨不同金属苯基膦配合物的催化活性，证实金属适宜的配位能力是筛选催化剂的关键。理论计算结果为优化设计高性能的生物质转化催化剂提供一定的理论指导。 |
| 英文摘要: |
| The reaction mechanism of the conversion of ethyl levulinate and formic acid into γ-valerolactone catalyzed by Fe(CF3SO3)2/PP3 were systematically studied via density functional theory (DFT). The thermodynamic and kinetic properties of the singlet and triplet surfaces have been compared. It is shown that the hydrogenation reaction is primarily occurred on the triplet surface except for the activation of the pre-catalyst which shows spin-crossover. A plausible catalytic cycle mainly includes the four steps: 1) the reposition between the Fe catalyst and formate; 2) β-H elimination leads to the active catalyst [FeH(PP3)]+; 3) a cascade protonation of the carbonyl carbon and oxygen of ethyl levulinate to afford the 4-hydroxyvalerate; 4) the concerted dealcoholization-cyclization assisted by protonated counterion CF3SO3H to produce the aimed product γ-valerolactone. Furthermore, the catalytic activities of different metal complexes with triphenylphosphine ligands were discussed. Suitable coordination ability of metals was confirmed as the key factor in screening catalysts. The theoretical results provide theoretical guidance for designing of high performance biomass conversion catalysts. |
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