Efficient catalytic hydrogenation of levulinic acid: a key step in biomass conversion
Efficient catalytic hydrogenation of levulinic acid: a key step in biomass conversion
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DOI：
10.1039/c2gc35503e
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发表时间：
2012-07
期刊：
影响因子：
9.8
通讯作者：
József M. Tukacs;D. Király;A. Strádi;Gyula Novodárszki;Zsuzsanna Eke;G. Dibó;T. Kégl;L. T. Mika
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作者：
József M. Tukacs;D. Király;A. Strádi;Gyula Novodárszki;Zsuzsanna Eke;G. Dibó;T. Kégl;L. T. Mika
γ-戊内酯（GVL）被认为是一种可持续的液体，可用于均相和非均相催化体系的烃类生产。乙酰丙酸（LA）选择性还原为GVL是基于平台分子的生物炼制概念的关键转变。我们报道了在Ru(acac)3和电子和立体表征的烷基-双（间磺化-苯基）-和二烷基-（间磺化-苯基）膦(RnP(C6H4-m-SO3Na)3−n （n = 1或2；R = Me, Pr, iPr, Bu, Cp）配体存在下，利用分子氢将LA转化为GVL的详细研究。加氢实验在5 ~ 100 bar H2范围内进行，催化剂用量为0.016 mol%，加氢量为5 ~ 20 eqv，加氢温度为140℃。的配体。考察了氢压力和Ru/配体比对LA转化的影响。nBuP(C6H4-m-SO3Na)2 （χ = 12.5, θTol = 153°）在无溶剂、无氯和无促进剂的反应混合物中表现出最高的活性，周转率高达6200，收率和选择性高于99%。该催化剂连续六次成功回收，没有损失活性。磺化和非磺化膦的表征表明，磺化对配体的空间和电子性质没有显著影响。
γ-Valerolactone (GVL) has been proposed as a sustainable liquid, and could be used for the production of hydrocarbons by using both homogeneous and heterogeneous catalytic systems. The selective reduction of levulinic acid (LA) to GVL is a key transformation for biorefinery concepts based on platform molecules. We report a detailed investigation of the conversion of LA to GVL using molecular hydrogen in the presence of a catalyst in situ generated from Ru(acac)3, and electronically and sterically characterized alkyl-bis(m-sulfonated-phenyl)- and dialkyl-(m-sulfonated-phenyl)phosphine (RnP(C6H4-m-SO3Na)3−n (n = 1 or 2; R = Me, Pr, iPr, Bu, Cp) ligands. The hydrogenation experiments were performed in the range of 5–100 bar H2 at 140 °C using 0.016 mol% catalyst and 5–20 eqv. of ligand. The effects of hydrogen pressure and Ru/ligand ratio on the LA conversion were determined. The nBuP(C6H4-m-SO3Na)2 (χ = 12.5, θTol = 153°) showed the highest activity achieving turnover numbers up to 6200 with a yield and selectivity higher than 99% in a solvent, chlorine and promoter free reaction mixture. The catalyst was successfully recycled for six consecutive runs without loss of activity. The characterization of sulfonated and non-sulfonated phosphines indicated that the sulfonation had no significant effect on the steric and electronic properties of the ligands.