Catalytic conversion of biomass-derived levulinic acid into γ-valerolactone using iridium nanoparticles supported on carbon nanotubes

Abstract

A new method has been developed for the catalytic conversion of biomass-derived levulinic acid (LA) into γ-valerolactone (GVL) with molecular hydrogen (H 2 ) using a series of heterogeneous noble metal catalysts. Excellent yields of the GVL were obtained under mild reaction conditions of 50°C and 2 MPa of H 2 using iridium nanoparticles supported on carbon nanotubes (Ir/CNT). It is noteworthy that the reaction proceeded smoothly in the presence of formic acid (FA, co-produced with LA in equimolar amounts during the acid-mediated hydrolysis of lignocellulosic biomass). Furthermore, the FA remained intact, highlighting the practical advantages of this process for the convenient and cost-effective processing of a biomass-derived LA/FA solution. The method is effective for the simultaneous production of GVL and FA from a wide variety of renewable biomass resources. 以碳纳米管(CNTs)担载Ir纳米粒子为催化剂进行生物质基平台化合物乙酰丙酸(LA)选择加氢制备γ-戊内酯(GVL)的研究, 并利用X射线衍射、X射线光电子能谱和透射电镜表征了使用前后的Ir/CNT催化剂, 探讨了影响LA催化加氢制GVL反应性能的因素和该反应的可能路径. 结果表明, 与Ru, Rh和Pd等传统铂族金属相比, Ir/CNT催化剂不但可在温和条件下(50 °C, 2.0 MPa, H 2 )实现LA至GVL的完全转化, 且可对多类直接源于生物质水解的含等量LA/甲酸的“真实”体系实现GVL的高效选择合成. Iridium nanoparticles supported on carbon nanotubes have been used as a highly efficient catalyst for the hydrogenation of biomass-derived levulinic acid to γ-valerolactone (GVL) in the presence of formic acid. The GVL was obtained in an excellent yield of 96% at an operating temperature of 50°C.