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1In situ synthesis of biomass-derived Ni/C catalyst by self-reduction for the hydrogenation of levulinic acid to γ-valerolactone显示文摘Herein,we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel.Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the entire preparation process was simplified to two steps, which was more straightforward. This synthesis method was green as Ni/C can be prepared without any additional chemical and the self-reduction process was realized in N2, which can avoid using H2 thus averting some problems such as storage, transportation and safety of H2. Meanwhile, the size and dispersion of Ni particles can be controlled by changing carbonization temperature.The synthesis mechanism of Ni/C catalyst with selfreduction was investigated, which was mainly attributed to the carbon and reducing gas produced during the carbonization process.For the catalytic performance of GVL synthesis, a high yield (94.5%) can be obtained and it exhibited good stability up to 5 cycles without obvious loss of catalytic activity.Shuqi Fang Zhibing Cui Yuting Zhu Chenguang Wang Jing Bai Xinghua Zhang Ying Xu Qiying Liu Lungang Chen Qi Zhang Longlong Ma 2019Journal of Energy Chemistry2019,28,10:1
2Enzymatic Conversion of Biobased Levulinic Acid into an Alternative Biofuel Candidate--Methyl Levulinate显示文摘Methyl levulinate(ML)is a promising green candidate for bio-based diesel fuel and fuel additives.An efficient enzyme-catalyzed process to synthesize ML from levulinic acid(LA)in methanol was developed.The catalytic activity of a series of lipases including Novozyme 435(N435),NRTL IM,and 40086 was screened,and the N435 was identified as the optimal biocatalyst for the process.The effects of lipase amount,methyl tert-butyl ether(MTBE)volume,methanol to LA molar ratio,reaction temperature,and magnetic stirrer speed on LA conversion and ML yield were investigated.The response surface methodology was adopted to optimize the enzymatic conversion process,and the model validation experiments showed that the predicted values corresponded well with the experimental values.A LA conversion of 90.1%and a ML yield of 89.8%were achieved under reaction conditions covering:a temperature of 45°C,a reaction time of 4.6 h,a N435 dosage of 26 mg,a methanol to LA molar ratio of 3.6:1,a MTBE volume of 3.85 mL,and a stirrer speed of 150 r/min.The N435 recycling experiment indicated that the lipase activity was quite high after 12 cycles.However,upon using crude LA prepared from carbohydrates as the reactant,the conversion of LA and the ML yield decreased due to impurities existing in the crude LA.Xu Yanli Li Pan Chang Chun Xu Guizhuan Du Zeji Wang Zihua 2020China Petroleum Processing & Petrochemical Technology2020,22,1:0
3The hydrogenation of levulinic acid to γ-valerolactone over Cu–ZrO2 catalysts prepared by a pH-gradient methodology显示文摘A novel pH gradient methodology was used to synthesise a series of Cu–ZrO2 catalysts containing different quantities of Cu and Zr.All of the catalysts were highly selective to the desired product,γ-valerolactone, and are considerably more stable than Cu–ZrO2 catalysts prepared by other co-precipitation methods for this reaction.Characterisation and further investigation of these catalysts by XRD, BET, SEM and XPS provided insight into the nature of the catalytic active site and the physicochemical properties that lead to catalyst stability.We consider the active site to be the interface between Cu/CuOxand ZrOx and that lattice Cu species assist with the dispersion of surface Cu through the promotion of a strong metal support interaction.This enhanced understanding of the active site and roles of lattice and surface Cu will assist with future catalyst design.As such, we conclude that the activity of Cu–ZrO2 catalysts in this reaction is dictated by the quantity of Cu–Zr interface sites.Igor Orlowski Mark Douthwaite Sarwat Iqbal James S.Hayward Thomas E.Davies Jonathan K.Bartley Peter J.Miedziak Jun Hirayama David J.Morgan David J.Willock Graham J.Hutchings 2019Journal of Energy Chemistry2019,28,9:0
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