Thermochemical conversion of lignocellulosic biomass with the use of heterogeneous catalysts

• Autor(a) principal: Pinho, Alexandra Mariza Menezes de
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/25835
• topic: Ruthenium catalyst; γ-valerolactone; biomass conversion; levulinic acid hydrogenation; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

The utilization of biomass for production of chemicals, materials and fuels has been intensively investigated in recent years. γ-Valerolactone (GVL) is one of the important platform molecules that can be obtained from lignocellulosic feedstock. GVL has drawn an increasing attention thanks to its interesting properties which make it suitable for several applications. However, the real challenge is to synthesize γ-valerolactone directly from biomass in a one-pot process of hydrolytic hydrogenation. Hydrolysis of biomass is conducted in the presence of mineral acid such as sulphuric acid (H2SO4) which is one of the problem for the catalyst performance. One of the solutions is a neutralization or separation of sulphuric acid from the mixture containing levulinic acid. This work is devoted to study the catalytic performance of ruthenium catalyst in hydrolytic hydrogenation of different wood such as pine, poplar, beech and birch towards γ-valerolactone (GVL). The reactions were performed in two steps, the first was hydrolysis of biomass samples and further hydrogenation of formed hydrolysis products. Quantitative and qualitative analyses of the produced liquors were made by high-performance liquid chromatography. The properties of different biomass samples were characterized by X-ray diffraction (XRD), Fourier Transmission Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The characterization of the surface properties of the investigated catalyst was performed by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Temperature-Programmed Reduction (TPR). The results showed that the reaction performance depends on several factors, such as pH which strongly influence the γ-valerolactone yield. The activity of the catalyst was influenced by the presence of impurities or carbon deposit, which was proved by ToF-SIMS and TPR.