Gamma-valerolactone synthesis in pervaporation membrane reactor

GAMMA-VALEROLACTONE SYNTHESIS IN PERVAPORATION MEMBRANE REACTOR SUMMARY In recent years, the interest of industries and consumers in environmentally friendly and sustainable alternatives has increased rapidly. The production of fuels and chemicals derived from renewable resources as an alternative to traditional petroleum-based products is becoming increasingly important. This trend is based on the idea that biodegradable and environmentally friendly products should be preferred. In this context, furfural derived from biomass sources such as agricultural wastes or lignocellulosic materials stands out as a remarkable renewable resource. Furfural is an important intermediate that can be converted into high-value chemicals and in particular can produce a versatile compound such as gamma-valerolactone (GVL). GVL is used as a solvent, fuel additive or intermediate in various industries and has significant potential in this context. Therefore, obtaining GVL from biomass resources is of great importance for the development of industries based on renewable resources. This study has a very unique value both in terms of the pervaporation membrane reactor process used for the GVL synthesis of furfural in a single vessel and in terms of the catalysts used in the reaction. The fact that the selected polybenzimidazole (PBI) membrane has not been previously preferred in both GVL synthesis and pervaporation membrane reactor application increases the originality of this study. The catalyst synthesis is also pioneering in terms of establishing a hybrid production method in terms of the hydrophilic membrane used and determination of the optimum reaction conditions. At the same time, all experiments were carried out in a batch reactor in order to compare with conventional synthesis methods and the results were comprehensively interpreted. In this study, the use of bifunctional H₃PW₁₂O₄-UiO-66 catalyst for the synthesis of gamma-valerolactone (GVL) from furfural was investigated. Membrane was prepared using PBI polymer and H₃PW₁₂O₄-UiO-66 catalysts containing different amounts of H₃PW₁₂O₄-UiO-66 were synthesised. The catalytic activities of these catalysts were tested in a pervaporation membrane reactor (PVMR) to obtain GVL from furfural and the catalyst containing 2 g H₃PW₁₂O₄ was found to be the most suitable catalyst. After the optimum catalyst was determined, the effects of temperature, molar feed ratio and catalyst concentration on reaction and separation performance were investigated. By evaluating the reaction and separation performances, the optimum conditions were determined as 90 °C, molar feed ratio of 10 and catalyst concentration of 6 g/L. The performance of PVMR was compared with a batch reactor operating under the same conditions. In the batch reactor, 65% furfural conversion and 51% GVL yield were obtained at 90 °C, molar feed ratio of 10 and 6 g/L catalyst concentration, while PVMR achieved 100% furfural conversion and 94,21% GVL yield. This comparison reveals that PVMR is more effective in increasing conversion and yield than the conventional batch reactor. This study shows that the proposed process for GVL production from furfural is a promising alternative with high conversion and yield values. Keywords: Pervaporation membrane reactor, Gamma-Valerolactone, Furfural.