Biomass derived efficient conversion of levulinic acid for sustainable production of γ-valerolactone over cobalt based catalyst

Nanocrystallite Zeolite BEA for Regioselective and Continuous Acetyl Functionalization of Anisole Using Acetic Anhydride: Catalyst Deactivation Studies

Ultrasonic pretreatment of gel composition followed by hydrothermal synthesis produces the nanocrystallite zeolite beta (ZB) with crystal sizes of 10.3, 22.6, and 9.1 nm for ZB-1, ZB-2, and ZB-3, respectively. The effect of ultrasonic pretreatment and the (SiO2/Al2O3) ratio of gel composition on physical, textural properties, and also on the catalytic activity of ZB catalysts with increasing time on stream (TOS) was investigated. The specific surface area and mesopore volume for ZB-1, ZB-2, and ZB-3 are 438, 380, and 429 m2/g and 0.17, 0.05, and 0.14 cm3/g, respectively. The activity studies of ZB-1 and ZB-3 catalysts were confirmed that the anisole conversion initially increased with TOS until it attained the maximum value and then started decreasing further with TOS due to the deactivation of the catalyst caused by the strong interaction of the product with the acidic sites in the mesopore region. However, in the case of ZB-2, the anisole conversion (>45%) was sustained for a longer TOS due to its smaller particle size, low mesopore volume, and more acidic sites in the micropore volume that are inclusively made for retardation in the catlytic deactivation rate. The CHNS and TGA analysis of the spent catalysts confirm that ZB-1 and ZB-3 catalysts are susceptible for a significant coke formation attributed due to strong product retention in their large mesopore volume, which lead to the catalytic deactivation.

Conversion of Biomass-Derived Levulinic Acid into γ-Valerolactone Using Methanesulfonic Acid: An Optimization Study Using Response Surface Methodology

γ-Valerolactone (GVL) is a platform chemical for the synthesis of both biofuels and biochemicals. The LA production from depithed sugarcane bagasse (DSB) resulted in a 55% LA yield, and the resulting LA was used to produce GVL. The effect of process parameters, namely, temperature (25–200 °C), time (2–10 h), and catalyst loading (0.5–5 g) were investigated for the GVL production from LA. Thereafter, the optimized conditions were used to produce GVL from LA derived from depithed sugarcane bagasse (DSB) yielded a GVL of 77.6%. The hydrogen required for the reduction of LA to GVL was formed in situ by formic acid and triethylamine in the presence of methanesulfonic acid (MsOH). Different solvents (including water and alcohols) were also tested to determine their effect on GVL yield, and water yielded the highest GVL of 78.6%. Different types of catalysts, which included mineral acids and ionic liquids, were used to determine their effect on GVL yield, and to provide a benchmark against MsOH. The GVL yield from DSB-derived LA is 1.0% lower than the GVL yield from a commercial sample of LA. LA generated from DSB has the potential to replace fossil fuel-derived LA.

Levulinic Acid Production from Waste Corncob Biomass Using an Environmentally Benign WO3-Grafted ZnCo2O4@CeO2 Bifunctional Heterogeneous Catalyst

Herein, a novel and environmentally benign solid catalyst was fabricated by grafting WO₃ active species onto the ZnCo₂O₄@CeO₂ support for efficient levulinic acid production from corncob waste biomass. The morphological, compositional, and textural properties of the designed catalyst were investigated using different characterization techniques to identify suitable catalyst formulation with enhanced catalytic activity and stability. The results demonstrated that WO₃ active species were successfully loaded with uniform distribution onto the support to develop a robust catalyst with both acidic and basic sites. The experimental investigation showed that among the catalysts, WO₃(10 wt %)/ZnCo₂O₄@CeO₂ exhibited the best catalytic activity, providing a maximum levulinic acid yield of 78.49% at the optimal conditions of 6 wt % catalyst dosage, reaction temperature of 180 °C, and reaction time of 200 min. The presence of an optimum number of both acid and base active sites on the catalyst surface could lead to the highest catalytic activity of the synthesized catalyst. Finally, the reusability investigation indicated that the synthesized catalyst possessed sufficient recyclability of up to four times for the levulinic acid production from the selected biomass with negligible drop in the catalytic activity.

Novel Intensified Alternatives for Purification of Levulinic Acid Recovered from Lignocellulosic Biomass

The development of a bio-based economy has its foundations in the development of efficient processes to optimize biomass potential. In this context there are a multitude of molecules that can be either synthetized or recovered from biomass, among those the so-called 12 building-blocks reported by the US Department of Energy. Even if their identification and importance is clearly defined, research efforts concerning the purification or separation of these platform molecules are limited. To fill this gap, different configurations for the purification of levulinic acid recovered from lignocellulosic biomass are examined and compared in this work. In particular, hybrid configurations obtained by the combination of liquid-liquid extraction and distillation have been considered. It was demonstrated how a deep understanding of the subspace including all extraction-assisted simple column distillation configurations represents a fundamental step in the synthesis of different process alternatives. From a separation efficiency and economic standpoint, the proposed intensified liquid-liquid thermally equivalent configuration (LL-TE) and liquid-liquid side stream column configuration (LL-SSC) are promising solutions. Nonetheless, their performances are deeply interrelated to the purity target defined by the designer.