Synthesis of a sulfated-group-riched carbonaceous catalyst and its application in the esterification of succinic acid and fructose dehydration to form HMF

Optimization of microwave-assisted esterification of succinic acid using Box-Behnken design approach

Esters of butanedioic acid (succinic acid) are appealing renewable esters as fuel additives and solvents. In the present study, we have investigated reaction routes for the esterification of succinic acid (SA) with alcohols like methanol (MeOH), ethanol (EtOH), and 2-propanol (2-PrOH) using heterogeneous catalyst D-Hβ (moderate Bronsted acidity) in a microwave (MW)-irradiated reactor to increase yield and minimize waste generation. Using the Box-Behnken design (BBD) approach, operating parameters such as reaction time, microwave power, and catalyst dosing were optimized for SA esterification with MeOH. At optimum conditions using D-Hβ catalyst, 99% maximum conversion was achieved with 98% selectivity of dimethyl succinate (DMS). At optimum conditions, the esterification of SA with EtOH and 2-PrOH was also performed. The use of D-Hβ is economically more advantageous as it can be reused directly without any prior washing and also showed significant activity.

Microwave-assisted biodiesel production using bio-waste catalyst and process optimization using response surface methodology and kinetic study

Providing sufficient energy supply and reducing the effects of global warming are serious challenges in the present decades. In recent years, biodiesel has been viewed as an alternative to exhaustible fossil fuels and can potentially reduce global warming. Here we report for the first time the production of biodiesel from oleic acid (OA) as a test substrate using porous sulfonic acid functionalized banana peel waste as a heterogeneous catalyst under microwave irradiation. The morphology and chemical composition of the catalyst was investigated using Powder X-ray diffraction (PXRD) analysis, Fourier transform infrared (FTIR) spectroscopy, Thermogravimetric analysis (TGA), Transmission electron microscopy (TEM), and Scanning electron microscopy- Energy dispersive X-ray spectroscopy (SEM-EDX). The SEM-EDX analysis of the catalyst revealed the presence of sulfur in 4.62 wt% amounting to 1.4437 mmol g^-1 sulfonic acids, which is accorded to the high acidity of the reported catalyst. Using response surface methodology (RSM), through a central composite design (CCD) approach, 97.9 ± 0.7% biodiesel yield was observed under the optimized reaction conditions (methanol to OA molar ratio of 20:1, the temperature of 80 °C, catalyst loading of 8 wt% for 55 min). The catalyst showed excellent stability on repeated reuse and can be recycled at least 5 times without much activity loss.