Modeling and optimization of two-step shea butter oil biodiesel synthesis using snail shell as a heterogeneous base catalyst

Shea butter oil (SBO) is underutilized in the biodiesel production industry in Nigeria because of its high free fatty acid (FFA) which reduces its biodiesel yield. This research aimed at...

Green Heterogeneous Base Catalyst from Ripe-Unripe Plantain Peels for the Transesterification of Waste Cooking Oil

Economical feedstocks such as agricultural wastes, food wastes, and waste cooking oil were used for biodiesel production to expand their application. Thus, a solid base catalyst was synthesized from a mixture of ripe and unripe plantain peels at a calcination temperature of 500 oC for 4 h. The catalyst was characterized using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) analysis, Fourier Transform Infrared (FT-IR) spectroscopy, Energy dispersive X-ray (EDX) analysis, and Brunauer-Emmett-Teller (BET) method. The waste cooking oil (WCO) used in this study was first pretreated with 3% (v/v) of H2SO4 via esterification reaction due to its high acid value. The esterified WCO was converted to biodiesel via transesterification reaction, and the process was then modeled and optimized using Taguchi L9 orthogonal array design method considering reaction temperature, reaction time, catalyst amount, and methanol/WCO molar ratio as the input variables. Based on the results, the synthesized catalyst predominantly contained potassium phases with 45.16 wt.%. The morphology of the catalyst revealed a crystalline mesoporous nanocomposite. At the end of WCO esterification, the acidity of the oil decreased from 5 to 1 mg KOH/g. The optimal conditions established for the transesterification process were catalyst amount of 0.5 wt.%, methanol/WCO molar ratio of 6:1, reaction temperature of 45 oC, and reaction time of 45 min with a corresponding biodiesel yield of 97.96 wt.%. The quality of the biodiesel produced satisfied the specifications (ASTM D6751 and EN 14241) recommended for biodiesel fuels. Hence, a blend of ripe and unripe plantain peels could serve as an efficient heterogeneous base catalyst in producing biodiesel from WCO.

Synthesis of Chitosan-La2O3 Nanocomposite and Its Utility as a Powerful Catalyst in the Synthesis of Pyridines and Pyrazoles

Recently, the development of nanocatalysts based on naturally occurring polysaccharides has received a lot of attention. Chitosan (CS), as a biodegradable and biocompatible polysaccharide, is considered to be an excellent template for the design of a hybrid biopolymer-based metal oxide nanocomposite. In this case, lanthanum oxide nanoparticles doped with chitosan at different weight percentages (5, 10, 15, and 20 wt% CS/La2O3) were prepared via a simple solution casting method. The prepared CS/La2O3 nanocomposite solutions were cast in a Petri dish in order to produce the developed catalyst, which was shaped as a thin film. The structural features of the hybrid nanocomposite film were studied by FTIR, SEM, and XRD analytical tools. FTIR spectra confirmed the presence of the major characteristic peaks of chitosan, which were modified by interaction with La2O3 nanoparticles. Additionally, SEM graphs showed dramatic morphological changes on the surface of chitosan, which is attributed to surface adsorption with La2O3 molecules. The prepared CS/La2O3 nanocomposite film (15% by weight) was investigated as an effective, recyclable, and heterogeneous base catalyst in the synthesis of pyridines and pyrazoles. The nanocomposite used was sufficiently stable and was collected and reused more than three times without loss of catalytic activity.

Rapid Synthesis of Asymmetric Methyl-Alkyl Carbonates Catalyzed by α-KMgPO4 in a Sealed-Vessel Reactor Monowave 50

Dimethyl-carbonate (DMC) is a green carboxymethylation agent for synthesis of the versatile long-chain alkyl carbonates through base-catalyzed transesterification with aliphatic alcohols. Herein, we demonstrated the facile preparation of a novel heterogeneous base catalyst α-KMgPO4 using commercially cheap metal salts via hydrothermal-calcination procedure. The combination of temperature programmed desorption (TPD) and FTIR measurements with CO2 pre-adsorbed revealed the presence of weak and medium base sites on α-KMgPO4. Furthermore, α-KMgPO4 catalyzed transesterification of DMC and n-octanol was performed in a sealed-vessel reactor (Monowave 50). The results show that the reaction was completed in only 10 min with the 97.5% conversion of n-octanol and >99% selectivity to asymmetric methyl-octyl carbonate under the optimal conditions. Additionally, the possible catalytic mechanism is proposed. As an extended contribution, the tribology performance of the asymmetric methyl-alkyl carbonates was further evaluated.