Activation of Commercial CaO for Biodiesel Production from Rapeseed Oil Using a Novel Deep Eutectic Solvent

OH-Impregnated Household Bleach-Making Sediments for the Catalysis of Waste Cooking Oil Transesterification: Parameter Optimization

Industrial and academic societies have been bothered with the generation and subsequent management of residues settled out from household bleach, due to its corrosive properties. Therefore, the aim of this research was to introduce a NaOH-impregnated calcium-based solid catalyst from the aforementioned sediments for waste cooking oil transesterification. To prepare the catalyst (RC-ITB), the wet impregnation technique was followed and successfully characterized via X-ray diffraction (XRD), X-ray fluorescence(XRF), differential scanning calorimetry (DSC), Brunauer-Emmett-Teller (BET), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM) methods. The study findings suggested that RC-ITB has a BET surface area of 9.312 m2 g-1 and is largely made up of calcium with its compound forms such as carbonates, hydroxides, and oxides. The evaluation of pH values verified that RC-ITB is more alkaline (i.e., pH = 12.65) relative to its precursor RC (pH = 10.66), largely attributable to OH impregnation. To study the catalytic performance, three numeric factors with three levels of treatment were used, and their influences were analyzed through a response surface approach. Accordingly, the optimal yield of biodiesel was found to be 80.04% at a reaction temperature of 61 ± 2 °C, catalyst weight of 6.33 wt %, and a molar ratio of 23.94. Moreover, FTIR analysis verified that the glycerol part of triglycerides had been replaced with a methoxyl unit. Also, the fuel quality parameters of the FAME product were examined, including density, kinematic viscosity, acid value, density, cetane number, cloud point, saponification value, and pour point; all of these values fall within the ASTM D6751-accepted limits. Thus, the findings showed that the sediments of household bleach production could be a candidate source to explore heterogeneous basic catalysts.

Sunflower oil methanolysis over modified CaO catalysts

Oil methanolysis over modified CaO catalysts was studied to assess the catalytic performance and to define an appropriate kinetic model. CaO was modified by commercial glycerol and a deep eutectic solvent (DES), choline chloride : glycerol (ChCl : Gly), to obtain catalytically active complexes of CaO and glycerol. The main goal was to investigate the effect of the obtained complexes on the reaction rate and fatty acid methyl ester (FAME) content and to describe the variation of the triacylglycerol (TAG) conversion degree during the reaction time. Fourier transform infrared spectroscopy (FTIR) was applied to confirm the formation of CaO complexes with glycerol or the glycerol-based DES. Different catalyst loadings (0.5, 1, and 5 % of oil weight) and methanol-to-oil molar ratios (6 : 1 and 12 : 1) were applied for investigation of the sunflower oil methanolysis at 60 oC. Two kinetic models were employed yielding the kinetic parameters, which depended on the catalyst loading and the methanol-to-oil molar ratio. Both models showed valid applicability for describing the kinetics of the reactions catalyzed by both complexes (the mean relative percent deviation was lower than 10 %).

Locally Sustainable Biodiesel Production from Waste Cooking Oil and Grease Using a Deep Eutectic Solvent: Characterization, Thermal Properties, and Blend Performance

As part of local sustainability efforts, biodiesel was synthesized via transesterification using a deep eutectic solvent (DES) without further washing from on-campus, dining facility waste cooking oil and grease. Before moving forward with repurposing used DES as a solvent in chemistry teaching labs, we determined the suitability of the biodiesel as an alternative fuel blended with diesel to power campus utility vehicles. Biodiesel components were characterized by gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹H NMR), viscometer, differential scanning calorimetry (DSC), and evolved gas analysis during pyrolysis with a thermogravimetric analyzer coupled with FTIR (TGA-FTIR). The four major components of fatty acid methyl esters (FAMEs) in the biodiesel were methyl oleate, methyl linoleate, methyl palmitate, and methyl stearate. Kinematic viscosity over typical temperature ranges was within optimal values recommended by the American Biodiesel Standard (ASTM D6751), with a 30:70 biodiesel/diesel blend experimental viscosity of 3.43 cSt at 40 °C and a calculated viscosity of 10.13 cSt at 0 °C. The pure biodiesel's cold-temperature onset of crystal formation is -10.1 °C versus -16.4 °C for a 30:70 biodiesel/diesel blend. Pyrolysis indicates good thermal stability, however, with an increased CO₂ evolution in the blended fuel at higher temperatures as compared to that in the pure biodiesel and the pure diesel. Combustion gas analysis indicates virtually complete combustion of the blended fuel to CO₂ and H₂O with only trace amounts of CO. Overall results indicate that the biodiesel synthesized using DES is a suitable fuel for campus utility vehicles in the local moderate temperature climate and affords increased local sustainability by using used DES repurposed in our chemistry teaching labs.

Deep Eutectic Solvents for Pretreatment, Extraction, and Catalysis of Biomass and Food Waste

Valorization of lignocellulosic biomass and food residues to obtain valuable chemicals is essential to the establishment of a sustainable and biobased economy in the modern world. The latest and greenest generation of ionic liquids (ILs) are deep eutectic solvents (DESs) and natural deep eutectic solvents (NADESs); these have shown great promise for various applications and have attracted considerable attention from researchers who seek versatile solvents with pretreatment, extraction, and catalysis capabilities in biomass- and biowaste-to-bioenergy conversion processes. The present work aimed to review the use of DESs and NADESs in the valorization of biomass and biowaste as pretreatment or extraction solvents or catalysis agents.

Waste cooking oil and waste chicken eggshells derived solid base catalyst for the biodiesel production: Optimization and kinetics

Waste chicken eggshells were used to derive two catalysts labeled in this study as Eggshell-CaO_C-H-D and Eggshell-CaDG. Both these catalysts were characterized by FTIR, XRD, BET, SEM, and basic strength was determined by the Hammett indicator method. The transesterification of waste cooking oil was carried out to compare the catalytic activity of Eggshell-CaDG and Eggshell-CaO_C-H-D. The effect of various reaction parameters-methanol molar ratio, temperature, speed of agitation, and catalyst loading on the progress of the reaction was also tested to produce higher biodiesel yield. Eggshell-CaDG catalyzed reaction produced 96.07% biodiesel under the optimized reaction conditions of methanol molar ratio 10:1, catalyst loading 1.50 wt%, temperature 60 °C and speed of agitation 300 rpm with a reaction time of 50 min. Whereas, Eggshell-CaO_C-H-D was yielded 93.10% biodiesel for the optimized operating parameters-methanol molar ratio 12:1, 400 rpm, 65 °C, catalyst loading of 3 wt% in the reaction time of 90 min. The reusability for both the catalysts was tested up to five cycles and found that biodiesel yield was decreased with successive cycles. The activation energies of the Eggshell-CaDG and Eggshell-CaO_C-H-D were found to be 31.39 and 54.05 kJ mol^-1, respectively. The physicochemical properties of the biodiesel were also found as per the ASTM standard range.

Comparative Study of Quick Lime and CaO as Catalysts of Safflower Oil Transesterification

This work aimed to contrast the performance of quicklime and CaO reagent grade as heterogeneous catalysts for the safflower oil transesterification reaction. Quicklime was characterized by TGA analysis, XRD, atomic absorption, nitrogen physisorption and by Hammett method. In the safflower transesterification reaction, four main variables were studied: addition reagents order, reagents dosage, type of catalyst and methanol-oil molar ratio. The addition reagents order was not found to be determinant on time for reaching equilibrium or maximum methyl esters yield. On the contrary, reagents dosage was found to negatively affect reaction rate and methyl esters yield. It was found that quicklime performs better than CaO and this was ascribed to an increased basicity found in the former. From the results can also be inferred that the use of quicklime as catalyst of the transesterification reaction allows the decrease of the process cost by reducing both, the reaction time and the required amount of alcohol.