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In this work, biodiesel was synthesized from castor and black mustard oil seeds, through homogenous alkaline transesterification with methanol. The impact of parameters such as alcohol amount, catalyst quantity, temperature, and reaction time have been optimized. The yield of castor biodiesel (COB) was 93.53% w/w at 20.7 wt.% methanol, and black mustard biodiesel (MOB) was 93.88% w/w at 20 wt.% methanol. The other conditions wt.% KOH, temperature, and reaction time were 0.5, 60 °C, and 60 min respectively. (COB) and (MOB) were mixed with diesel fuel (DI) in various ratios to obtain (B5, B10, B15, B20, B30, and B50), and the physicochemical properties of biodiesel are measured employing ASTM standards. The diesel one-cylinder engine was used as a test engine. CO2, CO, NOx, and SO2 emissions from biodiesel and its blends were measured and compared to DI. COB and MOB blends emitted less CO2, CO, and SO2 emissions than DI, along with a slight increase in NOx emissions. Based on the results, (COB) and (MOB) were reliable substitute fuels for reducing environmental pollution. [ABSTRACT FROM AUTHOR]

Standardization of the cultivation conditions is crucial for producing fungal biomass with effective whole-cell catalytic activity. Aspergillus flavus mutant was optimized for biomass transesterification and hydrolysis of waste frying oil (WFO) as a substrate. The glucose-polypeptone medium was selected among other culture media as the primary medium for the optimization of submerged cultivation. Biomass lipolytic activities and growth of A. flavus were higher under shaking conditions compared to static conditions, and 200 rpm was optimum. Olive oil was superior to soybean, rapeseed, and waste frying oils as biomass lipase and transesterification activities inducer. Replacing glucose with sugar cane molasses enhanced the growth but inhibited the biomass lipolytic capabilities. Urea improved the biomass lipolytic capabilities as an N-source feedstock compared to corn-steep liquor and whey. Plackett Burman screening of 9 factors showed that KH2PO4 (0.1–0.9 %, w/v), urea (0.1–1.3 %, w/v), and glucose (0.5–3.5 %, w/v) concentrations were significant factors with the highest main effect estimates 38.45, −19.04, and 11.82, respectively. These factors were selected for response surface methodology (RSM) optimization using central composite design (CCD). CCD models for growth, biomass lipase activity, and transesterification capability were significant, with R2 values of 0.93, 0.91, and 0.95, respectively. The optimum concentrations for growth and biomass transesterification capability were glucose (4.5 %, w/v), urea (0.7 %, w/v), and KH2PO4 (0.9 %, w/v), and those for lipase activity of the biomass were glucose (4.4 %, w/v), urea (0.7 %, w/v), and KH2PO4 (2.1 %, w/v). [ABSTRACT FROM AUTHOR]

The machining process is considered a basic procedure in any mechanical-based industry. Machining is the interaction between the tool and the raw material that results in material deformation and thus leads to heat generation in the work zone, and chip formation. Thus, for metal working operations, lubricants commonly employed are generally known as metal working fluids (MWFs). Besides lubrication, MWFs remove heat generated in the work zone, and the chips that form will be carried away. The widely available mineral oil–based MWFs are non-biodegradable and also cause several health disorders to the operator involved, which necessitates the need for biodegradable cutting fluids (CFs). The base-stock for the green cutting fluid (GCF) in this work is rice bran oil (RBO). The poor oxidation stability of the RBO is addressed by chemical modification method. Then clove oil was added as a bio-additive to further enhance the lubricant properties of chemically modified RBO. The performance of the GCF formulated was evaluated and compared with commercial cutting fluid using a pin on disc apparatus. The formulated green cutting fluid is observed to be better in terms of coefficient of friction, corrosion and oxidation stability with comparable performance test results. [ABSTRACT FROM AUTHOR]

This research aimed to model and optimize the growth factors and enhance the lipid yield from Botryococcus braunii microalgae, and to design a system for obtaining biodiesel from these lipids as this does not compromise food security. Botryococcus braunii, grown on a modified Chu‐13 medium, reached the stationary phase after 27 days with a maximum cell count of 265 × 104 cells mL−1 after 27 days and maximum biomass yield of 725 mg L−1 after 30 days on modified Chu‐13 medium, which was higher than growth on Basal SAG medium. The maximum lipid content (18.47%) and lipid yield (4.46 mg L−1day) were obtained when B. braunii was cultivated on modified Chu‐13 medium after 30 days. Gas chromatography (GC) analysis for the lipids indicated that the highest percentages of SFAs (51.03%) and lowest percentages of monounsaturated fatty acids (MUFAs) (36.47%) and polyunsaturated fatty acids (PUFAs) (12.49%) were obtained by culturing B. braunii on modified Chu‐13 medium. The effect of different growth parameters (N2 level, NaHCO3, and CO2 concentrations) on growth yield was modeled by using D‐optimal design response surface methodology (RSM). [ABSTRACT FROM AUTHOR]

Zeolite imidazolate frameworks (ZIFs) were composited with NaY zeolite using two different approaches to the ship‐in‐bottle method. The two synthesized nanocatalysts showed that the ZIF‐8 composite with NaY zeolite could stabilize their structure as catalysts in an acidic environment. The NaY@ZIF‐8 nanocomposites that were prepared were investigated using Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), elemental mapping (MAP), thermogravimetric (TGA), temperature‐programmed desorption of ammonia (NH3‐TPD), and inductively coupled plasma analyses. The synthesized composites were used as catalysts for the esterification reaction of acetic acid with four different alcohols and the transesterification reaction of animal fats, vegetable oils, and waste oils. The results show that the efficiency of the esterification reactions for the two catalytic composites was 98.5% and 94.3%, respectively, and 78.1% for the transesterification reaction. [ABSTRACT FROM AUTHOR]

Considerable synthetic effort has been devoted to acid‐ or base‐catalysed transesterification of alkyl salicylate with alcohol in order to synthesize salicylate esters efficiently. In this study, the transesterification of methyl salicylate with 12 different alcohols was carried out by the use of Zn dust as a catalyst. Depending on the alcohol used in the transesterification reaction, the completion of the reaction was within a range of 8–15 h at a temperature between 100 and 170°C. The use of Zn dust provided reusability and almost complete recovery with moderate to excellent yields (42%–97%). The structural elucidation of the products was performed using IR, 1H NMR, 13C NMR and GC–MS data obtained from the Wiley GC/MS Library and the in‐house "Parkim Fragrance House GC/MS Library." [ABSTRACT FROM AUTHOR]

The objective of this research work is to perform a kinetic study and thermometric analysis on waste cooking oil which has been reported along with the outcomes. Biodiesel was obtained through the process of base-catalyzed transesterification process, and it was carried out at 50 and 60 ֯C, methanol/oil molar ratio and catalyst concentration were taken as a 9:1 and 0.45% w/w for potassium hydroxide (KOH), respectively at different stirring speed and reaction time. The experimental data from the transesterification reaction were fitted to first and second-order kinetic models. But the regression coefficient (R2) showed that the first order was a better fit for the experimental behavior of the kinetic data. The Arrhenius equation was applied to calculate the activation energy and the frequency factor of a given system, resulting in 45.76 kJ/mol and 4.95 × 105 min−1, respectively. At different temperatures, thermodynamic parameters were also taken into consideration in terms of Gibbs free energy, enthalpy, and entropy. Results show that biodiesel obtained from waste cooking oil gave better results and can be used as an excellent substitute of fossil fuels. [ABSTRACT FROM AUTHOR]

AbstractA novel thermo-active and alkaliphilic strain of Gp-1, isolated from hot water springs of Ganeshpuri, Maharashtra, India, identified as Brevibacillus borstelensis based on 16SrDNA characterization, with accession no. MT292327, at NCBI database. Statistical optimization of lipase production was done using Plackett-Burman algorithm and response surface methodology. Fermentative production of Gp-1 lipase was followed by partial purification, with 24.10 fold purification. Gp-1 lipase has molecular mass of 31 kDa, as determined by SDS-PAGE. Gp-1 lipase exhibited maximal specific activity at pH 10 and 55 °C, with stability up to 70 °C. Kinetic parameters analysis revealed Gp-1 lipase has Km and Vmax values of 1.544 mM and 31.25 μM/mg. min, and specificity constant of 281.13 sec-1, with pNP caprylate as the base suited substrate. Gp-1 lipase was found to be retain more than 90% activity in presence of various organic solvents, and various commercial detergent formulations. The Gp-1 lipase was also tested for transesterification reactions, which revealed successful transesterification of coconut oil, olive oil and waste cooking oil, and conversion in esters. Hence, Gp-1 lipase stands out as a prospective candidate in biodiesel synthesis, a green energy alternative. [ABSTRACT FROM AUTHOR]

The imperative of utilising alternative fuels for the operation of internal combustion engines stems from the requirements to reduce the emissions of greenhouse gases and other contaminants, the substantial demand for fuels, and the diminishing reserves of natural resources. The global inclination towards sustainable development necessitates the employment of biofuels as a substitute for fossil fuels. Nonetheless, the expenditures on raw materials for the manufacture of biodiesel remain substantial, thus underlining the importance of exploring solutions for reducing them. An instance of this could be the utilisation of plant and animal by-products, such as used frying oils and slaughterhouse waste, as feedstock for biodiesel production. Not only will this facilitate the creation of less costly biofuel, but it will also provide an effective solution for the management of post-production waste. The objective of the research delineated in this paper was to ascertain select physicochemical attributes of second-generation biodiesel, derived from spent frying oil, as well as mixtures of this biodiesel with diesel and biodiesel concentrations of 10, 20, and 30% (v/v). The biodiesel produced is the waste frying oil methyl esters WFOME. The proprietary GW-201 reactor was employed in the production of biodiesel. For WFOME biodiesel, DF diesel, and their blends—B10, B20, and B30—properties that influence the formation process of the combustible mixture, autoignition, and combustion of fuel–air mixtures in self-ignition engines were determined. The conducted research has established that "B" type fuels prepared from WFOME and DF present a viable alternative to fossil fuels. Pure biodiesel exhibited a marginally reduced lower heating value, however, in the case of fuel mixtures comprising up to 30% (v/v) biodiesel and diesel, the lower heating values approximated that of diesel. An elevated cetane number alongside an increased flash point of pure B100 biodiesel have been noted. The values of cetane number for WFOME and DF mixtures were found to be either comparable or marginally higher than those of pure DF diesel fuel. [ABSTRACT FROM AUTHOR]

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Poly(ester-ether)s are biodegradable copolymers with excellent performance. These copolymers are used as scaffolds for tissue engineering and degradable materials in packaging. However, their synthesis procedures are generally tedious which restrict their widespread applications. Furthermore, the inadequate availability of their commercial monomers also hampers their production. Herein, we reported a facile strategy for the synthesis of linear and branched poly(ester-ether)s using a polyol and methyl acrylate (MA) as monomers. During the polymerisation, the vinyl bond of MA reacts with the hydroxyl groups of a polyol following an oxa-Michael polyaddition mechanism. Simultaneously, esterification takes place between the ester group of MA and polyol. As a result, poly(ester-ether)s were successfully synthesised by combining these two different types of reactions into one polymerisation system. The linear and branched structures of the products were confirmed by the nuclear magnetic resonance and triple-detector gel permeation chromatography. This work provides a facile strategy for the synthesis of poly(ester-ether)s from commercially available monomers. [ABSTRACT FROM AUTHOR]

Tyrosol is a principle phenolic compound present in olive oil and wine with great pharmacological potentials due to its strong antioxidant property. Its application can be highly extended by increasing its lipophilicity through esterification. In this study, tyrosol esters were synthesized by enzymatic transesterification of tyrosol with vinyl esters, with a commercial lipase from Novozymes (Novozym 435, Candida antarctica lipase B (CALB) immobilized on macroporous acrylic resin beads) as the catalyst, both in organic solvents and in ionic liquids. Methyl tert-butyl ether (MTBE) was the best solvent, offering complete conversions towards the synthesis of tyrosol esters with varying chain lengths (C2-C18) within 1 h. Taking the enzymatic transesterification between tyrosol and vinyl acetate as the model reaction, 18 organic solvents and 24 ionic liquids were screened, and their solvent properties (i.e. hydrophobicity, polarity, viscosity, water activity, and partition coefficients of substrate and product) were correlated to the enzyme activity. Upon enzyme screening, four new lipases were found to be highly efficient, relative to the best-performed Novozym 435 and Lipozyme TLIM (Thermomyces lanuginosus lipase (TLL) immobilized on silica gel), in tyrosol ester synthesis. This work provides enzymatic methods of esterifying tyrosol that are much more efficient than those reported in literature, and will shed light on re-consideration of the roles of solvents in nonaqueous enzymology. [ABSTRACT FROM AUTHOR]

Biodiesel, a third-generation biofuel, offers several advantages over regular diesel fuel. Waste cooking oil (WCO) emerges as an ideal feedstock due to its availability and easy accessibility. In this work, biodiesel was produced from two different types of immobilized lipases: Rhizomucor miehei lipase (RMIM) and Candida antarctica lipase B (CALB). The objective of this study was to evaluate the impact of the molar ratio of WCO to methyl acetate, toward biodiesel yield and triacetin formation, from transesterification reaction when using two different immobilized lipases namely, Rhizomucor miehei lipase (RMIM) and Candida antarctica lipase B (CALB) as catalyst, as well as to assess its resulting biodiesel in a diesel engine. The enzymatic transesterification reaction was carried out with ultrasonic assistance, and the results showed that the greatest yield of 81.20% was achieved at 45 °C using CALB as a biocatalyst, with a lipase concentration of 1.8% (w/v) and an oil to methyl acetate molar ratio of 1:12 within 3 h. Triacetin, a by-product was determined their concentration for each molar ratio and analyzed using FTIR range of 500 cm-1 to 4000 cm-1, revealing a significant absorption peak at 1238.90 cm-1. Biodiesel was then blended with commercial diesel fuel in varying quantities of 7, 10, and 20% by volume (B20). The results were compared to Industrial Diesel Fuel 7% (B7) and Commercial Diesel Fuel 10% (B10). NOx and CO2 emission drops as the percentage of diesel/biodiesel blends increases, supporting WCO as a cost-effective biodiesel feedstock with low petrol pollution. [ABSTRACT FROM AUTHOR]

Microstructured reactors offer fast chemical engineering transfer and precise microfluidic control, enabling the determination of reactions' kinetic parameters. This review examines recent advancements in measuring microreaction kinetics. It explores kinetic modeling, reaction mechanisms, and intrinsic kinetic equations pertaining to two types of microreaction: esterification and transesterification reactions involving acids, bases, or biocatalysts. The utilization of a micro packed-bed reactor successfully achieves a harmonious combination of the micro-dispersion state and the reaction kinetic characteristics. Additionally, this review presents micro-process simulation software and explores the advanced integration of microreactors with spectroscopic analyses for reaction monitoring and data acquisition. Furthermore, it elaborates on the control principles of the micro platform. The superiority of online measurement, automation, and the digitalization of the microreaction process for kinetic measurements is highlighted, showcasing the vast prospects of artificial intelligence applications. [ABSTRACT FROM AUTHOR]

This study investigated biodiesel production via the transesterification of grapeseed oil with plasma-modified biomass-based catalysts originating from starfish. Dried starfish was first converted into magnesium and calcium oxide through heat treatment and then further modified by plasma engineering to improve the catalyst's surface area and active sites via zinc addition. The Zn content was added via plasma engineering in the ratios of starfish (Mg0.1Ca0.9CO3): ZnO varying from 5:1, 10:1, to 20:1. The structure and morphology of the catalyst were confirmed through XRD, SEM, and XPS analysis. After the Zn addition and activation process, the surface area and the basicity of the synthesized catalysts were increased. The plasma-modified catalyst showed the highest basicity at the ratio of 10:1. Based on HPLC analyses, the optimized biodiesel yield in transesterification demonstrated 97.7% in fatty acid conversion, and its catalytic performance maintained 93.2% even after three repeated runs. [ABSTRACT FROM AUTHOR]

The development of more recyclable materials is a key requirement for a transition towards a more circular economy. Thanks to exchange reactions, vitrimer, an attractive alternative for recyclable materials, is an innovative class of polymers that is able to change its topology without decreasing its connectivity. In this work, a bisphenol compound (VP) was prepared from saturated cardanol, i.e., 3−pentadecylphenol and vanillyl alcohol. Then, VP was epoxidized to obtain epoxide (VPGE). Finally, VPGE and citric acid (CA) were polymerized in the presence of catalyst TBD to prepare a fully bio−based vitrimer based on transesterification. The results from differential scanning calorimetry (DSC) showed that the VPGE/CA system could be crosslinked at around 163 °C. The cardanol−derived vitrimers had good network rearrangement properties. Meanwhile, because of the dynamic structural elements in the network, the material was endowed with excellent self−healing, welding, and recyclability. [ABSTRACT FROM AUTHOR]

The synthesis of biodiesel can be achieved using either homogeneous or heterogeneous catalysts. Given the non-renewable nature of homogeneous catalysts, heterogeneous catalysts are increasingly preferred for biodiesel production. Agricultural wastes serve as a viable source for these heterogeneous catalysts, contributing to environmental sustainability. This study introduces a novel, eco-friendly, cost-effective, and efficient heterogeneous catalyst that was developed and derived from Citrus limetta peels for biodiesel production. The catalyst was thoroughly characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffractograms (XRD), Field Emission Scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX). Coconut oil, a rich and renewable resource, was used as the feedstock for the biodiesel synthesis. The conversion process was confirmed by 1H NMR, IR spectra, mass spectra, and 13C NMR of the biodiesel. The developed method using the Citrus limetta peel-derived catalyst demonstrated a 100% yield. The results show the optimum conditions for biodiesel synthesis are 1 w/v (for the catalytical dose), with a 6:1 methanol/oil ratio at 60 °C for 3 h. The synthesized biodiesel exhibited a high cetane value of 54, contributing to improved ignition and reduced engine noise. Its sulfur-free composition, boiling point of 294 °C, high viscosity of 2.5 mm2/s, acid value of 0.09 mgKOH/g, and flash point of 142 °C enhance its environmental profile. The catalyst can be used for up to five cycles, underscoring its potential as a cost-effective and sustainable approach for biodiesel production. [ABSTRACT FROM AUTHOR]

Given the ongoing crisis of depleting fossil fuel reserves and rising demand for biofuels, scientists are increasingly driven to explore more environmentally friendly and sustainable energy options in today's global landscape. Consequently, the utilization of solid catalysts, specifically Metal–Organic Frameworks (MOFs), in the transesterification process to produce biodiesel emerges as a promising avenue. This marks the innovative adoption of the metal–organic catalyst MIL-68 (Al) in the context of biodiesel production. This study focuses on the generation of green and efficient biodiesel using Waste Cooking Oil (WCO) as the primary raw material which involves a transesterification process utilizing of MIL-68 (Al). Using the Box-Behnken Design (BBD), a well-established method in Response Surface Methodology (RSM), we optimized key variables including catalyst quantity, duration, and temperature in the transesterification process. The optimization study includes parameter ranges: time (3–8 h), temperature (100–150 °C), and catalyst dosage (5–25%). The catalyst characteristics were investigated through AFM, BET, DLS, SEM, ICP, FTIR, NH3-TPD, TEM, TGA, and XRD analyses. Using a temperature of 145 °C and incorporating a catalyst quantity of 24.18%, a maximum oil conversion efficiency of 98.8% was attained within 7.5 h. Kinetic analysis showed that the experimental behavior followed a pseudo-first-order reaction kinetic model (R2 = 0.9991), and the transesterification reaction demanded an activation energy of Ea = 65.47 kJ/mol. The catalyst demonstrates excellent stability, maintaining consistent performance over four cycles without any noticeable decline. The yield after four cycles of reusability remains high at 92.6%. [ABSTRACT FROM AUTHOR]

This research work was aimed at studying the effects of transesterification process parameters on the production of biodiesel from oil extracted from catfish using raw, acid, alkaline, and thermally modified potassium hydroxide from clay as catalysts. The catfish oil was extracted using an oven at a temperature of 35 °C. The extracted catfish oil was converted into biodiesel using the transesterification method at a constant temperature of 60 °C for 60 min. The process parameters for the production of biodiesel from fish oil using raw, acidic, alkaline, and thermally modified potassium hydroxide from clay as catalysts were analyzed. The process parameters: methanol to oil molal ratio (mol/mol), catalyst concentration (weight%), reaction time (hours), reaction temperature (°C) and agitation speed (rpm) were the independent variables used in determining the biodiesel yield (vol/vol), which was the dependent variable. The experimental or actual maximum optimal biodiesel yield for biodiesel production from the process parameters had different yields using the fish oil with raw, acid, alkaline, and thermal KOH as catalysts. Results obtained showed the highest biodiesel yield was obtained at a reaction time of 3 hours, a reaction temperature of 70 °C, a methanol/sample molal ratio of 12:1, a catalyst concentration of 4 wt%, and an agitation speed of 400 rpm, respectively. It was also observed that the agitation speed and the thermally modified KOH catalyst had a significant effect on the biodiesel yield. [ABSTRACT FROM AUTHOR]

For the manufacture of extrusion dies, three‐dimensional (3D) printing with photopolymers offers numerous advantages including flexibility, high surface quality, decent build speed, low costs and a reduced amount of waste. However, the majority of photocurable resins used in vat photopolymerization 3D printing rely on acrylates, which entail 3D‐printed objects with poor mechanical properties. In particular, the high brittleness limits their application in rapid tooling, for which tough materials with high glass transition temperatures (Tg) are required. In the present study, we highlight the use of dual curable acrylate‐epoxy resins with dynamic covalent bonds for the direct fabrication of extrusion dies. During digital light processing (DLP) 3D printing the acrylate network is formed, whose toughness and thermal stability are significantly enhanced by the thermoactivated formation of a second network. By following a postbaking procedure, aminoglycidiyl monomers are cured with an anhydride hardener bearing bulky norbornene groups yielding interpenetrating polymer networks with a Tg > 100°C. The tertiary amine groups present in the structure of the aminoglycidyl derivatives do not only accelerate the ring‐opening reaction but also act as internal catalysts and activate bond exchange reactions between free –OH groups and ester moieties available in the photopolymer. This is confirmed by rheometer studies showing a distinctive stress relaxation at elevated temperature and giving rise to a possible reprocessability of the 3D‐printed dies. With a selected resin formulation, a set of dies is printed by DLP 3D printing, with which a highly filled rubber compound is successfully extruded. The results clearly show that dual curable resins with dynamic covalent bonds are a promising class of material for rapid tooling and pave the way towards a customized and convenient fabrication of extrusion dies for rubber processing. [ABSTRACT FROM AUTHOR]

Kraft lignin (KL), an abundant and underutilized biobased aromatic resource, was valorized into polyester vitrimers showing enhanced recyclability. KL was first modified with ethylene carbonate, to expose only highly reactive primary aliphatic OH groups, allowing the direct synthesis of polyester networks by polycondensation with PEG-based dicarboxylic acid. In addition to avoiding the use of toxic acyl halides or coupling agents, this fast synthetic process yields networks in which the amount of free OH groups can be easily controlled by adjusting the stoichiometry between COOH and OH groups. The presence of free OH groups allows transesterification reactions resulting in a vitrimer behavior. Increasing the number of free OH groups promotes the stress relaxation process, but does not affect the activation energy, which is relatively low compared to typical transesterification vitrimers, owing to the specific network topology. High performance materials with improved mechanical and chemical recyclability were clearly demonstrated. Besides, the modified lignin can be recovered and isolated in high yields with only minor changes in its chemical structure, offering further upcycling opportunities. This makes lignin, the first aromatic and biobased resource, a raw material that can also be recycled, in line with the concept of a circular bioeconomy. [ABSTRACT FROM AUTHOR]

We report the synthesis of arsenic heterocycles derived from saccharides 2–4 and AsCl3. Compounds 5 and 6 are stable in aqueous solutions, DMSO, or methanolic solutions. However, NMR and HPLC studies revealed that intramolecular trans‐esterification processes leads to dynamic equilibria. Theoretical studies revealed that three arsenates and two arsoranes participate in these intramolecular equilibria and account for the experimental spectroscopy and HPLC results. Through the correlation between the experimental and theoretical 13C NMR spectra, we proposed the speciation of arsenic Compounds 5 and 6. Moreover, experimental and theoretical IR spectra demonstrated that arsenates 5 A and 6 A predominate in the solid state. QTAIM studies were performed to explain the chemical shifts in the 13C NMR spectra. Biological studies suggest that the structural flexibility of Compounds 5 and 6 increase the cytotoxic and antiproliferative activities of these compounds. [ABSTRACT FROM AUTHOR]

Phosphonate, as an effective flame‐retardant group, has a dynamic phosphonate exchange behavior similar to the transesterification of carboxylate; and introducing it into the network of epoxy resin (EP) is beneficial for solving the fire risk and waste disposal problems of EP in the meantime. Herein, a reprocessable and flame‐retardant epoxy vitrimer (EV) with dual dynamic covalent reactions of phosphonate and carboxylate transesterifications is constructed by introducing a phosphonate‐containing diol named GHPP into an epoxy‐anhydride curing system. The presence of the phosphonate makes the EV intrinsically flame‐retardant; meanwhile, both of the dynamic phosphonate and carboxylate transesterifications are accelerated by the abundant primary hydroxyl groups, which show much higher activity than the as‐generated β‐hydroxyls during curing, leading to enhanced dynamic properties of the EV. As a result, on the one hand, the EV achieves the UL‐94 V‐0 rating with a high limiting oxygen index value of 37.3%; and it shows a 41% reduction for the peak heat release rate and a 39% reduction for the total heat release in the cone calorimetry test. On the other hand, such EV exhibits rapid stress relaxation and is reprocessed easily to maintain its mechanical properties, thermal properties and flame retardancy to the hilt. [ABSTRACT FROM AUTHOR]

Constructing self‐repairing epoxy materials based on transesterification chemistry can be regarded as a potential path for practical industrial applications given on its simplicity and ease of processing. However, there is still a challenge to improve the slow bonding exchange process for desired healing performances. Herein, this work reports a simple and effective strategy to prepare high‐biomass‐content self‐repairing epoxy materials by introducing polyester oligomer (PEO) dicarboxylic acid as modifier into epoxidized soybean oil and itaconic acid compounds. The PEO is synthesized from glutaric anhydride and 1,4‐cyclohexanediol, as well possess a unique pentamer molecular structure. It not only endows the epoxy system with improved molecular mobility in virtue of its long‐chain structure, but also increases the number the essential ester groups of transesterification process, thus synergistically promoting bonding exchange rate for expected properties. As a result, the employment of PEO decreases the activation energy from 100 to 70 KJ/mol, as well as presents optimized self‐repairing efficiency in storage modulus and tensile strength tests compared to the control group. It may provide a new and practical way to fabricate high‐effective self‐repairing epoxy system for industrial applications. [ABSTRACT FROM AUTHOR]

Polymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate‐2‐(4‐ethenylphenyl)‐5,5‐dimethyl‐1,3,2‐dioxaborinane) P(HMA‐co‐ViCL) copolymers. The ABn ${{AB}_{n}}$ ‐type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high‐performance HBV damping materials. We found that P(HMA‐co‐ViCL) 20k‐40‐60 HBV exhibited ultrahigh energy‐dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials. [ABSTRACT FROM AUTHOR]

A series of KF/Mg‐Fe oxides were fabricated via the solid‐state reaction between KF and Mg‐Fe oxides. Especially, when 20 wt % KF was supported on the Mg‐Fe bi‐metal oxides and calcined at 400–600 °C, the solid material with more basic sites than the support itself was obtained. When applied as catalyst to dimethyl carbonate (DMC) synthesis through transesterification of ethylene carbonate (EC) and methanol, this material can afforded up to 88 % yield and 97 % selectivity toward DMC in 2 h under reflux conditions with the molar ratio of methanol to ethylene carbonate set at 8. It is worth noting that the catalyst was easily separated and reused, retaining at least 89 % catalytic activity during the first four recycles. Although an attenuated activity was still observed due to the inevitable filtration loss and dissolution, this solid base can still provide clues to the development recyclable catalyst in green synthesis of DMC. [ABSTRACT FROM AUTHOR]

This present work explored the possible use of sandbox seed (Hura crepitans) shell (SSS) waste as a feedstock for synthesizing green solid alkali biocatalyst in the microwave-aided sandbox oil (SBO) transesterification to obtain SBO biodiesel (SBOB). The solid catalyst was produced using a calcination method by burning raw SSS in the open air to obtain ash heated for 3 h in a furnace at 500 °C. The calcined sandbox shell ash (CSSA) produced was characterized using standard techniques to establish its catalytic potency. Also, a model was developed to simulate the process and examine the interactive effect of process input variables on SBOB yield using the Taguchi approach. The CSSA characterization showed it composed of K (44.99 %), Ca (1.54 %), and Mg (1.87 %) with crystalline compounds of K and Mg. The physisorption results gave a mean pore size of 18.142 nm and a surface area of 6.1125 m2/g. The best combination of the input variables determined for the process is a heating power of 450 W, methanol:SBO of 8:1, time of 1.5 min, and CSSA loading of 2 wt% with an optimum SBOB yield of 98.27 wt%. The SBOB produced met standard specifications for biodiesel. Microwave application to the SBO transesterification aided in rapidly completing the reaction. The study concluded that sandbox seeds and their shells are promising feedstock for cheap and sustainable biodiesel production. [Display omitted] • Novel biocatalyst from Sandbox shell wastes was synthesized and characterized. • Sandbox oil biodiesel was produced via transesterification with the biocatalyst. • The transesterification process was modeled and optimized by Taguchi method. • 98.27 wt% biodiesel yield was achieved using the optimum values obtained. • Sandbox oil biodiesel produced satisfied the standard specifications. [ABSTRACT FROM AUTHOR]

The shocking ecological variations and dangers of phasing out fossil fuels are concerning for human progress. It has raised the apprehension of workers about shifting from old energy capitals to ecologically sustainable biofuels. The current work involves the preparation of biodiesel (BD) using non-edible neem oil via transesterification reaction (TR). The transesterification process was carried out using nickel-doped zinc oxide (Ni–ZnO) nanocatalysts produced using the sonochemical technique. XRD, EDX, and SEM were employed for characterizing synthesized nanoparticles. TR was performed for the evaluation of the catalytic performance of Ni–ZnO. Various parameters affecting reaction rates, such as catalyst amount, temperature, and the methyl alcohol to neem oil ratio, were tested to determine where the maximum BD production could be achieved. It was found that the best BD (90.1%) was produced at 60 °C with a 1:10 oil-to-methyl alcohol ratio using 0.9 g of the catalytic system. First-order kinetic modeling is best suited for TR. Vital thermodynamic factors such as energy of activation (E*), enthalpy (H*), and entropy (S*) were also found. TR was endothermic and entropy-driven. A Ni–ZnO nanocatalyst could be an appropriate catalytic system for the heterogeneous catalysis of transesterification, a key reaction for BD making. [ABSTRACT FROM AUTHOR]

Vitrimer materials have attained great interest owing to their sustainable functions and distinctive physical properties. Compared with conventional cross‐linked materials, the thermoplastic‐like nature, such as the stress relaxation and creep at high temperatures, is outstanding, which is owing to the activation of the bond exchange in the cross‐linked network. The activation temperature of the bond exchange, so‐called topology freezing temperature (Tv), are treated as the important material parameters, and non‐isothermal (i.e., temperature‐ramp) creep test is one of the method to determine the Tv. This study investigates effects of network defects, that is, the breaking point of network connectivity, on the creep and Tv. The transesterification vitrimer samples with varying fraction of the network defects are designed using thiol‐epoxy click reaction, where the overall fraction of the bond exchange units, that is, the ester bond and hydroxyl group, is kept constant. Non‐isothermal creep tests are conducted with varying temperature‐ramp rate and applied stress levels, and the difference of Tv and creep behaviors at T > Tv are discussed in terms of network strand diffusion during bond exchange and chain elongation under stress. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION The transesterification of butteroil has been shown to alter its lipid chemistry and thus alter the crystallization of the fat. The reaction kinetics and resulting crystallization of the butteroil differ depending on the nature of the catalyst used. Modeling the reaction with vegetable oils is a simpler method for the analysis of resulting products to understand the chemical and physiochemical changes that occur based on catalyst selection. The objective of this work is to perform a chemical transesterification of coconut and corn oil using monovalent and divalent catalysts to investigate the chemical and crystal changes that occur.Coconut and corn oil were subjected to chemical transesterification using both Ca(OH)2 and KOH as catalysts. In both the coconut and corn oil samples, transesterification caused monoglycerides (MAGs) and diacylglycerides (DAGs) to form from the most abundant fatty acid found in each sample. Coconut oil's melting temperature, solid fat content (SFC), and storage modulus decreased as a result of the transesterification, and crystals began to form in the corn oil causing melting thermograms to be evident, higher SFC, and a more viscous oil as a result. Using Ca(OH)2 as a catalyst resulted in more MAG formation, and a higher SFC and melting temperature than when KOH was used as a catalyst.The results demonstrate that the chemical changes that result from transesterification of plant‐based oils change the crystallization behavior of the oils and can therefore be used for different applications in the food industry. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In-situ stirring batch reactor transesterification is a widely used method for the conversion of various biomass into biodiesel, particularly Nannochloropsis sp microalgae. Therefore, this study aims to investigate the effect of CaO/Hydrotalcite catalyst loading ratio and stirring rate on in situ stirring batch reactor transesterification of Nannochloropsis sp microalgae to produce biodiesel. In-situ transesterification was carried out using stirring with a four-blade paddle (50 w), while CaO/Hydrotalcite catalyst preparation was performed using incipient wetness impregnation. Nannochloropsis sp microalgae were then converted into biodiesel with varying loading ratio of catalyst (1:1, 3:1, and 5:1 %wt/wt) and stirring speed of agitation (50, 100,150, 200, and 250 rpm) for 4 hours (60oC). Subsequently, biodiesel obtained from the process was analyzed using gas chromatography (GC). The results showed that the surface area of CaO/Hydrotalcite was 45.756 m2/g. The conversion yields of Nannochloropsis sp microalgae to biodiesel with CaO/Hydrotalcite reached 38.36% with an agitation rate of 250 rpm. Based on the fatty acids analyzed using GC methods, the products predominantly contained olefine (61.49%) and gasoline (38.51%). [ABSTRACT FROM AUTHOR]

Ring‐opening polymerizations (ROPs) of l‐lactide (LA) were performed with ethyl l‐lactate or 11‐bromoundecanol as initiators (In) and tin(II) ethyl hexanoate (SnOct2) as catalyst (Cat) using four different LA/In ratios (20/1, 40/1, 60/1, and 100/1). One series of ROPs was conducted in bulk at 120 °C, yielding PLAs with low dispersities (Ð ~ 1.2–1.4), and a second series was conducted in bulk at 160 °C, yielding higher dispersities (Ð ~ 1.3–1.9). Samples from both series were annealed for 1 or 14 days at 140 °C in the presence of SnOct2. Both polycondensation and disproportionation reactions occurred, so that all four samples tended to form the same type of molar mass distribution below 10,000 Da, regardless of their initially different number average molar masses (Mn). Both initiators gave nearly identical results. The thermodynamic control of all reversible transesterification processes favored the formation of crystallites composed of chains with a Mn around 3500–3700, corresponding to a crystal thickness of 10–13 nm. [ABSTRACT FROM AUTHOR]

In this investigation, a strongly acidic exchange resin was used for the transesterification of methyl acetate with n‐propanol, n‐butanol, and iso‐butanol. Kinetic and equilibrium experiments for the three systems were conducted using a temperature‐controlled batch reactor setup. The effects of the following operating parameters on the transesterification were explored: reaction temperature, catalyst loading, and methyl acetate‐to‐alcohol molar ratio. The conversion of the limiting reactant in the reaction mixture increased with increasing reaction temperature, catalyst loading, and varying reactant proportions from 1:1 to other ratios. It was found that excess methyl acetate would result in higher limiting reactant conversion than using excess alcohol with the same initial molar proportionality between the excess and the limiting reactants. It was found that an increase in the chain length of the alcohol and/or branching suppressed the conversion of the reactants owing to steric hindrance. To mathematically correlate the data, several kinetic models were tested, and the Eley–Rideal model was selected. Accordingly, a reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

Spent bleaching earth (SBE) is a waste from the crude palm oil CPO refining process which contains high oil content, around 20-30%. There are several methods to reduce SBE oil content, one of which is the solvent extraction method. SBE residual oil can be utilized as a raw material for biodiesel. This research aims to determine the mass ratio of SBE and solvent, the optimal temperature for extracting residual oil from SBE, and the potential of residual oil from SBE to be used as biodiesel using a microwave reactor. Residual oil extraction was carried out at varying mass ratios of SBE and solvent (1:2, 1:4, and 1:6) and varying temperatures (26, 40, and 50°C). The treated residual oil was esterified and subjected to transesterification reaction with 15% methanol and 1% KOH for 10 minutes at 60°C using a microwave reactor. The optimal extraction result for residual oil was at a 1:4 ratio and 26°C with a yield of 19.12%. There is also an increase in surface area in deoiled-SBE. The conversion of residual oil from SBE into biodiesel yielded 33.53% with a conversion value of 45.28% and a FAME content of 92.97%. The characteristics of the produced biodiesel meet the Indonesian National Standard (SNI) for biodiesel with density of 0.8674 g/cm3 and viscosity of 5.69 mm2/s.

Biodiesel, a third-generation bio-fuels, offering several advantages over regular diesel fuel. Waste cooking oil (WCO) emerges as an ideal feedstock due to its availability and easy accessibility. In this work, biodiesel is utilized from two different types of immobilized lipases: Rhizomucor miehei lipase (RMIM) and Candida antarctica lipase B (CALB). The impact of the molar ratio of oil to methyl acetate (1:3-1:12) was evaluated for both lipases, and the resultant biodiesel was tested in diesel engine. The enzymatic transesterification was carried out in ultrasonic assistance and the results showed that the greatest yield of 81.20% at 45℃, using CALB as a biocatalyst, 1.8% (w/v) lipase and oil to methyl acetate molar ratio of 1:12 within 3 hours. Triacetin, by-product was determined their concentration for each molar ratio and analyzed using FTIR range of 500cm-1 to 4000cm-1, revealing a significant absorption peak at 1238.90cm-1. Biodiesel was blended with commercial diesel fuel in varying quantities of 7, 10, and 20% by volume (B20). The results were compared to Industrial Diesel Fuel 7% (B7) and Commercial Diesel Fuel 10% (B10). NOx and CO2 emission drops as the percentage of diesel/biodiesel blends increases, supporting WCO as a cost-effective biodiesel feedstock with low petrol pollution.

Biodiesel, a renewable fuel for diesel vehicle engines, has been commonly produced from transesterification process involving triglycerides from vegetable oil with alcohol. One of the most promising candidates for vegetable oil due to its abundance in Indonesia is coconut oil. However, the short carbon chain present in coconut oil necessitates the use of longer-chain alcohol types to adjust to the biodiesel carbon chain, such as isopropanol. Therefore, this research focused on producing biodiesel (isopropyl ester) from coconut oil using isopropanol and NaOH catalyst through a transesterification process. To enhance this process, microwave technology was utilized for its ability to lower the biodiesel production reaction time from the conventional one-hour timeframe to less than ten minutes, increase energy efficiency, and improve biodiesel quality. The primary objective was to investigate the impact of reaction time, catalyst concentration, and microwave power on the isopropyl ester yield. Further optimization was conducted using Response Surface Methodology (RSM) with Box-Behnken Design (BBD) to illustrate the model's effectiveness and applicability. Based on BBD optimization simulation, the optimal condition for producing isopropyl ester from coconut oil using microwave technology is a 1-minute reaction time, 0.2 wt.% NaOH catalyst concentration, and 443.9 W microwave power, maximizing the yield to 99.89%. This research highlights the potential of microwave assisted transesterification and the reliability of this innovative approach, contributing to the development of isopropyl ester production with enhanced quality that meets the specifications of the Indonesian National Standard (SNI).

Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion, facile separation, and environmental friendliness. However, their widespread applications are impeded by basic components aggregation and low stability. In this work, we fabricate single calcium atoms on graphene (denoted as Ca1/G) by use of a redox strategy for the first time, producing solid strong base catalyst with high activity and stability. The precursor Ca(NO3)2 is first reduced to CaO at 400 °C by the support graphene, forming CaO/G with conventional basic sites, and the subsequent reduction at 850 °C results in the generation of Ca1/G with atomically dispersed Ca. Various characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination (Ca–C2–N2) where N is in situ doped from Ca(NO3)2. The atomically dispersed Ca, along with their anchoring on the support, endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with methanol. The turnover frequency value reaches 128.0 h−1 on Ca1/G, which is much higher than the traditional counterpart CaO/G and various reported solid strong bases (2.9–46.2 h−1). Moreover, the activity of Ca1/G is well maintained during 5 cycles, while 60% of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.

Empty Fruit Bunch (EFB) resulted from oil palm plantations and mills can be converted into ash through open combustion. The EFB ash then treated by simple calcination and used as a heterogeneous catalyst for biodiesel production. The characteristics of EFB ash were identified based on its elemental composition, porous structure, and active site size. The effectivity of the EFB ash as a catalyst was tested in a transesterification reaction of Refined Bleached Deodorized Palm Oil (RBDPO) with excess methanol (30 %-w) in various catalyst loads (in%-wt). The lab-scale experiments were conducted in a three-neck glass reactor, which was put on the hot plate stirrer at 450 rpm. The EFB ash performed the best as a catalyst by attaining optimal conversion at 65 °C for 1 h with a 16 %-wt of catalyst load. In this condition, most of the standard quality of biodiesel were complied with total glycerol under 0.24% and ester methyl contents up to 98.9 %. The characteristics tests showed that the properties and active side of the EFB ash are excellent after calcination at 600 for 5 h. The recyclability test of EFB ash as a catalyst showed high performance in two repetition cycles, each showing an increase in the yield of biodiesel, which was 92.21 % in cycle 2 and 91.23 % in cycle 3.