Search

This study compares the efficacy of reactive extrusion and traditional reactor methods in altering cellulose structure to produce cellulose esters (CEs) with targeted properties. Ionic liquids (ILs) afford high cellulose solubility and recyclability, while chemical reactors enable complete cellulose dissolution and homogeneous transesterification. However, prolonged reaction times and potential oxidation issues necessitate further optimization. Conversely, reactive extrusion allows shorter reaction times, reduced solvent usage, and scalability. The current study aims to investigate how the type of cellulose (microcrystalline and fibrous) and its degree of polymerization (DP) affect the transesterification process and properties of CEs produced by reactive extrusion, as opposed to traditional methods. It was obtained that it is possible to produce cellulose laurates (CLs) with a degree of substitution (DS) of up to 2.5 via reactive extrusion. Examination of CLs obtained from the reactor (R-CLs) and reactive extrusion (REX-CLs) reveals structural properties diverging, with REX-CLs maintaining residual crystallinity despite esterification. Additionally, reactive extrusion produces CLs with lower molar mass due to a reduced DS, and in the case of fibrous celluloses, shear-induced degradation may occur. Cellulose DP emerges as pivotal for attaining desired thermal stability, with higher DP compounds displaying enhanced resistance to thermal degradation. Furthermore, reactive extrusion enhances the thermal stability of CLs more than traditional methods. However, comparative rheological analysis reveals that REX-CLs exhibit higher complex viscosity and G-moduli values than R-CLs. This phenomenon suggests that the structural arrangement of REX-CLs promotes intermolecular interactions, contributing to increased viscosity and stiffness. Reactive extrusion in an IL environment shows promise for scaled-up production of CEs with tailored properties. This indicates its potential as a sustainable and efficient manufacturing method for cellulose-based materials. [ABSTRACT FROM AUTHOR]

The objective of this work was to synthesize a new catalyst x-MoO 3 /Ni 0.5 Zn 0.5 Fe 2 O 4 using the combustion reaction method and to evaluate its catalytic potential and reuse in biodiesel production from waste oil, optimizing the process through experimental design. The catalysts were characterized in terms of structure by X-ray diffraction and phase quantification by Rietveld refinement, surface area by the Brunauer-Emmett-Teller technique, experimental density by helium pycnometry, acidity tests by ammonia desorption at programmed temperature, chemical analysis by X-ray fluorescence, morphology by scanning and transmission electron microscopy, and catalytic properties. The products of the simultaneous transesterification and esterification reactions were characterized by gas chromatography and acidity index. The results indicate the formation of catalysts with surface area ranging from 1.5 to 1.7 m2/g and density ranging from 4.5 to 5.1 g/cm3, composed of major crystalline phases of MoO 3 in the orthorhombic configuration and cubic Ni 0.5 Zn 0.5 Fe 2 O 4 ferrite, with total acidity ranging from 70 to 182 μmol/g of NH 3. Morphological characterization revealed that the catalyst comprises irregular plates of various sizes and shapes with a wide range of cluster sizes. In the simultaneous transesterification and esterification reactions of residual oil, the catalysts were active under all conditions tested, with emphasis on the catalyst containing 50 % Mo ions and 50 % Ni 0.5 Zn 0.5 Fe 2 O4 presenting the best catalytic performance with a conversion of 95 % in ethyl esters and a reduction of 71 % in acidity, with a service life of 6 cycles, an average conversion of 90 % and good thermal and structural stability after use. The experimental design was significant and predictive, with a confidence level of 95 %. Statistical analysis identified that all input variables (temperature, time, and amount of catalyst) were significant for the adopted design. The new catalyst composed of molybdenum, iron, nickel, and zinc has a positive impact on biodiesel synthesis from frying oil and ethanol. [ABSTRACT FROM AUTHOR]

We report the fabrication of a novel spinel-type Pd₀.₁Cu₀.₉Co₂O₄ nano-flake material designed for Mizoroki-Heck and Suzuki coupling-cum-transesterification reactions. The Pd₀.₁Cu₀.₉Co₂O₄ material was synthesized using a simple co-precipitation method, and its crystalline phase and morphology were characterized through powder XRD, UV-Vis, FESEM, and EDX studies. This material demonstrated excellent catalytic activity in Mizoroki-Heck and Suzuki cross-coupling reactions, performed in the presence of a mild base (K₂CO₃), ethanol as the solvent, and microwave irradiation under ligand-free conditions. Notably, the Heck coupling of acrylic esters proceeded concurrently with transesterification using various alcohols as solvents. The catalyst exhibited remarkable stability under reaction conditions and could be recycled and reused up to ten times while maintaining its catalytic integrity. [ABSTRACT FROM AUTHOR]

The catalytic behavior of K/Fe catalyst in biodiesel synthesis by ethanolic transesterification of sunflower vegetable oil was investigated. The catalysts were prepared according to the conventional precipitation, impregnation, and calcination methods. The catalysts were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, thermogravimetric analysis (TGA), and Hammett-Benzoic acid indicator titration. Catalytic tests for biodiesel production revealed an excellent activity of the K/Fe3-800 catalyst, which is consistent with the number of basic sites (1.50 mmol/g) in bulk. Potassium polyferrite phases K1.55Fe11O17/K2Fe10O16 as basic active sites on the catalyst surface were generated, increasing the catalytic ability for biodiesel synthesis. The optimum conditions for transesterification reaction were catalyst amount of 5%, ethanol-to-oil molar ratio of 9:1, reaction temperature of 70 °C, and reaction time of 45 min. The maximum conversion of oil to ethyl esters reached 98.2%. The catalyst can tolerate free fatty acid and moisture up to 0.5% and 1%, respectively. K/Fe3-800 catalyst was successfully reused at least three times without post-treatment, and the obtained yield was higher than 92.3%. The XRD and TGA characterizations showed that poisoning of the active sites and pore fouling are the main reasons for the K/Fe3-800 deactivation. This finding indicates that the potassium loading on iron oxide catalysts provides valuable advantages such as low reaction time, easy recovery, and reuse in the transesterification reaction of sunflower oil. [ABSTRACT FROM AUTHOR]

Synthetic textiles such as polyesters are essential for daily life. However, large‐scale production generates large amounts of waste. This study introduces a new approach for valorising polyester textile waste (PTW) by transforming it into a catalyst for biodiesel production via pyrolysis. Specifically, a metal/carbon composite (PTW + steel slag [SS] composite—PSC) with enhanced catalytic properties was prepared by pyrolysing PTW with SS. The alkaline metals in SS facilitate the carbonisation of PTW via decarboxylation, resulting in a PSC rich in carbon, iron, and alkaline compounds. This composite featured mesopores that were larger than the micropores (MPs) typically found in PTW char. The use of porous material (silica) in thermally induced transesterification has been proven to be an efficient method for biodiesel production, achieving a yield of 97.20 wt.% in 1 min (faster than the 93.82 wt.% yields in 60 min observed from conventional alkali‐catalysed transesterification). However, the high reaction temperature (≥ 360°C) poses economic/technical challenges. To overcome this, PSC has been employed as a catalyst in thermally induced transesterification, leveraging its mesoporous structure and high alkaline content, particularly calcium oxide. The PSC achieved a biodiesel yield of 98.10 wt.% at a markedly lower reaction temperature of 120°C within 1 min. This performance was not attainable using silica or PTW char under similar conversion conditions. These findings highlight the potential of PSC produced through the pyrolysis of PTW and SS as effective catalysts for biodiesel production. This process is a promising strategy for converting waste into valuable resources and mitigating the environmental impacts associated with polyester waste. [ABSTRACT FROM AUTHOR]

Shell‐derived materials are promising heterogeneous catalysts for biodiesel production due to their nontoxic and renewable nature, but they have the disadvantage of being highly leachable. To overcome this issue, Ca(OCH3)2 formed through the reaction of CaO with methanol, and supported in turn on Al2O3 is proposed as a catalytic system for the transesterification of fresh soybean oil and waste cooking oil (WCO). First, catalysts with several Al/Ca molar ratios (0.2, 0.5, and 0.8‐AC), as well as their precursors (CaO and Al2O3) alone, were tested at 60 °C, catalyst loading 6% wt, methanol‐to‐oil molar ratio (MOR) 10, for 1 h for fresh oil, and 3 h for WCO. The 0.2‐AC catalyst generated the highest biodiesel yield for both oils. The optimum operating conditions for WCO transesterification, determined by using a univariable approach, were 60 °C, 9 wt% catalyst loading, MOR of 12.5, and a reaction time of 3 h. These improved conditions led to yields higher than 90% for pure CaO and the 0.2, 0.5, and 0.8‐AC catalysts. The density, kinematic viscosity, and refractive index of the biodiesel obtained were measured. [ABSTRACT FROM AUTHOR]

Oleaginous organisms accrue more than twenty percent of their biomass as lipids and hence are promising feedstocks for biodiesel production. In this study, lipid accumulating bacteria were isolated from diesel-contaminated soils and screened with Sudan black B stain. The most oleaginous was done using 16s rRNA gene sequencing. Lipid production was initially optimized based on media, nitrogen source, pH and temperature. Response surface methodology (RSM) was then employed for the enhancement of lipid weight and content. Obtained lipid was converted to biodiesel using direct transesterification, and both lipid and biodiesel were characterized using FTIR. A total of thirteen bacteria were isolated and the most prominent lipid producer was identified as Providencia vermicola with lab number BA6. Preliminary optimization studies revealed optimum lipid production when nutrient broth and acetic acid served as carbon source; KNO3 as nitrogen source, pH 7.0 and 30 °C. Optimization using RSM resulted in a 5.1% and 74.1% increase in the biomass and lipid content of BA6 respectively. FTIR analyses confirmed the presence of functional groups characteristic of lipids and biodiesel. P. vermicola is a novel oleaginous organism that represents a promising feedstock for biodiesel production. HIGHLIGHTS: The bacterium designated as BA6 identified as Providencia vermicola has the highest lipid contents of the oleaginous bacteria isolated. It accumulates lipids up to 47.73 % of its biomass The percentage lipids accumulation increased to about 74 % when RSM was used. Providencia vermicola is being reported as an oleaginous organism for the first time. [ABSTRACT FROM AUTHOR]

BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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]

The current energy scenario requires the use of alternatives for petrol-based products. In this context, the role of biodiesel and biolubricants can be promising, offering multiple advantages but also some challenges like their low oxidation stability. The use of antioxidants can offset this disadvantage, improving the general performance of these products during storage or usage. The aim of this work was to assess the combined and separate use of two different antioxidants (propyl gallate, PG, and tert-butylhydroquinone, TBHQ) on biodiesel and biolubricant based on waste cooking oil (WCO), carrying out a thorough characterization of these products and quantification of antioxidants through voltammetry techniques. Thus, the innovation of this work consists in the use of combined antioxidants and its simultaneous quality assessment and quantification. As a result, the combined use of antioxidants did not offer a synergistic effect, and the use of PG at low concentrations (300 ppm) is recommended in the case of WCO biolubricant. Voltammetry was a suitable and fast method to quantify both PG and TBHQ. [ABSTRACT FROM AUTHOR]

Pittosporum resiniferum oil was extracted from the seed and the oil together with methanol was use for the production of biodiesel through transesterification process using novel solid base catalyst (K2CO3 supported on MgO). 0.6:5 (K2CO3 loaded on MgO), a 5 h calcination time, 600°C calcination temperatures were the optimum conditions under which the catalyst was prepared. FTIR, SEM, CO2‐TPD, XRD, N2 adsorption‐desorption, Hammett indicators and other techniques were used to characterize the catalyst. The molar ratio of methanol‐to‐oil, the catalyst amount, time of the reaction as well as the temperature of the reaction were examined. The study found that 16:1 methanol‐to‐oil molar ratio, 5% catalyst loading amount, a reaction time of 2.0 h, and a reaction temperature of 60°C were sufficient for a maximum yield of 97.4%. With relative high activity, the catalyst can perhaps be used again possibly for five times. The characteristics of the biodiesel produced were consistent with international standards. [ABSTRACT FROM AUTHOR]

Biodiesel generated from oils and fats composed of fatty acid alkyl esters is a potential substitution for fossil fuels, gaining attention as the demand for sustainable energy grows. Enzymatic transesterification has emerged as a promising method for biodiesel production due to the low energy required, easy glycerol recovery and compatibility with various feedstocks. This method also offers high specificity and operates under mild reaction conditions. However, limitations such as enzyme production cost, low product yield, and low stability under harsh conditions, have hindered the progress of biocatalysis. Protein engineering has emerged as an important strategy to overcome these limitations, particularly through rational design. Rational design approaches are advantageous in lipase engineering, due to accessible experimental tools and existing knowledge of lipase structure and function. Site-directed mutagenesis has been applied to improve stability, substrate specificity, methanol tolerance, and catalytic efficiency of lipase by introducing molecular interactions like hydrogen bonds and disulfide bridges as well as improved lid flexibility by mutations at the lid or lid swapping. This targeted approach allows for the precise modification of amino acid residues, optimizing lipase for better performance, which is crucial for efficient biodiesel production. [ABSTRACT FROM AUTHOR]

Syngas produced from glycerol using aqueous phase reforming for nickel-based catalysts with different support materials were tested in a compression ignition (CI) engine. Experiments were conducted using nickel–alumina, nickel–lanthanum (NL), and nickel–ceria catalysts at 1:1, 1:2, 1:3, and 1:4 glycerol–water ratios and temperatures of 240°C, 260°C, and 280°C. The NL catalyst showed the highest syngas and hydrogen yield of 90.58% and 76.42%, respectively, at 1:3 ratio and 260°C. The optimized NL syngas and diesel were tested in a CI engine at 6 to 30 lpm flow rates. At 30 lpm flow, brake thermal efficiency increased by 3.15%, NOx emission was reduced by 21.22%, and smoke lowered significantly compared to diesel. The faster hydrogen combustion in syngas increased the heat release rate and cylinder peak pressure. CO and HC emissions increased at lower loads due to diluted combustion but reduced at higher loads. NL showed the best performance and emissions among the syngases due to higher hydrogen content. In summary, the NL syngas at 30 lpm showed great potential in CI engines by improving combustion and performance and reducing emissions. [ABSTRACT FROM AUTHOR]

Esters are important chemicals used in fine and bulk chemical industry with numerous applications: solvents, paints, varnishes, dyes, and cosmetics. Ester formation is dominated mainly by Fischer esterification and transesterification. Fischer reaction is generally used for ester production, but in certain cases, transesterification can be used with advantage. It is useful when the acid is less soluble in the alcohol or in the solvent used, thus forming two layers. Water formation creates purification problems during esterification reactions due to azeotrope formation and transesterification can be useful in such cases. Commercially, cheaply available methyl and ethyl esters can be conveniently used as raw materials for value added ester production by transesterification. Transesterification is also useful when the parent acids are highly reactive and pose difficulty in separation. Transesterifications are slow reactions and a catalyst is used: acids and bases, ion exchange resins, zeolites, and clays. Homogeneous catalysts were used in the past which are now replaced by their heterogeneous counterparts. Heterogeneous catalysts offer added advantages like reusability, lesser corrosion, and ease of separation. Transesterification can be commercially used to produce a number of esters of industrial importance like acrylics and biodiesel. This review considers all these aspects in considerable detail. A large literature set was scanned and its judicious extract is presented. [ABSTRACT FROM AUTHOR]

AbstractIn this study, biocatalytic transesterification reaction using Novozyme 435® (N435) lipase was employed to enhance the hydrophobicity of esculin, aiming to improve its solubility for commercial applications and enhance its bioactivity and oral viability. The acylation reaction of esculin with vinyl acetate was conducted at 60 °C and 200 rpm for 24 h. After chromatographic and spectroscopic analysis, two products were identified: the first one was monoacylated at the 6′-OH position of the glucosyl moiety of esculin (TR: 10.3 min and m/z 382.93 [M + H]+), and the second one was diacylated at the 6′-OH and 3′-OH positions (TR: 13.0 min and m/z 424.93 [M + H]+). The latter was the major product, with a conversion rate of 53.550 ± 0.368%, while the monoacetylated one showed 8.715 ± 0.064%. Both products were isolated by high-speed counter-current chromatography (HSCCC) using a two-phase system HEMWat 1:9:1:9 and characterized by NMR. In this way, these results improve the practical application of esculin, through the obtention of esculin mono and diacetates by fast and efficient biocatalysis reaction. [ABSTRACT FROM AUTHOR]

A novel type of alkyl amine‐based ILs [Et3N]+[OH]− (triethylammonium hydroxide) behaving strong alkali property have been chemically immobilized onto the polymeric 3D spheres with mesoporous structures, spherical morphology and more uniformed active species onto them to form alkali ILs supported 3D polymeric catalysts(3DPs‐ILsOH), which was synthesized via a combined method of substitution with its subsequent anion unites' exchanging process. The supported 3DPs‐ILsOH catalyzed the transesterification of ethylene carbonate (EC) with methanol, which preferred to exhibit the excellent, efficient activities. At milder reaction temperature of 70 °C within 4.0 h, the conversion of EC achieved to 83.3 % with 99.5 % selectivity of dimethyl carbonate (DMC). Under the same reaction conditions, this type of catalysts could be recovered by a simple filtration and was reused eight times without obvious losing catalytic activities and hardly without any leaching of catalytic species. Its' catalytic process for generating the chemical of DMC from the CO2 fixation material of EC was studied by using the in‐situ FTIR, and was further verified that the synergetic function roles of triethyl amino cations units with OH− anion units onto the supported catalysts might be one of the important reasons for progressing DMC's yields and its' catalytic efficiency in transesterification reaction. [ABSTRACT FROM AUTHOR]

Magnusiomyces capitatus A4C, a mycelium‐forming and lipase‐producing yeast‐like fungus, was employed in a five‐level factorial design to optimize the collective and interactive influences of carbon, nitrogen and emulsifying sources and their possible effects on cell‐bound lipase (CBL) and cell biomass production. The cell culture of M. capitatus A4C was incubated along with biomass support particles (BSPs) to immobilize the enzyme while anchoring CBL on their surfaces. Among the BSPs tested, CBL immobilized on loofah sponge under optimized conditions showed a substantial hydrolytic activity of 12.7 U mL−1 and a cell‐loading capacity of 0.61 g g−1 of BSPs. Immobilized CBL was applied for biodiesel production via transesterification and esterification. The conversion percentage of triacylglycerides was approximately 100% at 24 h with the addition of water at 1:1 (v/v). The conversion of oleic acid into biodiesel via esterification was 100% at 48 h in the presence of 15% (v/v) isooctane. Further, biodiesel production was scaled up using a packed bed reactor. The batch production of biodiesel in a packed bed reactor through transesterification was 96.2%, with a circulation flow rate of 5.5 mL min−1 for 18 h. On the other hand, oleic acid conversion into biodiesel via esterification was 99.5%, with a circulation flow rate of 5.5 mL min−1 for 24 h. Further investigation revealed that the immobilized biocatalyst exhibited higher stability with esterification (85.3% fatty acid methyl ester) after ten repeated cycles. [ABSTRACT FROM AUTHOR]

Epoxy resins, ubiquitous and indispensable thermosetting material in various industries, suffer from the resistance to crack initiation, poor ductility, and irreparable permanent cross‐linked network, which hinder their utilization in high‐performance applications and are detrimental to the development of a sustainable economy. However, achieving the trade‐off between toughness, robustness, and reprocessability of epoxy resins remains a formidable challenge. Herein, an epoxy resin that combines ultratoughness, robustness, and reprocessability by incorporating a hierarchical crosslink structure embedded in a transesterification network is reported. The construction of hierarchical coordination structures facilitates formation of dense nano‐hard domains, enabling enhancement of both strength and toughness at multilength scales. As a result, the epoxy resin, integrating covalent adaptable networks with sacrificial non‐covalent networks, exhibits exceptional elongation at break (280%), modulus (1.8 GPa), stress at break (56.3 MPa), and tensile toughness (142 MJ m−3), showcasing its excellent endurance and ability to undergo multiple reprocessability. The application of this epoxy resin in carbon fiber‐reinforced polymer composites further underscores its potential as the resulting HCEV‐CFRPs exhibit unprecedented tensile properties and facilitate multiple non‐destructive recycling of high‐value carbon fiber under mild conditions. This research provides novel design principles for recyclable and high‐performance materials that combine strength and toughness. [ABSTRACT FROM AUTHOR]

ABSTRACT Hydrolytic reactions of phosphodiester bonds of RNA have been extensively studied over several decades. Information on the factors that affect the reactivity of phosphodiester bonds in biomolecules is important for the development of new nucleic acid‐related therapeutics. Furthermore, the development of artificial nucleases requires efficient catalytic entities, and rational design of catalysts requires detailed understanding of the catalytic mechanisms. In the present article, we concentrate on the interplay between the nucleophile and leaving group both in the absence and in the presence of metal ion catalysts. The effect of the nucleophile on the reactivity of RNA model compounds has been studied with 2‐hydroxypropyl and uridine 3′‐aryl phosphates as well as with bis‐(p‐nitrophenyl)phosphate as substrates. pH‐rate profiles for three different 2‐hydroxypropyl arylphosphates were compared with those obtained with a uridine 3′‐alkyl and aryl phosphates. The observations are discussed in terms of the relative goodness/poorness of the nucleophile and the leaving group. Metal complex‐dependent reactions were studied in the presence of well‐known and robust CuTerPy and CuBiPy complexes. The results show that CuTerPy and CuBiPy favour different types of phosphodiesters as substrates, depending on the properties of the nucleophile and leaving group, and suggest that the complexes utilize different catalysis mechanisms, which may depend also on the structure of the substrate. The results obtained further the understanding on the basic principles of metal complex‐promoted cleavage of RNA and model compounds, help to assess the relevance of data obtained with model compounds and support the design of artificial enzymes for phosphodiester cleavage. [ABSTRACT FROM AUTHOR]

Biodiesel serves as a renewable, eco-friendly alternative fuel. Its production relies on converting triglyceride sources into methyl esters through transesterification. These triglycerides can be sourced from vegetable oils and animal fats. Previous studies often relied on acids and bases as catalysts. However, there's a lack of research exploring the use of modified zeolite and bentonite as catalysts, which hold the promise of higher yields compared to previous studies. In this study, biodiesel was derived from Calophyllum inophyllum via esterification and transesterification processes. Characterization of these catalysts was done using XRD and FTIR analyses. Transesterification to produce biodiesel occurred at temperatures ranging from 50 to 70℃ over a reaction period of 5 hours. The largest yield of biodiesel was obtained at 60℃, with 88.19% using modified zeolite catalyst, 78.84% using modified bentonite catalyst, and 82.36% using a blend of modified zeolite and bentonite catalysts in a 1:1 ratio. Biodiesel resulting from the highest yield using modified zeolite catalyst underwent characteristic testing in accordance with SNI standards. The findings revealed a density of 887 kg/m3, viscosity of 5.633 mm2/s, cetane number of 53, flash point at 121℃, and methyl ester content of 94.55%. [ABSTRACT FROM AUTHOR]

Biodiesel, a potent replacement for petroleum diesel, is derived from fatty acids in biomass through transesterification, which is renewable, non-toxic, and biodegradable and is a powerful replacement for petroleum diesel. Lewis acid has been proven effective for esterification and transesterification. The Lewis base enhances the electrophilic and nucleophilic properties of the molecules that bind to it, leading to the remarkable versatility of the Lewis base catalytic reaction. Many studies have shown that Lewis acid/base catalyzed in situ transesterification is a fast and environmentally friendly method for producing biodiesel. The utilization of Lewis acid-base sites to catalyze transesterification has been shown to enhance their efficiency and utilization of acid-base active sites. This review explores biodiesel production by different catalysts using Lewis acid-base sites, the conditions for catalytic transesterification, the effects of different reaction parameters on biodiesel production, and the biodiesel production process. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive optimization of algal oil extraction and transesterification for sustainable biodiesel production. Freshwater Spirogyra algae underwent Soxhlet extraction using n-hexane. response surface methodology (RSM), principal component analysis (PCA), and multivariate regression analysis (MRA) were employed to investigate the effects of biomass–solvent ratio (BSR), algae particle size (APS), and extraction-contact time (E-CT) on algal oil yield (AOY). The extracted oil was then converted to biodiesel via transesterification, and the impacts of the methanol–oil ratio (MOR) and transesterification-contact time (T-CT) on biodiesel conversion efficiency (BCE) were analyzed. Results demonstrate that optimal BSR, APS, and E-CT for maximal AOY are 1:7, 400 µm, and 3–4 h, respectively. For transesterification, a MOR of 12:1 and a T-CT of 4 h yielded the highest BCE. Predictive models exhibited exceptional accuracy, with R2 values of 0.916 and 0.950 for AOY and BCE, respectively. The produced biodiesel complied with ASTM D6751 and EN 14214, showcasing its potential for renewable energy applications. [ABSTRACT FROM AUTHOR]

Biodiesel (methyl esters) has been produced using numerous catalysts to enhance its quality and related productivity. Generally, the raw materials for biodiesel production and its catalysts significantly impact the produced biodiesel's quality. In addition, the heterogeneous catalysts are promising as catalysts in the transesterification for biodiesel production and can be used continuously during this production. In particular, these catalysts are essential for green biodiesel production because of their high activity, thermal stability, and reusability. Hence, several homogeneous and heterogeneous (acidic and alkaline) catalysts for biodiesel production, particularly the naturally derived heterogeneous catalysts, are reviewed in this article. Further, the different heterogeneous catalysts for biodiesel production have been studied extensively as replacements for the respective homogeneous catalyst. Specifically, this replacement is aimed at the simultaneous esterification and transesterification of the nonedible and low-cost biomasses under moderate conditions producing biodiesel. Moreover, this study analyzes biodiesel's impact and long-term performance in various applications. Finally, it also reports the advancements in biodiesel production in terms of the catalysts used in it and its processes to aid further developments in biodiesel production. [ABSTRACT FROM AUTHOR]

Biodiesel has been recognized as the most widely utilized biofuel around the world due to its significant role in reducing the consumption of crude oil and lowering environmental pollution levels. By serving as a renewable alternative to fossil fuels, bioethanol helps decrease greenhouse gas emissions and contributes to a more sustainable energy future. Traditionally, alkali hydroxides like NaOH and KOH have been mainstays in biodiesel synthesis. However, their overuse can lead to unwanted byproducts and operational complexities. Since calcium titanate can occur at a strong base condition, it presents an alternative avenue worth exploring. In this study, we investigate the influence of alkali hydroxides, namely LiOH, NaOH, and KOH, on the formation of calcium titanate through hydrothermal methods, with varying heating times. We aim to understand how different hydroxides affect the synthesis process and the resultant properties of calcium titanate. We delve into the vibrational properties of Ca-O-Ti and Ti-O bonds using Fourier Transform Infra Red (FTIR) spectroscopy, confirming the presence of calcium titanate (JCPDS No.42-0423) through Xray Diffractometry (XRD). This thorough characterization provides insight into the structural integrity and composition of the synthesized materials. Moreover, Scanning Electron Microscopy (SEM) reveals the intriguing cube-like morphology of calcium titanate, offering visual evidence of its unique structure. The fatty acid methyl ester impressively show that calcium titanate synthesized in 7 M NaOH and KOH solutions, heated for 24 h, emerges as a promising biodiesel catalyst. We observe fatty acid methyl ester provides the percentages of 63.67% and 90.02%, respectively, indicating the catalytic efficacy of these materials in biodiesel production. These findings not only contribute to the understanding of calcium titanate synthesis but also pave the way for a sustainable future in biodiesel production by introducing efficient and eco-friendly catalysts. [ABSTRACT FROM AUTHOR]

L‐lactide (LA) is polymerized with ethyl L‐lactate or trifluoroethanol as initiators (LA/In = 30/1), and the resulting poly(L‐lactide) esters are acetylated with acetic anhydride. The acetylated PLA esters are mixed with SnOct2, dibutyltin bis(4‐chlorophenoxide), or dibutyltin bis(pentafluorophenoxide) in solution and crystallized at 120 °C. The doped crystals are annealed at 140 °C or at 160 °C for 7, 14, and 28 days, and the chemical modifications that occurred in the solid state are monitored by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) measurements. All catalysts promoted polycondensation, while no significant formation of cycles is observed. However, in the presence of SnOct2, disproportionation of chains occurred upon annealing at 120 or 140 °C, and crystallites consisting of extended chains with Mn values ≈3500 – 3600 and low dispersities (Ð < 1.5) are formed. [ABSTRACT FROM AUTHOR]

Solid alkali KF/MgO catalysts were prepared using the impregnation method by combining alkali metal compounds with oxides, which performed the transesterification of isosorbide (IS) with dimethyl carbonate (DMC) into dicarboxymethyl isosorbide (DC). Characterization of the catalysts was conducted through X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and N2 adsorption–desorption analysis. The catalytic performance of KF/MgO was examined under diverse KF loading and calcination temperature conditions. The characterization of catalyst identified that the creation of innovative active components K2MgF4 and K2CO3 were produced at a calcination temperature of 500 ℃ and a KF loading amount of 40%. The catalyst of 40-KF/MgO-500 demonstrated the most effective, favourable activity and selectivity. Through the optimization of transesterification process conditions, it was discovered that the yield of DC was at its highest under the optimal reaction conditions of n(DMC)/n(IS) = 6.5, catalyst dosage of 0.21 wt% (relative to IS mass), transesterification temperature of 120 °C, and reaction time of 6 h. [ABSTRACT FROM AUTHOR]

Green heterogeneous bifunctional catalyst is sustainable for the production of biodiesel owning to its reusability, eco-friendly, and bifunctionality. In this work, a green heterogeneous bifunctional Zeolite-A/Biochar (Z-A/BC) catalyst was synthesized for the production of biodiesel from waste cooking oil (WCO) through one-pot esterification-transesterification reaction. The functional group, elemental composition, crystallographic structure, and morphology of the synthesized catalyst were characterized using FT-IR, EDX, XRD, and SEM, respectively. Furthermore, the catalytic proficiency of the synthesized catalyst was tested by optimizing methanol to oil ratio, catalyst amount, temperature, and reaction time. The maximum biodiesel yield (86.22%) was achieved at 2.5% wt. of catalyst amount, 10:1 of methanol to oil molar ratio, 70 °C of reaction temperature, and 240 min of reaction time. The synthesized Z-A/BC catalyst showed apparent catalytic efficiency than its parent materials Z-A (69.42%) and BC (74.27%). The recyclability of Z-A/BC catalyst was also found to be 86.22, 82.98, 79.08, 62.87, and 76.84% for 1st, 2nd, 3rd, 4th, and 5th cycles, sequentially which is cost effective. Furthermore, the physicochemical properties such as density, ash content, FFA, acid value, saponification value, and kinematic viscosity of the produced biodiesel were analyzed by comparing with standards. These results showed good agreement with ASTM and EN14214 biodiesel standards. Therefore, the produced biodiesel using heterogeneous bifunctional Z-A/BC catalyst from WCO could be used as an alternative engine fuel with/without blending with commercial diesel. [ABSTRACT FROM AUTHOR]

The transesterification reaction between ethylene carbonate (EC) and methanol is a sustainable method to produce dimethyl carbonate (DMC). As typical solid bases, carbon nitride (CN) materials have demonstrated catalytic application in many base-catalyzing reactions. In this work, in order to increase the surface area and improve the base intensity of the CN material, microporous MCM-22 was utilized to load CN, and then treated by NaOH (a.q.), thus enabling CN/MCM-22 composites being transferred into mesoporous CN-SiAlO materials. The physicochemical properties of the synthesized materials were analyzed by XRD, N2 adsorption–desorption, FT-IR, XPS, SEM, TG, and CO2-TPD. As mesoporous base catalysts, the CN-SiAlO materials showed superior catalytic activity to the bare CN and CN/MCM-22 in the transesterification reaction of EC with methanol. Under reaction temperature of 130 °C and reaction time of 3 h, the yield of DMC was up to 83.3%. [ABSTRACT FROM AUTHOR]

This article presents the production and performance analysis of biodiesel from a blended oil comprising 20% soybean oil and 80% rice bran oil. The production process utilizes transesterification with methanol and NaOH, and the biodiesel synthesis time is optimized using a homogenizer. The biodiesel is tested on a four-stroke single-cylinder internal combustion (IC) engine, where key parameters such as brake thermal efficiency and specific fuel consumption are measured. The study compares the performance of biodiesel derived from the blended oil with biodiesel produced from pure soybean oil. Experimental results reveal that the biodiesel from the blended oil offers higher efficiency. Specifically, the brake thermal efficiency of the blended biodiesel increases with load, achieving values of 7.4%, 14.3%, 21.9%, and 23.6% at loads of 1kg, 2kg, 3kg, and 4kg, respectively. In terms of brake-specific fuel consumption, the blended biodiesel showed values of 2.425, 1.536, 1.168, and 0.989 kg/kW-hr for the same loads. The time required to consume 5 ml of blended biodiesel at a constant 1500 RPM decreases as the load increases, with times of 38.50, 35.72, 28.19, 24.72, and 21.88 seconds for loads of 1 kg, 2 kg, 3 kg, and 4 kg, respectively. The overall findings suggest that biodiesel from the rice bran and soybean oil blend is more efficient than pure soybean oil biodiesel, indicating its potential for more effective use in IC engines. [ABSTRACT FROM AUTHOR]

This review explores the potential of green synthesised SBA-15 nanomaterials in biodiesel production, focusing on their promising application despite their lack of direct use in this field. The growing global demand for sustainable and renewable energy sources has intensified interest in biodiesel as a cleaner alternative to fossil fuels. Biodiesel, derived from renewable biomass sources such as agricultural residues and waste cooking oils, offers significant environmental benefits, including reduced greenhouse gas emissions. Traditional SBA-15 synthesis involves hazardous chemicals, but green synthesis methods using biomass-derived silica present an eco-friendly approach. This review examines the unique structural properties of SBA-15, such as its high surface area and uniform pore structure, which could improve biodiesel production when used as a catalyst. While the green-synthesised SBA-15 has not yet been applied directly in biodiesel production, this article proposes its potential utility and emphasises the need for future research to validate its effectiveness. This novel approach of directly using SBA-15 as a catalyst emphasises its potential to improve biodiesel production sustainability and efficiency, contributing to waste management and renewable energy goals. These findings underscore the scientific value of SBA-15 in the advancement of biofuel technology and highlight its potential for industrial applications.Article Highlights: Examines biomass waste as a viable and renewable resource for silica extraction. Evaluates green synthesis approaches for producing SBA-15 from renewable sources. Consider the prospective use of green-synthesised SBA-15 in the advancement of biodiesel production technologies. [ABSTRACT FROM AUTHOR]

Glycerol transesterification with diethyl carbonate (DEC) using catalysts with different porosities as support for CaO was performed, seeking the evaluation of how textural properties influence glycerol conversion and product selectivity. A total of 20% CaO was supported on ZSM-5, K-10, MCM-41, SiO2, and γ-Al2O3. Catalysts showed a well-dispersed active phase of CaO in all the supports and no changes in the support crystalline structure were noticed. Reactions were performed in dimethyl sulfoxide (DMSO), 10 wt.% of catalyst in relation to glycerol, at 130 °C, and 1:3 glycerol/DEC molar ratio. According to our results, the higher the pore volume and pore size, the higher the glycerol conversion. On the other hand, concerning selectivity, higher glycerol carbonate selectivities were reached when strong basic sites were present. A total of 86% glycerol conversion and 91% glycerol carbonate selectivity were found using 60% CaO supported on γ-Al2O3 after 5 h of reaction. [ABSTRACT FROM AUTHOR]

Conventional epoxy anhydride curing systems typically require large amounts of catalyst to ensure a high ester exchange rate, and the resulting cured epoxy vitrimer has renewable and self-repairing properties, but is limited by the amount of catalyst loading. In this study, a diol (VT) containing imine bonds was synthesized from vanillin (VAN) and tyramine (TA) to catalyze the epoxy-anhydride curing process, and glycerol triglycidyl ether (GTE) was co-cured with VT and methylhexahydrophthalic anhydride (MHHPA), which constructed a bio-based regenerative and repairable epoxy vitrimer with dual dynamic covalent bonds (GMV), the free hydroxyl groups in the crosslinked network could rapidly promote the ester exchange rate. The thermal, mechanical, solvent resistance, self-repairing, renewable and shape memory properties of GMV were systematically investigated by adjusting the ratio of anhydride and hydroxyl groups. It exhibits a better thermal stability property Td5% (281.27℃) and a shorter relaxation time τ (12.15 s) at 140 °C. In addition, the scratches of GMV could be almost completely healed at 120 °C for 60 min, and this test demonstrated that GMV has better self-healing and renewable tests. The present work promotes the epoxy vitrimer species and expands the esterification scheme performed without catalyst. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Compatibility of polycarbonate (PC) and polymethyl methacrylate (PMMA) alloys was improved by using a transesterification catalyst (SnCl2·2H2O). Modified PC/PMMA alloys exhibit single Tg, and their initial island phase existing in the SEM were transformed into uniform surface. Besides, the transmittance of the modified alloys was increased from original 40% to 85%. Moreover, PC/PMMA alloys and PC foams with micro‐cellular and nano‐cellular structures were prepared by solid‐state CO2 foaming in the presence of transesterification catalyst. Distinctively, there are obvious nano‐cellular structures existing in the PC samples, but no related nanostructures were found in PMMA samples, after treated by same amount of catalyst and foaming process for pure PC and PMMA matrix. Furthermore, the effects of foaming temperature and segment structure on their foaming behavior were also studied. Additionally, a uniaxial stress experiment was conducted at a specific temperature to simulate the biaxial stress during the foaming process for discovering the mechanism of nanopore formation. Therefore, the concept of nano‐cellular structures will point out a direction for the development of high‐performance, heat insulation PC materials of the next generation. Highlights: Transesterification catalysts enhanced compatibility between PC and PMMA.Nanopore structures were successfully constructed in PC foams.Segment stretching was the main reason for the formation of nanopores. [ABSTRACT FROM AUTHOR]

Palm kernel oil (PKO) is a non-edible oil which is enriched with saturated fatty acids that can be used as a raw material for many industrial applications. Indian PKO (IPKO) was chosen in this study which has been explored sporadically in industries. IPKO was characterized and utilized for the synthesis of fatty acid alkyl esters through transesterification (solvolysis) using methanol and ethanol solvents coupled with alkali catalysts such as sodium hydroxide (NaOH) and potassium hydroxide (KOH). Upon comparison, methanol and NaOH resulted in the maximum biodiesel (esters) yield of 67.77% as compared to ethanol-based solvolysis. Compositional analysis of fatty acid methyl esters (FAMEs) through GC–MS elucidated the presence of long chain (C12:0 to C18:1) esters, which can be utilized as biodiesel. Therefore, IPKO FAME has been tested as diesel blend in engines without any modification, where, B5 (5% v/v) blend showed at-par fuel characteristics and engine efficiency as compared to non-blended diesel with minimal emissions. To induct a waste circular reprocessing startegy, crude glycerol resulted from transesterification of IPKO was supplemented to Candida tropicalis NCIM3118 for xylitol (a sweetener) synthesis. The results indicated that upon supplemention of IPKO crude glycerol as co-substrate, enhancement in xylitol production of about 0.93 gxylitol/gtotal organic carbon as compared to only xylose as 'C' source (0.81 gxylitol/gtotal organic carbon) was observed with efficiency improvement in overall growth kinetic behavior. This study demonstrates the circular economy approach in which that the IPKO can be utilized for biodiesel production, while, the by-product (crude glycerol) generated could be deployed for xylitol production. [ABSTRACT FROM AUTHOR]

Biodiesel is rapidly becoming an efficient substitute for fuel and a potentially significant future renewable energy source. In recent years, used cooking oil has been used as a feedstock for biofuel to reduce production costs. Due to its high catalytic activity, low cost, and eco-friendliness, Nano magnesium oxide (MgO) has attracted attention as a catalyst for biodiesel production. Our work presents the preparation of nanomagnesium oxide (MgO) by the sol–gel method, and its characterization. Optimum conditions and the productive combination of waste cooking oil, methanol, and the synthesized nanocatalyst were predicted using response surface methodology. The optimum conditions were methanol to oil ratio of 7:1, temperature of 50 °C and time of 60 min. The expected values for the yield of biodiesel production responses are quite like the actual values, demonstrating the consistency of the models used for establishing a relationship between the independent process variables and the responses. The predicted model's F-value was 9.09 indicating that the model is significant. The model's pure error had a poor correlation, as the "Lack of Fit F-values" 4.16. The quadratic model fits the data well because the R-squared value for the model equation 92%. The expected values for the yield of biodiesel production responses are quite like the actual values, demonstrating the consistency of the models used for establishing a relationship between the independent process variables and the responses. Biodiesel was characterized using gas chromatography–mass spectrometry and Fourier transform infrared spectroscopy. [ABSTRACT FROM AUTHOR]

Non‐ribosomal peptide synthetases (NRPSs) and their tailored enzymes have diverse biological functions. In this study, we investigated the biosynthesis and function of chitinimides, which belong to the non‐ribosomal peptide (NRP) subfamily featuring a pyrrolidine‐containing part (X part) connected to the polypeptide chain via an ester bond. A conserved gene cassette, chmHIJK, is responsible for oxyacylation of the pyrrolidine moiety in the X part. The thioesterase (TE) domain of ChmC (ChmC‐TE) catalyzes transesterification reactions with a free X part or methanol as a nucleophilic reagent to form different chitinimides. The crucial amino acid residues in the ChmC‐TE domains responsible for the specific recognition of the X part were identified, and they were conserved in all the biosynthetic pathways of this NRP subfamily to form a signature motif, YNHNR, suggesting a special type of TE domain in NRPSs. Chitinimides demonstrate the biological function of promoting the swarming ability of the native producer. This study provides deep insights into the biosynthesis of this special NRP subfamily, and shows that the special TE domain could be used to generate diverse NRPs by combinatorial biosynthesis. [ABSTRACT FROM AUTHOR]

In this study, we report a base‐catalyzed transesterification reaction of glycerol, a waste product of the biodiesel industry, with various dialkyl carbonates, which act both as reactants and solvents, to convert glycerol carbonate into an industrially useful molecular building block. The catalyst, being used for the first time, is also a waste product from industry, present in bauxite residues and in the Portland cement, simply known as tricalcium aluminate. Despite being well‐known and readily available, this solid is only extremely poorly researched catalyst, nevertheless, using dimethyl and diethyl carbonate, glycerol conversion rates >80% and glycerol carbonate yields >60% could be achieved in just 1 h (under air atmosphere and reflux). In a comparison of the performance with other catalysts commonly researched today, as well as with other components of red mud and cements, the results showed that tricalcium aluminate is excellent, cheap, and largely environmentally friendly material for this purpose. Reusability studies of the catalysts have also shown that they provide high conversion and product yields even after repeated use, although different material characterization techniques showed intense glycerol‐catalyst surface interaction and intermediate product formation, the deactivating side effects of which could be avoided by catalyst regeneration steps. [ABSTRACT FROM AUTHOR]

A sustainable alternative process for the production of bio‐based esterquats via heterogeneous transesterification of palm methyl ester and N‐methyldiethanolamine was developed. The transesterification process conditions over CaO/γ‐Al2O3 catalyst were optimized using Response Surface Methodology (RSM). At 146°C, 83.2% di‐ester yield was obtained after 6 h when 4.1 wt% of the synthesized catalyst was used with 1.8:1 methyl ester/N‐methyldiethanolamine molar ratio. CaO/γ‐Al2O3 was able to be reused for 3 cycles without a significant deactivation. A kinetic model was proposed based on irreversible second‐order kinetics and it was the best‐fitted experimental data with an overall reaction rate constants ranging between 0.0892 and 0.695 L/mol.min and an activation energy of 48 kJ/mol. The first experimental investigation on kinetic can be applied to provide insights on large scale reactor design for bio‐based esterquats production. The synthesized esterquats was found to be readily biodegradable, as it reached the pass level of 60% of biodegradation within the period of incubation (28 days). It exhibits similar chemical and physical properties to the commercially available tallow‐based esterquats, thus offering a potential substitute for the animal fat‐based feedstock with the most abundantly available and renewable palm‐based oleochemicals. [ABSTRACT FROM AUTHOR]

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]

A bifunctional thiourea‐amine‐based organocatalyst (Takemoto's catalyst), employing a metal‐free approach, is presented for the regioselective ring‐opening polymerization (ROP) of optically active (D and L) methyl glycolide (MG). In this study, a chiral version of Takemoto's catalyst efficiently promotes the ROP of MG at room temperature, yielding poly(lactic‐co‐glycolic acids) (PLGAs) with predicted molecular weights and narrow polydispersity indices (PDI≤1.2). These PLGAs exhibit highly alternating structures without transesterification, as confirmed by 1H NMR, SEC, and MALDI‐TOF analyses. Additionally, various macromolecular architectures, including linear and star‐shaped PLGAs, were successfully synthesized using the corresponding multi‐functional alcohol initiators while maintaining the same alternating structures and regioselectivity with PLGA obtained from benzyl alcohol as initiator. Computational studies were conducted to elucidate the mechanism of alternating PLGA formation, revealing two key transition states (TSs): TS‐1, which implicates the nucleophilic attack of the hydroxyl group of the initiator or propagating chain on the carbonyl carbon of MG, and TS‐2, which involves the subsequent ring‐opening of the cyclic ester. The results indicate that ring‐opening occurs at both the glycolyl and lactyl sites, with a preference for the glycolyl site, as supported by experimental results. The resulting atactic PLGAs are amorphous, rendering them suitable for drug delivery applications. [ABSTRACT FROM AUTHOR]

The global demand for sustainable and ecologically friendly energy sources has spurred biodiesel research. Civilization, urbanization, and population growth have drastically boosted transportation energy consumption. Energy demand is causing fossil fuel crises. Replace petroleum diesel to solve energy and environmental problems. Biofuels have very vast scope in the area of energy sector. Karanja oil, derived from the seeds of the Karanja tree (Pongamia pinnata), is a promising biodiesel feedstock due to its high Free Fatty Acid content. This study uses Oscillatory Baffled Reactor (OBR) to produce biodiesel from Karanja oil. The feedstock is high-FFA Karanja oil trans-esterified in two steps. In OBR, reaction time is only 15 min, whereas in conventional reactor it takes 1–2 h to produce biodiesel. Optimizing biodiesel synthesis involved varying H2SO4 concentrations from 1 vol% to 5 vol% and 0.3 to1.0 wt% of NaOH concentration for first and second step respectively. Oil-to-alcohol molar ratios 1:6, 1:9 and 1:12. Optimization occurs at 1:12 oil-to-alcohol ratio, 1 vol% H2SO4 catalyst, and 0.6 wt% NaOH catalyst. Studies have also examined how catalyst concentration and oil: alcohol molar ratio affect biodiesel conversion and physical qualities such kinetic viscosity, specific gravity, and acid value. This study shows that OBR can increase biodiesel production from high-FFA Karanja oil, which further opens up opportunities for additional study and improvement. [ABSTRACT FROM AUTHOR]

A heterogeneous base catalyst transesterification process with a calcium oxide (CaO) catalyst was performed to produce high-purity methyl ester (ME) from pretreated sludge palm oil (PSPO) derived from sludge palm oil (SPO). Additionally, a comparative analysis was conducted with potassium hydroxide (KOH) as a homogeneous base catalyst to assess the distinctions between heterogeneous and homogeneous base catalysts. The response surface methodology (RSM) was utilized to determine the optimal and recommended conditions for both transesterification processes. For heterogeneous transesterification, a varying CaO catalyst loading (10–60 wt.%), methanol (25–65 wt.%), and reaction time (60–180 min) were essential parameters. Meanwhile, homogeneous transesterification involved investigating the KOH catalyst loading (1–3 wt.%), methanol (1.8–5.5 wt.%), and reaction time (20–60 min). For the heterogeneous-base-catalyzed reaction, the recommended conditions were as follows: a molar ratio of methanol to oil of 5.83:1 (41.61 wt.%), 31.3 wt.% CaO, and a reaction time of 119.0 min, which resulted in a ME purity of 96.51 wt.%. The optimal conditions for homogeneous transesterification were a molar ratio of methanol to oil of 0.49:1 (3.45 wt.%), a 40 min reaction time, and a 1.39 wt.% KOH concentration, which achieved 96.59 wt.% ME and met the standard. [ABSTRACT FROM AUTHOR]

Biodiesel is seen as more environmentally benign than petroleum-based fuels. It is also cheaper and capable of creating cleaner energy, which has a good impact on increasing the bioeconomy. An investigation was conducted on a novel heterogeneous catalyst system utilized in the synthesis of eco-friendly biodiesel from date seed oil, a non-edible feedstock obtained through the calcination of desiccated camel manure at varying temperatures. X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM) were utilized to characterize this catalyst. As a result of raising the calcination temperature, the results showed that the pore size of the catalyst decreased. The biodiesel production was optimized to be 86% by using the transesterification method. The optimal reaction parameters included a catalyst with 4% loading, a molar ratio of 1:8 between date seed oil and ethanol, and a temperature of 75 °C for a reaction period of three hours. The confirmation of FAME generation was achieved by gas chromatography–mass spectrometry (GC–MS). The fuel qualities of fatty acid ethyl ester are in accordance with ASTM, suggesting that it is a suitable alternative fuel option. Utilizing biodiesel derived from waste and untamed resources to establish and execute a more sustainable and ecologically conscious energy plan is praiseworthy. The adoption and integration of green energy practices could potentially yield positive environmental outcomes, thereby fostering enhanced societal and economic development for the biodiesel sector on a broader scale. [ABSTRACT FROM AUTHOR]

Biodiesel has received tremendous attention as a sustainable energy source. This review presents an overview of various catalysts utilized in biodiesel production and compares their potential for producing biodiesel. Presented here are the excellent features of the various catalysts while highlighting their drawbacks. For instance, production of biodiesel with homogeneous base catalysts is easy but it can only be used with refined oils having low levels of free fatty acid (FFAs). When homogeneous acid is used in esterification, it causes reactor corrosion. Water and FFAs do not affect heterogeneous acid catalysts. Thus, transesterification of triglycerides into biodiesel and converting FFAs into biodiesel through esterification can be catalyzed more efficiently using a heterogeneous acid catalyst. Biocatalysts are also being used to produce biodiesel from oils with high FFAs. However, heterogeneous acid catalysts and biocatalysts are not suitable for industrial application due to serious mass transfer limitations. Biodiesel yield and conversion were compared over various catalysts in this paper. Also presented are the effects of different reaction parameters on biodiesel yield over different catalysts. The correct interplay of factors like reaction temperature, time, alcohol-to-oil molar ratio, and catalyst loading produces optimal process conditions that give the highest biodiesel yield. [ABSTRACT FROM AUTHOR]

Citronellyl acetate is a crucial component of flavor and fragrance in the food, cosmetic, and pharmaceutical sectors. In non-aqueous media, it can be successfully produced via lipase catalysis. This study focuses on the lipase-catalyzed trans-esterification of citronellol alcohol with geranyl acetate ester in a non-aqueous medium to produce citronellyl acetate. For the synthesis of citronellyl acetate, crude acetone powders isolated from several plant seedlings of black cumin, fenugreek, coriander, flax, and rape seed were examined for lipase activity. Black cumin seedling lipase had the highest level of citronella acetate production with a yield of 76.32% in 72 h of reaction time. To assess the impact of different reaction parameters on citronellyl acetate production in organic solvents, hexane was chosen as the best solvent, and black cumin seedling lipase was selected as the best biocatalyst. The highest conversion yield of ester (76.32%) was found when 0.25 M of geraniol acetate and 0.25 M of citronellol reacted at 41 oC after 72 h in the presence of 0.25 g of seedling lipase enzyme in n-hexane. It has been determined that crude black cumin seedling lipase is inexpensive yet effective and has the potential to be used industrially for the synthesis of terpene esters. [ABSTRACT FROM AUTHOR]

In this paper, molten transesterification was used with diphenyl carbonate (DPC), 9,9'-bis[6-(2-hydroxyethoxy)naphthyl]fluorine (BNEF), 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthalene (BHEBN) were used as the polymeric monomers to prepare a series of co-polycarbonates with different molar feeding ratios. It is found that when the molar ratio of BHEBN and BNEF is 6:4, the copolymer has more comprehensive properties. The Mn of the copolymer is 23000 Mn, the Mw is 40700, and the PDI is 1.77. The glass transition temperature is 147.6℃, the initial thermal decomposition temperature (Td,5%) is 338.9℃, the refractive index is 1.6753, the Abbe number is 18.7, and the light transmittance is 86.23%. [ABSTRACT FROM AUTHOR]

Biomass diesel is one of the sustainable and renewable sources of energy envisaged to hold a prominent position in the world energy infrastructure. In this study, biodiesel was produced from baobab seed oil by transesterification using biogenic heterogeneous catalyst, derived from mixed wastes of white chicken eggshells and banana fruit peels. The production process was statistically analyzed using Box-Behnken Design-Response Surface Methodology (BBD-RSM). The influential transesterification reaction parameters investigated with their ranges include reaction time (40–80 min), molar ratio of oil to methanol (1:9–1:15) and catalyst weight (3–5 wt%). The nano-catalyst (CaO-BFP-850 NPs) was prepared by calcination at high temperature of 850 °C for 4 h, and its properties were found to contain majorly the basic elements of Ca and K when investigated with analytical instruments such as SEM, EDS, DSC-TGA, FT-IR, and XRD. The regeneration test of the CaO-BFP-850 NPs conducted showed it could be reused for more than four cycles with less catalytic efficiency reduction. The ideal conditions instituted by BBD-RSM was 75 min of reaction time, 12.8:1 molar ratio of oil to methanol, and 4.08 wt% CaO-BFP-850 at 65 °C and 650 rpm constant temperature and agitation speed respectively, with the validated biodiesel yield of 96.70 wt%. The assessment of the quality of the biodiesel produced showed compliance with the standard specifications of ASTM D6751, EN 14241, and SANS 833. [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]