Efficient Transesterification Research Articles

Basicity-tuned graphitic carbon nitride supported MgO heterogeneous catalysts for efficient transesterification of groundnut oil to biodiesel

Quality and quantity of biodiesel derived from oil depend on the type of feedstock and the transesterification process. To maximize biodiesel production efficiency and ensure the desired fuel quality, it is crucial to develop and optimize feedstock-specific production processes. This study reports on the transesterification of groundnut oil using a heterogeneous catalyst. Magnesium oxide (MgO) and its composites with graphitic carbon nitride (g-C3N4) at 10, 30, and 50 wt% (MG10, MG30, MG50) were used. The composite catalyst combines basic sites from MgO and Lewis acid sites from the nitrogen atoms in the g-C3N4 triazine unit, giving rise to synergistic effects that enhances biodiesel production. MgO nanoparticles were synthesized via precipitation, followed by calcination at 500 °C, and MgO/g-C3N4 composites were prepared by grinding at different ratios. Morphological and structural studies confirmed material characteristics. BET analysis indicated an increased surface area of 71.39 m2/g, enhancing catalytic activity, while SEM revealed the agglomerated g-C3N4 and the cubic morphology of MgO. Response surface methodology was used to optimize catalyst loading, temperature, and reaction time parameters. The optimal conditions for biodiesel conversion using MG50 composite was determined to be methanol/oil ratio of 6:1, 2.5 wt% catalyst loading, 41.7 °C reaction temperature and spanning 52 min of reaction, yielding 94 % efficiency. GC–MS analysis confirmed successful transesterification, identifying key fatty acid esters such as ethyl oleate (34.72 %) and hexadecanoic acid methyl ester (7.69 %). This work supports further research into feedstock-specific catalysts for industrial biodiesel applications.

Hypercrosslinked porous polymer as catalyst for efficient biodiesel production

While porous organic polymers (POPs) are known for their unique properties, their application in basic biodiesel catalysis is innovative. This study introduces a novel catalyst, hypercrosslinked polymer (HCP-SB-K), synthesized through mechanochemical polymerization of styrene and benzaldehyde with a cross-linking agent and FeCl3, followed by calcination of the previous polymer impregnated with KNO3. The synthesis costs 3.328 euros per gram of catalyst, covering energy and reagent expenses. The catalyst's basic character is explored, demonstrating efficient transesterification with diverse feedstocks. Under optimal conditions, the HCP-SB-K catalyst exhibits exceptional catalytic activity, yielding 99.9% FAME (Fatty Acid Methyl Esters) at 60 °C, 2 h and 3% w/w catalyst. Investigation of free fatty acid (FFA) content highlights the catalyst's effectiveness with oils varying FFA levels: oils with acid value of 0.44 mgKOH goil−1 reached 92.1% FAME at 60 °C, 1 h and 3% w/w catalyst; oils with an acid value of 1.11 mgKOH goil−1, reached 75.9% FAME, under the same conditions. Catalyst leaching evaluation indicates no discharge of basic sites. The regenerated catalyst (impregnation with KNO3 and calcination, after the first use) exhibits a 98.2% FAME like the fresh catalyst. This suggests that HCP-SB-K can be regenerated without noticeable deactivation, emphasizing its industrial potential.

Waste snail shells-derived mixed oxide catalyst for efficient transesterification of vegetable oil: Towards sustainable biodiesel production

This study explores the transesterification process of soybean oil for the production of biodiesel, utilizing an innovative mixed oxide catalyst obtained from discarded snail shells powder. The catalyst synthesis involved a thermal treatment at 900°C for 120 min, predominantly yielding calcium oxide (CaO). In order to evaluate its properties, we carried out a thorough characterization using various analytical techniques. The study explores the impact of crucial variables on the transesterification reaction, such as reaction time (from 30 to 150 min), methanol-to-oil ratio (from 3:1–18:1), and catalyst concentration (from 0.5% to 4% by weight). Optimal conditions emerged with a 90-min reaction time, a 12:1 methanol-to-oil ratio, and a 2% catalyst loading, yielding an impressive biodiesel conversion rate of approximately 93%. The validity of biodiesel conversion was confirmed through Fourier transform infrared spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance Spectroscopy (1 H NMR). The resultant biodiesel exhibited highly favorable characteristics, including an acid value of 0.85 mg of KOH/g, a density of 886.8 kg/m3, and a viscosity of 4.6 mm2/s. These measurements align with the standards set forth in EN 14214 and ASTM D6751 regarding biodiesel quality. The utilization of waste snail shells powder as a precursor for synthesizing the mixed oxide catalyst presents a promising approach for the sustainable production of biodiesel from soybean oil, offering a sustainable and efficient approach to biofuel production.

The catalytic effect of calcium oxide and magnetite loading on magnetically supported calcium oxide-zeolite catalyst for biodiesel production from used cooking oil

This research focuses on developing a magnetically supported catalyst for efficient transesterification reaction of used cooking oil (UCO). The catalyst consists of calcium oxide (CaO) and ZSM-5 zeolite, which were synthesized using waste chicken eggshell and rice husk. Meanwhile, magnetite (Fe3O4) was used as a magnetic component. Various magnetic zeolite-supported CaO catalysts (CaZ/Fe) were prepared with different amounts of CaO (10, 30, 50, and 80 wt% of zeolite) and Fe3O4 (1:0.5, 1:1, 1:1.5 and 1:2 of CaO-zeolite:Fe3O4 ratio). The results identified the 50CaZ/0.5Fe catalyst as the most effective. The catalyst displayed a high surface area, strong basicity, and ideal morphology, thus contributing to a higher biodiesel yield of 91%. The recovery rate of the 50CaZ/0.5Fe catalyst was 88%, suggesting minimal loss and easy catalyst separation post-reaction using an external magnetic field. It also displayed superior stability, obtaining 85% biodiesel yield after 4 uses. The activation energy calculated in the kinetic study was 14.085 kJ/mol. Moreover, the properties of the synthesized biodiesel met the standards set by the ASTM D6751. Overall, the 50CaZ/0.5Fe catalyst with good magnetic behaviour and exhibits excellent catalytic activity suggested that this catalyst is promising for application in biodiesel production.

General Construction of Asymmetric Amine Ethers via Efficient Transesterification.

A novel method to prepare asymmetric amine ethers is reported. Tertiary amine alcohol hydrogen sulfate intermediates are prepared through a reactive distillation process, followed by the transesterification process to afford eventually asymmetric amine ethers. Experiments and DFT calculations revealed the essential roles the sulfate group plays in the highly selective monoesterification process. This clean method is tolerant towards various functional groups with good yields under mild condition, which is obviously superior compared to the conventional processes.

Two-dimensional Mo catalysts supported on the external surface of planar Silicalite-1 zeolite for biodiesel production from waste cooking soybean oil: Transesterification experiment and kinetics

Customized and two-dimensional Mo catalyst supported on external surface of planar Silicalite-1 (Mo/S-1-p) zeolite was prepared for efficient transesterification of waste cooking soybean oil (WCSO) to produce biodiesel. Structural characteristics show the framework structure of Mo/S-1-p was almost unchanged by introducing different Mo-loading, and the Mo6+ oxide species were only well dispersed on the outer surface of Mo/S-1-p with low Mo-loading, but the aggregation of bulky MoO3 were detected under the high Mo-loading above 5 %. Furthermore, the 5Mo/S-1-p catalyst showed a good performance and stability, which exhibited the WCSO conversion of 80.73 % and biodiesel selectivity of 99.32 %. Additionally, the intrinsic kinetics of the transesterification of WCSO catalyzed by 5Mo/S-1-p catalyst was studied after eliminating mass transfer diffusion. The corresponding kinetic equation was established through the correlation of the initial rate and the reactant concentration, and the apparent Ea was calculated to be 48.03 kJ mol−1. Finally, the fuel properties of the as-synthesized biodiesel are matched with the current international standards. This research provides a beneficial technology for the synthesis of green and inexpensive sustainable fuel.

Fabrication of hierarchically porous MgO with high surface area and adjustable alkalinity for efficient transesterification synthesis of ethyl methyl carbonate

Hierarchically porous MgO catalysts with high surface area and adjustable alkalinity were prepared with a carbon deposit template in-situ generated via pyrolysis of organic compounds (OCs) in an inert atmosphere. The effects of the preparation parameters, such as calcination temperature, atmosphere, types and dosage of OCs, etc., on the physicochemical properties of synthesized MgO were investigated. The characterization results suggested that the base strength varied with preparation conditions due to the different microstructure caused by various parameters and the influence mechanism of microstructure on the base strength of synthesized MgO was speculated and discussed. A yield of ethyl methyl carbonate as high as 49.5% was achieved for the best sample synthesized in this work at 103 °C in only 20 min. High specific surface area (∼206 m2·g−1), large pore volume (0.48 cm3·g−1) and suitable base strength enable the obtained MgO an eligible candidate for transesterification reaction. Additionally, the new strategy for controlling the base strength of as-prepared MgO also suggested good prospects in other practical applications.

A cleaner approach with magnetically assisted reactor setup over CaO-zeolite/Fe3O4 catalyst in biodiesel production: Evaluation of catalytic performance, reusability and life cycle assessment studies

This study reports the magnetic catalyst constructed by incorporating magnetite (Fe3O4) within zeolite-supported calcium oxide (CaO) in conventional and magnetic reactors for heterogeneous catalytic biodiesel production. The CaO-zeolite/Fe3O4 catalyst demonstrated remarkable characteristics, including a substantial surface area, acid-base properties, and high magnetization. These attributes enable efficient transesterification of used cooking oil (UCO) with high free fatty acid (FFA) content and facilitate the easy separation of the solid catalyst by utilizing magnetic force once the reaction is complete. In the conventional reactor, employing a 3 wt% catalyst dosage and a 5:1 methanol to oil molar ratio, the maximum biodiesel yield reached 93.64% after 240 min at 55 °C. Meanwhile, the magnetic reactor yielded a maximum biodiesel yield of 96.91% when operating for 300 min, using a 4 wt% catalyst dosage, 5:1 methanol to oil molar ratio, and maintaining a reaction temperature of 55 °C. The catalyst reusability result did not indicate an appreciable reduction in biodiesel yield in 4 cycles with the magnetic reactor. The life cycle assessment (LCA) study also revealed fewer negative effects of biodiesel production by using a magnetic reactor on the environment. The efficient utilization of CaO-zeolite/Fe3O4 catalyst in the magnetic reactor has shown great potential for industrial application.

Revolutionizing biodiesel production: A breakthrough synthesis and characterization of bismuth ferrite nanocatalysts for transesterification of palm and waste cooking oil

The present work deals with the successful synthesis of heterogeneous bismuth ferrite nanocatalysts (BiFeO3) using kappa-carrageenan polysaccharides to study the efficient transesterification of palm cooking oil for biodiesel production. The optimized size of pristine BiFeO3 obtained was 95.8 nm, at a molar ratio of (Bi: Fe; 1:2) with a 1 % carrageenan biotemplate and calcined at 823 K for 2 h. The nanocatalysts have been producing high thermal stability, and X-ray diffraction (XRD) analysis showed the rhombohedral crystalline phases. The BiFeO3 nanocatalysts demonstrated outstanding catalytic performance during the transesterification of palm and waste cooking oils. The abovementioned processes with different reaction parameters for the production of fatty acid methyl ester (FAME) were investigated in batches. The effects of the catalyst dosage, temperature, time, and molar ratio (oil/methanol) have been conducted. A maximum FAME yield of 98% was achieved using optimized conditions: oil and methanol at a molar ratio of 1:15, and BiFeO3 with a 7 wt% catalyst dosage in 2 h at 353 K. The results indicated high chemical stability of the catalyst after five consecutive cycles with the same catalytic performance and proved to be a suitable catalyst for the production of biodiesel with high reaction rates and low catalyst usage.

Composition of fatty acid methyl ester in microalgae Chlorella vulgaris: Comparison between various methods of harvesting, extraction and transesterification

The aim of the study was to identify which of methods produces the highest yield of fatty acid methyl ester (FAME) from microalgae. Different methods of harvesting (centrifugation, Cen & coagulation, Co), extraction (Test Tube, TT & Soxhlet, Sox) and transesterification (direct transesterification, d-trans & extraction transesterification, ext-trans) were considered. The procedures of this research consists of microalgae cultivation, harvesting of biomass and extraction of oil to obtain the lipid. The further process of converting lipid into FAME is followed by transesterification process. The FAME compositions of Chlorella vulgaris were analyzed using Gas chromatography mass spectrometry (GC–MS). The main components were consists of palmitic, stearic and oleic acids for both transesterification methods. However, FAME extracted from d-trans contained more components (linoleic and linolenic acid) than ext-trans. Furthermore, the highest amount of FAME gained by ext-trans was produced by the method of centrifugation-test tube (Cen-TT). Although Cen-TT produced the highest amount of FAME for ext-trans, it still cannot meet the highest amount of FAME produced by d-trans. Therefore, the Cen-TT method was selected to be the best microalgae harvesting and extraction method in ext-trans meanwhile the most efficient transesterification method was d-trans.

Flexible Vitrimers for Self‐healable Triboelectric Nanogenerators

AbstractDespite rapid advancements in the development of triboelectric nanogenerators (TENG), mechanical defects generated during their working condition limit the service lifetime of these devices. Polyester‐based vitrimers can offer a solution to solve this issue via their dynamic bond exchange reactions. However, they often require high temperatures and a long time to crosslink, rendering them not useful for large‐scale TENG fabrication. To solve these issues, a self‐healable vitrimer‐based triboelectric nanogenerator (VITENG) is developed based on diacrylate poly(dimethylsiloxane) (AA‐PDMS) via a fast thiol‐Michael reaction. By including 2,3‐dihydroxypropyl methacrylate (DHPMA), hydroxy end dangling side chains are generated in the matrix, which increase the PDMS network's flexibility and transesterification efficiency. Efficient transesterification occurs on the abundant dynamic β‐hydroxy ester bonds in the PDMS network, resulting in 100% efficient mechanical damage repair. The VITENG demonstrates a good performance with an output voltage of 135 V under a load of 10 N, demonstrating the potential for mechanical energy harvesters with long lifetimes and high design flexibility.

Isopropenyl phosphate as an atom efficient reagent for phosphorylation of alcohols with catalytic base.

The atom efficient transesterification of phosphate esters with catalytic base was investigated using an isopropenyl leaving group, generating acetone as the only by-product. The reaction proceeds in good yields at room temperature, with excellent chemoselectivity towards primary alcohols. Mechanistic insights were obtained by obtaining kinetic data using in operando NMR-spectroscopy.

Enhanced conversion of dairy waste oil to biodiesel via novel and highly reactive UiO-66-NH2/ZnO/TiO2 nano-catalyst: Optimization, kinetic, thermodynamic and diesel engine studies

This study focuses on developing a novel UiO-66-NH2/ZnO/TiO2 nano-catalyst for efficient biodiesel generation from dairy waste scum oil (DWSO). UiO-66-NH2, UiO-66-NH2/TiO2, and UiO-66-NH2/ZnO/TiO2 nano-catalysts were prepared via the sol–gel approach and their structural features were analyzed by XRD, FT-IR, BET, ED/Map, SEM, TEM, and CO2-TPD approaches. The UiO-66-NH2/ZnO/TiO2 nano-catalyst demonstrated a mesoporous surface with a specific surface area and an average particle size of 568.1 m2/g and 28.35 nm, respectively. The central composite design (CCD) was also utilized to optimize crucial variables. Biodiesel conversion of 98.7 % was achieved under the optimized process circumstances such as the methanol to DWSO ratio of 9.8:1, reaction temperature of 61 °C, and nano-catalyst concentration of 2 wt%. As a novelty, biodiesel conversion is the highest methyl ester achieved from DWSO so far. The survey of the reaction kinetics employing UiO-66-NH2/ZnO/TiO2 indicated that the rate constant, activation energy and Arrhenius factor are 0.1325 min−1, 48.73 kJ mol−1, and 39.6 × 105 min−1, respectively. Besides, the thermodynamic scrutiny implicates that the process is nonspontaneous (ΔG = 88.94 kJ/mol at 338 K) and endothermic (ΔH = 46.01 kJ/mol). Moreover, the impact of adding DWSO-derived biodiesel to diesel on the diesel engine parameters and viscosity alterations was scrutinized. Fuel rheological behaviour appraisal exhibited that biodiesel follows the Newtonian model. The stability of the UiO-66-NH2/ZnO/TiO2 nano-catalyst was assessed in transesterification successive processes. The nano-catalyst could be reused multiple times, and a conversion of 90.14 % was obtained during the 7th consecutive run. It can be concluded that UiO-66-NH2/ZnO/TiO2 nanoparticles can be employed as a highly retrievable nano-catalyst for efficient transesterification of DWSO.

Molecular dynamics-assisted process design and multi-objective optimization for efficient production of N-butyl acetate by reactive-extractive distillation/pervaporation

At present, the market demand for methyl acetate (MEOAC) is small and there is the problem of overcapacity. As an important organic solvent, n-butyl acetate (nBuOAC) is widely used in industry. It is very important to explore the efficient transesterification synthesis and separation process of nBuOAC. In this work, the schemes of reactive-extractive distillation (RED), side-line reactive extractive distillation (SLRED) and reactive distillation-pervaporation (RDPV) were proposed for the transesterification of MEOAC and n-butanol (nBuOH) to synthesize nBuOAC and methanol (MEOH). Firstly, according to the relative volatility of MEOAC and MEOH azeotrope systems, and the interaction energy and radial distribution function (RDF) were calculated by molecular dynamics (MD) to complete the screening of extractants. Then the process design is completed based on reaction kinetics, and the established processes with optimal operating conditions were obtained by the multi-objective particle swarm optimization algorithm. Finally, the total annual cost (TAC) and gas emissions are used to assess the economic efficiency and environment performance of these processes and the optimal process was obtained. The calculation results show that among the three proposed processes, the RDPV process performs best economically and environmentally. The TAC of RDPV is 8.17% lower than that of RED and 6.46% lower than that of SLRED. Meanwhile, the TAC of SLRED is 1.83% lower than that of RED. The gas emissions of RDPV is 23.13% lower than that of RED and 23.51% lower than that of SLRED, and there is little difference between RED and SLRED process.

Stabilizing Triglyceride in Methanol Emulsions via a Magnetic Pickering Interfacial Catalyst for Efficient Transesterification under Static Conditions.

Pickering emulsion systems provide potential platforms for simultaneously intensifying and catalyzing transesterification between triglyceride and methanol under static conditions. However, realizing static transesterification with high biodiesel yield is still challenging due to low emulsion stability at the reaction temperature. Here, a series of magnetically recyclable Pickering interfacial catalysts (PICs) with similar surface affinities but different densities were constructed as stabilizers of a soybean oil/methanol emulsion. The variations in the emulsion volume fraction and droplet size were comparatively studied and analyzed from the viewpoint of droplet settling and catalyst particle shedding. It is found that, except for surface affinity, PIC density also plays a pivotal role in emulsion stability owing to the non-negligible effect of gravity on catalyst adsorption in triglyceride/methanol emulsion (especially at elevated temperature). By reducing the density, finely improving the lipophilicity, and optimizing the addition amount of PIC, the obtained soybean oil/methanol emulsion can remain stable for at least 12 h at 60 °C, enabling static transesterification with a high biodiesel yield of 95.6%. Moreover, the best performing PIC can be reused for at least 7 cycles. This efficient static transesterification system offers a green strategy for biodiesel production.

Introduction of Photolatent Bases for Locally Controlling Dynamic Exchange Reactions in Thermo-Activated Vitrimers.

Vitrimers exhibit a covalently crosslinked network structure, as is characteristic of classic thermosetting polymers. However, they are capable of rearranging their network topology by thermo-activated associative exchange reactions when the topology freezing transition temperature (Tv ) is exceeded. Despite the vast number of developed vitrimers, there is a serious lack of methods that enable a (spatially) controlled onset of these rearrangement reactions above Tv . Herein, we highlight the localized release of the efficient transesterification catalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) by the UV-induced cleavage of a photolatent base within a covalently crosslinked thiol-epoxy network. Demonstrated with stress relaxation measurements conducted well above the network's Tv , only the controlled release of TBD facilitates the immediate onset of transesterification in terms of a viscoelastic flow. Moreover, the spatially resolved UV-mediated photoactivation of vitrimeric properties is confirmed by permanent shape changes induced locally in the material.

Waste Fish Scale Derived Ferromagnetic Heterogeneous Biocatalyst (Α-Fe2O3-Β-Ca3(PO4)2) for Efficient Transesterification of Waste Silkworm Pupal Lipids into Biodiesel

This paper reports an eco-friendly, cost-effective facile route to prepare bio-derived heterogeneous magnetic biocatalysts from the waste fish scale via thermal treatment and used for efficient transesterification to produce biodiesel. The hydroxyapatite of fish scales was impregnated with the varied concentrations (10–30 wt. %) of Fe2+ precursor (FeCl2.4H2O) through the wet impregnation method and transformed into α-Fe2O3-β-TCP via calcination at 700–1000 °C. The transformation of hydroxyapatite to β-Ca3(PO4)2 impregnated with α-Fe2O3 confirmed through XRD and Raman analysis. The FTIR spectra of the prepared sample α-Fe2O3-β-TCP support its structural and chemical composition. The SEM images confirm the presence of α-Fe2O3 in the waste fish scales derived catalysts. The magnetic studies revealed the soft ferromagnetic behavior for the optimized catalysts Fe-FSC-30 with saturation magnetization 0.59 emu/g at 300 K. The magnetic fish scale catalysts was used for the transesterification of silkworm pupa lipids. The FTIR and 1H-NMR spectroscopy recognized the conversion of silkworm pupa lipids into biodiesel. The transesterification efficiency of heterogeneous magnetic biocatalysts is estimated to be ~90 % via 1H-NMR. The GC-MS identified the presence of the main constituents of SPL-biodiesel. The study demonstrated waste fish scale-derived low-cost magnetic catalysts for efficient transesterification of lipids for biodiesel production.

Epoxy-polyhedral oligomeric silsesquioxanes (POSS) nanocomposite vitrimers with high strength, toughness, and efficient relaxation

Although considerable progress has been made in developing vitrimers, on-going challenges for vitrimers for high-performance applications include the improvement in mechanical properties and identification of more efficient exchange reactions. By incorporation of glycidyl polyhedral oligomeric silsesquioxane (POSS) as a nanoscale filler in epoxy, we produced epoxy-POSS nanocomposite vitrimers that show high strength, toughness, thermal stability, and efficient relaxation. With 10 wt% POSS, the ultimate tensile strength and strain at break of the epoxy-POSS nanocomposite vitrimers increased by ~64% and ~76%, respectively, while at 160 °C the stress relaxation time increased by ~260% in comparison to that of pure epoxy vitrimer. The epoxy-POSS nanocomposite vitrimers show high malleability due to the efficient transesterification reaction and re-processability with little degradation of their initial mechanical properties, suggesting opportunities for sustainable plastics.

Efficient Transesterification of Methyl Acetate with 2-Propanol by the Selective Removal of Methanol Using Zeolite Membranes

Abstract An FAU-type zeolite membrane was applied to the efficient transesterification of methyl acetate with 2-propanol. When the transesterification reaction was carried out using DOWEX 50W as a catalyst, the conversion of methyl acetate reached 38% at equilibrium. Removal of the by-produced methanol selectively from the equilibration solution using the FAU-type zeolite membrane increased the conversion of methyl acetate to 57% by shifting the chemical equilibrium. This suggests that methanol-selective membranes have the potential to promote efficient transesterification reactions.

Efficient transesterification over two-dimensional zeolites for sustainable biodiesel production

Basic zeolites have shown great potential as efficient catalysts for biodiesel production in the transesterification reactions. However, conventional three-dimensional (3D) basic zeolites generally suffer from limited base sites and severe mass-transfer restriction, thereby suppressing their catalytic activity. Herein, 2D basic zeolites with large external surface areas, hierarchical characteristics, and abundant accessible and stable base sites are prepared by expansion, delamination and subsequent solid-state ion-exchange (SSIE) approach. The facile SSIE method provides more advantages in stabilizing and dispersing high concentration of strong basic sites than the conventional liquid-phase ion-exchange (LIE) approach. Due to the excellent mass transportation and stable basic sites, the 2D Na/ITQ-2 prepared by the SSIE approach shows remarkably enhanced activity and recyclability in the transesterification of triglycerides to produce biodiesel, compared to 3D zeolites and other reported basic zeolites. This work will open the boulevard to the rational design of 2D basic catalysts and expand the potential application of 2D zeolites to biodiesel production and other industrial reactions involving bulky molecules.