Ethanolysis Reaction Research Articles

Catalytic Transfer Hydrogenation of Furfural for the Production of Ethyl Levulinate: Interplay of Lewis and Brønsted Acidities

AbstractEthyl levulinate is sought after due to its applications as a fuel additive in biodiesel fuels. Currently it's industrially produced using harmful, highly reactive acids like H2SO4 and HCl, which are used to produce levulinic acid, the common precursor used for EL production. Herein, ethyl levulinate is produced from the synergistic effect of Brønsted and Lewis acids, which catalyze the hydrogenation of furfural leading to the alternative precursor for EL production, furfuryl alcohol. The subsequent ethanolysis reaction of furfuryl alcohol to produce EL, is also enhanced by using an optimal ratio of Brønsted to Lewis acids. Ethanol is chosen as the sacrificial hydrogen donor for proton transfer hydrogenation since it is environmentally friendly, more abundant and affordable than other alcohols that are commonly used for large‐scale production processes. The tandem catalytic reaction can be effectively used to sustainably and responsibly produce ethyl levulinate in relatively short reaction times.

Synthesis of omega-3 ethyl esters from chia oil catalyzed by polyethylene glycol-modified lipases with improved stability

Enzymatic synthesis of fatty acid ethyl esters (FAEE) from chia (Salvia hispanica L.) oil has been performed with different modified derivatives and compared with commercial immobilized lipases to produce omega-3 rich FAEE. Therefore, the main objective was to synthesize omega-3 esters from chia oil catalysed by polyethylene glycol-modified lipases using a biocatalyst with higher stability than commercial derivatives. Lipase from Thermomyces lanuginosus (TLL) was immobilized by hydrophobic adsorption on Sepabeads C-18 followed by a physicochemical coating of lipase surface with a dense layer of PEG. Ethanolysis reactions were carried out using pressurized liquid extracted chia seed oil and with different lipase derivatives to compare the omega-3 FAEE yield and ratio of reaction products, which were analysed by HPLC-ELSD. Furthermore, reutilization of lipase derivatives was studied to evaluate the stability after several reaction cycles to minimize decreasing of catalytic activity and develop a feasible enzymatic process for food industrial applications.

Utilization of Atlantic Salmon By-product Oil for Omega-3 Fatty Acids Rich 2-Monoacylglycerol Production: Optimization of Enzymatic Reaction Parameters

The research work was aimed to produce 2-monoacylglycerol rich omega-3 polyunsaturated fatty acids from supercritical carbon dioxide (SC-CO2) extracted Atlantic salmon frame bone oil (SFBO) by using sn-1,3 lipase catalyzed ethanolysis. SFBO was extracted by SC-CO2 at 45 °C, 25 MPa at carbon dioxide flow rate of 27 g/min for 3 h. Four sn-1,3 specific immobilized lipases namely Novozym-435, Lipozyme TLIM, Lipozyme RMIM, and Lipase DF were screened to evaluate the efficiency of catalyzing ethanolysis reaction for 2-monoacylglycerol production. Response surface methodology (RSM) was applied to optimize ethanolysis parameters such as reaction temperature, time, enzyme load, and ethanol: oil molar ratio to maximize 2-monoacylglycerol production. Salmon frame bone was found rich in oil and the yield was 35.15% in supercritical CO2 extraction. Lipozyme TLIM showed the highest catalyzing activity for 2-monoacylglycerol production from SFBO. The optimum reaction temperature, time, enzyme load, and ethanol: oil molar ratio determined by RSM were 42.5 °C, 4.15 h, 42.81%, and 49.82, respectively at which the yield of 2-monoacylglycerol was 41.81%. Thin layer chromatography analysis proved that the solvent extraction process performed in this study for the separation and purification of 2-MAG from ethanolysis reaction products was successful. The ω-3 polyunsaturated fatty acids content was found 21.34% in 2-monoacylglycerol whereas SC-CO2 extracted SFBO contained 11.25%. Production of 2-monoacylglycerol by ethanolysis reaction of SFBO at the optimized conditions with Lipozyme TLIM may be an efficient approach for human food supplement and potential for food and pharmaceutical industry.

LIQUID-LIQUID EQUILIBRIA FOR SYSTEMS CONTAINING FATTY ACID ETHYL ESTERS, ETHANOL AND GLYCEROL AT 333.15 AND 343.15 K: EXPERIMENTAL DATA, THERMODYNAMIC AND ARTIFICIAL NEURAL NETWORK MODELING

Abstract In this study, the liquid-liquid equilibrium (LLE) data of systems containing ethyl linoleate/oleate/palmitate/laurate, ethanol and glycerol at temperatures ranging from 323.15 to 353.15 K were used to evaluate the performance of the NRTL, UNIFAC, Cubic-Plus-Association Equation of State (CPA EoS), and artificial neural network (ANN) models. The systems evaluated correspond to the most important components formed at the end of the ethanolysis reaction of soybean, palm and coconut oils. The temperature range selected is very important for heterogeneous catalysts, especially for high-pressure systems. The accuracy of the models was evaluated by average global deviation. UNIFAC, UNIFAC-LLE and CPA EoS models showed lower accuracy with deviations of 10.1, 8.01 and 5.95%, respectively. In spite of this predictive limitation, these models show high extrapolation capability for the description of LLE behavior when few experimental data are available in the literature. The ANN model shows the best agreement between experimental and predicted data with an average deviation of 1.12%. In this regard, ANN is offered in this work as an alternative to equations of state and activity coefficient models to be used in a more reliable and less cumbersome way for process simulators of biodiesel production and separation equipment design.

Immobilization Effects on the Catalytic Properties of Two Fusarium Verticillioides Lipases: Stability, Hydrolysis, Transesterification and Enantioselectivity Improvement

Fusarium verticillioides lipases were purified in a “cascade” method using octadecyl Sepabeads and octyl Sepharose resins, which led to the isolation of two proteins with lipolytic activities. Lip 1 was purified after octyl Sepharose adsorption presenting 30.3 kDa and, Lip 2 presented 68.0 kDa after octadecyl adsorption. These immobilization processes resulted in an increase of 3-fold in activity of each immobilized enzyme. These enzymes presented optima of pH of 5.0 and 6.0, respectively and temperature at 40 °C. They were thermostable at 40 °C and both remained more than 50% of its activity at the pH range of 5.0 to 7.0, with 180 min of incubation. The sardine oil hydrolysis showed higher EPA/DHA ratio. Concerning the ethanolysis reaction, Lip 2 showed higher conversion (5.5%) and both lipases showed activity in the release of the S enantiomers from 2-O-butyryl-2-phenylacetic acid (mandelic butyrate acid) and HPBE hydrolysis. Lip 2 also demonstrated capacity of transesterification. These applications made these enzymes attractive for industrial application.

Biocatalysts based on nanozeolite-enzyme complexes: Effects of alkoxysilane surface functionalization and biofuel production using microalgae lipids feedstock.

Nanozeolites with different crystallographic structures (Nano/TS1, Nano/GIS, Nano/LTA, Nano/BEA, Nano/X, and Nano-X/Ni), functionalized with (3-aminopropyl)trimethoxysilane (APTMS) and crosslinked with glutaraldehyde (GA), were studied as solid supports for Thermomyces lanuginosus lipase (TLL) immobilization. Physicochemical characterizations of the surface-functionalized nanozeolites and nanozeolite-enzyme complexes were performed using XRD, SEM, AFM, ATR-FTIR, and zeta potential measurements. The experimental enzymatic activity results indicated that the nanozeolitic supports functionalized with APTMS and GA immobilized larger amounts of enzymes and provided higher enzymatic activities, compared to unfunctionalized supports. Correlations were observed among the nanozeolite surface charges, the enzyme immobilization efficiencies, and the biocatalyst activities. The catalytic performance and reusability of these enzyme-nanozeolite complexes were evaluated in the ethanolysis transesterification of microalgae oil to fatty acid ethyl esters (FAEEs). TLL immobilized on the nanozeolite supports functionalized with APTMS and GA provided the most efficient biocatalysis, with FAEEs yields above 93% and stability during five reaction cycles. Lower FAEEs yields and poorer catalytic stability were found for nanozeolite-enzyme complexes prepared only by physical adsorption. The findings indicated the viability of designing highly efficient biocatalysts for biofuel production by means of chemical modulation of nanozeolite surfaces. The high biocatalyst catalytic efficiency observed in ethanolysis reactions using a lipid feedstock that does not compete with food production is an advantage that should encourage the industrial application of these biocatalysts.

Production of Fuel Quality Ethyl Ester Biodiesel: 1. Laboratory-Scale Optimization of Waste Frying Oil Ethanolysis, 2. Pilot-Scale Production with the Optimal Reaction Conditions

In this study, to produce fuel quality biodiesel, optimization of homogeneous alkaline-catalyzed ethanolysis reaction of waste frying oil was performed. In the first stage of the study, laboratory-scale experiments were carried out to determine the appropriate alkaline catalyst type. Ethanolysis reactions were initially conducted with hydroxide catalysts (KOH and NaOH), but glycerol phase separation could not be obtained. Therefore, alkoxide catalysts (CH3OK and CH3ONa) were used and glycerol phase separation could be obtained with the reaction conditions of ethanol:feedstock molar ratio of 6:1, 1.40 wt% CH3ONa, 75 °C and 4 h. The product yield, viscosity and density were 91.24%, 4.89 mm2s−1, and 880.8 kgm−3, respectively. In the second stage, to increase the yield, optimization experiments were performed and the yield was increased to 99.08% while viscosity and density were almost the same with the reaction conditions of ethanol:feedstock molar ratio of 8:1, 1.40 wt% CH3ONa, 45 °C and 2 h. In the third and the last stage, pilot-scale ethyl ester production was carried out with the optimal reaction conditions. In the pilot-scale ethanolysis, yield decreased to 91.0% because of saponification and emulsification, but the produced ethyl ester biodiesel fuel met the European Biodiesel Fuel Standard (EN 14214:2013).

Biodiesel production by ethanolysis of palm oil using SrO as a basic heterogeneous catalyst

In this study, SrO was used as a solid catalyst for simple conversion of palm oil to biodiesel production via the ethanolysis reaction. This catalyst has a high basic strength (H_) and a total basic site of about 3725 μmol/g. The results showed that under optimum reaction conditions at catalyst loading amount of 5 wt.%, ethanol/oil molar ratio of 12:1 and reaction temperature 80 °C; 98.2% yield of fatty acid ethyl ester (FAEE or biodiesel) could be achieved in 3 h. The SrO catalyst can be reused for at least 5 times with excellent catalytic activity without regeneration or treatment. The obtained biodiesel product after purification and treatment process shows high quality fuel properties according to ASTM D6751 and EN 14214 standards for bio-auto fuels. The results indicated that transesterification of palm oil with ethanol using SrO as a basic heterogeneous catalyst is a commercially viable way for biodiesel production in the industrial scale.

Synthesis of 2-docosahexaenoylglycerol by enzymatic ethanolysis

Synthesis of 2-docosahexaenoylglycerol with high nutritional value was conducted by enzymatic ethanolysis of algal oil. The effects of lipase type, substrate molar ratio of algal oil to ethanol, reaction time, reaction temperature and lipase load on the content of 2-monoacylglycerols (2-MAGs) in the crude product were investigated. Under the optimal conditions, 27–31% 2-MAGs were obtained in the ethanolysis reaction. Lipozyme 435 exhibited 1,3-specific selectivity and maintained stable operational stability after 7 successive reuse cycles. The enzymatic ethanolysis catalyzed by Lipozyme 435 could both synthesize 2-MAGs and concentrate DHA. Further purification of 2-MAGs was performed with solvent extraction by 85% ethanol aqueous solution and hexane, obtaining 95% 2-MAGs in a yield of 67%. The contents of DHA in 2-MAGs product and 2-MAGs fraction were 74.76% and 75.66%, respectively, which were about 26% higher than that in the algal oil. Therefore, this method is efficient and environmental-friendly for synthesis of 2-docosahexaenoylgylcerol.

Effect of acyl‐acceptor stepwise addition strategy using alperujo oil as a substrate in enzymatic biodiesel synthesis

AbstractBACKGROUNDUsing renewable feedstock sources for biodiesel production seems to be a promising strategy and even more so when enzymatic catalysis with lipases are used. However, it is well known that these enzymes could be inactivated by reaction conditions such as temperature or alcohol concentration. In this work, the effect of temperature and initial water activity (aw) value on immobilised recombinant Rhizopus oryzae lipase (rROL) were studied. Methanolysis and ethanolysis reactions using alperujo oil with three different stepwise addition strategies were employed.RESULTSRecombinant 1,3‐positional selective rROL covalently immobilised on polymethacrylate amino‐epoxy activated support showed maximum initial reaction rate at low aw value (0.093). It was found that 30 °C was the optimal temperature in terms of biocatalyst stability during transesterification reactions. Adding alcohol at once, ethanol was clearly a better acyl‐acceptor in terms of stability than methanol. Productivity was found to be 2‐fold higher when five pulses of ethanol were used instead of methanol.CONCLUSIONSAlperujo oil has great potential as a low cost feedstock for biodiesel production through enzymatic catalysis using a nearly semi‐continuous alcohol addition strategy. © 2017 Society of Chemical Industry

Omega-3 fatty acids concentrate production by enzyme-catalyzed ethanolysis of supercritical CO2 extracted oyster oil

The separation of oil by a suitable technique from the Pacific oyster muscle is important for the utilization of the oil as a ω-3 polyunsaturated fatty acids (ω-3 PUFAs) source and production of bio-functional peptides/ oligosaccharides from oil-free residue. This study was conducted to prepare ω-3 PUFAs concentrate from supercritical carbon dioxide (SC-CO2) extracted Pacific oyster oil by enzyme-catalyzed ethanolysis reactions. SC-CO2 extractions were done at different temperatures and pressures to optimize suitable extraction conditions and extracted oils were compared with Soxhlet (n-hexane) extracted oil to evaluate the yield and quality. Oil extracted by SC-CO2 at optimized conditions was used for ethanolysis reaction catalyzed by immobilized sn-1,3 specific lipases, namely Novozymes-435, Lipozyme TLIM, and Lipozyme RMIM to produce 2-monoacylglycerols (2-MAG) rich in ω-3 PUFAs. The optimum temperature and pressure for SC-CO2 extractions of oyster oil was 50°C and 30 MPa. In this condition, the yield of oil was 5.96% and the acid, peroxide, free fatty acid, and p-anisidine values were 4.49 mg KOH/g, 4.72 meq/kg, 3.42%, and 10.03, respectively. The ω-3 PUFAs content significantly increased in 2-MAG obtained from Novozymes 435, Lipozyme TLIM, and Lipozyme RMIM to 43.03 ± 0.36, 45.95 ± 0.29, and 40.50 ± 0.77%, respectively (p < 0.05). A thin layer chromatography (TLC) analysis confirmed the production and separation of 2-MAG in the ethanolysis process. The ratio of total ω-3 to ω-6 fatty acids was almost twice in 2-MAG of SC-CO2 extracted oyster oil. SC-CO2 extracted Pacific oyster oil can be used for sn-1,3 specific lipases catalyzed ethanolysis to produce ω-3 PUFAs rich in 2-MAG.

Fabrication of propylsulfonic acid functionalized SiO2 core/PMO shell structured PrSO3H-SiO2@Si(R)Si nanospheres for the effective conversion of d-fructose into ethyl levulinate

Propylsulfonic acid functionalized SiO2 core/alkyl- or phenyl-bridged organosilica shell structured PrSO3H-SiO2@Si(R)Si (R=C2H4, C6H4 or C6H4C6H4) nanospheres are facilely prepared by a CTAB-directed one-pot two-step condensation strategy. The morphological characteristics, textural properties, Brønsted acid nature and structure of the PrSO3H-SiO2@Si(R)Si nanospheres are well characterized. The materials are successfully applied in the catalytic transformation of D-fructose into the important organic chemical, ethyl levulinate, in the presence of ethanol as both reactant and solvent. The catalytic activity of the PrSO3H-SiO2@Si(R)Si nanospheres outperform commercially available Amberlyst-15, HY zeolite and HCl, mainly attributing to their strong Brønsted acid nature; additionally, unique core-shell structure with excellent porosity properties and well-adjusted hydrophilicity/hydrophobicity also give the positive influence on the ethanolysis activity, which can improve the accessibility of the reactants to the PrSO3H sites and facilitate the multi-step ethanolysis reaction proceeding to the formation of the final product. The PrSO3H-SiO2@Si(R)Si nanospheres can be reused three times without obvious activity loss, contributed from covalent bonding of the PrSO3H groups with the silica and organosilica framework as well as hydrophobic PrSO3H-functionalized organosilica shell.

Supercritical carbon dioxide as solvent in the lipase-catalyzed ethanolysis of fish oil: Kinetic study

Supercritical carbon dioxide (SC-CO2) has been used as green solvent in the lipase-catalyzed ethanolysis of fish oil by Lipozyme RM IM at mild, non-oxidative conditions and with no solvent residues. The effect of experimental conditions, initial substrate ethanol/oil molar ratio (2–38), pressure (7.5–30MPa), and temperature (323.15–353.15K) on equilibrium conversion, reaction rate and oxidative status of the products has been studied. No ethanol inhibition has been observed at high concentrations of ethanol, when putting in contact first the fish oil with the enzyme avoiding direct contact between the biocatalyst and ethanol. Operating pressure affected positively the reaction performance in the range investigated. Visual observation of the phase behaviour of the initial reaction mixture showed an “expanded liquid phase” that helped enhancing reaction rate, and a gas phase. Raising temperature accelerated the reaction up to a limit (343.15K), observing higher enzyme thermal stability than in other reaction media (313.15K). However, lipid oxidation increases with temperature. Up to 86±1% FAEE yield has been found at MR=6:1, 30MPa and 323.15K. Kinetic data have been correlated by using a mathematical model based on the elementary reactions of the 3-step transesterification. Kinetic rate constants, apparent activation volumes and energies are reported for the first time for a lipase-catalyzed ethanolysis reaction in SC-CO2.

ChemInform Abstract: Catalytic and Mechanistic Insights into the Production of Ethyl Levulinate from Biorenewable Feedstocks

AbstractReview: 175 refs.

Modeling chemical kinetics of avocado oil ethanolysis catalyzed by solid glycerol-enriched calcium oxide

The catalytic activity of glycerol-enriched calcium oxide for the alcoholysis reaction between avocado oil and ethanol was investigated. The calcium oxide was derived from Mytilus Galloprovincialis shells. This study systematically examined the influence of temperature, ethanol-to-oil molar ratio, and the catalyst amount on the variation in the concentration of triacylglycerols and biodiesel with reaction time. The interaction between the reaction variables (ethanol-to-oil molar ratio and catalyst amount), their influence on the ethanolysis process, and the optimum variables affecting the process were determined through the response surface methodology. A previously developed mathematical model was applied for the current ethanolysis process, and the model parameters were determined. The ethanolysis reaction occurred between the surface chemisorbed ethoxide ions and oil molecules in the liquid phase, while, the overall process was controlled by the ethanol-adsorption step. The physico-chemical properties of biodiesel, produced using potassium methoxide catalyst, were additionally measured.

Efficient conversion of levulinic acid or furfuryl alcohol into alkyl levulinates catalyzed by heteropoly acid and ZrO2 bifunctionalized organosilica nanotubes

A series of heteropoly acid and ZrO2 bifunctionalized organosilica nanotubes (PW12/ZrO2-Si(Et)Si-NTs) were fabricated via a P123 single-micelle-templated sol–gel co-condensation route and carefully adjusted Si-to-Zr molar ratio and acidity in the initial gel mixture. The morphological characteristics, textural properties, Brønsted and Lewis acidity, and structural integrity of the incorporated Keggin units, as well as the formation of the carbon/silica framework, were well characterized. The PW12/ZrO2-Si(Et)Si-NTs hybrid nanocatalysts were applied in the synthesis of alkyl levulinates by esterification of levulinic acid and ethanolysis of furfuryl alcohol, and the obtained excellent catalytic activity was explained in terms of the strong Brønsted and Lewis acidity, unique hollow tubular nanostructure, and hydrophobic surface of the hybrid nanocatalysts; additionally, the catalysts could be reused at least three times without significant loss of activity. Finally, the possible reaction mechanism of the PW12/ZrO2-Si(Et)Si-NTs-catalyzed esterification and ethanolysis reactions were put forward.

Beauveria bassiana Lipase A expressed in Komagataella (Pichia) pastoris with potential for biodiesel catalysis.

Lipases (EC 3.1.1.3) comprise a biotechnologically important group of enzymes because they are able to catalyze both hydrolysis and synthesis reactions, depending on the amount of water in the system. One of the most interesting applications of lipase is in the biofuel industry for biodiesel production by oil and ethanol (or methanol) transesterification. Entomopathogenic fungi, which are potential source of lipases, are still poorly explored in biotechnological processes. The present work reports the heterologous expression and biochemical characterization of a novel Beauveria bassiana lipase with potential for biodiesel production. The His-tagged B. bassiana lipase A (BbLA) was produced in Komagataella pastoris in buffered methanol medium (BMM) induced with 1% methanol at 30°C. Purified BbLA was activated with 0.05% Triton X-100 and presented optimum activity at pH 6.0 and 50°C. N-glycosylation of the recombinant BbLA accounts for 31.5% of its molecular weight. Circular dichroism and molecular modeling confirmed a structure composed of α-helix and β-sheet, similar to α/β hydrolases. Immobilized BbLA was able to promote transesterification reactions in fish oil, demonstrating potential for biodiesel production. BbLA was successfully produced in K. pastoris and shows potential use for biodiesel production by the ethanolysis reaction.

Synthesis and modification of polyurethane for immobilization of Thermomyces lanuginosus (TLL) lipase for ethanolysis of fish oil in solvent free system

We report the synthesis of polyurethane (PU) with polyethylene glycol (PEG) by miniemulsion polymerization as technique to produce a support for enzyme immobilization and stabilization. In order to study the influence of molar weight and concentration of PEG in the enzyme⿿support interaction, different PEG (400, 4000 and 6000Da) was used during the synthesis of PU⿿PEG support to immobilize Thermomyces lanuginosus lipase (TLL). The enzymatic derivatives were effectively used in the production of polyunsaturated fatty acids (PUFAs), particularly derivative TLL⿿PU⿿PEG6000. This derivative showed the best results in terms of Km (0.183mM) and Vmax (45.79mmol/min/mL), calculated by Lineweaver⿿Burk plot (double reciprocal plot) and catalytic efficient (250.22), 100% of yield immobilization and recovered activity, reaching the highest values to the ethyl esters production (260mM ethyl esters. U⿿1) making this derivative a potential low cost catalyst for ethanolysis reactions in solvent free system.

Kinetic studies on biodiesel production using a trace acid catalyst

Biodiesel was produced by transesterification in the presence of trace sulfuric acid (0.02–0.1wt% of oil mass). The kinetics for the transesterification of corn oil with ethanol was investigated between 155–195°C. The transesterification in the pseudo-homogeneous system consisted of three consecutive steps. All steps were found to be second order reactions, with the first and the second steps being irreversible, while the third step was reversible. It was observed that the apparent rate constants of the forward reactions increased linearly with increasing acid concentration. Compared to the initial two steps of the ethanolysis reaction, the effect of the reversible transformation in the third step is significant, as the conversion of monoglyceride to glycerol is difficult. In addition, the presence of free fatty acids (<30wt%), water (<3wt%), and the use of stirring had little effect on the final content of biodiesel. Finally, it was observed that methanol exhibited a higher reactivity than ethanol in transesterification, while corn oil exhibited higher reactivity than Pennycress oil.

Cellulose reactivity in ethanol at elevate temperature and the kinetics of one-pot preparation of ethyl levulinate from cellulose

Cellulose reactivity in ethanol at elevated temperature (170–210 °C) was investigated in this study. Water and acid catalyst can improve the solubilization and the conversion of cellulose in ethanol. In ethanol/water medium, more humic solids will be formed, but the amounts of diethyl ether decreased greatly. In ethanol medium, the ethanolysis reaction of cellulose played a dominant role, with ethyl levulinate (EL) as the main liquid product. In addition, organic esters and furan derivatives were the main small molecules in the liquid, and diethoxymethane and diethyl sulfate were considered as the main liquid by-products. On the basis, the kinetics of one-pot preparation of EL from cellulose was further investigated at a temperature range of 170–210 °C and an acid concentration range of 0.5–2.0 wt%. Artificial Neural Network (ANN) was employed to develop an approach for the evaluation of the process. A good agreement of the ANN model results and the experimental data was obtained, and the optimum reaction conditions for one-pot preparation of EL were temperature 188 °C, reaction time 30 min, acid concentration 1.2 wt%. Under the conditions, higher EL yield can be obtained, which was close to the ANN model result.