Ethyl Ester Yield Research Articles

Ethanolysis of rapeseed oil to produce biodiesel fuel catalyzed by Fusarium heterosporum lipase-expressing fungus immobilized whole-cell biocatalysts

We demonstrated ethanolysis of rapeseed oil to produce biodiesel fuel using lipase-producing filamentous fungi immobilized on biomass support particles (BSPs) as a whole-cell biocatalyst. We prepared two types of whole-cell biocatalyst: wild-type Rhizopus oryzae producing triacylglycerol lipase (w-ROL) and recombinant Aspergillus oryzae expressing Fusarium heterosporum lipase (r-FHL). Both w-ROL and r-FHL successfully catalyzed the ethanolysis of rapeseed oil, and the fatty acid ethyl ester yield was as high as 79% (w-ROL) or 94% (r-FHL). In the case of r-FHL, the residual monoglycerides (MGs) and diglycerides (DGs) were no more than 0.73 and 0.18%, respectively. In addition, r-FHL could be recycled for the ethanolysis of rapeseed oil, retaining over 85% fatty acid ethyl ester yield by the fifth cycle. r-FHL was revealed to be a promising catalyst for biodiesel production using rapeseed oil and ethanol.

Bioenergy II: Tin Catalysed Esterification of Free Fatty Acids

Tin(II) chloride dihydrate (SnCl2.2H2O) has been an efficient Lewis acid catalyst in the ethanolysis of saturated and saturated free fatty acids (FFA). This compound is stable under aerobic conditions and it has shown to be as active as the mineral acid H2SO4, a common acid catalyst in the conventional production of biodiesel. The carbon chain length of FFA and the fatty acid/alcohol molar ratio were parameters of investigation herein in association with the yield and reaction rate of free fatty ethyl esters (FAEE) formation. The efficiency of the process of recovery of SnCl2 also has been evaluated. It was verfified that the catalytic activity of the recovered SnCl2 has remained unaltered in successive reactions with oleic acid. The residual content of catalyst in the biodiesel was determinated by spectrophotometry of atomic absorption. The use of SnCl2 has advantages in comparison with mineral acid catalysts. For instance, the absence of corrosion in the reaction vessel as well as the unnecessary neutralization of the catalyst after the reaction finishes. The results in this work put forward the SnCl2 as a promising catalyst for the production of biodiesel.

New Approaches to Biodiesel Production by Ethanolysis with Calcium Hydroxide Catalyst Using Thermal Pretreatment with Glycerol

This was a study to pursue new sustainable sources of power in Malawi and other developing countries of Sub-Saharan Africa by investigating a novel approach for biodiesel production via ethanolysis of pretreated oil feedstock with calcium hydroxide using thermal pretreatment with glycerol. 0.5 g of Groundnut (Arachis hypogaea) oil feedstock premixed with glycerol and Ca(OH)2 was thermally pretreated at 100 °C and stirred at 1000 rpm for 1-3 h. The triglycerides (TG) decomposed into diglycerides (DG) and monoglycerides (MG), which are reactive intermediates of the ethanolysis. This effect of pretreatment was investigated in comparison with the effect of other catalyst. Then, the pretreated oil was reacted under the following conditions: 100 °C, 12-to-1 ethanol (EtOH)-to-oil molar ratio, stirring at 1000 rpm, catalyst load of 2 wt%, time from 0.5-2 h. Thermal pretreatment with glycerol achieved a significant fatty acid ethyl ester (FAEE) yield of 76 wt% (comparable to the yields obtained with calcium oxide (h-CaO) and surface-modified calcium oxide (s-CaO)). In tests on the reuse of the Ca(OH)2 catalyst in repeated reactions, the yield did not decrease sharply with repetitive use. Given that all of the materials tested in our experiments are available renewably in Sub-Saharan Africa, we believe that biodiesel production via ethanolysis has the potential to provide a sustainable source of power in that region.

Bioenergy II: Acid Diphosphates as Catalysts for the Production of Methyl and Ethyl Esters from Vegetable Oils

Acidic lanthanum and aluminum diphosphates were prepared and characterized (surface area, XRD, FT-IR, 31P-NMR and 27Al-NMR). These materials were used as catalyst for the esterification of oleic acid and transesterification of soybean oil. Under optimized conditions the methyl and ethyl ester yields were above 95%. Although the catalysts are recyclable, they slowly lost their catalytic activities, due to leaching of the phosphate.

Continuous Production of Biodiesel from Soybean Oil in Supercritical Ethanol and Carbon Dioxide as Cosolvent

This work investigates the effect of carbon dioxide as cosolvent on the production of fatty acid ethyl esters from soybean oil transesterification in supercritical ethanol in a continuous catalyst-free process. The experiments were performed in a tubular reactor in the temperature range of 573−623 K, from 7.5 to 20 MPa, with an oil to ethanol molar ratio ranging from 1:10 to 1:40 and cosolvent to substrates mass ratio from 0:1 to 0.5:1. Results showed that the yield of ethyl esters decreased with increasing addition of carbon dioxide to the system. The reaction conversion was noticed to decrease at lower substrates flow rates due to products decomposition. Considerable reaction yields were achieved at 623 K, 10 MPa, oil to ethanol molar ratio of 1:40 and using a CO2 to substrate mass ratio of 0.05:1. It is shown that the use of a tubular reactor with smaller inner diameter can provide high reaction conversions in short residence times, thus offering a promising route for the investigation of biodiesel production.

Transesterification of Vegetable Oils with Ethanol and Characterization of the Key Fuel Properties of Ethyl Esters

The transesterification reactions of four different vegetable oils (sunflower, rapeseed, olive oil and used frying oil) with ethanol, using sodium hydroxide as catalyst, were studied. The ester preparation involved a two-step transesterification reaction, followed by purification. The effects of the mass ratio of catalyst to oil (0.25 – 1.5%), the molar ratio of ethanol to oil (6:1 – 12:1), and the reaction temperature (35 – 90 °C) were studied for the conversion of sunflower oil to optimize the reaction conditions in both stages. The rest of the vegetable oils were converted to ethyl esters under optimum reaction parameters. The optimal conditions for first stage transesterification were an ethanol/oil molar ratio of 12:1, NaOH amount (1% wt/wt), and 80 °C temperature, whereas the maximum yield of ethyl esters reached 81.4% wt/wt. In the second stage, the yield of ethyl esters was improved by 16% in relation with the one-stage transesterification, which was obtained under the following optimal conditions: catalyst concentration 0.75% and ethanol/oil molar ratio 6:1. The fuel properties of the esters were measured according to EN test methods. Based on the experimental results one can see that the ethyl esters do not differ significantly from methyl esters. Moreover, the results showed that the values of density, viscosity, and higher heating value of ethyl esters were similar to those of automotive and heavy duty engine diesel fuel. However, the CFPP values were higher, which may contribute to potential difficulties in cold starts. On the other hand, the flash points, which were higher than those of diesel fuel constituted a safety guarantee from the point of view of handling and storage.

Optimization of the production of ethyl esters by ultrasound assisted reaction of soybean oil and ethanol

Biodiesel is a renewable liquid fuel that can be produced by a transesterification reaction between a vegetable oil and an alcohol. This paper evaluates and optimizes the production of ethyl esters (biodiesel) from soybean oil and ethanol. The reaction was carried out by applying ultrasound under atmospheric pressure and ambient temperature. Response surface methodology was used to evaluate the influence of alcohol to oil molar ratio and catalyst concentration on the yield of conversion of soybean oil into ethyl esters. The process resulted in a maximum yield of 91.8% after 30 minutes of reaction. The process variables alcohol to oil ratio and catalyst to oil ratio were statistically significant regarding the yield of ethyl esters. The optimal operating condition was obtained applying an alcohol to oil molar ratio of 10.2 and a catalyst to oil weight ratio of 0.0035.

Enzymatic Synthesis of Biodiesel via Alcoholysis of Palm Oil

The enzymatic alcoholysis of crude palm oil with methanol and ethanol was investigated using commercial immobilized lipases (Lipozyme RM IM, Lipozyme TL IM). The effect of alcohol (methanol or ethanol), molar ratio of alcohol to crude palm oil, and temperature on biodiesel production was determined. The best ethyl ester yield was about 25 wt.% and was obtained with ethanol/oil molar ratio of 3.0, temperature of 50 degrees C, enzyme concentration of 3.0 wt.%, and stepwise addition of the alcohol after 4 h of reaction. Experiments with 1 and 3 wt.% of KOH and 3 wt.% of MgO were carried out to compare their catalytic behavior with the enzymatic transesterification results. The commercial immobilized lipase, Lipozyme TL IM, showed the best catalytic performance.

Impact of transesterification mechanisms on the kinetic modeling of biodiesel production by immobilized lipase

Three kinetic models of the transesterification of palm oil fatty acids to ethanol using an immobilized lipase were developed. The models differ from one another with respect to the rate-limiting step and the point at which the ethanol molecule becomes involved in the reaction. The kinetic parameters were estimated by fitting experimental data of the transesterification of palm oil with various ethanol concentrations. The models are able to account for the effects of substrates and products involved in the transesterification throughout the entire reaction. There was a good agreement between experimental results and those predicted by the proposed model equations in which ethanol was assumed to be involved directly in an alcoholysis reaction with palm oil. Furthermore, the calculated results show that the rate constants for alcoholysis of palm oil with ethanol are much higher than those for the hydrolysis reaction. From the proposed model equations, the effects of ethanol concentration on the initial production rates and yields of fatty acid ethyl ester and free fatty acids were simulated. The simulation results show that increasing the initial ethanol concentration produces an increase in the initial production rate and yield of fatty acid ethyl ester and lowers the final concentration of free fatty acid whereas lower ethanol concentration led to a higher final concentration of free fatty acid.

Transesterification of Fish Oil to Produce Fatty Acid Ethyl Esters Using Ultrasonic Energy

AbstractThis study evaluated the production of fatty acid ethyl esters from fish oil using ultrasonic energy and alkaline catalysts dissolved in ethanol. The feasibility of fatty acid ethyl ester production was determined using an ultrasonic bath and probe, and between 0.5 and 1% KOH (added to the fish oil). Furthermore, factors such as ultrasonic device (bath and probe), catalyst (KOH and C2H5ONa), temperature (20 and 60 °C), and duration of exposure (10–90 min) were assessed. Sodium ethoxide was found to be a more efficient catalyst than KOH when transesterifying fish oil. Ultrasonic energy applied for greater than 30 min at 60 °C using 0.8% of C2H5ONa as a catalyst transesterified over 98% fish oil triglycerides to fatty acid ethyl esters. It is reasonable to conclude that the yield of fatty acid ethyl esters produced by applying ultrasonic energy to fish oil is related to the sonication time. Due to increases in the surface area contact between the reactants and the catalyst, ultrasonic energy has the potential to reduce the production time required by a conventional large‐scale commercial transesterification method that uses agitation as a way of mixing.

Evolving factor analysis-based method for correcting monitoring delay in different batch runs for use with PLS: On-line monitoring of a transesterification reaction by ATR-FTIR

In this work, the base-catalyzed transesterification of soybean oil with ethanol was monitored on-line using mid-infrared spectroscopy (MIRS) and the yield of fatty acid ethyl esters (biodiesel) was obtained by 1H NMR spectroscopy. The MIRS monitoring carried out for 12 min, was performed using a cylindrical internal reflectance cell of PbSe in the range of 3707–814 cm −1 with eight co-added scans. Two different data treatment strategies were used: in the first, the models were built using the raw data and in the other, evolving factor analysis (EFA) was used to overcome the sensor time delay due to the on-line analysis, producing significantly better results. In addition, models based on partial least squares (PLS) using three batches for calibration and another for validation were compared with models with just one batch for calibration and three for validation. The models were compared between each other using root mean square error of prediction (RMSEP) and root mean square prediction difference (RMSPD), obtaining relative errors under 3%.

Biodiesel fuel production by the transesterification reaction of soybean oil using immobilized lipase

The enzymatic alcoholysis of soybean oil with methanol and ethanol was investigated using a commercial, immobilized lipase (Lipozyme RMIM). The effect of alcohol (methanol or ethanol), enzyme concentration, molar ratio of alcohol to soybean oil, solvent, and temperature on biodiesel production was determined. The best conditions were obtained in a solvent-free system with ethanol/oil molar ratio of 3.0, temperature of 50 degrees C, and enzyme concentration of 7.0% (w/w). Three-step batch ethanolysis was most effective for the production of biodiesel. Ethyl esters yield was about 60% after 4 h of reaction.

Ethanolysis of Refined Soybean Oil Assisted by Sodium and Potassium Hydroxides

AbstractThe ethanolysis of refined soybean oil was investigated through a 23 experimental design that was carried out under the following levels: ethanol:oil molar ratios (MR) of 6:1 and 12:1, NaOH concentrations of 0.3 and 1.0 wt% in relation to the oil mass, and reaction temperatures of 30 and 70 °C. The ethanol:oil MR and the alkali concentration had an almost equivalent influence on the reaction yield, whereas the influence of increased reaction temperatures was very limited and higher catalyst concentrations led to greater yield losses due to the formation of soap. Ethyl ester yields of 97.2% were obtained at 70 °C, MR of 12:1 and 0.3 wt% NaOH. Replacement of 0.3 wt% NaOH by 1.0 wt% KOH under the same reaction conditions led to lower ester yields. Likewise the former, KOH provided the maximum ester yield (95.6%) at the highest molar ratio (12:1), with the reaction temperature having little influence on the catalyst performance. Ester yields beyond 98% were only achieved when a second ethanolysis stage was included in the process. In this regard, the application of 2 wt% Magnesol® after the first ethanolysis stage eliminated the need for water washing prior to the second ethanolysis stage and helped to generate a final product with less contaminating unreacted glycerides.

Ethanolysis of used frying oil. Biodiesel preparation and characterization

The transesterification reaction of used frying oil by means of ethanol, using sodium hydroxide, potassium hydroxide, sodium methoxide, and potassium methoxide as catalysts, was studied. The objective of the work was to characterize the ethyl esters for its use as biodiesels in compression ignition motors. The operation variables used were ethanol/oil molar ratio (6:1–12:1), catalyst concentration (0.1–1.5 wt.%), temperature (35–78 °C), and catalyst type. The evolution of the process was followed by gas chromatography, determining the concentration of the ethyl esters at different reaction times. The biodiesel was characterized by its density, viscosity, flash point, combustion point, cold filter plugging point, cloud and pour points, Conradson carbon residue, characteristics of distillation, cetane index and high heating value according to ISO norms. The biodiesel with the best properties was obtained using an ethanol/oil molar ratio of 12:1, potassium hydroxide as catalyst (1%), and 78 °C temperature. The density, viscosity, cetane index, Conradson carbon residue and calorific power of the biodiesel obtained had values close to those of a no. 2 diesel. On the contrary, the cold filter plugging point, and cloud and pour points are higher than the conventional diesel fuel. Although higher, flash and combustion points fulfil the norms for ethyl esters derived from vegetable oils. In consequence, the final product obtained had very similar characteristics to a no. 2 diesel oil, and therefore, these ethyl esters might be used as an alternative to fossil fuels. The two-stage transesterification was better than the one-stage process, and the yields of ethyl esters were improved 30% in relation with the one-stage transesterification.

Lipase-mediated conversion of vegetable oils into biodiesel using ethyl acetate as acyl acceptor

Ethyl acetate was explored as an acyl acceptor for immobilized lipase-catalyzed preparation of biodiesel from the crude oils of Jatropha curcas (jatropha), Pongamia pinnata (karanj) and Helianthus annuus (sunflower). The optimum reaction conditions for interesterification of the oils with ethyl acetate were 10% of Novozym-435 (immobilized Candida antarctica lipase B) based on oil weight, ethyl acetate to oil molar ratio of 11:1 and the reaction period of 12 h at 50 °C. The maximum yield of ethyl esters was 91.3%, 90% and 92.7% with crude jatropha, karanj and sunflower oils, respectively under the above optimum conditions. Reusability of the lipase over repeated cycles in interesterification and ethanolysis was also investigated under standard reaction conditions. The relative activity of lipase could be well maintained over twelve repeated cycles with ethyl acetate while it reached to zero by 6th cycle when ethanol was used as an acyl acceptor.

Immobilized lipase-catalysed production of alkyl esters of restaurant grease as biodiesel.

Simple alkyl ester derivatives of restaurant grease were prepared using immobilized lipases as biocatalysts. The lipases studied included those of Thermomyces lanuginosa and Candida antarctica supported on granulated silica (gran- T.l. and gran- C.a., respectively), C. antarctica supported on a macroporous acrylic resin (SP435) and Pseudomonas cepacia immobilized within a phyllosilicate sol-gel matrix (IM PS-30). All alcoholysis reactions were carried out in solvent-free media employing a one-step addition of the alcohol to the reaction system. Of the lipases studied, IM PS-30 was found to be the most effective in catalysing the methanolysis and ethanolysis of grease. The processes catalysed by gran- T.l. and gran- C.a. lipases gave poor conversions to esters, and the SP435-catalysed reactions gave intermediate yields of ethyl and methyl esters. Water activity (a(w)) was an important factor in the methanolysis reactions; reaction media with a(w)<0.5 resulted in the highest conversions to methyl esters. Molecular sieves also improved methyl ester yields by as much as 20% in transesterification reactions catalysed by IM PS-30. The immobilized lipases also were evaluated for their ability to produce alkyl esters of grease with several additional normal and branched-chain alcohols.

Optimizing production of ethyl esters of grease using 95% ethanol by response surface methodology

AbstractPrevious research suggested that ethyl esters derived from recycled restaurant grease might be a potential source of biodiesel. Accordingly, response surface methodology (RSM) was employed to optimize reaction parameters—temperature, time, level of lipase, mole ratio of reactants—in the PS‐30 lipase‐catalyzed transesterification reaction of grease to ethyl esters using 95% ethanol. The regression equation obtained by a modified central composite design of RSM predicted optimal reaction conditions of 38.4°C, 2.47 h, 13.7 wt% lipase (PS‐30), and a mole ratio of grease to ethanol of 1:6.6. Under these conditions the predicted optimal percentage ethyl ester yield was 85.4%. Subsequent experiments using the predicted parameter combinations indicated a trend where experimental percentage yields of ethyl ester were consistently lower than predicted values. In an effort to improve the experimental yield of esters, a second portion of PS‐30 lipase was added without success; however, the addition of 5% SP435 one hour after the start of the initial reaction increased the yield of esters to &gt;96%. Neither lipase PS‐30 nor lipase SP435 alone, however, gave the RSM‐predicted yield of ethyl esters.

Determination of acid and hydroxybenzonitrile herbicide residues in soil by gas-liquid chromatography after ion-pair alkylation

The herbicides are extracted from soil with saturated calcium hydroxide solution. After clean-up the residues are ethylated using iodoethane and tetrabutylammonium hydrogen sulphate as counter ion. Liquid-liquid partition and the use of a macroreticular resin column were compared as clean-up steps and the reaction conditions for optimum yield of ethyl ester or ether were evaluated. Recoveries in excess of 80% were achieved for 2,4-D, dicamba, 3,6-dichloropicolinic acid, dichlorprop, picloram, 2,4,5-T, fenoprop, 2,3,6-TBA, bromoxynil and ioxynil.

Syntheses with the aid of γ‐picolyllithium II: Preparation of oxygen‐containing derivatives

Abstractβ‐(Pyridyl‐4′)‐propionaldehyde‐diethylacetal (II) is obtained in a yield of 39% by the action of bromoacetal on γ‐picolyllithium (I). By allowing I to react with acetyl bromide or with ethyl acetate, a 34% yield of (pyridyl‐4′)‐propanone (III) is obtained. By the action of carbon dioxide on I, (pyridyl‐4′)‐acetic acid is prepared, which is isolated as the ethyl ester (IV) (yield 34%).