Showing papers on "Transesterification published in 2006"
TL;DR: In this paper, various methods of preparation of biodiesel with different combination of oil and catalysts have been described and technical tools and processes for monitoring the transesterification reactions like TLC, GC, HPLC, GPC, 1H NMR and NIR have also been summarized.
Abstract: Biodiesel is gaining more and more importance as an attractive fuel due to the depleting fossil fuel resources. Chemically biodiesel is monoalkyl esters of long chain fatty acids derived from renewable feed stock like vegetable oils and animal fats. It is produced by transesterification in which, oil or fat is reacted with a monohydric alcohol in presence of a catalyst. The process of transesterification is affected by the mode of reaction condition, molar ratio of alcohol to oil, type of alcohol, type and amount of catalysts, reaction time and temperature and purity of reactants. In the present paper various methods of preparation of biodiesel with different combination of oil and catalysts have been described. The technical tools and processes for monitoring the transesterification reactions like TLC, GC, HPLC, GPC, 1H NMR and NIR have also been summarized. In addition, fuel properties and specifications provided by different countries are discussed.
3,232 citations
TL;DR: The results suggested that the new process, which combined bioengineering and transesterification, was a feasible and effective method for the production of high quality biodiesel from microalgal oil.
1,379 citations
TL;DR: In this paper, a review of the methods for the transesterification of waste cooking oil and the performance of biodiesel obtained from waste cooking oils in a commercial diesel engine is presented, and the effects of the products formed in the frying process on biodiesel quality are examined.
Abstract: Biodiesel (fatty acid methyl ester) is a nontoxic and biodegradable alternative fuel that is obtained from renewable sources. A major hurdle in the commercialization of biodiesel from virgin oil, in comparison to petroleum-based diesel fuel, is its cost of manufacturing, primarily the raw material cost. Used cooking oil is one of the economical sources for biodiesel production. However, the products formed during frying, such as free fatty acid and some polymerized triglycerides, can affect the transesterification reaction and the biodiesel properties. Apart from this phenomenon, the biodiesel obtained from waste cooking oil gives better engine performance and less emissions when tested on commercial diesel engines. The present paper attempts to review methods for the transesterification of waste cooking oil and the performance of biodiesel obtained from waste cooking oil in a commercial diesel engine. The paper also examines the basic chemistry involved during frying and the effects of the products formed in the frying process on biodiesel quality.
1,166 citations
TL;DR: In this article, the characteristics and performance of three commonly used catalysts used for alkaline-catalyzed transesterification i.e. sodium hydroxide, potassium hydroxides and sodium methoxide, were evaluated using edible Canola oil and used frying oil.
933 citations
TL;DR: An increase in the amount of methanol or catalyst quantity seems to simplify the separation/purification of the methyl ester phase, as showed by a viscosity reduction and an increasing purity to values higher than 98% for methyl esters phase.
609 citations
TL;DR: Studies were carried out on transesterification of Karanja oil with methanol for the production of biodiesel using optimized reaction parameters such as catalyst concentration, alcohol/oil molar ratio, temperature, and rate of mixing.
570 citations
TL;DR: In this article, the preliminary results of using several acidic and basic solids, such as ZrO2, ZnO, SO42−/ZrO 2, KNO3/KL zeolite and KNO 3/ZRO2 as heterogeneous catalysts for crude palm kernel oil (PKO) and crude coconut oil (CCO) transesterification with methanol.
516 citations
TL;DR: In this article, an environmentally benign process for the transesterification of soybean oil to methyl esters using alumina loaded with potassium as a solid base catalyst in a heterogeneous manner was developed.
Abstract: Biodiesel fuel, consisting of methyl esters of long chain fatty acids produced by transesterification of vegetable oils or animal fats with methanol, is a promising alternative diesel fuel regarding the limited resources of fossil fuels and the environmental concerns. In this work, an environmentally benign process for the transesterification of soybean oil to methyl esters using alumina loaded with potassium as a solid base catalyst in a heterogeneous manner was developed. The catalyst loaded KNO 3 of 35 wt.% on Al 2 O 3 , after being calcined at 773 K for 5 h, it was found to be the optimum catalyst, which can give the highest basicity and the best catalytic activity for this reaction. The effects of various reaction variables such as the catalyst loading, oil to methanol ratio, reaction time and temperature on the conversion of soybean oil were investigated. The catalysts were characterized by means of XRD, IR and Hammett titration method. The results indicated that K 2 O derived from KNO 3 at high temperature and that the Al–O–K groups were, probably, the main reasons for the catalytic activity towards the reaction. The catalyst activity was correlated closely with its basicity as determined by the Hammett method.
509 citations
TL;DR: In this article, the traditional acid and the new two-step catalyzed processes for synthesis of biodiesel expressed as fatty acid methyl ester (FAME) were comparatively studied to achieve an economic and practical method for utilization of waste cooking oil (WCO) from Chinese restaurants.
Abstract: The traditional acid and the new two-step catalyzed processes for synthesis of biodiesel expressed as fatty acid methyl ester (FAME) were comparatively studied to achieve an economic and practical method for utilization of waste cooking oil (WCO) from Chinese restaurants. WCO samples with the acid value of 75.92 ± 0.04 mgKOH/g mixed with methanol were catalyzed under 95 °C for various reaction time, followed by methanol recovery under vacuum (10 ± 1 mmHg) at 50 °C with a rotational evaporation. FAME analyzed by gas chromatography (GC) was obtained directly from sulfuric acid catalyzed reaction in the traditional acid method, whereas in the two-step method it was produced from ferric sulfate (2.0%) catalyzed reaction followed by alkali (1.0% potassium hydroxide) transesterification. The conversion of free fatty acids of WCO into FAME in the two-step method was 97.22% at the reaction time of 4 h, mole ratio of methanol to TG of 10:1, compared in the acid method with 90%, 10 h, and 20:1, respectively, showing much higher catalyzed activity of ferric sulfate. This new two-step process showed advantages of no acidic wastewater, high efficiency, low equipment cost, and easy recovery of catalyst compared with the limitations of acidic effluent, no reusable catalyst and high cost of equipment in the traditional acid process.
457 citations
TL;DR: The reaction kinetics of acid-catalyzed transesterification of waste frying oil in excess methanol to form fatty acid methyl esters (FAME), for possible use as biodiesel, was studied in this paper.
Abstract: The reaction kinetics of acid-catalyzed transesterification of waste frying oil in excess methanol to form fatty acid methyl esters (FAME), for possible use as biodiesel, was studied. Rate of mixing, feed composition (molar ratio oil:methanol:acid) and temperature were independent variables. There was no significant difference in the yield of FAME when the rate of mixing was in the turbulent range 100 to 600 rpm. The oil:methanol:acid molar ratios and the temperature were the most significant factors affecting the yield of FAME. At 70 °C with oil:methanol:acid molar ratios of 1:245:3.8, and at 80 °C with oil:methanol:acid molar ratios in the range 1:74:1.9–1:245:3.8, the transesterification was essentially a pseudo-first-order reaction as a result of the large excess of methanol which drove the reaction to completion (99±1% at 4 h). In the presence of the large excess of methanol, free fatty acids present in the waste oil were very rapidly converted to methyl esters in the first few minutes under the above conditions. Little or no monoglycerides were detected during the course of the reaction, and diglycerides present in the initial waste oil were rapidly converted to FAME.
431 citations
TL;DR: In this paper, the authors investigated the possibility of using MgO and calcined hydrotalcites as catalysts for the transesterification of soybean oil with methanol.
Abstract: Biodiesel production has increased greatly in recent years, because of the less-detrimental effects of this fuel on the environment, compared to a conventional diesel obtained from petroleum. This work investigates the possibility of using MgO and calcined hydrotalcites as catalysts for the transesterification of soybean oil with methanol. The achieved experimental data show a correlation not only with the catalysts basicity, but also with its structural texture. However, the structural texture of the examined catalysts is dependent on both the precursor and the preparation method. At least four different types of basic sites have been individuated on the surface of MgO and calcined hydrotalcite catalysts. The strongest basic sites (super-basic) promote the transesterification reaction also at very low temperature (100 °C), while the basic sites of medium strength require higher temperatures to promote the same reaction. Ultimately, all the tested catalysts are resistant to the presence of moisture in the...
TL;DR: In this paper, the transesterification of soybean oil with methanol has been studied in a heterogeneous system, using alumina loaded with potassium iodide as a solid base catalyst.
Abstract: Biodiesel fuel, a promising alternative diesel fuel produced by a catalytic transesterification of vegetable oils, has become more attractive recently because of its environmental concerns and the fact that it is made from renewable resources. In this work, the transesterification of soybean oil with methanol has been studied in a heterogeneous system, using alumina loaded with potassium iodide as a solid base catalyst. After loading KI of 35 wt.% on alumina followed by calcination at 773 K for 3 h, the catalyst gave the highest basicity and the best catalytic activity for this reaction. The catalysts were characterized by means of XRD, IR, SEM and the Hammett indicator method. Moreover, the dependence of the conversion of soybean oil on the reaction variables such as the catalyst loading, the molar ratio of methanol to oil and the reaction time was studied. The conversion of 96% was achieved under the optimum reaction conditions. Besides, a correlation of the catalyst activity for the transesterification reaction with its basicity was proposed.
TL;DR: In this paper, 12-Tungstophosphoric acid (TPA) impregnated on four different supports such as hydrous zirconia, silica, alumina and activated carbon was evaluated as solid acid catalysts for the biodiesel production from low quality canola oil containing upto 20 wt% free fatty acids.
TL;DR: In this paper, a transesterification of vegetable oils in supercritical methanol is performed without using any catalyst, and the most important variables affecting the methyl ester yield during the transterification reaction are the molar ratio of alcohol to vegetable oil and the reaction temperature.
TL;DR: There was no obvious loss in lipase activity even after being repeatedly used for 200 cycles with tert-butanol as the reaction medium, and it has been found that lipase also showed good stability in this novel system.
Abstract: tert-Butanol, as a novel reaction medium, has been adopted for lipase-catalyzed transesterification of rapeseed oil for biodiesel production, with which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated. Combined use of Lipozyme TL IM and Novozym 435 was proposed further to catalyze the methanolysis and the highest biodiesel yield of 95% could be achieved under the optimum conditions (tert-butanol/oil volume ratio 1:1; methanol/oil molar ratio 4:1; 3% Lipozyme TL IM and 1% Novozym 435 based on the oil weight; temperature 35 °C; 130 rpm, 12 h). There was no obvious loss in lipase activity even after being repeatedly used for 200 cycles with tert-butanol as the reaction medium. Furthermore, waste oil was also explored for biodiesel production and it has been found that lipase also showed good stability in this novel system.
TL;DR: In this paper, a promising route for the production of biodiesel via transesterification of soybean oil (SBO) and poultry fat with methanol in quantitative conversions at room temperature has been developed using nanocrystalline calcium oxides as catalysts.
Abstract: A promising route for the production of biodiesel (fatty acid methyl esters, FAMES) via transesterification of soybean oil (SBO) and poultry fat with methanol in quantitative conversions at room temperature has been developed using nanocrystalline calcium oxides as catalysts. Under the same conditions, laboratory-grade CaO gave only 2% conversion in the case of SBO, and there was no observable reaction with poultry fat. The soybean oil/methanol ratio in our protocol is 1:27. With our most active catalyst, deactivation was observed after eight cycles with SBO and after three cycles with poultry fat. Deactivation may be associated with one or more of the following factors: the presence of organic impurities or adventitious moisture and enolate formation by the deprotonation of the carbon alpha to the carboxy group in the triglyceride or FAMES. The biodiesel from our protocol meets the ASTM D-874 standard for sulfated ash for both substrates.
TL;DR: In this paper, a lipase from Candida sp, suitable for transesterification of fats and oils to produce fatty acid methyl ester (FAME), was immobilized on a cheap cotton membrane, and the conversion ratio of salad oil to biodiesel could reach up to 96% with the optimal reaction conditions.
Abstract: A lipase from Candida sp., suitable for transesterification of fats and oils to produce fatty acid methyl ester (FAME), was immobilized on a cheap cotton membrane, in this paper. The conversion ratio of salad oil to biodiesel could reach up to 96% with the optimal reaction conditions. Continuous reaction in a fixed bed reactor was also investigated. A three-step transesterification with methanol (methanolysis) of oil was conducted by using a series of nine columns packed with immobilized Candida sp. 99–125 lipase. As substrate of the first reaction step, plant or waste oil was used together with 1/3 molar equivalent of methanol against total fatty acids in the oil. Mixtures of the first- and second-step eluates and 1/3 molar equivalent of methanol were used for the second- and third-reaction steps. A hydrocyclone was used in order to on-line separate the by-product glycerol after every 1/3 molar equivalent of methanol was added. Petroleum ether was used as solvent (3/2, v/v of oil) and the pump was operated with a flow rate of 15 L/h giving an annual throughput of 100 t. The final conversion ratio of the FAME from plant oil and waste oil under the optimal condition was 90% and 92%, respectively. The life of the immobilized lipase was more than 10 days. This new technique has many strongpoints such as low pollution, environmentally friendly, and low energy costs.
TL;DR: In this paper, an environmentally benign process was developed for the production of biodiesel from jatropha curcas oil using a heterogeneous solid super base catalyst, calcium oxide, and the results showed that the base strength of calcium oxide was more than 26.5 after dipping in ammonium carbonate solution followed by calcination.
TL;DR: In this paper, the XRD, IR and Hammett indicator method were employed for the catalyst characterization and the results showed the activity of the catalysts was correlated with their basicity.
Abstract: Biodiesel was produced by transesterification of soybean oil with methanol using ZnO loaded with KF as a solid base catalyst. It was found that the catalyst with 15 wt.% KF loading and calcined at 873 K showed the optimum activity. XRD, IR and Hammett indicator method were employed for the catalyst characterization. The results showed the activity of the catalysts was correlated with their basicity. The influence of various reaction variables on the conversion was also discussed.
TL;DR: In this article, the continuous production of biodiesel (fatty acid methyl esters) by the transesterification reaction of coconut oil and palm kernel oil was studied in supercritical methanol without using any catalyst.
Abstract: The continuous production of biodiesel (fatty acid methyl esters) by the transesterification reaction of coconut oil and palm kernel oil was studied in supercritical methanol without using any catalyst. Experiments were carried out in a tubular flow reactor, and reactions were studied at 270, 300, and 350 °C at a pressure of 10 and 19 MPa with various molar ratios of methanol-to-oils from 6 to 42. It was found that the best condition to produce methyl esters from coconut oil and palm kernel oil was at a reaction temperature of 350 °C, molar ratio of methanol-to-vegetable oil of 42, and space time 400 s. The % methyl ester conversions were 95 and 96 wt % for coconut oil and palm kernel oil, respectively. The regression models by the least-squares method were adequate to predict % methyl ester conversion with temperature, molar ratio of methanol-to-oil, and space time as the main effects. The produced methyl ester fuel properties met the specification of the ASTM biodiesel standards.
TL;DR: In this article, a catalyst-free conjugate addition of thiols to α,β-unsaturated carbonyl compounds in water was reported, which constitutes an easy, highly efficient and green synthesis of β-sulfido carbonyls.
TL;DR: In this paper, the transesterification reaction occurs between methanol adsorbed on a magnesium oxide free basic site and ethyl acetate or the glyceride from the liquid phase.
Abstract: A heterogeneous magnesium oxide catalyst is a good alternative for homogeneous catalysts for the transesterification of alkyl esters for the production of fine-chemicals as well as for the production of biodiesel. The transesterification of ethyl acetate with methanol was used as a model reaction to simulate fine-chemical production in a batch slurry reactor at industrial conditions. The transesterification of triolein with methanol to methyl oleate was chosen to simulate continuous production of biodiesel from rapeseed oil. A kinetic model based on a three-step ‘Eley–Rideal’ type of mechanism in the liquid phase was used in both process simulations. The transesterification reaction occurs between methanol adsorbed on a magnesium oxide free basic site and ethyl acetate or the glyceride from the liquid phase. Methanol adsorption is assumed to be rate-determining in both processes. Activity coefficients were required to account for the significant non-ideality of the reaction mixture in the simulations of both processes. The simulations indicate that a production of 500 tonnes methyl acetate per year can be reached at ambient temperature in a batch reactor of 10 m 3 containing 5 kg of MgO catalyst, and that a continuous production of 100,000 tonnes of biodiesel per year can be achieved at 323 K in a continuous stirred reactor of 25 m 3 containing 5700 kg of MgO catalyst. Although various assumptions and simplifications were made in these explorative simulations the assumptions concerning the reaction kinetics used, the results indicate that for both processes a heterogeneous magnesium oxide catalyst shows promising potential as a viable industrial scale alternative.
TL;DR: In this article, the transesterification of ethyl acetate with methanol over magnesium oxide as solid base catalyst was investigated, and a kinetic model was developed based on a three-step Eley-Rideal mechanism applied in liquid phase, describing the experimental data over a range of experimental conditions.
Abstract: The transesterification of ethyl acetate with methanol over magnesium oxide as solid base catalyst was investigated. Intrinsic kinetic data have been obtained in a perfectly mixed slurry batch reactor. The influence of the temperature (283–323 K) and the initial methanol to ethyl acetate molar ratio (M/E: from 0.1 to 10) was investigated over a broad ethyl acetate conversion range (1–95%). A kinetic model was developed based on a three-step ‘Eley–Rideal’ type of mechanism applied in liquid phase, describing the experimental data over the investigated range of experimental conditions. Transesterification reaction occurs between methanol adsorbed on a magnesium oxide free basic site and ethyl acetate from the liquid phase. Methanol adsorption is assumed to be rate-determining. Other models derived from other mechanisms were rejected based on statistical analysis, mechanistic considerations and physicochemical interpretation of the parameters. The calculation of activity coefficients accounting for non-ideality had to be incorporated in the parameter estimation procedure.
TL;DR: In this paper, the transesterification reactions of castor oil with ethanol and methanol as transterification agents were studied in the presence of several classical catalytic systems and the effects of the nature of the alcohol and catalyst on the yields of monoalkyl fatty acid esters were evaluated.
Abstract: The transesterification reactions of castor oil with ethanol and methanol as transesterification agents were studied in the presence of several classical catalytic systems. The effects of the nature of the alcohol and catalyst on the yields of monoalkyl fatty acid esters were evaluated. The results indicate that biodiesel can be obtained by transesterification of castor oil using either ethanol or methanol as the transesterification agent. Similar yields of fatty acid esters may be obtained following ethanolysis or methanolysis; however, the reaction times required to attain them are very different, with methanolysis being much more rapid.
TL;DR: In this article, the catalytic properties of CeO 2 catalysts in direct synthesis of dimethyl carbonate (DMC) from CH 3 OH and CO 2 were investigated, and the formation rate of DMC over the catalysts calcined at 873 K and above was almost proportional to the surface area of catalysts.
TL;DR: In this article, a novel application of Fe-Zn double-metal cyanide (DMC) complexes as solid catalysts in the preparation of fatty acid alkyl esters (biodiesel/biolubricants) from vegetable oils is reported.
Abstract: A novel application of Fe–Zn double-metal cyanide (DMC) complexes as solid catalysts in the preparation of fatty acid alkyl esters (biodiesel/biolubricants) from vegetable oils is reported. The catalysts are hydrophobic (no H 2 O adsorption at reaction temperatures) and contain only Lewis acidic sites (NH 3 and pyridine adsorption). Bronsted acid sites are absent (absence of 1546 and 1639 cm −1 bands on adsorption of pyridine). Basic sites are also absent (no CO 2 adsorption). Unlike the homogeneous or other solid catalysts (like ZnO–Al 2 O 3 , for example), the Fe–Zn, DMC catalysts are highly active even for the simultaneous transesterification of triglycerides and esterification of the free fatty acids (FFA) present in unrefined and waste cooking oils as well as non-edible oils. They are also tolerant of water, probably, due to their surface hydrophobicity. A relationship between the transesterification activity and the concentration of strong Lewis acid sites has been observed. Coordinatively unsaturated Zn 2+ ions in the structure of the Fe–Zn complex are the probable active sites.
TL;DR: In this article, the transesterification of karanja oil with methanol was carried out using solid basic catalysts, and the reaction conditions, such as catalyst concentration, reaction temperature and molar ratio, were optimized with the solid basic Li/CaO catalyst.
Abstract: The transesterification of karanja oil with methanol was carried out using solid basic catalysts. Alkali metal-impregnated calcium oxide catalysts, due to their strong basicity, catalyze the transesterification of triacylglycerols. The alkali metal (Li, Na, K)-doped calcium oxide catalysts were prepared and used for the transesterification of karanja oil containing 0.48-5.75% of free fatty acids (FFA). The reaction conditions, such as catalyst concentration, reaction temperature and molar ratio of methanol/oil, were optimized with the solid basic Li/CaO catalyst. This catalyst, at a concentration of 2 wt-%, resulted in 94.9 wt-% of methyl esters in 8 h at a reaction temperature of 65 °C and a 12 : 1 molar ratio of methanol to oil, during methanolysis of karanja oil having 1.45% FFA. The yield of methyl esters decreased from 94.9 to 90.3 wt-% when the FFA content of karanja oil was increased from 0.48 to 5.75%. The performance of this catalyst was not significantly affected in the presence of a high FFA content up to 5.75%. The catalytic activities of Na/CaO and K/CaO were also studied at the optimized reaction conditions. In these two cases, the reaction initially proceeds slowly, however, leading to similar yields as in the case of Li/CaO after 8 h of reaction time. The purified karanja methyl esters have an acid value of 0.36 mg KOH/g and an ester content of 98.6 wt-%, which satisfy the American as well as the European specifications for biodiesel in terms of acid value and ester content.
TL;DR: Amorphous zirconia catalysts, titanium-, aluminum-, and potassium-doped Zirconias, were used in the transesterification of soybean oil with methanol at 250°C, and the esterification of n-octanoic acid with methenol at 175-200°C.
Abstract: Amorphous zirconia catalysts, titanium-, aluminum-, and potassium-doped zirconias, were prepared and evaluated in the transesterification of soybean oil with methanol at 250 °C, and the esterification of n-octanoic acid with methanol at 175–200 °C. Titanium- and aluminum-doped zirconias are promising solid catalysts for the production of biodiesel fuels from soybean oil because of their high performance, with over 95% conversion in both of the esterifications.
TL;DR: In this article, a process to convert Jojoba oil-wax to biodiesel by transesterification with methanol, catalysed with sodium methoxide (1.5% of the oil), was described.
Abstract: The Jojoba oil-wax is extracted from the seeds of the Jojoba ( Simmondsia chinensis Link Schneider), a perennial shrub that grows in semi desert areas in some parts of the world. The main uses of Jojoba oil-wax are in the cosmetics and pharmaceutical industry, but new uses could arise related to the search of new energetic crops. This paper summarizes a process to convert the Jojoba oil-wax to biodiesel by transesterification with methanol, catalysed with sodium methoxide (1 wt% of the oil). The transesterification reaction has been carried out in an autoclave at 60 °C, with a molar ratio methanol/oil 7.5:1, and vigorous stirring (600 rpm), reaching a quantitative conversion of the oil after 4 h. The separation of the fatty acid methyl esters (the fraction rich in FAME, 79% FAME mixture; 21% fatty alcohols; 51% of methyl cis -11-eicosenoate) from the fatty alcohols rich fraction (72% fatty alcohols; 28% FAME mixture; 26% of cis -11-eicosen-1-ol, 36% of cis -13-docosen-1-ol) has been accomplished in a single crystallization step at low temperature (−18 °C) from low boiling point petroleum ether. The fraction rich in FAME has a density (at 15 °C), a kinematic viscosity (at 40 °C), a cold filter plugging point and a high calorific value in the range of the European standard for biodiesel (EN 14214).
TL;DR: In this article, the authors used ultrasonication to achieve a yield in excess of 99% in a remarkably short time duration of 5 min or less in comparison to 1 h or more using conventional batch reactor systems.
Abstract: There is an increasing demand for alternative fuels that are environmentally friendly, especially because of the fact that crude petroleum reserves are dwindling. Also, research on alternative fuels is essential for increased energy security. Biodiesel is a renewable, biodegradable, and nontoxic fuel. At present, biodiesel is primarily produced in batch reactors in which the required energy is provided by heating accompanied by mechanical mixing. Alternatively, ultrasonic processing is an effective way to attain required mixing while providing the necessary activation energy. We found that, using ultrasonication, a biodiesel yield in excess of 99% can be achieved in a remarkably short time duration of 5 min or less in comparison to 1 h or more using conventional batch reactor systems.