Showing papers on "Transesterification published in 2007"
TL;DR: In this article, a response surface methodology (RSM) based on central composite rotatable design (CCRD) was used to optimize the three important reaction variables (methanol quantity, acid concentration, and reaction time) for reduction of free fatty acid (FFA) content of the oil to around 1% as compared to methanol quantity (M′) and reaction times (T′), and for carrying out transesterification of the pretreated oil.
Abstract: Response surface methodology (RSM) based on central composite rotatable design (CCRD) was used to optimize the three important reaction variables—methanol quantity (M), acid concentration (C) and reaction time (T) for reduction of free fatty acid (FFA) content of the oil to around 1% as compared to methanol quantity (M′) and reaction time (T′) and for carrying out transesterification of the pretreated oil. Using RSM, quadratic polynomial equations were obtained for predicting acid value and transesterification. Verification experiments confirmed the validity of both the predicted models. The optimum combination for reducing the FFA of Jatropha curcas oil from 14% to less than 1% was found to be 1.43% v/v H2SO4 acid catalyst, 0.28 v/v methanol-to-oil ratio and 88-min reaction time at a reaction temperature of 60 °C as compared to 0.16 v/v methanol-to-pretreated oil ratio and 24 min of reaction time at a reaction temperature of 60 °C for producing biodiesel. This process gave an average yield of biodiesel more than 99%. The fuel properties of jatropha biodiesel so obtained were found to be comparable to those of diesel and confirming to the American and European standards.
843 citations
TL;DR: In this article, the role of H 2 O and CO 2 in the degradation of catalytic performance by contact with room air, the stability of the catalyst by reutilization in successive runs and the heterogeneous character of the catalytic reaction was investigated.
Abstract: This work studies the activity of activated CaO as a catalyst in the production of biodiesel by transesterification of triglycerides with methanol. Three basic aspects were investigated: the role of H 2 O and CO 2 in the deterioration of the catalytic performance by contact with room air, the stability of the catalyst by reutilization in successive runs and the heterogeneous character of the catalytic reaction. The characterization by X-ray diffraction (XRD), evolved gas analysis by mass spectrometry (EGA-MS) during heating the sample under programmed temperature, X-ray photoelectron (XPS) and Fourier transform-infrared (FT-IR) spectroscopies allowed to concluding that CaO is rapidly hydrated and carbonated by contact with room air. Few minutes are enough to chemisorb significant amount of H 2 O and CO 2 . It is demonstrated that the CO 2 is the main deactivating agent whereas the negative effect water is less important. As a matter of fact the surface of the activated catalyst is better described as an inner core of CaO particles covered by very few layers of Ca(OH) 2 . The activation by outgassing at temperatures ≥973 K are required to revert the CO 2 poisoning. The catalyst can be reused for several runs without significant deactivation. The catalytic reaction is the result of the heterogeneous and homogeneous contributions. Part of the reaction takes place on basic sites at the surface of the catalyst, the rest is due to the dissolution of the activated CaO in methanol that creates homogeneous leached active species.
730 citations
TL;DR: In this paper, a two-step catalyzed process was adopted to prepare biodiesel from waste cooking oil whose acid value was 75.92 − 0.036 ǫmgKOH/g.
483 citations
TL;DR: In this article, the transesterification reaction of used frying oil by means of ethanol, using sodium hydroxide, potassium hydroxides, sodium methoxide, and potassium methoxide as catalysts, was studied.
415 citations
TL;DR: The transesterification reactions of triolein with ethanol using various ion-exchange resin catalysts were conducted to produce ethyl oleate as a biodiesel using an expanded bed reactor packed with the most active resin.
392 citations
TL;DR: The two-phase membrane reactor was particularly useful in removing unreacted canola oil from the FAME product yielding high purity biodiesel and shifting the reaction equilibrium to the product side.
375 citations
TL;DR: In this paper, the performance of transesterification of soybean oil to biodiesel using SrO as a solid base catalyst was studied and the reaction mechanism was proposed and the separate effects of reaction temperature, molar ratio of methanol to oil, mass ratio of catalyst to oil and repeated experiments were investigated.
373 citations
TL;DR: In this article, a system for continuous transesterification of vegetable oil using supercritical methanol was developed using a tube reactor, and a new technology was proposed to reduce the loss caused by the side reactions of unsaturated fatty acid methyl esters at high reaction temperature.
334 citations
TL;DR: In this article, the monoethyl esters of the long chain fatty acids (biodiesel) were prepared by alcoholysis of Jatropha oil, a non-edible oil, by a lipase.
334 citations
TL;DR: In this article, an acid-promoted direct methanolysis of cellular biomass of oleaginous yeasts and filamentous fungi was used to achieve up to 98% yield with reaction conditions of 70 degrees C, under ambient pressure for 20h and a dried biomass to methanol ratio 1:20 (w/v).
Abstract: Biodiesel is a renewable fuel conventionally prepared by transesterification of pre-extracted vegetable oils and animal fats of all resources with methanol, catalyzed by strong acids or bases. This paper reports on a novel biodiesel production method that features acid-promoted direct methanolysis of cellular biomass of oleaginous yeasts and filamentous fungi. The process was optimized for tuning operation parameters, such as methanol dosage, catalyst concentration, reaction temperature and time. Up to 98% yield was reached with reaction conditions of 70 degrees C, under ambient pressure for 20h and a dried biomass to methanol ratio 1:20 (w/v) catalyzed by either 0.2 mol L-1 H2SO4 or 0.4 mol L-1 HCl. Cetane numbers for these products were estimated to range from 56 to 59. This integrated method is thus effective and technically attractive, as dried microbial biomass as feedstocks omits otherwise tedious and time-consuming oil extraction processes.
320 citations
TL;DR: In this paper, the conceptual design of a production process in which waste cooking oil is converted via supercritical transesterification with methanol to methyl esters (biodiesel) is described.
Abstract: This paper describes the conceptual design of a production process in which waste cooking oil is converted via supercritical transesterification with methanol to methyl esters (biodiesel). Since waste cooking oil contains water and free fatty acids, supercritical transesterification offers great advantage to eliminate the pre-treatment capital and operating cost. A supercritical transesterification process for biodiesel continuous production from waste cooking oil has been studied for three plant capacities (125,000; 80,000 and 8000 tonnes biodiesel/year). It can be concluded that biodiesel by supercritical transesterification can be scaled up resulting high purity of methyl esters (99.8%) and almost pure glycerol (96.4%) attained as by-product. The economic assessment of the biodiesel plant shows that biodiesel can be sold at US$ 0.17/l (125,000 tonnes/year), US$ 0.24/l (80,000 tonnes/year) and US$ 0.52/l for the smallest capacity (8000 tonnes/year). The sensitive key factors for the economic feasibility of the plant are: raw material price, plant capacity, glycerol price and capital cost. Overall conclusion is that the process can compete with the existing alkali and acid catalyzed processes. Especially for the conversion of waste cooking oil to biodiesel, the supercritical process is an interesting technical and economical alternative.
TL;DR: In this article, Sunflower seed oil was subjected to the transesterification reaction with calcium oxide (CaO) in supercritical methanol for obtaining biodiesel for obtaining soybean oil to alcohol.
TL;DR: In this article, a two-stage (acid and alkali catalyzed) method was used for biodiesel synthesis and more than 90% ester was obtained when two stage method is used compared to ∼ 50% esters in single stage alkaline catalyst.
TL;DR: In this article, a series of NaOH catalysts supported on alumina for the transesterification with methanol of refined sunflower oil have been investigated and the performance of the supported catalysts has been compared with that of homogeneous NaOH.
TL;DR: This study consists of the development and optimisation of the potassium hydroxide-catalysed synthesis of fatty acid methyl esters (biodiesel) from sunflower oil, using second-order models to predict biodiesel purity and yield as a function of temperature, catalyst concentration and methanol:vegetable oil molar ratio.
TL;DR: A series of insoluble heteropolytungstate (H3PW12O40 HPW) salts were synthesized and characterized using a range of bulk and surface sensitive probes including N2 porosimetry, powder XRD, FTIR, XPS, 31P MAS NMR, and NH3 calorimetry as mentioned in this paper.
TL;DR: In this article, the synthesis of biodiesel from edible oils like palm oil and groundnut oil and from crude non-edible oils like Pongamia pinnata and Jatropha curcas was investigated in supercritical methanol and ethanol without using any catalyst.
TL;DR: In this article, a batch esterification of palm fatty acid methyl ester (FAME) from PFAD having high free fatty acids (FFA) was investigated, and the final FAME product met with the Thai biodiesel quality standard.
Abstract: Production of fatty acid methyl ester (FAME) from palm fatty acid distillate (PFAD) having high free fatty acids (FFA) was investigated in this work. Batch esterifications of PFAD were carried out to study the influence of: including reaction temperatures of 70–1001C, molar ratios of methanol to PFAD of 0.4:1–12:1, quantity of catalysts of 0–5.502% (wt of sulfuric acid/wt of PFAD) and reaction times of 15–240 min. The optimum condition for the continuous esterification process (CSTR) was molar ratio of methanol to PFAD at 8:1 with 1.834 wt% of H2SO4 at 701C under its own pressure with a retention time of 60 min. The amount of FFA was reduced from 93 wt% to less than 2 wt% at the end of the esterification process. The FAME was purified by neutralization with 3 M sodium hydroxide in water solution at a reaction temperature of 801C for 15 min followed by transesterification process with 0.396 M sodium hydroxide in methanol solution at a reaction temperature of 651C for 15 min. The final FAME product met with the Thai biodiesel quality standard, and ASTM D6751-02. r 2007 Elsevier Ltd. All rights reserved.
TL;DR: In this paper, the use of heterogeneous base catalysts derived from Mg-Al hydrotalcite was investigated for the conversion of poultry lipids to biodiesel.
Abstract: The synthesis of biodiesel from poultry fats provides a way to convert the by-product of a renewable resource to a very important value-added biofuel. In this work, the use of heterogeneous base catalysts derived from Mg–Al hydrotalcite was investigated for the conversion of poultry lipids to biodiesel. This solid base showed high activity for triglyceride (TG) transesterification with methanol without signs of catalyst leaching. Catalytic performance was significantly affected by pretreatment and operating conditions. Calcination at optimum temperature was key in obtaining the highest catalyst activities. Rehydration of the calcined catalyst before reaction using wet nitrogen decreased catalytic activity for the transesterification of poultry fat, opposite to what has been reported for condensation reactions. Also, methanol had to be contacted with the catalyst before reaction; otherwise, catalyst activity was seriously impaired by strong adsorption of triglycerides on the active sites. Both temperature (60–120 °C) and methanol-to-lipid molar ratio (6:1–60:1) affected the reaction rate in a positive manner. The use of a co-solvent (hexane, toluene, THF), however, gave rise to a change in TG conversion profile which cannot be explained solely by a dilution effect. The catalyst underwent significant deactivation during the first reaction cycle probably due to deactivation of the strongest base sites. Subsequent reaction cycles showed stable activity. By re-calcination in air, complete catalyst regeneration was achieved.
TL;DR: In this article, the authors provide a thermo-analytical and physical-chemistry characterization of castor oil and biodiesel, and show that biodiesel data are very close to the volatilization temperatures of conventional diesel.
Abstract: The castor oil seed has 47–49% of oil. Biodiesel obtained from castor oil has a lower cost compared to the ones obtained from other oils, as due its solvability in alcohol transesterification occurs without heating. The use of biodiesel will allow a reduction on the consumption of petroleum-derived fuels minimizing the harmful effects on the environment. This work wants to provide a thermoanalytical and physical-chemistry characterization of castor oil and biodiesel. Biodiesel was obtained with methyl alcohol and characterized through several techniques. Gas chromatography indicated methyl ester content of 97.7%. The volatilization of biodiesel starts and finishes under inferior temperatures than the beginning and final volatilization temperatures of castor oil. Biodiesel data are very close to the volatilization temperatures of conventional diesel.
TL;DR: In this article, the preliminary results of using alkaline earth metal-doped zinc oxide as a heterogeneous catalyst for transesterification of soybean oil were reported, where the highest catalytic activity was obtained with ZnO loaded with 2.5mmol Sr(NO 3 ) 2 /g, followed by calcination at 873k for 5h.
TL;DR: A review of the literature regarding both catalytic and non-catalytic methods and catalysts used in the production of biodiesel can be found in this article, where the authors discuss the importance of developing a single catalyst for both esterification and transesterification reactions.
Abstract: Biodiesel is a renewable substitute fuel for petroleum diesel fuel which is made from nontoxic, biodegradable, renewable sources such as refined and used vegetable oils and animal fats. Biodiesel is produced by transesterification in which oil or fat is reacted with a monohydric alcohol in the presence of a catalyst. The process of transesterification is affected by the mode of reaction, molar ratio of alcohol to oil, type of alcohol, nature and amount of catalysts, reaction time, and temperature. Various studies have been carried out using different oils as the raw material and different alcohols (methanol, ethanol, butanol), as well as different catalysts, notably homogeneous ones such as sodium hydroxide, potassium hydroxide, sulfuric acid, and supercritical fluids or enzymes such as lipases. Recent research has focused on the application of heterogeneous catalysts to produce biodiesel, because of their environmental and economic advantages. This paper reviews the literature regarding both catalytic and noncatalytic production of biodiesel. Advantages and disadvantages of different methods and catalysts used are discussed. We also discuss the importance of developing a single catalyst for both esterification and transesterification reactions.
TL;DR: In this paper, a continuous-flow preparation of biodiesel using a commercially available scientific microwave apparatus offers a fast, easy route to this valuable biofuel, allowing for the reaction to be run under atmospheric conditions and performed at flow rates of up to 7.2 L/min using a 4 L reaction vessel.
Abstract: The continuous-flow preparation of biodiesel using a commercially available scientific microwave apparatus offers a fast, easy route to this valuable biofuel. The methodology allows for the reaction to be run under atmospheric conditions and performed at flow rates of up to 7.2 L/min using a 4 L reaction vessel. It can be utilized with new or used vegetable oil with methanol and a 1:6 molar ratio of oil/alcohol. Energy consumption calculations suggest that the continuous-flow microwave methodology for the transesterification reaction is more energy-efficient than using a conventional heated apparatus.
TL;DR: The transesterification of soybean oil with methanol to methyl esters was carried out using NaX zeolites loaded with KOH as a solid base catalyst with best result obtained with NaXZeolite loaded with 10% KOH.
TL;DR: In this article, the catalytic activity of the strong solid acid tungstated zirconia (WZ) was studied for the esterification of acetic acid and the transesterification of triacetin (a synthetic triglyceride in the liquid phase) with methanol.
TL;DR: In this paper, a fundamental transesterification kinetic study was carried out using triacetin and methanol on Nafion® (perfluorinated-based ion exchange resin) catalysts.
TL;DR: In this article, the authors used n-hexane, methanol, acetone, and supercritical CO2 solvents to extract lipids from sewage sludge.
Abstract: Municipal wastewater treatment plants in the USA produce over 6.2 × 106 t of dried sewage sludge every year. This microorganism-rich sludge is often landfilled or used as fertilizer. Recent restrictions on the use of sewage sludge, however, have resulted in increased disposal problems. Extraction of lipids from sludge yields an untapped source of cheap feedstock for biodiesel production. Solvents used for extraction in this study include n-hexane, methanol, acetone, and supercritical CO2. The gravimetric yield of oil was low for nonpolar solvents, but use of polar solvents gave a considerably increased yield; however, the percentage of saponifiable material was less. Extraction of lipids with a mixture of n-hexane, methanol, and acetone gave the largest conversion to biodiesel compared with other solvent systems, 4.41% based on total dry weight of sludge. In situ transesterification of dried sludge resulted in a yield of 6.23%. If a 10% dry weight yield of fatty acid methyl esters is assumed, the amount of biodiesel available for production in the USA is 1.4 × 106 m3/year. Outfitting 50% of municipal wastewater plants for lipid extraction and transesterification could result in enough biodiesel production to replace 0.5% of the national petroleum diesel demand (0.7 × 106 m3).
TL;DR: In this paper, nano-MgO was added from 0.5 wt% to 3 wt%, and the transesterification rate increased evidently, while the catalyst content was further enhanced to 5 wt%.
TL;DR: In this article, the effects of methanol and palm oil concentrations on the rate of their enzymatic transesterification were investigated and a mathematical model was developed from a proposed kinetic mechanism and was used to identify the regions where the effect of inhibition by both substrates arised.
TL;DR: In this article, an ion exchange method was used to synthesize the biodiesel (fatty acid methyl esters, FAME), which was applied as the ion exchange precursor to incorporate La ion into zeolite beta.