Silica-bonded N-propyl sulfamic acid used as a heterogeneous catalyst for transesterification of soybean oil with methanol

The transesterification of soybean oil with methanol was carried out, to produce biodiesel, over silica-bonded N-propyl sulfamic acid in a heterogeneous manner. Results showed that a maximum conversion of 90.5% was achieved using a 1:20 M ratio of soybean oil to methanol and a catalyst amount of 7.5 wt.% at 423 K for 60 h. It was found that the free fatty acid (FFA) and water present in the feedstock had no significant influence on the catalytic activity to the transesterification reaction. Besides, the catalyst also showed activities towards the esterification reaction of FFAs, in terms of the FFA conversion of 95.6% at 423 K for 30 h. Furthermore, the catalyst could be recovered with a better reusability.     

Microwave assisted alkali-catalyzed transesterification of Pongamia pinnata seed oil for biodiesel production

In this study, microwave assisted transesterification of Pongamia pinnata seed oil was carried out for the production of biodiesel. The experiments were carried out using methanol and two alkali catalysts i.e., sodium hydroxide (NaOH) and potassium hydroxide (KOH). The experiments were carried out at 6:1 alcohol/oil molar ratio and 60 °C reaction temperature. The effect of catalyst concentration and reaction time on the yield and quality of biodiesel was studied. The result of the study suggested that 0.5% sodium hydroxide and 1.0% potassium hydroxide catalyst concentration were optimum for biodiesel production from P. pinnata oil under microwave heating. There was a significant reduction in reaction time for microwave induced transesterification as compared to conventional heating.     

Ultrasonic monitoring of glycerol settling during transesterification of soybean oil

A low-intensity ultrasonic measurement system was used to monitor the products of transesterification of soybean oil in methanol to FAME (biodiesel). The byproducts of the transesterification reaction are methyl esters, glycerol and other products. During the transesterification reaction, the glycerol, having a higher density than the methyl ester, settles at the bottom of the reaction vessel. The aim of this study was to measure the glycerol deposition rate during transesterification and to assess the reaction rate and end time. Soybean oil was converted into biodiesel at four temperature levels. The amount of catalyst (KOH) used in the transesterification reactions was determined by titration. The ultrasonic waveforms captured during the reaction were recorded and analyzed automatically. The ultrasonic system monitored the effects of reaction temperatures on the glycerol settling rate and the reaction end times. The ultrasonic measurement of glycerol settling would be a useful non-destructive method for evaluating the effects of parameters such as catalyst amount, mixing time and temperature on transesterification reactions.     

Transesterification of canola oil in mixed methanol/ethanol system and use of esters as lubricity additive

Transesterification of canola oil was carried out with methanol, ethanol, and various mixtures of methanol/ethanol, keeping the molar ratio of oil to alcohol 1:6 and using KOH as a catalyst. Mixtures of alcohol increased the rate of transesterification reaction and produced methyl as well as ethyl esters. The increased rate was result of better solubility of oil in reaction mixture due to better solvent properties of ethanol than methanol and equilibrium due to methanol. With 3:3 molar ratio of methanol to ethanol {MEE (3:3)} the amount of ethyl ester formed was 50% that of methyl ester. Properties (acid value, viscosity, density) of all esters including mixed esters were within the limits of ASTM standards. Lubricities of these esters are in the order: ethyl ester>methyl ethyl ester>methyl ester.     

Process optimization for biodiesel production from mahua (Madhuca indica) oil using response surface methodology

A central composite rotatable design was used to study the effect of methanol quantity, acid concentration and reaction time on the reduction of free fatty acids content of mahua oil during its pretreatment for making biodiesel. All the three variables significantly affected the acid value of the product, methanol being the most effective followed by reaction time and acid catalyst concentration. Using response surface methodology, a quadratic polynomial equation was obtained for acid value by multiple regression analysis. Verification experiments confirmed the validity of the predicted model. The optimum combinations for reducing the acid level of mahua oil to less than 1% after pretreatment was 0.32 v/v methanol-to-oil ratio, 1.24% v/v H2SO4 catalyst and 1.26 h reaction time at 60 degrees C. After the pretreatment of mahua oil, transesterification reaction was carried out with 0.25 v/v methanol-to-oil ratio (6:1 molar ratio) and 0.7% w/v KOH as an alkaline catalyst to produce biodiesel. The fuel properties of mahua biodiesel so obtained complied the requirements of both the American and European standards for biodiesel.     

K_2CO_3/γ-Al_2O_3催化棕榈油和甲醇酯交换反应制备生物柴油

采用浸渍法制备K2CO3/γ-Al2O3负载型固体碱催化剂,用X线衍射(XRD)和热质量分析法(DSC-TGA)表征催化剂的物化性质,考察催化剂在棕榈油和甲醇酯交换制备生物柴油中的反应性能。结果表明:活性组分已成功负载到载体γ-Al2O3上,且在高温焙烧过程中K2CO3和γ-Al2O3之间产生了相互作用;在K2CO3负载量22.6%、醇油摩尔比12∶1、反应时间3h、催化剂质量分数3%、反应温度65℃的条件下,甲酯产率最高可达91.6%。     

Ethyl ester production by homogeneous alkaline transesterification: influence of the catalyst

In this work, the process for ethyl ester production is studied using refined sunflower oil, and NaOH, KOH, CH₃ONa, and CH₃OK, as catalysts. In all cases, the reaction is carried out in a single reaction step. The best conversion is obtained when the catalyst is either sodium methoxide or potassium methoxide. We found that during the transesterification with ethanol, soap formation is more important than in the case of methanol. The saponification reaction consumes an important fraction of the catalyst. The amount of catalyst consumed by this reaction is 100% in the case of using hydroxides as catalyst (KOH or NaOH), and 25%, and 28% when using CH₃ONa and CH₃OK as catalysts, respectively. Ethanol increases the catalyst solubility in the oil-ethyl ester phase, thus accelerating the saponification reaction.It is possible to obtain high conversions in a one-step reaction, with a total glycerine concentration close to 0.25%.     

Acceleration of catalytic activity of calcium oxide for biodiesel production

This research was aimed at studying the acceleration of the catalytic activity of calcium oxide (CaO) for developing an effective heterogeneous catalyst for biodiesel production by the transesterification of plant oil with methanol. CaO was activated by pretreatment with methanol and was used for the transesterification reaction. The activation and transesterification reaction conditions were examined. The obtained optimal reaction conditions were 0.1-g CaO, 3.9-g methanol, 15-g rapeseed oil, and 1.5-h activation time at room temperature that provided methyl ester in approximately 90% yield within a reaction time of 3h at 60 degrees C. The activation mechanism was also investigated, and the proposed mechanism is as follows. By pretreatment with methanol, a small amount of CaO gets converted into Ca(OCH(3))(2) that acts as an initiating reagent for the transesterification reaction and produces glycerin as a by-product. Subsequently, a calcium-glycerin complex, formed due to the reaction of CaO with glycerin, functions as the main catalyst and accelerates the transesterification reaction.     

Ethanesulfonic acid-based esterification of industrial acidic crude palm oil for biodiesel production

An industrial grade acidic crude palm oil (ACPO) pre-treatment process was carried out using ethanesulfonic acid (ESA) as a catalyst in the esterification reaction. ESA was used in different dosages to reduce free fatty acid (FFA) to a minimum level for the second stage of biodiesel production via alkaline transesterification reaction. Different process operating conditions were optimized such as ESA dosage (0.25-3.5% wt/wt), methanol to ACPO molar ratio (1:1-20:1), reaction temperature (40-70 °C), and reaction time (3-150 min). This study revealed the potential use of abundant quantities of ACPO from oil palm mills for biodiesel production. The lab scale results showed the effectiveness of the pre-treatment process using ESA catalyst. Three consecutive catalyst recycling runs were achieved without significant degradation in its performance. Second and third reuse runs needed more reaction time to achieve the target level of FFA content. Esterification and transesterification using ESA and KOH respectively is proposed for biodiesel industrial scale production. The produced biodiesel meets the international standards specifications for biodiesel fuel (EN 14214 and ASTM D6751).     

Direct preparation of biodiesel from rapeseed oil leached by two-phase solvent extraction

A new method which coupled the two-phase solvent extraction (TSE) with the synthesis of biodiesel was studied. Investigations were carried out on transesterification of methanol with oil-hexane solution coming from TSE process in the presence of sodium hydroxide as the catalyst. Biodiesel (fatty acid methyl esters) were the products of transesterification. The influential factors of transesterification, such as reaction time, catalyst concentration, mole ratio of methanol to oil and reaction temperature were optimized. The results showed that the optimal reaction parameters were sodium hydroxide concentration 1.1% by weight of rapeseed oil, mole ratio of methanol to oil 9:1, reaction time 120 min, and reaction temperature 55-60 degrees C. Under these conditions, the TG conversion would rise up to 98.2%. Based on the new method, biodiesel production process could be simplified and the biodiesel cost could be reduced.     

Production of biodiesel and lactic acid from rapeseed oil using sodium silicate as catalyst

Biodiesel and lactic acid from rapeseed oil was produced using sodium silicate as catalyst. The transesterification in the presence of the catalyst proceeded with a maximum yield of 99.6% under optimized conditions [3% (w/w) sodium silicate, methanol/oil molar ratio 9/1, reaction time 60 min, reaction temperature 60 °C, and stirring rate 250 rpm]. After six consecutive transesterification reactions, the catalyst was collected and used for catalysis of the conversion of glycerol to lactic acid. A maximum yield of 80.5% was achieved when the reaction was carried out at a temperature of 300 °C for 90 min. Thus, sodium silicate is an effective catalyst for transesterification and lactic acid production from the biodiesel by-product, glycerol.     

Preparation of biodiesel from crude oil of Pongamia pinnata

Biodiesel was prepared from the non-edible oil of Pongamia pinnata by transesterification of the crude oil with methanol in the presence of KOH as catalyst. A maximum conversion of 92% (oil to ester) was achieved using a 1:10 molar ratio of oil to methanol at 60 degrees C. Tetrahydrofuran (THF), when used as a co-solvent increased the conversion to 95%. Solid acid catalysts viz. Hbeta-Zeolite, Montmorillonite K-10 and ZnO were also used for this transesterification. Important fuel properties of methyl esters of Pongamia oil (Biodiesel) compare well (Viscosity = 4.8 Cst @ 40 degrees C and Flash point = 150 degrees C) with ASTM and German biodiesel standards.     

Heterogeneous solid base nanocatalyst: preparation, characterization and application in biodiesel production

A solid base nanocatalyst was prepared by ZrO₂ loaded with C₄H₄O₆HK and investigated for transesterification of soybean oil with methanol to biodiesel. The obtained nanocatalyst was characterized by means of XRD, FTIR, TEM, TGA, N₂ adsorption-desorption measurements and the Hammett indicator method. TEM photograph showed that the nanocatalyst had granular and porous structures with particle sizes of 10-40 nm. The nanocatalyst had longer lifetime and maintained sustained activity after being used for five cycles. The separate effects of the molar ratio of methanol to oil, reaction temperature, nanocatalyst amount and reaction time were investigated. The experimental results showed that a 16:1 M ratio of methanol to oil, 6.0% catalyst, 60 °C reaction temperature and 2.0 h reaction time gave the best results and the biodiesel yield of 98.03% was achieved. Production of biodiesel has positive impact on the utilization of agricultural and forestry products.     

Production of biodiesel from Jatropha curcas L. oil catalyzed by SO₄²⁻/ZrO₂ catalyst: effect of interaction between process variables

This study reports the conversion of Jatrophacurcas L. oil to biodiesel catalyzed by sulfated zirconia loaded on alumina catalyst using response surface methodology (RSM), specifically to study the effect of interaction between process variables on the yield of biodiesel. The transesterification process variables studied were reaction temperature, reaction duration, molar ratio of methanol to oil and catalyst loading. Results from this study revealed that individual as well as interaction between variables significantly affect the yield of biodiesel. With this information, it was found that 4h of reaction at 150°C, methanol to oil molar ratio of 9.88 mol/mol and 7.61 wt.% for catalyst loading gave an optimum biodiesel yield of 90.32 wt.%. The fuel properties of Jatropha biodiesel were characterized and it indeed met the specification for biodiesel according to ASTM D6751.     

Two step ethanolysis: A simple and efficient way to improve the enzymatic biodiesel synthesis catalyzed by an immobilized–stabilized lipase from Thermomyces lanuginosus

In this study the immobilization and stabilization of a lipase from Thermomyces lanuginosus (TLL) on aldehyde-Lewatit (Lew-TLL) are described. TLL immobilization was rapid and over 90% of lipase activity was recovered after the immobilization. Lew-TLL was 10-fold more thermo stable than the commercial TLL preparation, Lipozyme TL-IM. The stabilized Lew-TLL was used for the enzymatic transesterification of ethanol and soybean oil. The transesterification was carried out following different strategies. First, with 7.5:1 molar ratio of ethanol:soybean oil, 15% immobilized enzyme and 4% water at 30 °C. In the presence of n-hexane, the transesterification reached 100% conversion, while in solvent-free system the yield was 75%. Second, at stoichiometric molar ratio, the yield was 70% conversion after 10 h of reaction in both systems. After this, transesterification was carried out by three stepwise additions of ethanol with a yield of 80% conversion, while a two step ethanolysis produced 100% conversion after 10 h of reaction in both solvent and solvent-free systems.     

Synthesis of methyl esters from palm (Elaeis guineensis) oil using cobalt doped MgO as solid oxide catalyst

The potential of Mg(x)Co(2-)(x)O(2) as heterogeneous reusable catalyst in transesterification of palm oil to methyl ester was investigated. The catalyst was prepared via co-precipitation of the metal hydroxides at different Mg-Co ratios. Mg(1.7)Co(0.3)O(2) catalyst was more active than Mg(0.3)Co(1.7)O(2) in the transesterification of palm oil with methanol. The catalysts calcined at temperature 300 °C for 4 h resulted in highly active oxides and the highest transesterification of 90% was achieved at methanol/oil molar ratio of 9:1, catalyst loading of 5.00 wt.%, reaction temperature of 150 °C and reaction time of 2 h. The catalyst could easily be removed from reaction mixture, but showed 50% decrease in activity when reused due to leaching of active sites.     

Transesterification of palm oil to methyl ester on activated carbon supported calcium oxide catalyst

In this study, methyl ester (ME) was produced by transesterification of palm oil (CPO) (cooking grade) using activated carbon supported calcium oxide as a solid base catalyst (CaO/AC). Response surface methodology (RSM) based on central composite design (CCD) was used to optimize the effect of reaction time, molar ratio of methanol to oil, reaction temperature and catalyst amount on the transesterification process. The optimum condition for CPO transesterification to methyl ester was obtained at 5.5 wt.% catalyst amount, 190 °C temperature, 15:1 methanol to oil molar ratio and 1 h 21 min reaction time. At the optimum condition, the ME content was 80.98%, which is well within the predicted value of the model. Catalyst regeneration studies indicate that the catalyst performance is sustained after two cycles.     

Transesterification of soybean oil using combusted oyster shell waste as a catalyst

Transesterification of soybean oil catalyzed by combusted oyster shell, which is waste material from shellfish farms, was examined. Powdered oyster shell combusted at a temperature above 700 degrees C, at which point the calcium carbonate of oyster shell transformed to calcium oxide, acted as a catalyst in the transesterification of soybean oil. On the basis of factorial design, the reaction conditions of catalyst concentration and reaction time were optimized in terms of the fatty acid methyl ester concentration expressed as biodiesel purity. Under the optimized reaction conditions of a catalyst concentration and reaction time of 25wt.%. and 5h, respectively, the biodiesel yield, expressed relative to the amount of soybean oil poured into the reaction vial, was more than 70% with high biodiesel purity. These results indicate oyster shell waste combusted at high temperature can be reused in biodiesel production as a catalyst.     

Influence of vegetable oils fatty-acid composition on biodiesel optimization

Biodiesel is an alternative fuel for diesel engines produced through transesterification of oleaginous feedstocks. To analyze the influence of the fatty-acid composition on biodiesel optimization, transesterification of several vegetable oils has been studied. Reactions were carried out in flasks filled with vegetable oils, heated to the reaction temperature and stirred at 1100 rpm. The reactions started when the methanol and potassium hydroxide solutions were added to the flasks. Concentration of catalyst, amount of methanol, reaction temperature and time were optimized using a factorial design and a surface response design. Also, a kinetics study was carried out to optimize the reaction time. Results showed that reaction parameters optimal values depend on the oil chemical and physical properties. It can be concluded from this field trial that the effect of both catalyst concentration and reaction time over the transesterification yield is greatly influenced by the saturation degree and fatty-acid chain length.     

Optimization of lipase-catalyzed biodiesel by response surface methodology

Biodiesel prepared by catalyzed mild transesterification has become of much current interest for bioenergy. The ability of a commercial immobilized lipase (Novo Industries--Bagsvaerd, Denmark) from Rhizomucor miehei (Lipozyme IM-77) to catalyze the transesterification of soybean oil and methanol was investigated in this study. Response surface methodology and 5-level-5-factor central composite rotatable design were employed to evaluate the effects on reaction time, temperature, enzyme amount, molar ratio of methanol to soybean oil, and added water content on percentage weight conversion to soybean oil methyl ester by transesterification. Based on ridge max analysis, the optimum synthesis conditions giving 92.2% weight conversion were: reaction time 6.3 h, temperature 36.5 degrees C, enzyme amount 0.9 BAUN (Batch Acidolysis Units NOVO), substrate molar ratio 3.4:1, and added water 5.8%.