Search

A convenient solvent-free technique was employed in the functionalization of Micelle-Templated Silica using Cashew Nut Shell Liquid (MTS-CNSL) as a template and magnesium nitrate as a precursor salt. Magnesium oxide species was highly dispersed in MTS-CNSL by manually grinding the precursor salt and the as-synthesized mesoporous silica followed by calcination. The resultant modified mesoporous silicas MgO/MTS-CNSL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR, N2 adsorption/desorption), and scanning electron microscopy/energy dispersive X-ray (SEM/EDX). MgO/MTS-CNSL (30) having small specific surface area of 16.7 m2/g and larger pore volume of 0.02 cm3/g, presented higher activity of 81.45% for jatropha oil under optimized conditions (200°C, 4 h, 36 : 1 methanol : oil ratio, 500 rpm, and 6% wt of catalyst). This method of catalyst development has an advantage of being highly energy- and time-efficient. [ABSTRACT FROM AUTHOR]

In the present study, a comparison of reaction kinetics for catalytic and non-catalytic transesterification processes using jatropha curcas oil has been evaluated. Optimization of reaction parameters was done using the response surface methodology (RSM) experimental design to establish the optimal parameters for the non-catalytic method. The optimal parameters for the catalytic methods were adopted from our previous published works. The study shows that the yield for non-catalytic method is lower compared to the catalytic methods. This might be attributed by the presence of poly-unsaturated fatty acids such as linoleic acid in jatropha oil which decompose easily at higher temperatures. The activation energies and methanol to oil ratios for catalytic and non-catalytic methods show that the latter is more energy and material consuming. However, the rate constants reveal that the non-catalytic method using supercritical methanol is faster than the catalytic methods. [ABSTRACT FROM AUTHOR]

Abstract: Cultivating microalgae for biodiesel production is a new and emerging research field that has the potential to revolutionize the renewable energy industries. However, up to now, comprehensive study on the conversion efficiency of microalgae lipid to biodiesel is still inadequate. In the present study, reaction optimization studies were carried out to convert high viscosity microalgae lipid (extracted from Chlorella vulgaris) to biodiesel by using sulfuric acid (H2SO4) as catalyst. In order to attain 95% fatty acid methyl ester (FAME) content, the optimized reaction conditions were as follows: methanol to lipid molar ratio of 180, catalyst concentration of 35wt.%, temperature of 60°C and reaction time of 6h. Due to the high requirement of methanol and catalyst concentration, attempt was made to improve the reaction conditions by introducing a co-solvent into the reaction mixture. It was found that tetrahydrofuran (THF) could significantly enhance the reaction rate by homogenizing the reaction mixture. The optimum reaction conditions with a co-solvent were found to be less extreme: methanol to THF to lipid molar ratio of 60:15:1, catalyst concentration of 21wt.%, temperature of 60°C and reaction time of 3h. [Copyright &y& Elsevier]

Abstract: Simultaneous supercritical extraction and transesterification (SET) process is a novel biodiesel production process for oil seeds in which the solid oil-bearing material is used as the primary reactant together with short-chain alcohol directly in supercritical condition. In this experimental work, SET process with methanol was carried out in a high-pressure batch reactor to produce fatty acid methyl esters (FAME) from Jatropha curcas L. seeds (15.0g feed, 300°C, 5.0ml/g methanol to solid ratio and 30min). Different types of co-solvents (pentane, heptane, toluene, tetrahydrofuran, nitrogen and carbon dioxide) with varying amount (1.0–5.0ml/g for liquid and 10–50bar for gas) were added into the process to study their influences towards the extraction efficiency, Ey and FAME yield, Fy . It was found that pentane and CO2 provided higher responses (Ey : 102.6% and 107.0%, Fy : 100.4% and 102.3%) at concentration of 1.0ml/g and 50bar respectively. Addition of pentane and CO2 was also discovered to lower the critical conditions of the reactant mixture and could achieve near optimum product yield at lower temperature (280°C) and lower methanol to solid ratio (4.0ml/g). Addition of appropriate co-solvents could increase the extraction rate (solid–liquid) and enhance methanol–oil inter-phase miscibility during the reaction phase. This proved that SET process can be rather promising as another alternative route for biodiesel production. [Copyright &y& Elsevier]

Abstract: In this study, the feasibility of using potash from cocoa pod husks (CPHs) in the transesterification of soybean oil into biodiesel was investigated. Both supported (CPH/MgO) and unsupported (CPH ash) catalysts of potash prepared from CPH were used as green heterogeneous catalysts for biodiesel production. Under optimum conditions for the CPH/MgO-catalyzed (oil/methanol ratio of 1:6, 60°C, 60min, 1wt.% of MgO doped CPH ash catalyst) and the CPH-catalyzed (60°C, oil/methanol ratio of 1:6, 120min, 1wt.% of CPH ash) transesterification reactions, biodiesel samples (98.7% and 91.4% yields for CPH/MgO and CPH ash catalysts respectively) with specifications falling within the limits of the European biodiesel quality standard (EN 14112) were obtained. Brake thermal efficiencies and torque were measured for each fuel sample at different loads. Engine test showed a better performance for all the fuel samples (B100 and B40) with B40 showing close characteristics of petroleum diesel. Thus, this first report on the utilization of CPH as catalyst for biodiesel shows a high feasibility of producing green heterogeneous base catalysts commercially from CPH for sustainable biodiesel production. [Copyright &y& Elsevier]

Abstract: In a bid to increase the cost competitiveness of biodiesel production against mineral diesel, process intensification has been studied for numerous biodiesel processing technologies. Subsequently, reactive extraction or in situ transesterification is actively being explored in which the solid oil-bearing seeds are used as the reactant directly with short-chain alcohol. This eliminates separate oil extraction process and combines both extraction and transesterification in a single unit. Supercritical reactive extraction takes one step further by substituting the role of catalyst with supercritical conditions to achieve higher yield and shorter processing time. In this work, supercritical reactive extraction with methanol was carried out in a high-pressure batch reactor to produce fatty acid methyl esters (FAMEs) from Jatropha curcas L. seeds. Material and process parameters including space loading, solvent to seed ratio, co-solvent (n-hexane) to seed ratio, reaction temperature, reaction time and mixing intensity were varied one at a time and optimized based on two responses i.e. extraction efficiency, M extract and FAME yield, F y. The optimum responses for supercritical reactive extraction obtained were 104.17% w/w and 99.67% w/w (relative to 100% lipid extraction with n-hexane) for M extract and F y respectively under the following conditions: 54.0ml/g space loading, 5.0ml/g methanol to seeds ratio, 300°C, 9.5MPa (Mega Pascal), 30min reaction time and without n-hexane as co-solvent or any agitation source. This proved that supercritical reactive extraction is rather promising as another alternative for biodiesel production. [Copyright &y& Elsevier]

Abstract: In the present study, the use of immobilization technology to cultivate microalgae in entrapped matrix gel beads was demonstrated. Since the gel beads are denser in water, the beads can be easily collected through simple filtration method and hence, simplifying the overall separation process. Various parameters were investigated to optimize the growth rate of immobilized microalgae and the optimum conditions were obtained as: alginate to microalgae volume ratio of 0.3, Ca2+ concentration of 2%, organic nutrients concentration of 50mL (equivalent to 13.09mg/L nitrate), initial culture pH of 4 and photoperiod of 24h. Using this optimum culture condition, 0.50mg biomass/bead was attained on the 10th day of cultivation. Apart from that, this study also attempted to co-immobilize nutrients into microalgae beads in order to minimize free cell culture (microalgae cells that are released into the culture medium due to rupturing of beads) and to reduce water consumption. Through this approach, it was found that microalgae biomass yield increased to 0.67mg/bead within a shorter culturing time (5 days) with insignificant amount of free cell culture detected. Furthermore, lipid extracted from immobilized microalgae biomass has high potential for biodiesel production due to the similarity of fatty acid profile with other oil bearing crops. [Copyright &y& Elsevier]

Abstract: This study was conducted to investigate the active role of sulfated zirconia catalyst in the transesterification of palm (Elaeis guineensis) and sea mango (Cerbera odollam) oils. Initially, the sulfated zirconia catalysts were prepared and optimized under various preparation conditions – calcination temperature, calcination period and ratio of Zr-species/support - and then characterized for its physical and chemical properties. The performance of the sulfated zirconia catalysts was tested in the transesterification of palm oil and sea mango oil. The optimized sulfated zirconia catalyst was also tested for its reusability and regenerability. From this study, it was found that the best (optimum) sulfated zirconia catalyst was prepared using calcination temperature of 400 °C, calcination period of 2.5 h and ratio of Zr-species/support of 2 g g−1. It was also found that the prepared sulfated zirconia catalyst contains acid sites which become the key factor in the transesterification process. The optimized sulfated zirconia catalyst was shown to be able to produce high yield of fatty acid methyl esters (>80%) even with oil that has high free fatty acids content i.e. sea mango oil. The reusability and regenerability study showed that the optimized sulfated zirconia can be regenerated and reused repeatedly with an average of 5% loss in activity after each run. [Copyright &y& Elsevier]

Abstract: Experimental studies for in situ extraction and transesterification of oil seeds had been carried out recently for the process intensification of biodiesel production. As opposed to the conventional method, the solid oil seeds would be in direct contact with the transesterification reagent. Both the oil extraction and subsequent transesterification process to biodiesel will occur simultaneously. Consequently, solid pre-treatments would play a critical role to ensure that the oil seeds are in a state for optimal oil extraction. Apart from obtaining a higher yield, this could also ensure that the oil extraction phase would not bottleneck the entire in situ extraction and transesterification process. However, solid pre-treatments could be both cost and energy intensive and therefore should be carefully selected for optimum advantages. In this experimental work, ground Jatropha curcas L. seeds were subjected to pre-treatments processes including de-shelling, sieving, drying and heat treatment at five different temperatures (45–105°C) and two different durations (12 and 24h) before undergoing single-step supercritical methanol extraction and transesterification. Conventional two-step extraction and transesterification was also performed as comparison to the single-step process. The effects of each pre-treatment were analyzed and optimized towards two responses (extraction and FAME yield). The highest extraction and FAME yield for the two-step and single-step processes were 66.82% w/w, 114.87% w/w and 68.50% w/w, 128.78% w/w respectively. Single-step supercritical methanol extraction and transesterification was found to be able to provide a higher extraction and FAME yield for the production of biodiesel with less pre-treatment stages and intensity as compared to the conventional two-step process. Therefore, this is a highly promising approach to reduce the high biodiesel production cost which is currently impairing the industry. [Copyright &y& Elsevier]

Abstract: This study reports the conversion of Jatropha curcas 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 9.88mol/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. [Copyright &y& Elsevier]

Abstract: Solid acid catalysts are normally used to catalyze the transesterification of oil with high free fatty acid (FFA) to biodiesel. However, the immiscible phases of methanol-oil-catalyst in the initial reaction mixture usually lead to slow reaction rate and long reaction time. One possible way to overcome this limitation is by using co-solvent that has high solubility in oil and methanol. Therefore, in the present study, the use of biodiesel as co-solvent for transesterification reaction catalyzed by (solid acid catalyst) was investigated. It was found that with the use of biodiesel as co-solvent, a high FAME yield of 88.2% (almost 30% higher than without using co-solvent) can be obtained in a shorter reaction time (1.5h) using the following reaction conditions; reaction temperature of 150°C, methanol to oil ratio of 15 and catalyst loading of 6wt.% (weight of oil). [Copyright &y& Elsevier]

Abstract: In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through transesterification reaction. However, current commercial usage of refined vegetable oils for biodiesel production is impractical and uneconomical due to high feedstock cost and priority as food resources. Low-grade oil, typically waste cooking oil can be a better alternative; however, the high free fatty acids (FFA) content in waste cooking oil has become the main drawback for this potential feedstock. Therefore, this review paper is aimed to give an overview on the current status of biodiesel production and the potential of waste cooking oil as an alternative feedstock. Advantages and limitations of using homogeneous, heterogeneous and enzymatic transesterification on oil with high FFA (mostly waste cooking oil) are discussed in detail. It was found that using heterogeneous acid catalyst and enzyme are the best option to produce biodiesel from oil with high FFA as compared to the current commercial homogeneous base-catalyzed process. However, these heterogeneous acid and enzyme catalyze system still suffers from serious mass transfer limitation problems and therefore are not favorable for industrial application. Nevertheless, towards the end of this review paper, a few latest technological developments that have the potential to overcome the mass transfer limitation problem such as oscillatory flow reactor (OFR), ultrasonication, microwave reactor and co-solvent are reviewed. With proper research focus and development, waste cooking oil can indeed become the next ideal feedstock for biodiesel. [Copyright &y& Elsevier]

Abstract: In this study, fatty acid methyl esters (FAME) have been successfully produced from transesterification reaction between triglycerides and methyl acetate, instead of alcohol. In this non-catalytic supercritical methyl acetate (SCMA) technology, triacetin which is a valuable biodiesel additive is produced as side product rather than glycerol, which has lower commercial value. Besides, the properties of the biodiesel (FAME and triacetin) were found to be superior compared to those produced from conventional catalytic reactions (FAME only). In this study, the effects of various important parameters on the yield of biodiesel were optimized by utilizing Response Surface Methodology (RSM) analysis. The mathematical model developed was found to be adequate and statistically accurate to predict the optimum yield of biodiesel. The optimum conditions were found to be 399°C for reaction temperature, 30mol/mol of methyl acetate to oil molar ratio and reaction time of 59min to achieve 97.6% biodiesel yield. [Copyright &y& Elsevier]

Abstract: Biodiesel is a renewable, biodegradable and non-toxic fuel which can be easily produced through transesterification reaction. However, current commercial usage of refined vegetable oils for biodiesel production is impractical and uneconomical due to high feedstock cost and priority as food resources. Low-grade oil, typically waste cooking oil can be a better alternative; however, the high free fatty acids (FFA) content in waste cooking oil does not allow efficient production of biodiesel via current commercial homogeneous transesterification process. Therefore in the present study, superacid sulfated tin oxide catalyst, SO4 2−/SnO2 has been prepared using impregnation method for biodiesel production via heterogeneous tranesterification process. The bi-metallic effect of the catalyst was also studied, in which SnO2 was mixed with SiO2 and Al2O3, respectively, at different weight ratios in order to enhance the catalytic activity of SnO2. The effect of different reaction parameters such as calcination temperature and period of the catalyst, reaction temperature, catalyst loading, methanol-to-oil ratio and reaction time were studied to optimize the reaction conditions. It was found that SO4 2−/SnO2-SiO2 with weight ratio 3 exhibited an exceptional high activity with an optimum yield of 92.3% at reaction temperature 150°C, catalyst loading 3wt%, methanol-to-oil ratio 15 and reaction time 3h. The physical and chemical properties of the catalysts were also characterized using XRD analysis and FT-IR imaging. [Copyright &y& Elsevier]

Abstract: Biodiesel is currently produced from transesterification reaction of various types of edible oil with methanol. However, the requirement of methanol makes the current biodiesel produce not totally 100% renewable as methanol is derived from fossil based products. Ethanol, on the other hand, can be produced from agricultural biomass via fermentation technology and is already easily available in the market at a high purity. Thus, in this work, possible 100% renewable biodiesel fuel was prepared from refined palm oil by using non-catalytic transesterification reaction in supercritical ethanol. The effect of various process parameters on the yield of biodiesel was studied using design of experiments (DOE). The process parameters studied are: reaction temperature (300–400°C), reaction period (2–30min) and ethanol-to-oil ratio (5–50). The optimum process conditions were then obtained using response surface methodology (RSM) coupled with center composite design (CCD). The results revealed that at the following optimum process conditions; reaction temperature of 349°C, reaction period of 30min and ethanol-to-oil ratio of 33, a biodiesel yield of 79.2wt.% can be obtained. [Copyright &y& Elsevier]

Abstract: This paper presents the study of the transesterification of palm oil via heterogeneous process using montmorillonite KSF as heterogeneous catalyst. This study was carried out using a design of experiment (DOE), specifically response surface methodology (RSM) based on four-variable central composite design (CCD) with α (alpha)=2. The transesterification process variables were reaction temperature, x 1 (50–190°C), reaction period, x 2 (60–300min), methanol/oil ratio, x 3 (4–12molmol−1) and amount of catalyst, x 4 (1–5wt%). It was found that the yield of palm oil fatty acid methyl esters (FAME) could reach up to 79.6% using the following reaction conditions: reaction temperature of 190°C, reaction period at 180min, ratio of methanol/oil at 8:1molmol−1 and amount of catalyst at 3%. [Copyright &y& Elsevier]

Abstract: This paper explores the feasibility of converting Cerbera odollam (sea mango) oil into biodiesel. The first part of this study focused on the extraction of oil from the seeds of C. odollam fruits, whereas the second part focused on the transesterification of the extracted oil to fatty acid methyl esters (FAME). The transesterification reactions were carried out using three different catalysts; sodium hydroxide (NaOH) as a homogenous catalyst, sulfated zirconia alumina and montmorillonite KSF as heterogeneous catalysts. The seeds were found to contain high percentage of oil up to 54% while the yield of FAME can reach up to 83.8% using sulfated zirconia catalyst. [Copyright &y& Elsevier]

In this study, sea mango ( Cerbera odollam ) oil which is rich in free fatty acid was utilised as the feedstock in one-step superheated methanol vapour (SMV) transesterification reaction without going through pre-treatment step. SMV transesterification reaction was initiated by injecting superheated methanol vapour into sea mango oil phase. Effect of methanol flow rate at the range of 1–4 mL/min as well as effect of reaction temperatures at the range of 260–290 °C was studied based on FAME production rates at constant initial oil volume of 100 mL. Kinetic modelling of semi-batch system, incorporating second-order of three-stepwise reversible transesterification of triglycerides (TG) and second order of reversible esterification of free fatty acid (FFA) were verified simultaneously using ordinary differential equation (ODE45) solver. It shows that transesterification reaction of TG and esterification of FFA would occur simultaneously. The high activation energy of 50 kJ/mol and low reaction rate constant of 1.62 × 10 −4 dm 3 /mol min verified that the reaction of TG to become diglycerides (DG) as the rate limiting step in this semi-batch SMV system. [ABSTRACT FROM AUTHOR]

In this high demand of renewable energy market, biodiesel was extensively produced via various catalytic and non-catalytic technologies. Conventional catalytic transesterification for biodiesel production has been shown to have limitation in terms of sensitivity to high water and free fatty acid, complicated separation and purification of biodiesel. In this study, an alternative and innovative approach was carried out via non-catalytic superheated methanol technology to produce biodiesel. Similar to supercritical reaction, the solvent need to be heated beyond the critical temperature but the reactor pressure remained at 0.1 MPa (atmospheric pressure). Transesterification reaction with superheated methanol was carried out at different reaction temperature within the limit of 270–300 °C and at different methanol flow rate ranging from 1 ml/min to 3 ml/min for 4 h. Results obtained showed that the highest biodiesel yield at 71.54% w/w was achieved at reaction temperature 290 °C and methanol flow rate at 2 ml/min with 88.81% w/w FAME content, implying the huge potential of superheated technology in producing FAME. [ABSTRACT FROM AUTHOR]

Abstract: In this review, recent development of glycerol-free supercritical fluid transesterification for biodiesel production was discussed. Glycerol-free supercritical fluid processes including single-step and two-step transesterification for biodiesel production were reviewed and subsequently the advantages and limitations were highlighted. Value-added by-product from glycerol-free production such as triacetin is more profitable compared with glycerol produced in conventional biodiesel production. Furthermore, the quality of biodiesel could be enhanced with the presence of triacetin, which is co-produced in supercritical methyl acetate transesterification reaction. However, there are concerns regarding the huge energy required to conduct supercritical reaction at elevated temperature and pressure. Hence, economic consideration in terms of equipment needed and profit margin were discussed in order to study the profitability of glycerol-free supercritical biodiesel production in the industry. Results showed that glycerol-free supercritical dimethyl carbonate process has the highest profit margin, indicating that it is economically competitive and could provide larger revenue to biodiesel producers. [Copyright &y& Elsevier]

Abstract: Transesterification of crude Jatropha oil in presence of tungstophosphoric acid (TPA) supported on activated carbon (AC) using ultrasound-assisted process was investigated. The generated catalysts were characterized for physical and chemical properties to examine the effects of different TPA loadings (15%, 20%, 25% w/w). The catalysts were then used in the transesterification of Jatropha oil with high free fatty acid content. The catalyst with 20% TPA loading achieved the best methyl ester yield, achieving 87.33% in just 40 min. The quality of the feed stock was varied by increasing the water content and FFA content to test the tolerance of the catalysts towards these parameters separately. The catalyst showed good water tolerance to a limit of 1% w/w and proven to be insensitive to the increment of FFA in the feed stock. The catalyst was also investigated for possible reusability and TPA leaching under ultrasonic conditions. [Copyright &y& Elsevier]

Highlights: [•] Ultrasound-assisted transesterification of crude Jatropha oil. [•] Heteropolyacid-based solid catalysts to accelerate the reaction. [•] Central composite design data for artificial neural network (ANN) modeling. [•] Model optimization to identify the network topology and training method. [•] Good accuracy of ANN model in FAME yield prediction. [ABSTRACT FROM AUTHOR]

Biodiesel has recently gained popularity as an alternative biofuel to substitute fossil fuel. Utilization of magnetic biochar catalyst (MBC) in biodiesel production can enhance the catalyst separation process. In this research, MBC was synthesized from oil palm waste such as palm kernel shell (PKS), oil palm frond (OFP), and empty fruit bunch (EFB). Biodiesel production parameters were studied using the Central Composite Design-based Response Surface Method. Based on the characterization results, EFB is the most suitable palm lignocellulosic biomass for MBC synthesis. The MBC has a BET surface area of 44.42 m2 g−1, an average acid density value of 3.85 mmol g−1, and a σ s value of 3.19 Am2 kg−1. MBC synthesis is at its optimal by using 1.5 M FeCl 3 ·6H 2 O solution, 800 °C carbonization temperature, and 2.5 M H 2 SO 4. The optimized transesterification parameters are: catalyst loading of 10.25 wt%, methanol to oil molar ratio of 28, 70 °C, and 8 h gave a maximum fatty acid methyl ester yield of 91.50 %. After five cycles, the yield dropped to 67.37 %. Biodiesel production is reported to be the pseudo-irreversible first-order kinetic with an activation energy of 29.20 kJ mol−1. The physicochemical characterization showed the biodiesel has met the ASTM D6751 standard. [ABSTRACT FROM AUTHOR]

Abstract: Transesterification of crude Jatropha oil in the presence of cesium doped heteropolyacid catalyst and assisted by ultrasonic irradiation was investigated. Different Cs heteropolyacid catalysts with different levels of cesium exchange were synthesized and characterized for physical and chemical properties. They were subsequently tested in pre-elementary reaction conditions to identify the most active catalyst. Cs1.5H1.5PW12O40 catalyst showed the highest FAME (fatty acid methyl ester) yield of 81.3% in 60 min while higher Cs levels resulted in poorer activity. Four reaction variables i.e. reaction time (10–50 min), methanol to oil molar ratio (5:1–25:1), ultrasonic amplitude (30–90% of the maximum sonifier power) and catalyst amount (2.5–4.5 w/w oil) were optimized to generate mathematical representation of FAME yield. The highest yield of 90.5% was achieved in just 34 min under the optimum reaction conditions i.e. at an ultrasonic amplitude of ∼60%, and a molar ratio of 25:1. The catalyst was also investigated for possible reusability and leaching under ultrasonic conditions. The reaction was mostly heterogeneous in nature and the catalyst also showed minimal reduction in the activity after three successive reaction runs under the optimum reaction conditions. [Copyright &y& Elsevier]

Abstract: Fatty acid methyl esters synthesis from crude Jatropha oil using an ultrasound-assisted process was investigated. Several gamma alumina (Al) supported tungstophosphoric acid (TPA) catalysts were synthesized and characterized to elucidate their catalytic behaviors. TPA loadings on the support between 15% and 35% were investigated. The catalyst with 25% loading achieved the highest yield of 64.3% in 60min. Effects of reaction time (10–50min), reaction molar ratio (5:1–25:1), ultrasonic amplitude (30–90% of the maximum sonifier power) and catalyst amount (2.5–4.5w/w oil) were investigated and optimized. Mathematical representation of FAME yield was successfully generated and statistically validated. A highest reaction yield of 84% was achieved under the optimum conditions i.e. at an ultrasonic amplitude of ∼60%, a molar ratio of 19:1 and a reaction temperature of 65°C in just 50min. Interactions between the reaction variables were also statistically validated. The catalyst was also investigated for possible reusability. [Copyright &y& Elsevier]

Abstract: Biodiesel is a good alternative fuel to petroleum diesel. It is produced through transesterification reaction between vegetable oil or animal fats and alcohol. The process faces various problems related to the immiscible nature of the reactants causing poor mass transfer rate. This drawback is responsible for long reaction time and low reaction rate leading to an energy intensive process. Process intensification through the use of active catalyst, pressure reactor, high temperature, high stirring rate or even non-conventional approaches such as supercritical method and Biox process often subjects to drawbacks with respect to energy consumption, product quality and reactants cost. This paper highlights recent development in the production of biodiesel under ultrasonic irradiation conditions. It handles the drawback of poor immiscibility between reactants as ultrasonic energy can emulsify the reactants to reduce the catalyst requirement, reaction time and reaction temperature. Ultrasonic energy also neglects the limitations in the use certain feed stocks. Fundamental aspects of the ultrasonic-assisted process using homogeneous and heterogeneous catalysts are reviewed. Recent achievement and future development in this technology in a batch and continuous process are also highlighted. [Copyright &y& Elsevier]

Abstract: In this study, optimization of non-catalytic supercritical methanol reaction via response surface methodology analysis was carried out. Subsequently, the results obtained were compared with reported results of supercritical ethanol in order to investigate the effect of alcohol in supercritical alcohol reaction. Important variables such as reaction time, reaction temperature and molar ratio of alcohol to oil were optimized in order to obtain the optimum yield of biodiesel. Apart from single-parameter effect, response surface methodology also considered the influence of variable interactions in the experimental design. Hence, this method of analysis allows a comprehensive understanding of the process by minimal number of experimental runs. Results obtained from optimization studies showed that supercritical methanol reaction can achieve optimum yield (81.5%) at relatively lower reaction time compared to supercritical ethanol process (79.2%). [Copyright &y& Elsevier]

Abstract: K/SBA 15 was investigated for the transesterification of palm oil. The influence of temperature, reactants'' ratio, catalyst loading and reaction time on the biodiesel yield was studied using a Central Composite Design (CCD). The process optimization using Response Surface Methodology (RSM) was performed and the interactions between the operational variables were elucidated. The optimum conditions were found to be 70 °C for the reaction temperature, 11.6 mol/mol for methanol to oil ratio, 3.91 wt.% for the catalyst loading and 5 h for the reaction time to achieve 93% of biodiesel yield. High catalytic activity was attributed to high surface area of the catalyst and the relatively easy diffusion of reactants in the mesopores. The effect of catalyst loading and reaction time was relatively more dominant in affecting the biodiesel yield. High potential of SBA-15 as catalyst for biodiesel production was demonstrated. [Copyright &y& Elsevier]

Abstract: Generally, water and free fatty acid (FFA) content in oils could cause a serious problem during conventional transesterification such as saponification. Thus, without any pre-treatment, vegetable oil, especially with high FFA content, will be affected. In this study, a non-catalytic supercritical methyl acetate (SCMA) process was utilized to produce biodiesel from Jatropha curcas L. oil. The effects of water and FFA content on the yield of biodiesel were investigated. The results obtained for the effects of water on the yield of biodiesel were compared with the supercritical methanol (SCM) process and conventional catalytic reaction. Results revealed that the catalytic reaction suffers from low yield with the presence of high water content in oil. Meanwhile, the yield of both the SCM and SCMA reactions were found to increase slightly with the increment of water content in the mixture. On the other hand, the results for the effect of FFA on the yield of biodiesel were compared with the SCM reaction. It was found that the presence of FFA has a negligible effect in both the SCMA and SCM reactions. These findings demonstrate that pre-treatment procedures are not necessary in the SCMA process for Jatropha oil which normally contains a high FFA content. [Copyright &y& Elsevier]

Sea mango ( Cerbera odollam ) oil, which is rich in free fatty acids, was utilized to produce fatty acid methyl esters (FAME) via supercritical transesterification reaction. Sea mango oil was extracted from seeds and was subsequently reacted with methanol in a batch-type supercritical reactor. Response surface methodology (RSM) analysis was used to optimize important parameters, including reaction temperature, reaction time and the molar ratio of methanol to oil. The optimum conditions were found as 380 °C, 40 min and 45:1 mol/mol, respectively, to achieve 78% biodiesel content. The first kinetic modelling of FAME production from sea mango oil incorporating reversible transesterification and reversible esterification was verified simultaneously. The kinetic parameters, including reaction rate constants, k , the pre-exponential constant, A , and the activation energy, Ea , for transesterification and esterification were determined using an ordinary differential equation (ODE45) solver. The highest activation energy of 40 kJ/mol and the lowest reaction rate constant of 2.50 × 10 −5 dm 3 /mol s verified that the first stepwise reaction of TG to produce DG was the rate-limiting step. [ABSTRACT FROM AUTHOR]

Heterogeneous solid mixed oxide (CaO–La 2 O 3 ) catalysts with different molar ratios of calcium to lanthanum (Ca-to-La) were synthesized by co-precipitation method. The synthesized solid CaO–La 2 O 3 mixed metal oxide catalysts were utilized in transesterification of Jatropha curcus oil as feedstock to produce biodiesel. Under the optimized conditions at 65 °C, 4% catalyst dose with 24:1 MeOH to Jatropha oil molar ratio, the transesterification reaction exhibited 86.51% of biodiesel yield. The prepared catalysts were characterized using various techniques such as X-ray diffraction (XRD), nitrogen sorption with Brunauer–Emmer–Teller (BET) method, temperature-programmed desorption of CO 2 (CO 2 -TPD) and scanning electron microscopy (SEM). Influence of Ca-to-La atomic ratio in the mixed metal oxide catalyst, catalyst amount, methanol to oil molar ratio, reaction time, different oils on the fatty acid methyl ester (FAME) yield were appraised. Different catalyst regeneration procedures were also performed to investigate the reusability of the CaO–La 2 O 3 catalyst. [ABSTRACT FROM AUTHOR]

Abstract: Similarity between the properties of biodiesel and petroleum-derived diesel has made the former one of the most promising alternatives to a renewable and sustainable fuel for the transportation sector. In Malaysia, palm oil can be a suitable feedstock for the production of biodiesel due to its abundant availability and low production cost. However, not many assessments have been carried out regarding the impacts of palm biodiesel on the environment. Hence, in this study, life cycle assessment (LCA) was conducted for palm biodiesel in order to investigate and validate the popular belief that palm biodiesel is a green and sustainable fuel. The LCA study was divided into three main stages, namely agricultural activities, oil milling and transesterification process for the production of biodiesel. For each stage, the energy balance and green house gas assessments were presented and discussed. These are important data for the techno-economical and environmental feasibility evaluation of palm biodiesel. The results obtained for palm biodiesel were then compared with rapeseed biodiesel. From this study, it was found that the utilization of palm biodiesel would generate an energy yield ratio of 3.53 (output energy/input energy), indicating a net positive energy generated and ensuring its sustainability. The energy ratio for palm biodiesel was found to be more than double that of rapeseed biodiesel which was estimated to be only 1.44, thereby indicating that palm oil would be a more sustainable feedstock for biodiesel production as compared to rapeseed oil. Moreover, combustion of palm biodiesel was found to be more environment-friendly than petroleum-derived-diesel as a significant 38% reduction of CO2 emission can be achieved per liter combusted. [Copyright &y& Elsevier]