Biodiesel Production by Methanolysis of Rapeseed Oil-Influence of SiO2/Al2O3 Ratio in BEA Zeolite Structure on Physicochemical and Catalytic Properties of Zeolite Systems with Alkaline Earth Oxides (MgO, CaO, SrO).

Alkaline earth metal oxide (MgO, CaO, SrO) catalysts supported on BEA zeolite were prepared by a wet impregnation method and tested in the transesterification reaction of rapeseed oil with methanol towards the formation of biodiesel (FAMEs-fatty acid methyl esters). To assess the influence of the SiO2/Al2O3 ratio on the catalytic activity in the tested reaction, a BEA zeolite carrier material with different Si/Al ratios was used. The prepared catalysts were tested in the transesterification reaction at temperatures of 180 °C and 220 °C using a molar ratio of methanol/oil reagents of 9:1. The transesterification process was carried out for 2 h with the catalyst mass of 0.5 g. The oil conversion value and efficiency towards FAME formation were determined using the HPLC technique. The physicochemical properties of the catalysts were determined using the following research techniques: CO2-TPD, XRD, BET, FTIR, and SEM-EDS. The results of the catalytic activity showed that higher activity in the tested process was confirmed for the catalysts supported on the BEA zeolite characterized by the highest silica/alumina ratio for the reaction carried out at a temperature of 220 °C. The most active zeolite catalyst was the 10% CaO/BEA system (Si/Al = 300), which showed the highest triglyceride (TG) conversion of 90.5% and the second highest FAME yield of 94.6% in the transesterification reaction carried out at 220 °C. The high activity of this system is associated with its alkalinity, high value of the specific surface area, the size of the active phase crystallites, and its characteristic sorption properties in relation to methanol.

Harnessing the Carrier Solvent Complexity of Crop Biostimulant Liquid Formulations Using Locally Available Transesterified Waste Cooking Oil: Economic Recycling, Solvent Performance, and Bioefficacy Evaluation.

Locally sourced waste cooking oil (WCO) was successfully base-catalyzed and transesterified with methanol into biodiesel to produce biostimulant (nitrobenzene) formulations and replace high-risk carrier solvents. Ideal synthesis conditions were composed of 1% NaOH, MeOH/oil molar ratio (6:1), reaction temperature (65 °C), a 3 h mixing rate, and 97-98% yields. Gas chromatography-mass spectrometry (GC-MS) analysis identified five fatty acid methyl esters (FAMEs) including palmitic, linoleic, oleic, stearic, and eicosenoic acids with high solubilization and olfactory characteristics. Using anionic and nonionic emulsifiers in conjunction with recycled biodiesel, a stable emulsifiable concentrate (NB 35% EC) was created with greater storage stability, wettability, and spreading capabilities than those of organic solvent-based ones. The highest counts of fruits per plant (35.80), flowers per plant (60.00), yield per plant (3.56 kg), and yield per hectare (143.7 quintals) were recorded in treatments with 4 mL/L biodiesel-based EC in field bioassays. In addition to having superior biosafety, FAME-based EC exhibits minimal phytotoxicity and is less harmful to aquatic creatures. It was discovered that the average cost-effectiveness was 5.49 times less expensive than solvent-based EC. In order to utilize waste oils as a locally obtained, sustainable alternative solvent with a wide solubilization range, low ecotax profile, circular economy, and high renewable carbon index, this integrative technique was expanded.

Analyzing the performance of synthesized nano-catalysts for transesterification of waste cooking oil as environment friendly drilling fluid.

Ester-based drilling fluids (EBDF) are preferred over oil-based drilling fluids (OBDF) and water-based drilling fluids (WBDF) because of their great biodegradability, low toxicity, and improved performance. In this work, waste cooking oil methyl ester (WCOME) was used to prepare an environmentally friendly EBDF. Through a transesterification process utilizing a modified calcium oxide based heterogenous catalyst, the waste cooking oil is transformed into waste cooking oil methyl ester. Response surface approach was used to strengthen the transesterification. The optimize conditions for CaO/Al2O3 resulted in the highest yield of 96.56% at a molar ratio of 11.9:1, 3.19 wt % of CaO/Al2O3, 53.79 °C, and 76.86 min. In contrast, CaO/TiO2 yielded 98.15% at a molar ratio of 11.99:1, with a CaO/TiO2 of 2.53 wt % at 59.79 in 68.14 min. Additionally, two separate densities of 9 ppg and 12 ppg EBDF are formulated with two distinct oil-to-water ratios (70:30 and 80:20) using synthesized WCOME. To assess the effectiveness of formulated EBDF thorough rheological investigation is conducted at 150°. Additionally, the filtration loss at HPHT conditions, emulsion stability, and Barite sag analysis of the drilling fluid are all analyzed at before ageing and after dynamic ageing. With better rheological features, less fluid loss, good emulsion stability, and minimal barite sagging, the designed EBDF performs efficiently. The drilling fluid met the API requirement and demonstrated stability even after ageing at 250 °F for 72 h, suggesting that it may be used for extended periods of time in drilling.

Synthesis, catalysts and enhancement technologies of biodiesel from oil feedstock - A review.

Biodiesel is considered as one of the most promising alternative fuels due to the depletion of fossil fuels and the need to cope with potential energy shortages in the future. This article provides a thorough analysis of biodiesel synthesis, covering a variety of topics including oil feedstock, synthesis methods, catalysts, and enhancement technologies. Different oil feedstock for the synthesis of biodiesel is compared in the review, including edible plant oil, non-edible plant oil, waste cooking oil, animal fat, microbial oil, and algae oil. In addition, different methods for the synthesis of biodiesel are discussed, including direct use, blending, thermal cracking, microemulsions, and transesterification processes, highlighting their respective advantages and disadvantages. Among them, the transesterification method is the most commonly used and a thorough examination is given of the benefits and drawbacks of utilizing enzymatic, heterogeneous, and homogeneous catalysts in this process. Moreover, this article provides an overview of emerging intensification technologies, such as ultrasonic and microwave-assisted, electrolysis, reactive distillation, and microreactors. The benefits and limitations of these emerging technologies are also reviewed. The contribution of this article is offering a thorough and detailed review of biodiesel production technologies, focusing mainly on recent advances in enhanced chemical reaction processes. This provides a resource for researchers to assess and compare the latest advancements in their investigations. It also opens up the potential for enhancing the value of oil feedstocks efficiently, contributing to the development of new energy sources.

Synthesis and characterization of magnetic bifunctional nano-catalyst for the production of biodiesel from Madhuca indica oil.

The reusable magnetic multimetal nano-catalyst (Fe3O4.Cs2O) was synthesized using co-precipitation and incipient wetness impregnation methods. It was used to esterify and transesterify Madhuca indica (M. indica) oil to produce biodiesel with methanol. The prepared catalyst, caesium oxide doped on the nano-magnetite core, was characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Further, the activity of the catalyst was investigated by subjecting it to a biodiesel reaction. To maximize biodiesel conversion, studies were carried out by varying the process variables like catalyst concentration, methanol-to-oil molar ratio, reaction temperature, and reaction time. A maximum conversion of 97.4% was obtained at the holding conditions of 18:1 methanol-to-oil ratio, 7 wt% catalyst loading, 65 °C reaction temperature, and 300 min reaction time. Moreover, the catalyst recyclability study showed that it could be recycled up to 12 cycles with a conversion of 90% and above. The biodiesel's fuel properties were analysed and found to be within the limits of ASTM D6751 standard.

Antifungal Activity of Water-Based Adhesives Derived from Pineapple Stem Flour with Apple Cider Vinegar as an Additive.

As a byproduct of bromelain extraction procedures, pineapple stem flour is underutilized. Since water glues derived from gelatinization typically have poor mold resistance, this study aims to produce flour-based value-added products, such as mold-resistant water-based adhesives. To address this issue, this study explored the use of apple cider vinegar (ACV) as a low-cost, non-toxic, commercially available antifungal agent to improve the mold resistance of adhesives. Furthermore, laurate flour was produced via a transesterification of the flour and methyl laurate using a K2CO3 catalyst. Both the unmodified flour and the functionalized flour were employed to prepare water-based adhesives. For both flour systems, adding ACV at concentrations of at least 2.0% v/v enhanced the mold resistance of the adhesives and completely inhibited the development of A. niger mycelia for up to 90 days of storage. The adhesives made from the transesterified flour exhibited a higher shear strength for the paper bonding (ca. 8%) than the unmodified ones. Additionally, the ACV additive had no negative effects on the shear strengths of the water-based adhesives. All of the flour-based adhesives developed in this study had a higher shear strength for paper substrates than two locally available commercial water glues.

Valorization of hazardous waste cooking oil for the production of eco-friendly biodiesel using a low-cost bifunctional catalyst.

Biodiesel is considered the prospective substitute for non-renewable fossil fuel-derived sources of energy. However, the high costs of feedstocks and catalysts inhibit its large-scale industrial implementation. From this perspective, the utilization of waste as the source for both catalyst synthesis and feedstock for biodiesel is a rare attempt. Waste rice husk was explored as a precursor to prepare rice husk char (RHC). Sulfonated RHC was employed as a bifunctional catalyst for the simultaneous esterification and transesterification of highly acidic waste cooking oil (WCO) to produce biodiesel. The sulfonation process coupled with ultrasonic irradiation proved to be an efficient technique to induce high acid density in the sulfonated catalyst. The prepared catalyst possessed a sulfonic density and total acid density of 4.18 and 7.58 mmol/g, respectively, and a surface area of 144 m2/g. A parametric optimization was conducted for the conversion of WCO into biodiesel using the response surface methodology. An optimal biodiesel yield of 96% was obtained under the conditions of methanol to oil ratio (13:1), reaction time (50 min), catalyst loading (3.5 wt%), and ultrasonic amplitude (56%). The prepared catalyst showed higher stability up to five cycles with biodiesel yield greater than 80%.

Preparation and characterization of diacylglycerol via ultrasound-assisted enzyme-catalyzed transesterification of lard with glycerol monolaurate.

The study aimed to evaluate the effect of ultrasonic pretreatment on the transesterification of lard with glycerol monolaurate (GML) using Lipozyme TL IM to synthesize diacylglycerol (DAG), and the physicochemical properties of lard, GML, ultrasonic-treated diacylglycerol (named U-DAG), purified ultrasonic-treated diacylglycerol obtained by molecular distillation (named P-U-DAG), and without ultrasonic-treated diacylglycerol (named N-U-DAG) were analyzed. The optimized ultrasonic pretreatment conditions were: lard to GML mole ratio 3:1, enzyme dosage 6 %, ultrasonic temperature 80 °C, time 9 min, power 315 W. After ultrasonic pretreatment, the mixtures reacted for 4 h in a water bath at 60 °C, the content of DAG reached 40.59 %. No significant variations were observed between U-DAG and N-U-DAG in fatty acids compositions and iodine value, while P-U-DAG had lower unsaturated fatty acids than U-DAG. Differential scanning calorimetry analysis showed that the melting and crystallization properties of DAGs prepared by ultrasonic pretreatment significantly differed from lard. FTIR spectra noted transesterification reaction from lard and GML with and without ultrasonic pretreatment would not change the structure of lard. However, thermogravimetric analysis proved that N-U-DAG, U-DAG, and P-U-DAG had lower oxidation stability than lard. The higher the content of DAG, the faster the oxidation speed.

Unlocking the potential of transesterification catalysts for biodiesel production through machine learning approach.

The growing demand for fossil fuels has motivated the search for a renewable energy source, and biodiesel has emerged as a promising and environmentally friendly alternative. In this study, machine learning techniques were employed to predict the biodiesel yield from transesterification processes using three different catalysts: homogeneous, heterogeneous, and enzyme. Extreme gradient boosting algorithms showed the highest accuracy in predictions, with a coefficient of determination accuracy of nearly 0.98, as determined through a 10-fold cross-validation of the input data. The results indicated that linoleic acid, behenic acid, and reaction time were the most crucial factors affecting biodiesel yield predictions for homogeneous, heterogeneous, and enzyme catalysts, respectively. This research provides insights into the individual and combined effects of key factors on transesterification catalysts, contributing to a deeper understanding of the system.

Exploiting the Waste Biomass of Durian Shell as a Heterogeneous Catalyst for Biodiesel Production at Room Temperature.

Durian shell, a biomass waste, was simply burned and then could serve as a heterogeneous catalyst for the transesterification reaction of palm oil with methanol at room temperature. The chemical composition, structure, and morphology of the catalyst were well-characterized by XRD, BET, SEM, TEM, EDS, TGA, FT-IR, and XPS measurement. With the preparation temperature rising to 350 °C, the maximum yield of the biodiesel could reach 94.1% at room temperature, and the optimum reaction conditions were 8 wt.% catalyst, 8:1 methanol/oil molar ratio, ad 2.5 h reaction time. The characterizations results indicated that K2O and K2CO3 existed on the surface of catalyst, and a moderate amount of carbon, which acts as a carrier, attributed to the activity of the catalyst. After repeating five times, the catalyst prepared at 350 °C showed better stability than other catalysts. This might be because the incomplete combustion of the remaining carbon slowed down the loss of K to some extent.

Ultrasound-assisted Pickering Interfacial Catalysis for Transesterification: Optimization of Biodiesel Yield by Response Surface Methodology.

Recently, Pickering interfacial catalyst (PIC) was widely applied for liquid-liquid reactions, in view of not only intensifying the mass transfer through significant reducing both the drop sizes and the diffusion distance, but also supplying a flexible platform for the immobilization of valuable active sites. However, the restriction of the mobility of catalyst somehow decreases the activity of a catalyst. To obtain a promise reaction efficiency, we firstly report a synergistic method to enhance the biphasic reaction by Pickering emulsion and ultrasound concepts, targeted at efficient production of biodiesel. Response surface methodology based on Box-Behnken design was applied to optimize the reaction conditions, such as composition of catalyst, reaction temperature, ultrasound power, methanol to oil molar ratio and catalyst amount. An over 98% yield of biodiesel could be achieved within 2.5 hours by ultrasound assisted Pickering interfacial catalysis, which is over two times higher than that of ultrasound assisted homogeneous transesterification system. Besides, the ultrasound assisted Pickering emulsion shortened the reaction time by 3.6 fold when compared to mechanical stirring assisted Pickering emulsion system.

Comparative impact of exogenous phenylalanine on oenological isolates of Kluyveromyces marxianus and Saccharomyces cerevisiae.

AIMS: Kluyveromyces marxianus' high production of 2-phenylethyl acetate (2-PEA) via L-phenylalanine (Phe) catabolism makes it relevant for industries relying on the production of aroma compounds through fermentation processes. This study assessed the physiological impact of exogenous supplementation of Phe on cell viability, fermentation performance, and, by extension, on lipid and amino acid metabolism in a wine isolate of this yeast. METHODS AND RESULTS: The data showed that Phe exerted cytotoxic effects on K. marxianus IWBT Y885, which were minimal on Saccharomyces cerevisiae and impacted amino acid metabolism and aroma production. We demonstrated that K. marxianus strains fermented sugars more effectively in the absence of Phe. While lipid supplementation did not mitigate any deleterious effects of Phe, it supported viability maintenance and fermentation performance in the absence of Phe. Phe supplementation succeeded in augmenting the production of 2-PE and 2-PEA. CONCLUSIONS: The enhanced production of 2-PEA in K. marxianus suggests that this transesterification may be, at least in part, a compensatory detoxification mechanism for this yeast.

Methyl 2-naphthoates with anti-inflammatory activity from Morinda officinalis.

Chemical fractionation of the EtOH extract of the roots of a traditional Chinese herb, Morinda officinalis, afforded an array of methyl 2-naphthoate derivatives (1-9) including four pairs of enantiomers (1-4), two pimarane diterpenes and two ursane triterpenoids. Among them, eight compounds (1a/1b-3a/3b, 11 and 13) were reported in the current work for the first time. The structures of the new compounds, including their absolute configurations, were defined by spectroscopic analyses in combination with quantum chemical electronic circular dichroism (ECD) and gauge-independent atomic orbital (GIAO) NMR calculations. All the isolates were evaluated for their inhibitory effect on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in murine RAW264.7 macrophage cells, and the enantiomers 1a and 3b exhibited moderate activity with IC50 values of 41.9 and 26.2 µM. Meanwhile, compound 3b also dose-dependently inhibited the secretion of two pro-inflammatory cytokines TNF-α and IL-6 in the same cell model.

Black soldier fly (Hermetia illucens) larvae as potential feedstock for the biodiesel production: Recent advances and challenges.

Black soldier fly larvae (BSFL) Hermetia illucens is fastest growing and most promising insect species especially recommended to bring high-fat content as 5th generation bioenergy. The fat content can be fully optimized during the life-cycle of the BSFL through various organic dietary supplements and environmental conditions. Enriched fat can be obtained during the larval stages of the BSF. The presence of high saturated and unsaturated fatty acids in their body helps to produce 70 % of extractable oil which can be converted into biodiesel through transesterification. The first-generation biodiesel process mainly depends on catalytic transesterification, however, BSFL had 94 % of biodiesel production through non-catalytic transesterification. This increases the sustainability of producing biodiesel with less energy input in the process line. Other carbon emitting factors involved in the rearing of BSFL are less than the other biodiesel feedstocks including microalgae, cooking oil, and non-edible oil. Therefore, this review is focused on evaluating the optimum dietary source to produce fatty acid rich larvae and larval growth to accumulate C16-18 fatty acids in larger amounts from agro food waste. The process of optimization and biorefining of lipids using novel techniques have been discussed herein. The sustainability impact was evaluated from the cultivation to biodiesel conversion with greenhouse gas emissions scores in the entire life-cycle of process flow. The state-of-the-art in connecting circular bioeconomy loop in the search for bioenergy was meticulously covered.

Application of dewatered paper sludge-derived porous solid base catalyst for biodiesel production: Physicochemical properties, reaction kinetics and thermodynamic studies.

A new porous solid base catalyst was prepared using dewatered paper sludge and successfully employed to produce biodiesel from soybean oil. The as-prepared catalyst was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transforms infrared spectroscopy, X-ray photoelectron spectroscopy, thermal gravity/differential thermal gravity analysis, Brunauer-Emmet-Teller analysis, and CO2-temperature programmed analysis. The results showed that the formation of CaO and uniformly distributed porous structure should account for the high catalytic activity of the as-prepared catalyst. The optimum reaction conditions were observed at 180 ℃, 8 wt.% catalyst/oil weight ratio, 16:1 methanol/oil molar ratio, and 300 min reaction time with 91.6% biodiesel yield. After being used several times and recycled, the regenerated catalyst still exhibited effective catalytic activity without apparent deactivation. The kinetic study confirmed that the experimental data satisfied with Pseudo-first-order kinetic model controlled by reaction temperature and catalyst/oil weight ratio. The reaction activation energy was 24.98 kJ/mol. The change of enthalpy ΔH (14.98 kJ/mol), entropy ΔS (-208.57 J/mol/K), and Gibbs free energy ΔG (109.46 kJ/mol) indicated that the transesterification reaction catalyzed by the dewatered paper sludge-derived catalyst is endothermic, endergonic, and non-spontaneous. Our research finding indicated that the CaO-based catalyst derived from dewatered paper sludge was an economically promising and eco-friendly solid base catalyst for biodiesel production.

Transesterification of castor oil catalyzed by a fermented solid produced by Burkholderia contaminans using a bioreactor coupled with ultrasound irradiation.

In this work, ultrasound was used to assist the ethanolysis of castor oil in a solvent-free system, catalyzed by a dry fermented solid containing the lipase from Burkholderia contaminans (BCFS). Reactions were done at 45°C. The maximum conversion in Erlenmeyer flasks was 71% in 96 h, using a loading of 9% (mass of BCFS in relation to the mass of triacylglycerols in the castor oil) and a molar ratio of ethanol:oil of 6:1, with addition of ethanol in 12 steps. In a packed-bed reactor containing 12 g of BCFS, the conversions were 78% in 48 h, and 83% in 72 h with an ethanol to oil molar ratio of 3:1 and treatment with an ultrasound probe, with maximum power of 500 W, frequency of 20 kHz, and 75% of the maximum power. These results are promising given that, with an ultrasound assisted bioreactor, a higher conversion in a shorter time was achieved, with a lower ethanol to oil molar ratio than was the case in the Erlenmeyer flasks without ultrasound.

Ultrasound-assisted enzymatic indirect determination of total 3-monochloropropane-1,2-diol esters in canned fish oil fraction.

A novel, fast, and cost-effective indirect enzymatic method was successfully developed to assess the total 3-monochloropropane-1,2-diol (3-MCPD) in canned food's oil fraction by the action of Burkholderia cepacia lipase. The total 3-MCPD were derivatized with n-Heptafluorobutyrylimidazole (HFBI) for GC-MS analysis during dispersive liquid-liquid microextraction (DLLME). An asymmetrical 2213//8 screening design was used to study the influence of critical factors on the method's effectiveness. The analytical features of the proposed method were assessed following Food and Drug Administration (FDA) guidelines using extra virgin olive oil (EVOO) as a blank sample. Outstanding results were achieved in terms of linearity (r2 = 0.9995), sensitivity, precision (2.1 % to 10.4 % RSD), and accuracy (98.7 % ≤ recovery ≤ 101.9 %). Method efficacy was tested by comparing the results of 10 edible oils for total 3-MCPD with those reported in previous works. A total of 41 samples were analyzed. The lowest 3-MCPD content was found in samples of albacore canned in EVOO oil, while the highest amounts were found in albacore, mackerel, and Atlantic saury samples, all preserved in refined sunflower oil.

Ball-milling as effective and economical process for biodiesel production under Kraft lignin activated carbon stabilized potassium carbonate.

Biodiesel is a typical renewable energy and the previous transesterification processes for biodiesel production mainly focus on thermocatalytic methods. In this paper, the ball-milling process was investigated into the biodiesel production under Kraft lignin activated carbon stabilized K2CO3. Biodiesel yield increased to 66 % after only 5 min and reached 100 % within 25 min under optimal ball-milling conditions (0.5 g of the catalyst; methanol/oil molar ratio 18:1; 195 g of ball-mill beads; 1400 rpm; 25 °C). The power demand between the thermocatalytic method and the ball-milling method was also compared. Based on the computation, the ball-milling method has lower power demand than the traditional method (38 vs 201 kWh·mol-1). Therefore, the ball-milling method is an effective and economical process for biodiesel production.

Sustainable Castor Bean Biodiesel Through Ricinus communis L. Lipase Extract Catalysis.

The rise in oil prices, global warming, and the depletion of nonrenewable resources have led researchers to study sustainable alternatives to increasing energy demand. The autocatalysis from castor oil and castor lipases to produce biodiesel can be an excellent alternative to reduce the production costs and avoid the drawbacks of chemical transesterification. This study aimed to evaluate the catalytic activity of castor bean lipase extract (CBLE) on three vegetable oils hydrolysis, to obtain and enhance biodiesel yield by an autocatalysis from castor oil and CBLE. Furthermore, the enzymatic biodiesel physicochemical quality was analyzed. The enzymatic activity for olive oil was 76.12 U, 90.06 U for commercial castor oil, and 75.60 U in raw castor oil. The hydrolysis percentages were high at 25 °C, pH 4.5, for 4 h with 97.18% for olive oil, 98.86%, and 96.19% for commercial and raw castor oil, respectively. The CBLE catalyzed the transesterification reaction on castor oil to obtain 82.91% biodiesel yield under the selected conditions of 20% lipase loading, 1:6 oil/methanol molar ratio, and 10% buffer pH 4.5, 37 °C for 8 h. The castor biodiesel quality satisfied the ASTM-D6751 (USA) and EN-14214 (European Union) values, except for the density, viscosity, and moisture, as expected for this kind of biodiesel.

Kinetic studies on the extraction of oil from a new feedstock (Chukrasia tabularis L. seed) for biodiesel production using a heterogeneous catalyst.

This study has identified a new feedstock Chukrasia tabularis L. (C. tabularis) seed for the production of biodiesel. Oil was extracted from the seeds with and without autoclave-assisted ultrasonic homogenization (AUH) pretreatment using different solvents. The solvent n-hexane with AUH pretreatment yielded a maximum oil yield of 32 wt%. The kinetics and thermodynamics of the extraction process were studied in a batch. The data showed that extraction followed first-order kinetics with a rate constant of 1.4 × 10-4 min-1, activation energy of 63.604 kJ mol-1 and pre-exponential factors of 66.66 × 104 s-1. The physiochemical properties of the oil were determined from which it was identified that C. tabularis oil has high free fatty acid (FFA) content, requiring a single-step esterification cum transesterification reaction to produce biodiesel economically. The modified aryl diazonium salt reduction process was used to synthesize a heterogeneous acid catalyst (HAC) from activated carbon precursor and was used to catalyze biodiesel reaction. Furthermore, HAC was characterized by different analytical techniques and it was found that it had an acid site density of 1.02 mmol g-1 and a specific surface area of 602 m2 g-1. The parameters affecting the biodiesel process were studied to obtain a maximum biodiesel conversion of 98.5% at 6 wt% catalyst loading, 15:1 methanol to oil molar ratio, 120 min reaction time, 70 ºC reaction temperature, and 500 rpm stirring rate. Reusability studies were performed which showed that HAC can be recycled up to five cycles with a conversion above 90% in the fifth cycle. Moreover, the fuel properties of biodiesel were determined using standard methods and were compared with ASTM D6751 and EN14241 standards.