Conversion Of Free Fatty Acids Research Articles

Two-stage co-pyrolysis of Kraft lignin and palm oil mixture to biofuels: The role of lignin as a methylation agent for methyl ester formation

In this work pyrolysis of palm oil and lignin has been investigated using a two-stage process at 550 °C, with a first step configuration of continuous condensation for vapors and separation of gases, and a second step with distillation of vapors. Experiments were realized as pyrolysis of palm oil, palmitic acid, and Kraft lignin, as well as co-pyrolysis of palm oil/lignin, palmitic acid/lignin and palmitic acid/guaiacol. It has been shown that the addition of lignin improves the quality of palm oil pyrolysis bio-oil, thanks to the conversion of fatty acids coproduct to fatty acid methyl esters (FAME). The production of methyl esters in the reaction environment using palm oil and lignin was studied by conducting experiments with palmitic acid and lignin, as well as palmitic acid and guaiacol (the main product obtained from lignin pyrolysis). The results highlighted that during pyrolysis, the production of FAME is a consequence of a direct esterification reaction on palmitic acid. The formation of FAMEs during pyrolysis presents a promising avenue to optimize the utilization of palm oil by generating FAMEs as supplementary fuel products, Furthermore, it is possible to consider the application of the studied process for the conversion of free fatty acids into FAME.

Preparing vegetable oils-based metalworking fluids by a hydrolysis-esterification two-step process

Oil-soluble esters of free fatty acids were synthesized with a 2-step process including the first step of reacting vegetable oil with water in the presence of sulfuric acid and p-Toluenesulfonic acid as a catalyst, followed by removing water and glycerol, and the second step of reacting the obtained free fatty acids with various polyhydric and fatty alcohols. The best conditions were 190 °C, 6 h, 30 to 1 water to oil molar ratio, 5 wt% PTSA catalyst loading in the hydrolysis reaction (the 1st step), and 150 °C, 10 h, 4 to 1 fatty acid to trimethylolpropane molar ratio, 1 wt% PTSA catalyst loading in the esterification reaction (the 2nd step). Under the best conditions, the process achieved the final product with the 87% yield of free fatty acid trimethylolpropane ester and 82% conversion of free fatty acid. Different esters were made concurring to the aforementioned conditions with distinctive polyhydric and fatty alcohols. Hydrolysis reactions facilitated by catalysts offer an alternative approach to traditional hydrolysis in supercritical conditions, enabling efficient substrate conversion under milder operating conditions. Furthermore, the inclusion of the obtained esters mixed with base oil and additives produced bio-based metalworking fluids with exceptionally lubricant performance in wear resistance, with a wear scar diameter of 0.33 mm.

Utilization of Keplerate-type polyoxomolybdates {Mo132} supported on hierarchical porous SOM-ZIF-8 as reusable catalyst boosts biodiesel production from acidic soybean oils by simultaneous transesterification-esterifications

Improving the reactant mass transfer on the catalyst surface is a feasible approach to fabricate a robust solid catalyst for efficiently promoting the biomass macromolecules-involving reactions, specifically for biodiesel production by using non-edible acidic oils as feedstocks. In this premise, to reduce the mass transfer resistance, the hierarchical porous SOM-ZIF-8 was firstly synthesized using polystyrene spheres (PS) as templates and then employed as catalyst supports for loading of Keplerate-type polyoxomolybdates {Mo132} to prepare a novel {Mo132}@SOM-ZIF-8 solid acid catalyst. The catalyst characterization results revealed that the active species of {Mo132} clusters were well-dispersed on the SOM-ZIF-8 support and the primary framework of the SOM-ZIF-8 support remained nearly unaltered after the preparation processes. This prepared catalyst featured three-dimensional ordered hierarchical porous structure and dual Bronsted-Lewis acid sites, with a large surface area of 736.26 m2/g and high acidity of 903 μmol/g, presenting high activities for concurrent triglyceride transesterification and free fatty acids (FFAs) esterification. With the acidic soybean oils as feedstocks, 93.9 % of oil conversion and full FFA conversion to biodiesel were achieved over this solid catalyst at 130 °C for 8 h with a catalyst loading of 2 wt%, thus imparting the great potential for a one-pot efficient biodiesel manufacture from the acidic oils to comply with the demand of green and clean production. The synergy between the hierarchical porous structure and the strong acidity emerged, thus boosting the catalytic performance of this solid catalyst for the heterogeneous biodiesel production. The good FFA and moisture-resistance capacity was shown for this catalyst even in the case of moisture content of 3 % and FFA content of 25 %. Further, this catalyst showed excellent reusability without significantly losing its catalytic performance even after five runs, providing a deeper insight into constructing efficient solid catalysts with hierarchical porous structure that are utilized for cost-effective production of biodiesel from the non-edible acidic oils.

Hierarchical porous SAPO-34 decorated with Mo and W oxides for concurrent transesterification-esterifications for efficient biodiesel production from acidic soybean oil

Hierarchical porous materials have gained much attention as promising heterogeneous catalyst supports due to their high efficiency of mass transfer and high exposure of active centers. In this research, the hierarchical porous SAPO-34 support with microporous, mesoporous, and macroporous hierarchical structure was initially prepared by in-situ alkali etching. Then, Mo and W oxides were incorporated into this hierarchical porous support by using the impregnation method to prepare Mo15W15/HSAPO-34/70 catalyst. This developed catalyst was applied to concurrently catalyze the oil transesterification and free fatty acid (FFA) esterification to biodiesel as the low-value oils severed as feedstocks. The textural and physicochemical properties of the nanocatalysts were evaluated by XRD, XPS, SEM, EDS, TEM, UV–vis, NH3-TPD, Py-FTIR, and nitrogen porosimetry measurement. This catalyst had hierarchical porous structure to ameliorate the large oil molecular transfer, and featured dual Brønsted-Lewis acid sites to synergistically boost the catalytic efficiency for the biodiesel production. Over this catalyst, the oil conversion of 90.1 % and full FFA conversion were achieved under optimized operation conditions, therefore imparting to one-pot conversion to biodiesel with low-value oils as feedstocks. In addition, this catalyst not only exhibited superior tolerance to moisture and FFAs, but also retained high activities after five reuse cycles, thus revealing its tremendous potential of being used in durable and efficient biodiesel production. The present work opens a new avenue for synthesizing a robust solid acid catalyst to achieve a one-pot biodiesel production from low-value oils.

Ultrasound intensification of two‐stage biodiesel production: optimization for palm empty fruit bunch oil as a palm oil industry by‐product

AbstractPalm empty fruit bunch oil (palm EFB oil) is a waste product that can be used to produce biodiesel at a low cost. However, high free fatty acid (FFA) content is the primary obstacle to biodiesel production. Before the transesterification process can begin, the oil must be esterified to reduce its acid content. This study seeks to employ dual‐frequency ultrasound at frequencies of 28 kHz (200 W) and 40 kHz (200 W) to aid in the esterification and transesterification of ZSM‐5‐38 and CaO catalysts, respectively. Central composite design and response surface methodology were used to determine the optimal conditions for the three primary parameters of methanol to oil (M:O molar ratio), catalyst loading and reaction time. A 12:1 M:O molar ratio, 11.36 wt% catalyst loading (ZSM‐5‐38) and 60 min of reaction duration were the optimal conditions for esterification to achieve a FFA conversion of 91.51%. The reusability of ZSM‐5‐38 revealed a decrease in FFA conversions of 87.36, 75.11, 67.13 and 58.68% with each reused cycle. The optimal transesterification conditions were a 3.28:1 M:O molar ratio, 4.62 wt% catalyst loading (CaO) and 64 min of reaction time, yielding 83.58% biodiesel. The viscosity value (D 445), the flash point (D 93) and the heating value (ASTM D240) of biodiesel produced under optimal conditions were evaluated. The biodiesel properties were determined to be 4.7931 mm2/s, 176°C and 40 398 kJ/kg, respectively.

Amyloid β Induces Lipid Droplet‐Mediated Microglial Dysfunction in Alzheimer’s Disease

AbstractBackgroundSeveral microglia‐expressed genes have emerged as top risk variants for Alzheimer’s disease (AD) that are involved in lipid droplet (LD) formation and processing. Impaired microglial phagocytosis is one of the main proposed outcomes by which these AD‐risk genes may contribute to neurodegeneration, but the mechanisms translating genetic association to cellular dysfunction remain unknown. LD accumulation in aging (Nat Neurosci. 23(2),194‐208, 2020) appears to increase microglial inflammatory responses, while inflammatory challenges increase LD formation, thereby potentially setting up a feed‐forward injury that could contribute to the relentless progression in AD.MethodLD formation is dependent upon age and disease progression, and is more prominent in the hippocampus in brains from human patients and the AD mouse model 5xFAD. Despite variability in LD load between microglia from male versus female animals and between cells from different brain regions, LD‐laden microglia exhibited a deficit in amyloid‐beta (Aβ) phagocytosis evaluated using AβpH ‐ a human Aβ1‐42 analog that exhibits fluorescence upon lysosomal internalization (Chem Sci. 12, 10901‐10918, 2021). Extensive unbiased lipidomic and metabolomic profiling in microglia identified a substantial decrease in free fatty acids (FFAs) and a parallel increase in triacylglycerols (TAGs) as the key metabolic transition underlying LD formation.ResultWe show that microglia form LDs upon exposure to Aβ, and that their LD load increases with proximity to amyloid plaques in brains from human patients and the AD mouse model 5xFAD. Mechanistically, Aβ alone is sufficient to induce LD formation in microglia and that this conversion requires a specific metabolic conversion of FFAs to TAGs (the building blocks of LDs). This conversion is likely protective for the brain and microglia, as we recently showed that long‐chain saturated FFAs can be neurotoxic (Nature 599,102‐107, 2021), but it is not without cost for microglial phagocytic abilities. We demonstrate that a key enzyme for the conversion of FFAs to TAGs, promotes microglial LD formation, is increased in microglia from 5xFAD and human AD brains, and that inhibiting it improved microglial uptake of Aβ.ConclusionThese findings identify a new lipid‐mediated mechanism underlying microglial dysfunction that could become a novel therapeutic target for AD.

Esterification effect on the recovery of vitamin E from palm oil refining residues by molecular distillation

AbstractWaste edible oils are an alternative source of high‐value natural compounds. Vitamin E can be recovered from palm oil refining residues by molecular distillation. However, the presence of other lipophilic molecules compromises the selective separation of vitamin E. Esterification of the free fatty acids can enhance the selective separation of vitamin E by molecular distillation, but the conditions for carrying out the reaction need to be investigated to simultaneously ensure the conversion of free fatty acids and the reduction of vitamin E losses. Thus, this study investigated the effect of the esterification of the industrial waste on the recovery of vitamin E by molecular distillation. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and analysis for fats and oils preconized by the American Oil Chemists' Society (AOCS) were used in the characterization of the industrial waste. Determination of the best condition to carry out the reaction was obtained by a central composite rotational design (CCRD) using the response surface methodology (RSM) and the desirability profile. The results showed that the best condition for the esterification was at 64°C, 213 min, 2 wt.% sulphuric acid, and a 10/1 methanol/free fatty acids molar ratio. This reaction condition achieved 97.9% conversion of free fatty acids and less than 3% of vitamin E loss. The esterification promoted concentration of vitamin E in the residue stream (145.4%) and reduction in the distillate stream (87.8%). Therefore, the obtained results presented a suitable route to obtaining vitamin E concentrate and adding value to an industrial residue.

Investigating biodiesel production from Chicken fat oil using bi-functional catalysts and microbubble mediated mass transfer

Biodiesel production has been limited by slow kinetics of acid catalyzed esterification, downstream product separation before transesterification and expensive feedstock. Bi-functional catalysts can carry out esterification and transesterification simultaneously. However, an energy efficient method is still required to enhance the kinetics of esterification. Similarly, the thermodynamic equilibrium hindering the overall conversion of the esterification needs to be manipulated to increase the overall conversion of the process. The manuscript proposes a new bi-functional catalyst, 7 % Sr/ZrO2, along with microbubble mediated injection of alcohol. The conversion of free fatty acids (FFA) and Triglycerides by bi-functional catalysts was compared with three naturally occurring bi-functional catalysts- Zwitterions. Chicken fat oil was chosen as the feedstock. Preliminary experiments were conducted to select alcohol. Experiments were designed using Response Surface Methodology. The current study shows that the use of heterogeneous catalysts and CFO as a feedstock has lucrative potentials. The rate of reaction and conversion of the process are further increased by overcoming the thermodynamic equilibrium using microbubble mediated mass transfer increasing process feasibility. Response Surface Methodology (RSM) was used to design the experiments. 7 % Sr/ZrO2 was found to give significantly higher conversion of triglycerides as compared with the Zwitterions. However, conversion of FFA using Aspartic acid was almost similar to 7 % Sr/ZrO2. For triglycerides and FFA, the conversion of CFO at optimize conditions using (Molar ratio = 1: 14, temperature 70 °C, and catalyst loading 1 %) was 75 % and 57 %, as compared with aspartic acid (61 % and 63 %), arginine (58 % and 73 %), and isoleucine (54 % and 39 %) respectively. Detailed comparison between other reported bi-functional catalysts showed that 7 %Sr/ZrO2 yielded a high conversion in significantly less time. The higher performance can be attributed to the use of microbubble mediated mass transfer. The results indicate that integration of microbubble mediated mass transfer and a bi-functional catalyst can accelerate the industrial reactive separations comprising biodiesel production.

Homogenizer-intensified amidation of free fatty acids in waste cooking oil for biodiesel production

Biodiesel production from waste cooking oil is a viable alternative both to satisfy renewable energy demand and utilize a low-cost feedstock. However, a preparatory procedure is required to reduce free fatty acid contained in waste cooking oil to a specific value which is time- and energy-extensive. Herein, a fast and non-catalytic amidation reaction performs at room temperature is established as an alternative method to reduce the free fatty acid level. The effect of the molar ratio of waste cooking oil to monoethanolamine, reaction time and rotational speed of homogenizer were investigated on the conversion of free fatty acid to alkanolamide compounds. The highest conversion of 95.9 ± 0.02% was achieved in presence of a molar ratio of 1:1.5, reaction time of 0.5 min and rotational speed of 5000 rpm. Further, a homogenizer was used to facilitate the transesterification reaction using an alkaline catalyst at room temperature. The conversion of waste cooking oil to biodiesel of 91.4 ± 0.2% was achieved after 5 min of reaction time. In terms of processing parameters, the non-catalytic amidation and alkaline base catalytic transesterification reaction assisted by a homogenizer device is a time-saved process as it could save 92% and 94% of reaction time compared to one- and two-steps method and was performed in ambient condition.

Two-Stage Conversion of Used Cooking Oil to Biodiesel Using Ion Exchange Resins as Catalysts

This study focuses on the development of a novel two-stage (esterification–transesterification) synthesis of biodiesel from used cooking oil (UCO) using ion exchange resins as catalysts. Esterification of the UCO has been conducted using various types of ion exchange resin catalysts. Purolite D5081, a hyper cross-linked resin, showed the best catalytic performance among all the catalysts investigated, with 92% of free fatty acid (FFA) conversion. The transesterification of pre-treated used cooking oil (P-UCO) was carried out sequentially using several acidic and basic ion exchange resin catalysts. In the screening process, the Diaion PA306s catalyst showed the best catalytic performance and was selected for the optimisation study. A triglyceride conversion of ca. 75% was recorded at the optimum reaction conditions (9% (w/w) catalyst loading, 328 K reaction temperature, 18:1 methanol to P-UCO feed mole ratio, and 350 rpm stirring speed). Furthermore, the reusability study of the Diaion PA306s catalyst gave a similar triglyceride conversion after a couple of cycles without losing its catalytic activity. A dry purification technique was found to give the lowest percentage of glycerides and glycerine content and, therefore, was chosen as the best biodiesel purification route.

Intensification and Optimization of FAME Synthesis via Acid-Catalyzed Esterification Using Central Composite Design (CCD).

The acid-catalyzed pre-treatment esterification process is required for low-cost feedstock with high free fatty acids (FFAs) to avoid the saponification that occurs during alkali-catalyzed transesterification for the production of fatty acid alkyl esters (FAAE). Reverse hydrolysis in acid-catalyzed esterification causes a decrease in fatty acid methyl ester (FAME) yield. Therefore, the esterification process must be intensified. This study aims to develop and optimize a low-temperature intensification process to enhance biodiesel yield and reduce energy consumption. Three intensification systems were studied: co-solvent technique, co-solvent coupled with adsorption of water using molecular sieves, and entrainer-based continuous removal of water. The process variables of esterification reaction in co-solvents without the adsorption system were optimized by using central composite design (CCD). The study showed that the co-solvent without the adsorption system was effective in intensifying the FFA conversion (XFFA) at low temperatures, compared to the other two systems, due to the dilution effect at high co-solvent/entrainer amount required for sufficient vapors in the adsorption system. Optimized process variables have achieved 95% XFFA within 75 min at 55 °C, 20 mL/100 g of oil DEE, 9 MR, 3 wt % H2SO4, and 320-350 RPM in a co-solvent without the adsorption system.

Sulfation of metal-organic framework (MOF) nanocatalyst for esterification of oleic acid with methanol to produce biodiesel

Background: Metal-organic frameworks (MOFs) represent tremendous potential as heterogeneous catalyst in renewable energy production. In this study, biodiesel production using the modified MOF nanocatalyst was investigated in the esterification reaction. Methods: MOF nanocatalyst was prepared using solvothermal method and modified through sulfation process. The nanocatalysts was characterized by XRD, FT-IR, FE-SEM, TEM, N2 adsorption-desorption, and NH3 -TPD techniques. The performance of the nanocatalysts was evaluated in the esterification reaction of free fatty acid (FFA) at different operating conditions. Results: The results showed the high crystallinity, appropriate textural properties (995.6 m2 g-1), well-adjusted acidity, and high hydrophobicity. The sulfation degree of 4 cc g-1 resulted in the best nanocatalyst, which led to the highest FFA conversion (97%) at the optimal conditions: methanol to FFA ratio of 10:1, 3wt.% nanocatalyst, 160 °C, and 6 hours. Surprisingly, the developed nanocatalyst had a great reusability while the conversion reduction was only 8% after six sequence cycles. Conclusion: These results proved the high capability of the developed nanocatalyst in the esterification reaction to produce biodiesel.

Application of Quaternary Ammonium-Based Deep Eutectic Solvents as Catalysts for the Glycerolysis of Free Fatty Acids

Nonedible waste sourced lipids such as fatty acid distillates, brown grease, and animal tallow, among many others, are excellent alternatives for expanding the feedstock inventory for biodiesel synthesis. A quaternary ammonium-based deep eutectic solvents (DESs) was used as a catalyst in the glycerolysis of free fatty acids (FFAs) in this study. Reaction optimization was carried out with oleic acid as the model molecule, followed by an in-depth examination of the reaction mechanism. Optimum conditions such as 130 °C and 10 wt % catalyst dosage with 10 min of reaction time gave an equilibrium conversion of 94%. The catalyst was found to remain in the glycerol phase allowing its reuse. Palm fatty acid distillate, brown grease, and crude glycerol were utilized for testing the novel DES at optimum conditions. FFA conversion was found to be 94% for both palm fatty acid distillate and brown grease. In the case of crude glycerol, FFA conversion decreased proportionally to the impurity level. Water was responsible for restricting equilibrium conversion and decreasing catalyst recyclability, necessitating further research into effective removal during the reaction. Aggressive nitrogen purging to remove water during the reaction pushed the reaction toward near-completion in 60 min. The catalyst reusability study showed a drop in equilibrium conversion to 62.5% at the end of the 5th cycle, even when water was removed.

Box-Behnken Design for Optimization on Esterification of Free Fatty Acids in Waste Cooking Oil Using Modified Smectite Clay Catalyst

A potential alternative fuel option is biodiesel, which is produced mostly from natural resources due to the limited availability of petroleum supplies and environmental issues. Waste cooking oil (WCO) containing a high concentration of free fatty acid (FFA) can be transformed into biodiesel, which substantially benefits the environment and for reducing the fuel . The use of smectite clay as a catalyst in the esterification reaction of WCO with methanol was studied. Smectite was chemically activated by sulfuric acid (H2SO4) to obtain the acid-modified smectite. The utilization of an acid-catalyzed esterification procedure as a pre-treatment for WCO for biodiesel synthesis has been studied in some detail. However, there aren't many effective ways to optimize this operation. The process variables used in this study's esterification of FFAs in WCO were optimized using a Box-Behnken design (BBD). At atmospheric pressure, the catalyst amount of 5.03 wt%, the methanol to WCO molar ratio of 22.38, and the reaction time of 3.01 h are the optimal running parameters for accomplishing 97.96% FFA conversion. The catalyst was employed five times in a row without noticeably lowering its catalytic effectiveness. The results showed that smectite clay is an essential, low-cost, and recyclable catalyst for the esterification of FFA in WCO.

Design of a New Chemoenzymatic Process for Producing Epoxidized Monoalkyl Esters from Used Soybean Cooking Oil and Fusel Oil

The aim of this study was to produce epoxidized monoalkyl esters (EMAE), a valuable class of oleochemicals used in a wide range of products and industries, from used soybean cooking oil (USCO) and fusel oil via a three-step chemoenzymatic process. This process consists of a first enzymatic hydrolysis of USCO to produce free fatty acids (FFA). Here, five microbial lipases with different specificities were tested as biocatalysts. Full hydrolysis of USCO was obtained after a 180 min reaction time under vigorous stirring (1500 rpm) using a non-specific lipase from Candida rugosa (CRL). Then, monoalkyl esters (MAE) were produced via the esterification of FFA and fusel oil in a solvent-free system using the lipase Eversa® Transform 2.0 (ET2.0) immobilized via physical adsorption on poly(styrenene-divinylbenzene) (PSty-DVB) beads as a biocatalyst. Different water removal strategies (closed and open reactors in the presence or absence of molecular sieves at 5% m.m−1) on the reaction were evaluated. Maximum FFA conversions of 64.3 ± 2.3% (open reactor after a 30 min reaction time) and 73.5 ± 0.4% (closed reactor after a 45 min reaction time) were observed at 40 °C, using a stoichiometric FFA:fusel oil molar ratio (1:1), without molecular sieves, and 5 mg of immobilized protein per gram of reaction mixture. Under these conditions, maximum FFA conversion was only 30.2 ± 2.7% after a 210 min reaction time in a closed reactor using soluble lipase. Reusability tests showed better retention of the original activity of immobilized ET2.0 (around 82%) after eight successive batches of esterification reactions conducted in an open reactor. Finally, the produced MAE was epoxidized via the Prilezhaev reaction, a classical chemical epoxidation process, using hydrogen peroxide and formic acid as a homogeneous catalyst. The products were characterized by standard methods and identified using proton nuclear magnetic resonance (1H NMR). Maximum unsaturated bond conversions into epoxy groups were at approximately 33%, with the experimental epoxy oxygen content (OOCexp.) at 1.75–1.78%, and selectivity (S) at 0.81, using both MAEs produced (open or closed reactors). These results show that this new process is a promising approach for value-added oleochemical production from low-cost and renewable raw materials.

Obtaining hydrolysate from macauba oil and its application in the production of methyl esters

This work aimed to obtain a hydrolyzate rich in free fatty acids (FFA) from the hydrolysis of macauba oil for subsequent esterification and obtaining of methyl esters. To determine the conditions that maximize FFA yield in the hydrolysis step, the effects of buffer solution percentage and catalyst concentration (Lipozyme® RM IM) were determined at 55 ºC and 6 h. From the results, it was verified that both variables evaluated in the experimental range had an influence on the reaction and their increase favored the production of FFA. Additional experiments were carried out to assess the influence of reaction time with a progressive increase up to 8 h. Hydrolyzate with ~92 wt % FFA was obtained and its use in the enzymatic esterification step using Novozym® 435 as catalyst resulted in ~95 % FFA conversion. Regarding the reuse of enzymes at each stage, a ~50 % reduction in FFA yield was found and only 98 % FFA conversion.

Conversion of Free Fatty Acid in Calophyllum inophyllum Oil to Fatty Acid Ester as Precursor of Bio-Based Epoxy Plasticizer via SnCl2-Catalyzed Esterification.

The preparation and application of bio based plasticizers derived from vegetable oils has gained increasing attention in the polymer industry to date due to the emerging risk shown by the traditional petroleum-based phthalate plasticizer. Epoxy fatty acid ester is among the prospective alternative plasticizers since it is ecofriendly, non-toxic, biodegradable, low migration, and low carbon footprint. Epoxy plasticizer can be synthesized by the epoxidation reaction of fatty acid ester. In this study, the preparation of fatty acid ester as a green precursor of epoxy ester plasticizer was performed via esterification of free fatty acid (FFA) in high acidic Calophyllum inophyllum Seed Oil (CSO) using methanol in the presence of SnCl2.2H2O catalyst. The analysis of the process variables and responses using Box-Behnken Design (BBD) of Response Surface Methodology (RSM) was also accomplished. It was found that the quadratic model is the most appropriate model for the optimization process. The BBD analysis demonstrated that the optimum FFA conversion and residual FFA content were 75.03% and 4.59%, respectively, achieved at the following process condition: a reaction temperature of 59.36 °C, a reaction time of 117.80 min, and a catalyst concentration of 5.61%. The fatty acid ester generated was an intermediate product which can undergo a further epoxidation process to produce epoxy plasticizer in polymeric material production.

ZrMo oxides supported catalyst with hierarchical porous structure for cleaner and sustainable production of biodiesel using acidic oils as feedstocks

Ameliorating the reactant mass transfer and fabricating the multiple active sites on the catalyst surface are feasible strategies to synthesize efficient and recyclable catalysts for efficient biodiesel production by using acidic oils as feedstocks. Herein, hierarchical porous solid acids with Zr and Mo oxides as active sites were prepared by using polystyrene spheres (PS) and P123 as templates. It was shown that the active species of Zr and Mo oxides were uniformly dispersed on the hierarchical porous silica support, and the solid catalysts featured high surface area and interconnected mesoporous/macropores with high mass diffusive extent, showing improved catalytic performances for the biodiesel production as compared to the control catalyst without hierarchical pores, owing to the mass transfer enhancement and more easily accessible active sites. The transesterification reaction in 93.8% of oil conversion as well as complete conversion of free fatty acids (FFAs) were simultaneously performed by using this solid catalyst, hence achieving one-pot transformation of acidic oils to biodiesel and minimizing the complex and tedious separation process. Moreover, the higher water and FFA-resistance capacity was shown for this solid catalyst, posing its more suitable for the biodiesel production with acidic oils as feedstocks. This hierarchical porous solid catalyst could be facilely recycled using simple filtration, and still maintained high activities after reuse for five runs, which rendered it to have the potential of cost-effective production of biodiesel in particular from low-grade acidic oils.

Exploiting the Complementary Potential of Rice Bran Oil as a Low-Cost Raw Material for Bioenergy Production

Rice is one of the most consumed cereals in the world. From rice processing, rice bran is obtained, and only a part of this by-product is effectively used. Rice bran oil can be obtained and used as an alternative feedstock for biodiesel production, although few studies exist to support its exploitation. In addition, pretreatment is required to reduce its acidity and allow for its integration in the conventional industrial process. This work evaluated two pretreatment processes aiming to reduce the free fatty acids (FFAs) content of rice bran oil by employing an acid-catalyzed process and a biocatalyzed process. The results allowed us to assess the efficiency and effectiveness of both pretreatments. For that purpose, acid (45, 55 and 65 °C, using H2SO4 concentrations of 2 wt.% or 4 wt.% and a methanol:oil molar ratio of 9:1) and enzymatic FFAs conversion (35 °C using a 6:1 methanol:oil molar ratio and 5 wt.% of Thermomyces lanuginosus) were evaluated using rice bran oil with an acid value around 47 mg KOH.g−1, and the reaction kinetics were assessed. Acid esterification enabled a 92% acidity reduction (65 °C, 4 wt.% of catalyst) after 8 h, with the final product presenting an acid value of 3.7 mg KOH.g−1 and a biodiesel purity of 42 wt.%. The enzymatic process allowed an acidity reduction of 82%, resulting in a product with an acid value of 7.0 mg KOH.g−1; however, after 24 h, the biodiesel purity was 87 wt.% (almost a two-fold increase compared to that obtained in the homogeneous process), revealing the conversion of both free fatty acids and glycerides. The study of the reaction kinetics of the homogeneous (acid) esterification showed that, for temperatures > 45 °C, the constant rate increased with temperature. A higher constant rate was obtained for the temperature of 55 °C using 4 wt.% of catalyst (k′ = 0.13 min−1). For the heterogeneous (enzymatic) esterification, the constant rate obtained was lower (k′ = 0.028 min−1), as expected. The study revealed the technical viability of the esterification pretreatment of rice bran oil and the important parameters concerning the performance of the pretreatment solutions. Finally, the enzymatic process should be further explored, aiming to develop more ecofriendly processes (water and energy savings) to produce biodiesel from oils with a high acidity (low-cost raw materials).

Kinetic Parameters Investigation for The Esterification of Free Fatty Acid from Coconut Oil Mill Waste using Montmorillonite-Sulfonated Carbon from Glucose Composite Catalyst

Coconut oil mill waste (CMW) contained high free fatty acid (FFA) content which potentially could be converted into a value-added product such as fatty acid methyl ester (FAME). In this study, a montmorillonite-sulfonated carbon catalyst was used to evaluate the kinetic parameter of FFA conversion from CMW into FAME. The characterization of FTIR and SEM-EDX confirmed that the -SO3H groups were successfully incorporated into montmorillonite- carbon catalyst. The highest catalyst acidity (9.4 mmol/g) was achieved by a ratio of montmorillonite to sulfonated carbon of 1:3 % w/w. The kinetic study using montmorillonite-sulfonated carbon 1:3 % w/w showed that the reaction temperature and molar ratio of methanol to FFA (% v/v) were positively correlated to the reaction rate. The highest rate constant of esterification towards the product (k1), reactant (k2), and equilibrium were 0.1187, 0.0595, and 1.995, achieved by a temperature of 80 ˚C, respectively. The Arrhenius constant and activation energy towards the product were 3.3085×106 and 50.3 J/mole, respectively. The reaction temperature was positively correlated to the equilibrium constant, which indicated that the reaction was endothermic. The kinetic model validation revealed that the predicted value from the model was adequately in accordance with the experimental value, as indicated by a high coefficient of determination.