Fatty Acid Methyl Ester Conversion Research Articles

A Green Nanocatalyst for Fatty Acid Methyl Ester Conversion from Waste Cooking Oil

This study used a novel combination of cellulose nanocrystals (CNCs) and calcium oxide (CaO) nanocomposite (CaO/CNCs) for the production of biodiesel from waste cooking oil. The filter paper was used as a raw cellulose source to produce the CNCs from the acid hydrolysis of cellulose with sulfuric acid. The as-synthesized CaO/CNC nanocomposite is recyclable and environmentally friendly and was characterized using Fourier transform infrared spectroscopy, energy dispersive X-ray, scanning electron microscopy, and X-ray diffraction. The optimum process parameters investigated are a 20:1 methanol-to-oil molar ratio, 3-weight percent catalyst concentration, 60 °C temperature, and 90 min of reaction time. Under the optimum conditions, a biodiesel yield of 84% was obtained. The CaO/CNC nanocomposite achieved five times reusability, indicating its effectiveness and reusability in the transesterification reaction. The synthesized biodiesel chemical composition was examined using FTIR, GCMS, 1H-NMR, and 13C-NMR, and its properties, including specific gravity, color, flash point, cloud point, pour point, viscosity, sulfur content, sediments, water content, total acid number, cetane number, and corrosion test, were ascertained using ASTM standard practices. The outcomes were determined to fulfill global biodiesel standards (ASTM 951, 6751). Five successive transesterification processes were used to test the regeneration of the catalyst; the first three showed no distinct change, while the fifth cycle showed a reduction of up to 79%. The innovative composite CaO/CNC and used cooking oil are stable, affordable, and extremely successful for long-term biodiesel generation.

Enhanced ruthenium selectivity for the conversion of FAMEs to diesel-range alkanes by surface decoration of FeOx species

Ruthenium-based catalysts have been widely used in the lignin depolymerization and polystyrene hydrogenolysis reactions due to its superior hydrogenolysis activity for C-O and C-C bonds. However, serious cleavage of C-C bonds at high temperatures greatly limits its application in the production of green biodiesel from the conversion of natural oils and bio-derived fatty esters. In this work, we found that introducing a suitable second less-reactive metal (e.g., Fe, Zn) can effectively suppress the hydrogenolysis activity of ruthenium (Ru) metal for C-C bonds and exhibit a high selectivity (>90 %) to diesel-range alkanes (C15-C18 alkanes) in the conversion of fatty acid methyl esters (FAMEs) even at high reaction temperature (250 °C) over the Ru1Fe0.5 catalyst, while an obvious cracking reaction was observed from 210 °C over the monometallic Ru catalyst. Detailed characterization and theoretical calculation results reveal that the introduction of Fe species in the RuFe catalysts weakens the interaction between catalyst and the resulting alkanes, which inhibits the cracking of alkanes. Specifically, adding Fe species breaks the ensemble of Ru atoms and decreases the binding affinity of metallic Ru for H2, which suppresses the activity of Ru metal for the hydrogenolysis of C-C bonds and exhibits a high selectivity to diesel-range alkanes. This research provides valuable information for improving the hydrodeoxygenation (HDO) selectivity of Ru-based catalysts while inhibiting its high hydrogenolysis activity for C-C bonds.

Facile Production of Biodiesel from Candlenut Oil (<i>Aleurites moluccana</i> L.) Using Photocatalytic Method by Nano Sized-ZnO Photocatalytic Agent Synthesized via Polyol Method

Biodiesel production from non-edible oil is an alternative way to reduce edible oil dependency and reduce the competition for feed and food. Candlenut oil (Aleurites moluccana L.) is one of the non-edible oils which can be used as feedstock for biodiesel production since they have a high oil content. Herein, the biodiesel production from candlenut oil has been conducted using zinc oxide (ZnO) synthesized by the polyol method. Polyol methods facilitated the formation of ZnO nanoparticles with various shapes, including spherical, rod, and hexagonal. Besides, ZnO showed a mesoporous characteristic, facilitating the conversion of fat fatty acid to fatty acid methyl ester (FAME) of 61%. Increasing ZnO dosage led to enhancing the FAME yield. Similarly, the FAME yield was also improved by increasing the reaction time. The results of esterification of candlenut oil and methanol yielded 70.76% FAME with 2% nano-ZnO polyol catalyst at 180 min reaction time at room temperature whilst being stirred constantly at 400 rpm. A good FAME conversion using ZnO at room temperature provides good information to produce biodiesel with a simple method. Apart from that, photocatalytic promoted transesterification at room temperature, which is beneficial for reducing energy consumption.

Design of a sodium peroxide/sulfonic acid functionalized SBA-16 bi-functional catalyst for improving the conversion of waste cooking oil to biodiesel

A sodium peroxide/sulfonic acid-functionalized SBA-16 (Na2O2/SBA-16-SO3H) bifunctional catalyst was successfully developed to improve the conversion of waste cooking oil (WCO) to biodiesel. High-resolution X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and Fourier transform infrared spectroscopy analysis results showed that 3D cubic mesoporous SBA-16 and SBA-16-SO3H were successfully synthesized through a hydrothermal reaction and that the 3D cubic mesoporous structure of SBA-16 was not damaged after modifying the Na2O2 particles and -SO3H functional groups. The results of the activity tests showed that modifying SBA-16 with Na2O2 as the alkali catalyst and the -SO3H group as the acidic catalyst could remarkably accelerate transesterification and esterification reactions simultaneously, resulting in an increased conversion efficiency of WCO to biodiesel. The biodiesel conversion efficiency of Na2O2/SBA-16-SO3H reached 81% after a 6 h reaction, which is approximately 3.5 times higher than that of SBA-16. Moreover, the results show that increasing the methanol/WCO molar ratio from 6:1 to 18:1 inhibited saponification and accelerated the transesterification and esterification reactions, shortening the reaction time for fatty acid methyl ester conversion from 8 h to 4 h, providing possibilities for practical application in the future. The Na2O2/SBA-16-SO3H catalyst showed optimal activity when the free fatty acid content was controlled at 3%, the methanol/WCO ratio was controlled at 18:1, and the biodiesel yield reached 93% after 4 h of reaction.

Partial Hydrogenation of FAME on Trickle Bed Reactor using Nickel Catalyst

FAME (fatty acid methyl ester) is an alternative fuel that is still limited in its application to engines because its low oxidation stability affects the quality of biodiesel storage. A solution to overcome this problem is the partial hydrogenation process in which polyunsaturated FAMEs react with hydrogen, and a catalyst breaks down unsaturated bonds which are oxidation determinants. The use of Ni/Al2O3 catalyst is more advantageous due to its lower cost and higher activity. In this research, partial hydrogenation was carried out in a trickle-bed reactor. The objective of the research is to investigate the effect of operating conditions on FAME conversion. The experimental result shows that the partial hydrogenation of polyunsaturated FAMEs in a trickle bed reactor broke down the polyunsaturated bonds (C19:2) of FAME’s into monounsaturated bonds (C19:1) and saturated bonds (C19:0). The conversion of polyunsaturated FAMEs reaches 8.93% under the inlet pressure of 0.7 MPa, the inlet temperature of 160°C, the hydrogen flowrate of 250 ml/min, the biodiesel flowrate of 0.667 ml/min, and the catalyst size of 1.5 mm.

A commercial lipase Resinase® HT (Aspergillus oryzae) efficiency on triglycerides transesterification and process optimization

In this study, the efficiency of Resinase HT enzyme on the transesterification reaction was investigated. Response surface methodology (RSM) was applied for optimization. After the experimental studies the lowest fatty acid methyl ester (FAME) conversion was found as 71% when the enzyme content was 15%(g% w/w), oil/methanol molar ratio was 0.17 and the reaction temperature value was 45 °C. According to the design response, 70.83% was observed in the same conditions. The highest FAME conversion of 97% was found when the enzyme content was 5% (g% w/w), oil/methanol molar ratio was 0.25 and the reaction temperature value was 35 °C. The experimental run gave the FAME conversion of 96.80% at the same reaction conditions. The model fitted with the experimental values with R2 = 0.98.

In situ formation of fatty acid methyl esters via thermally assisted methylation by lignin during torrefaction of oil palm biomass

Torrefaction of oil palm empty fruit bunch (EFB) biomass was performed at six temperatures between 210 and 360 °C. The composition of the evolved and trapped condensates was analyzed by GC/MS and the torrefied biomass samples were characterized by pyrolysis-GC/MS (Py-GC/MS). The analyses showed that the thermal treatment of the biomass produced significant amounts of fatty acid methyl esters (FAMEs). The in situ FAME formation was explained by the reaction of the lipid and lignin contents of the biomass; i.e., the fatty acid moieties of triglycerides were methylated by the methoxy side groups of lignin during the thermal treatment. The reaction was verified by the pyrolysis of a model mixture, using Py-GC/MS and thermogravimetry/mass spectrometry, which consisted of the EFB lipid extract and an isolated beech wood lignin. Demethylation of lignin resulted changes in its thermal decomposition; smaller amounts of 4-methylguaiacol and 4-methylsyringol were evolved and the char yield was increased. The GC/MS analysis of the EFB condensates showed that FAME conversion was the highest and the sources of fatty acid moieties were depleted if the torrefaction temperature had been set at and above 330 °C. The free fatty acid content of EFB was relatively high, which evaporated at lower temperatures before the rate of FAME formation increased between 270 and 300 °C. In comparison with torrefaction, only a small portion of FAMEs formed during the flash pyrolysis of raw EFB at 450 °C indicating that the prolonged heating of the oily biomass favors the FAME formation. Pyrolysis-GC/MS measurements of the torrefied samples showed that the triglyceride residue could also be utilized if the torrefaction as pretreatment was performed at or below 300 °C. In addition, torrefaction increased the accessibility of the biomass components for FAME formation. Some other fatty acid derivatives (i.e., ketone, hydrocarbon, amide, and nitrile) were also detected in smaller amounts. The phenomenon of in situ FAME formation during pyrolysis might be a useful process to enhance pyrolytic biomass utilization by producing FAMEs as additional fuel products and increasing the char yield simultaneously.

Green Synthesis, Characterization, and Catalytic Activity of Amine-multiwalled Carbon Nanotube for Biodiesel Production

An amine-functionalized multiwalled carbon nanotube (MWCNT) was prepared for use as a basic heterogeneous catalyst for the conversion of Cocos nucifera (coconut) oil and Hibiscus cannabinus (kenaf) oil to biodiesel. The 3-aminopropyltrimethoxysilane (3-APTMS) was chosen to form an amine-reactive surface to bind with hydroxyl (−OH) and carboxyl (−COOH) groups of oxidized MWCNT. Silanization took place using a green surface modification method in which supercritical carbon dioxide fluid was utilized under the following conditions: 55 °C, 9 MPa, and 1 h. The synthesized catalyst was characterized using Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), Field emission scanning electron microscopy–energy dispersive x-ray (FESEM-EDX), Time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray powder diffraction (XRD), and Brunauer–Emmett-Teller (BET). Transesterification of coconut oil using 10 wt% NH2-MWCNT catalyst (3 wt% APTMS), 12:1 molar ratio of methanol and oil at 63 °C for 1 h resulted in a >95% conversion. On the other hand, the same catalyst was used in the transesterification of kenaf oil, and formation of ammonium carboxylated salt was observed. The effects of temperature, pressure, and silane concentration on surface modification of MWCNT were evaluated in terms of the catalyst’s basic site density and fatty acid methyl ester conversion. The results indicate that reaction temperature and silane concentration had the most significant effects. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Ultrasound-assisted solid Lewis acid-catalyzed transesterification of Lesquerella fendleri oil for biodiesel synthesis

Biodiesel, a mixture of fatty acid methyl esters (FAME), is bio-renewable, non-toxic, biodegradable, and is an attractive alternative to petroleum diesel. This work studied the sonochemical transesterification of Lesquerella fendleri oil (LFO) using inexpensive solid Lewis acid (LA) catalysts with an aim to reduce environmental pollution and dependance on non-renewable fuel sources. Due to the presence of hydroxy fatty acid methyl esters (HFAME) in LFO (∼60%), in addition to producing biofuel it can also be used to generate chemically important estolides and cyclic lactones. AlCl3, SnCl2, and Sn(CH3COO)2 showed catalytic activity using direct immersion ultrasound (DI-US) among a list of LA catalysts investigated, with AlCl3 being the best catalyst. Ultrasound increased the reaction rate by facilitating carbocation formation of glyceridic carbons. Experiments were carried out at room temperature in a solvent range from 3:1 to 18:1 methanol-to-oil molar ratio and catalyst loading from 1 wt% to 6 wt% over 10 to 60 min sonication time at 48% ultrasound amplitude (roughly 17 W/cm2). Complete conversion (>99%) was achieved in 40 min with 5 wt% AlCl3 catalyst. A statistical regression analysis with STATA 14.0 software was performed to optimize process parameters. Chemical characterizations of the compounds were performed with nuclear magnetic resonance (NMR) spectroscopy (1H NMR &13C NMR), and % conversion of FAMEs was calculated from the 1H NMR spectra. The fatty acid profile was determined by GC-FID and GC–MS analysis. FT-IR spectroscopic analysis and thermogravimetric analysis (TGA) were performed to investigate the infrared absorption pattern of the compound and the volatility difference between Lesquerella fendleri biodiesel and oil under nitrogen atmosphere. Results indicate that this is a fast, green, energy-efficient, sustainable, and industrially applicable method for biodiesel production from LFO.

Bifunctional mixed rare earth solid catalyst for biodiesel production from acid palm oil

Solid mixed rare earth catalysts (MREEs) were synthesized by co-precipitation of raw mixed rare earth hydroxide cake obtained from monazite ore processing at different pH values (6, 7 and 12). The wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) results show that MREEs catalyst co-precipitated at pH 12 contain high contents of active Ce, Nd, La and Y for facilitating both esterification and transesterification reactions. The synthesized MREE by co-precipitated at pH 12 and calcined at 300 °C possess high amounts of Lewis basic and acidic sites, allowing it to act as bifunctional catalyst. The catalyst shows high catalytic activity for the accelerating of the initial reaction rate and converting triglycerides/free fatty acid (FFA) into fatty acid methyl ester (FAME) in both esterification and transesterification reactions. Under the reaction conditions of 3 wt% catalyst, 20:1 methanol/oil molar ratio, 200 °C reaction temperature, 3.9 MPa reaction pressure and 600 r/min stirring rate, FAME conversion reaches 99.57% in 180 min of reaction time.

Comparative study of different catalysts mediated FAME conversion from macroalga Padina tetrastromatica biomass and hydrothermal liquefaction facilitated bio-oil production

Marine macroalgae offer an endurable source of renewable biomass, which do not require cultivable area, fertilizers for cultivation for bioproducts production. In this study, marine brown macroalga Padina tetrastromatica as an alternate sustainable feedstock for the production of liquid fuels. Padina tetrastromatica biomass was collected from Mandapam; the coastal region of Rameswaram, Tamil Nadu, India. and the algal oil was extracted using sequential extractions using various solvents. Petroleum ether (PE) and dichloromethane (DCM) solvent fractions were found to have high lipids and further utilized for biodiesel production, wherein four different heterogeneous nanocatalysts (TiO2, Bio-Fe, GO, and MgO) and commercial homogeneous catalysts (HCl and NaOH) were employed for the transesterification. High fatty acid methyl ester (FAME) recovery (92.3%) was achieved from TiO2 mediated transesterification than the other conventional catalysts. Further, the conversion of algal biomass into bio-oil and by-products was carried out using hydrothermal liquefaction (HTL). Subsequently, the compounds were characterized by FT-IR and GC-MS analysis. The quality parameters of liquid biofuels were examined and they are in accordance with the international fuel standards. Thus, brown macroalga Padina tetrastromatica may be considered as an alternate feedstock for biofuel and other bioproducts production and TiO2 would be a suitable catalyst for the conversion of FAME.

Biodiesel production from transesterified waste cooking oil by zinc-modified anthill catalyst: Parametric optimization and biodiesel properties improvement

Biodiesel, an unconventional fuel to substitute the existing fossil diesel, is non-toxic, biodegradable, possesses high lubricity and better combustion capacity. In this paper, a new eco-friendly solid catalyst was developed from anthill-zinc modification for methanolysis of low-grade feedstock (waste cooking oil, WCO) to make biodiesel. The zinc-modified anthill was prepared via the sol-gel technique and characterized by EDX, TGA/DTA, FTIR, XRD, SEM, BET and CO2-TPD. The optimum experimental conditions obtained by a central composite design were 17.99:1, 0.51 wt%, and 66.54 °C for the molar ratio of methanol to WCO, catalyst loading and reaction temperature, respectively. At these optimum values, the highest experimentally obtained biodiesel yield was 83.16%, which matched the predicted value (82.71%) reasonably well with R2 = 0.9914. According to gas chromatography analysis, the fatty acid methyl ester conversion under optimum conditions was 97.05%. While 20% blending of biodiesel on a volume basis with petroleum-based diesel showed remarkable fuel properties, the catalyst exhibited better stability after being regenerated and reused for six cycles. This study extends the frontier of knowledge in the economical production of biofuels from waste products.

Hydrodeoxygenation of fatty acid methyl esters and simultaneous products isomerization over bimetallic Ni‐Co / SAPO ‐11 catalysts

Bimetallic Ni-Co/SAPO-11 catalysts were prepared and investigated for hydrodeoxygenation (HDO) of fatty acid methyl esters (FAMEs) and sequential isomerization of the products in a continuous fixed-bed reactor. The physicochemical properties of the catalysts were characterized by means of N2 adsorption-desorption, temperature-programmed reduction of H2, temperature-programmed desorption of NH3, infrared spectra of adsorbed pyridine, and thermogravimetry. The conversion of FAMEs and selectivity of C15-18 are enhanced over the bimetallic Ni-Co/SAPO-11 catalysts compared with that of the corresponding monometallic counterparts, which is attributed to the modification effect by Co species. The balance between metal Ni and Co and the acidity of the support plays an important role in the catalytic performance. The Ni-Co/SAPO-11 catalysts with composition of 3% Ni and 6% Co exhibit optimal catalytic performance, specifically the conversion of FAMEs, selectivity of C15-18, and isomerization ratio of C15-18, respectively, reaching 100.0%, 93.0%, and 36.1% at 400°C and 1.5 Mpa H2.

Esterification of a waste cooking oil using metal-hybrid catalysts for chemoenzymatic reactions

Waste cooking oil (WCO) serve as a cheap feedstocks for biodiesel production. However, the high acidity of this oil disqualifies it from using alkaline transesterification as the synthesis reaction for biodiesel production. Thus, the integration of enzymatic and chemical catalysts to form a hybrid catalyst for reducing oil acidity is a new option in the biodiesel industry. In the present study, five types of metal oxides and Candida rugosa lipase (CRL) were sequentially co-immobilized on the Alumina (Al2O3) for esterification of free fatty acid (FFA) to fatty acid methyl esters (FAMEs).The lowest FFA content achieved was 1.10% using CRL-CaO-Al2O3 for 24 h esterification reaction, correspond to a conversion rates of 66.94%. The FAMEs conversion of the treated WCO indicates that the hybrid catalyst also can perform transesterification of triglycerides in the oil. Among all the hybrid catalysts, CRL-MgO-Al2O3 shows the highest FAME conversion of 69.10%. The best immobilization time was recorded at 7 h which successfully reduced the FFA content until 1.39%. The application of heterogeneous enzyme-metal hybrid catalysts promise a better insight in the biodiesel industry in terms of its simplicity and catalyst recovery.

Optimization of biodiesel synthesis from microalgal (Spirulina platensis) oil by using a novel heterogeneous catalyst, β-strontium silicate (β-Sr2SiO4)

The β-Strontium silicate (β -Sr2SiO4) was synthesized by physicochemical methods and was used as a heterogeneous catalyst in biodiesel production from microalgal oil (-Spirulina platensis) by transesterification process. The physical and chemical properties of the catalyst were analysed using TGA, XRD, ATR-FTIR, SEM-EDX, and surface area analyser. XRD and FTIR analyses confirmed the formation of β-Sr2SiO4 which was able to perform transeterification reaction. Several reaction parameter such as catalyst wt %, molar ratio (methanol :oil) and time have been optimized for transesterification reaction. The optimization of reaction parameters was accomplished by response surface methodology based on Box-Behnken design. Reusability study of catalyst was accomplished up to six run with 76.34% fatty acid methyl ester (FAME) conversion. A 97.88% maximum FAME conversion was observed at 65 °C, 600 rpm, 2.5 wt% catalyst, 1:12 methanol to oil molar ratio and 104 min reaction time.The biodiesel properties conform to ASTM standards.

Green energy from Coelastrella sp. M-60: Bio-nanoparticles mediated whole biomass transesterification for biodiesel production

Application of nanoparticles in microalgal biodiesel production comprise of nanoparticle usage for lipid accumulation, lipid extraction and transesterification process. Conventionally, microalgal biomass/oil are converted into fatty acid methyl esters (FAME) using methanol in the presence of homogeneous acid/base catalysis through transesterification. In this study, bio-nanoparticles were synthesized from bio-waste (seashell) and employed them as heterogeneous catalysts in the direct/whole-cell transesterification of wet microalgal biomass. Bio-nano CaO and bio-nano CaCO3 were characterized by Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FT-IR) analyses. Specific surface areas of bio-nano CaCO3 and bio-nano CaO were found to be 73.519 and 19.810 m2/g with an average pore size diameter of 7.141 and 2.348 nm respectively through BET analysis. FT-IR analysis of the synthesized bio-nanoparticles showed similar absorption frequencies as that of bulk counterpart with noticeable differences in absorption at some frequencies. Thus, the present study employs the as-synthesized bio-nanoparticles from waste seashell as heterogeneous catalysts for whole-cell/direct transesterification of N starved Coelastrella sp. M-60 for FAME conversion and compared with (i) conventional acid catalyst and (ii) commercial TiO2 nanocatalyst. The above mentioned direct transesterification reactions had yielded C 16:0 (7.5–22.3%) and C 18:1 (63.2–78%) as the major FAME products. Bio-nano CaCO3 and bio-nano CaO had yielded an average of 1.29 and 1.02 folds increase in FAME proportions respectively than conventional acid catalysis. Hence, this study shows the potential of bio-nanocatalysts for direct transesterifcation of Coelastrella sp. M-60 as a greener approach for biodiesel production.

Sustainable biofuel from microalgae: Application of lignocellulosic wastes and bio-iron nanoparticle for biodiesel production

Biofuels from microalgae are being considered as an alternate renewable energy to fossil fuels, which could extinct by the year 2050 due to its exhaustive usage. Microalgae are tiny cell factories that accumulate large amount of lipids under nutrients starvation, which are sustainable sources for biofuels production. In this study, hydrolysate of lignocellulosic biomass (LCB) was used as a carbon source to improve the production of microalgal biomass, which was further subjected to nitrogen starvation for the enhanced lipid accumulation. The lipid content of LCB supplement 3% and 2% grown cultures of Dictyococcus sp. VSKA18 and Coelastrella sp. M-60 were 44% and 52%, respectively. Further, recovery of fatty acid methyl esters (FAME) was achieved using two different catalysts such as acid (homogeneous) and iron nanoparticles (heterogeneous) synthesized using Sargassum polycystum. Moreover, the saturated fatty acid (SFA) of Dictyococcus sp. VSKA18 and Coelastrella sp. M-60 supplemented with 3% of LCB hydrolysates along with N starvation had yielded 90% and 28% respectively. Fuel quality parameters were also analyzed and compared with ASTM and European standards. Thus, the synthesized bio-iron nanoparticles mediated FAME conversion would be a suitable choice for improving biodiesel production.

Reduction of Vegetable Oil‐Derived Fatty Acid Methyl Esters toward Fatty Alcohols without the Supply of Gaseous H2

AbstractAn alternative route to the conventional one for fatty alcohol synthesis was investigated. It was possible to synthesize lauryl alcohol from methyl laurate via reduction by transfer of hydrogen and hydride in liquid phase, in noncatalytic reactions and without the supply of H2 gaseous. Pure NaBH4 or alumina‐supported NaBH4 and methanol were used as co‐reactants and 100% fatty alcohol selectivities were achieved. The aim of supporting the metal hydride was to increase its stability and achieve the full recovery of the solid at the end of reaction. When alumina‐supported NaBH4 was used, a final fatty alcohol yield of 93% was achieved. The use of methanol and NaBH4 in amounts higher than stoichiometric is important to generate alkoxyborohydride anions which act as better reducing species than NaBH4. The reaction conditions effect was investigated and the role of short carbon chain alcohol structure was elucidated. The effect of fatty acid methyl ester structure was also studied. Fatty acid methyl esters with shorter carbon chain length and without unsaturation (methyl laurate, methyl myristate) were easily reduced using NaBH4/Al2O3 and methanol reaching high conversions and fatty alcohol selectivities. Unsaturated fatty acid methyl ester with longer carbon chain (methyl oleate) introduced steric hindrance which disfavoured interaction between ester and reducing solid surface and fatty acid methyl ester conversion was noticeably lower. A reaction mechanism based on alkoxyborohydride anions as the actual reducing species was proposed. This mechanism fully interprets results obtained during fatty acid methyl ester reduction using short carbon chain alcohols and metal hydride.

Green synthesis of biodiesel from Ricinus communis oil (castor seed oil) using potassium promoted lanthanum oxide catalyst: kinetic, thermodynamic and environmental studies

Large scale production of biodiesel from a lignocellulosic biomass using an efficient heterogeneous catalyst has several benefits like low production cost, reduction in CO2 emission along with other greenhouse gases, agricultural development and assurance of future energy supply. In present study, a solid base catalyst named as potassium (K) promoted lanthanum oxide (La2O3) has been synthesised by sol-gel auto-combustion method (Pechini's method) and introduced in transesterification of castor oil. Synthesized K promoted La2O3 catalyst was characterised by TGA-DTA, FT-IR, XRD, XPS, BET surface area analysis, HRSEM-EDX, Hammett indicator titration for basicity evaluation. Optimum K/La atomic ratio and catalyst activation temperature was investigated in terms of highest activity of the catalyst which was found at 1.5K/La atomic ratio and 900 °C calcination temperature for transesterification of castor oil. The following reaction influencing factors were optimised to be 1:16 oil to methanol molar ratio, 65 °C reaction temperature, 2 wt% catalyst loading, 500 rpm rotating speed of mechanical stirrer, 150 min reaction duration. Maximum 97.5% fatty acid methyl ester (FAME) conversion of castor oil was obtained under optimum circumstances. The product biodiesel was characterized by 1HNMR spectroscopy. Then reusability study and active metal leaching tests were performed simultaneously to find out the reason behind deterioration in activity of the catalyst during recycling process. It was found that the catalyst was efficient to produce 85.3% FAME conversion up to five reaction cycles at optimised reaction condition. The reaction activation energy (Ea) and pre-exponential factor (A) were estimated to be 47.13 kJ/mole and 9.93×105 per min respectively by the study of kinetics and thermodynamics regarding methyl esterification process of castor oil using K promoted lanthanum oxide catalyst. Additionally, the corresponding enthalpy of activation (ΔH#), entropy of activation (ΔS#) and Gibb’s free energy of activation (ΔG#) were evaluated to be 45.27 kJ.mol−1, −142.81 J.mol−1.K−1 and 93.53 kJ.mol−1 accordingly by the mean of Eyring-Polanyi’s plot. Turnover frequency and environmental studies implied that biodiesel production from castor oil using K promoted La2O3 is an efficient and green process.

PENGARUH KECEPATAN PENGADUKAN DAN SUHU REAKSI PADA ESTERIFIKASI MINYAK MENTAH DEDAK PADI BERKANDUNGAN ASAM LEMAK TINGGI

Rice bran oil (RBO) derived from rice bran (RB) which could use as an alternative raw material for biodiesel production. Rice bran (dedak) are used as feed for poultry, pigs, and some dairy cattle because they are relatively cheap and do not require processing. The utilization of these oil further cheapen the cost of biodiesel and increased the economonic value of RB. The choice of RBO as a raw material for biodiesel due to the rice bran oil’s potentials. RBO is considered to be one of the most nutritious oils due to its favorable fatty acids composition and a unique combination of naturally occurring biologically active and antioxidant compounds (oryzanol, tocopherol, tocotrienol, phytosterol, polyphenol, dan squalene). The research emphazised on esterification reaction because of the rapid increase of FFA content in RBO after the milling of rice. Storage time of RB increased the FFA content. Mixing velocity dan time reaction was the other two variables which are affecting the esterification reaction. Those two variables are studied in this experiment.
 Experiment were designed to examine the mixing velocity and temperature reaction to the conversion of fatty acid methyl ester (FAME). Reaction condition 20:1 molar ratio methanol to FFA content and 5%-v/v catalyst (to the oil) was used in all experiments. Mixing velocity and time reaction was arranged as follows: 500, 750, 1000 rpm and 40, 50, 60oC, respectively. Research conducted in four parts: soxhlet extraction with n-hexane as a solvent; oil-solvent separation process; and the last step was esterification reaction. Reaction conducted on three neck round bottom flask equipped with magnetic stirrer, refluk condenser and thermometer. Crude product was separated first from unreacted methanol, glycerol, and catalyst prior to physical analyzed of biodiesel’s properties. Conversion of FAME was calculated from acid value difference, after and before reaction conducted.
 It was found that mixing velocity influenced the FAME conversion not significantly (specially in crude rice bran oil high fatty acid content esterification); increasing in temperature will increase the FAME conversion; kinetic reaction controlled by chemical reaction; and biodiesel product from this research already fullfill the requirements of Indonesian Standard of Biodiesel (FBI-SO1-03).