Esterification Process Research Articles

Biodiesel Production of Palm Oil Mill Effluent by Using Hydrotalcite Catalyst

Biodiesel is currently preferred for consumption and has been widely used as a substitute for diesel. This study aimed to determine the effect of various methanol-to-oil ratios in the esterification process and also the effect of hydrotalcite catalyst weight on the transesterification product. The catalyst was characterized with SEM, XRD, FTIR, and TG-DTG-DTA. The esterification process was operated at various oil-to-methanol ratios, i.e., 1:12-1:36 and the transesterification was performed using several catalyst weights, 0.5%-2.5%. The results showed that the optimum conditions of esterification were at the 1:30 molar ratio of oil-to-methanol, which decreased the amount of acid number by 95.75%, while the optimum condition of transesterification was at 1.5% catalyst weight. The characteristics of biodiesel using 0.5-2% hydrotalcite catalyst (acid number, total glycerol, free glycerol, ester levels, viscosity, density, oxidation stability) have met the Indonesian biodiesel standard of SNI-04-7182-2012.

Continuous Double-Step Esterification Production of Palm Fatty Acid Distillate Methyl Ester Using Ultrasonic Tubular Reactor.

Double-step esterification to produce biodiesel from palm fatty acid distillate (PFAD) was performed by utilizing an ultrasound clamp reactor. Six pairs of ultrasonic clamps were attached to the left and right sides of the stainless-steel tube, and each pair was separated 100 mm apart from each other. Therefore, a total of 12 units of ultrasound clamps distributed 4800 W maximum power (12 × 400 W) throughout the continuous reactor by an ultrasonic generator. To optimize each step of the continuous esterification process for producing methyl ester from PFAD, a response surface methodology was used. The final 93.32 wt % methyl ester purity was attained under a double-step esterification process. For the first step, a 3.75:1 molar ratio of methanol to PFAD (46.4 vol % methanol), 6.6 vol % sulfuric acid, and 400 mm length of ultrasound clamp at 25 L/h PFAD flow rate for converting the PFAD to 60.24 wt % methyl ester were recommended. For the second step, the esterification was repeated under a molar ratio of methanol to the first esterified oil of 2.87:1 (61.6 vol % methanol), 5.6 vol % of sulfuric acid, and 400 mm length of ultrasound clamp at 25 L/h esterified oil flow rate. The ultrasonic clamp reactor achieved high yields of esterified oil and the crude biodiesel in a relatively short residence period of 32 s. To determine the product yields of a double-step esterification process, the maximum yields were 103.9 wt % first esterified oil, 107.6% crude biodiesel, and 98 wt % purified biodiesel when calculated on the basis of 100 vol % initial PFAD. The average energy consumed in the production of double-step esterification biodiesel was 0.05796 kWh/L. Therefore, this current approach has a high potential for producing biodiesel with less energy and requires less time to convert the PFAD to a high purity of methyl ester.

The Influence of Nanoparticle Additive on the Thermophysical Properties of Bionanolubricant Using Castor Oil

Lubricants are commonly used in machining and energy system to reduce friction and wear within moving parts and aid in the transfer of heat. The use of lubricants enhances the overall performance and operation life of systems. Synthetic lubricants commonly used are non-biodegradable and are harmful to aquatic and land habitats. To overcome these challenges, biolubricants from vegetable and animal sources were considered as an alternative to synthetic and mineral lubricants. In this study, the esterification and transesterification processes were used to produce biolubricant from castor oil. Methanol and sulphuric acid (H2SO4) were used as alcohol and catalyst respectively for the acid catalysed esterification while ethylene glycol and sodium hydroxide (NaOH) were used for the transesterification process. The average biodiesel yield was 99.87%. The two-step method was deployed in the preparation of the castor nanobiolubricant. The nanobiolubricants were prepared using aluminium oxide (Al2O3) nanoparticles of 20 – 30 nm nominal diameter. The volume concentrations of 0.1%, 0.2%, and 0.4% were used in the preparation of the nanobiolubricants. The results showed that the addition of Al2O3 nanoparticles into the castor oil biodiesel altered the thermophysical properties (density, dynamic viscosity, pH, acidity, free fatty acid (FFA), flash point, and cold properties) of the biolubricants. The addition of Al2O3 nanoparticles reduced the acidity, flash point, and pH value of biolubricant while the cold flow property was improved. The dynamic viscosity decreased with an increase in temperature and increased as the nanoparticle concentration increased. The results were compared with the thermophysical properties of mineral oil, and from these analyses, Al2O3 nanobiolubricant can be successfully deployed as an alternative to synthetic and mineral lubricants in machining and energy systems. Fourier transform infrared (FTIR) and UV-Vis analyses were conducted on the castor oil, its biolubricant, and nanobiolubricants.

Selective synthesis of alpha monoglycerides by a clean method: Techno-economic and environmental assessment

This work proposes an alternative green and selective biocatalytic route for Glycerin Monostearate (α-monostearin) production. The conventional method of production uses an elevated temperature. Apart from the high energy consumption, such high temperatures darken the final product's color, lead to random reactions, and produce high orders of diglycerides and triglycerides instead of monoglycerides. The proposed production process was performed by esterifying stearic acid with glycerin in an organic medium using Candida antarctica lipase (Novozym 435) at a mild temperature. The reaction conditions were optimized using the response surface methodology (RSM): optimum conditions were a temperature of 60 °C, glycerin to stearic acid molar ratio of 8:1, and Novozym 435 amount of 6% w/w. The solvent addition remarkably improved the α-monostearin yield to nearly 80% without the need for the energy-intensive distillation step. The conventional autocatalytic esterification (AUT) process was also performed to investigate the comparative monoglyceride yield, and it was found to be 22.5%. Proton nuclear magnetic resonance and gas-chromatography confirmed that α-monostearin could be produced with the highest purity using the proposed enzymatic method (ENZ). Economic and environmental analyses were also conducted for the proposed ENZ process, and the results were compared with those of the AUT process. The total capital investment of α-monostearin production, considering a projected capacity of 4950 t year−1 and 11% interest for the proposed ENZ process, was favorably 2.5 times lower than that of the AUT process, suggesting a promising investment opportunity. However, the total production costs showed unfavorable negative net present value (NPV) and return on investment (ROI) for the ENZ process and favorable positive NPV and ROI for the AUT process, indicating that the proposed venture is not profitable for α-monostearin production. However, the process can be profitable at improved operational stability of Novozym 435 up to 1 kg per 3-ton product. The carbon footprint was calculated on the basis of the given capacity and conditions of 50 and 656 t CO2 eq./year for the ENZ and AUT processes, respectively. The synthesis of α-monostearin using the proposed route can be considered a building block toward a cleaner large-scale production of α-monoglycerides.

FTIR coupled with machine learning to unveil spectroscopic benchmarks in the Italian EVOO

AbstractNon‐destructive analytical analyses coupled with classification and regression algorithms are promising techniques for monitoring quality, traceability and safety assessment in food industry. To prevent food fraud, Italian Extra Virgin Olive Oil (EVOO) is particularly held in check. Here, attenuated total Reflectance‐Fourier Transform Infrared spectroscopy (ATR‐FTIR) with Machine Learning is carried out to study an Italian EVOO data set coming from 6 regions to verify the geographical traceability, the cultivar and the repeatability of the agronomical practices, till the adulterated EVOO from soy and corn. The present work is carried out without reagents or esterification processes and considering the entire frequency range without any spectral windows selection, drastically reducing time and costs. Toscana, Lazio, Puglia and Calabria result regions well reproducible in terms of geo‐traceability, unlike the Sicilia and Umbria. The model extracts spectral benchmarks in EVOO in the following vibrational modes at 3004, 2952, 2922, 2852, 1742 and 1160 cm‐1.

Experimental and simulation studies of a continuous reactive distillation for an esterification process

Abstract Esterification of acetic acid and methanol to produce methyl acetate and water has been studied in a continuous packed bed catalytic reactive distillation column. Indion 180, an ion-exchange resin solid catalyst has loaded in an equivalent Katapak-S into the reactive section of the column. The experiments were conducted under different operating conditions of reboiler temperature, total feed flow rate of the reactants, methanol to acetic acid mole ratio, feed location of acetic acid and methanol with respect to reactive section, reflux ratio and catalyst amount to investigate the composition of distillate and reboiler respectively. The maximum methyl acetate composition and acetic acid conversion is obtained at reboiler temperature of 80 °C, reflux ratio of 2, total feed flow rate of 16.3 g/min, catalyst loading of 60 g and mole ratio of methanol to acetic acid is 1. From the experimental investigations, it is found that the composition of the methyl acetate in the distillate is 95% by mole at an optimized experimental condition. The experimental data has been compared with equilibrium and non-equilibrium model predictions and found that non-equilibrium model is able to predict the experimental data reasonably good. The calculated error from equilibrium model relative to experimental data is 4.71% and rate based model relative to experimental data is 0.61%. It is observed that the error is less in rate based model compared to equilibrium model.

Optimization of engine parameters using NSGA II for the comprehensive reduction of emissions from VCR engine fuelled with ROME biodiesel.

Diesel engines are most widely used as power plant for many applications, like automotive, agricultural purposes, portable machines and remote location power generation, because of their higher torque, power output, energy content per unit mass and cost of fuel. Because of the higher compression ratios, the diesel engines are able to produce greater cylinder pressures resulting in higher temperatures and thermal efficiency. On other hand, the diesel engines produce COx, NOx, Soot and sulphur emissions which are harmful and these pollute the environment leading to acid rain, global warming and variety of human diseases. Also, the present emission regulations are framed such a way to ensure the environmental sustainability in addition to the economic and social importance. These constraints make the researchers find an alternate fuel for replacing the diesel fuel on the existing diesel engines for the reduction of environmental pollutions. Biodiesel is found to be a very good alternative fuel obtained from natural resources and having good energy with least possible emissions. Rubber seed methyl ester (ROME) is one kind of the biofuel can be used in the existing diesel without any engine modifications. The ROME is produced using trans esterification process and the biodiesel blends are prepared in the sequence of B20, B40, B60 and B80. The ROME is tested on the Variable Compression Ratio (VCR) engine to test the emission characteristic in line with the performance characteristics. To reduce the emissions, the prediction models are developed forCO andNOx using the Response Surface Methodology (RSM). The models are verified through the ANOVA and p-test for their adequacy to create the hypothesis of the experimentation. The NSGA II evolutionary multi-objective optimization is used to optimise the engine parameters to minimise the pollutions from the ROME fuelled engine. The optimized parameters are tested and verified experimentally for the least possible emissions.

Synthesis of Magnetic Catalyst Derived from Oil Palm Empty Fruit Bunch for Esterification of Oleic Acid: An Optimization Study

Biomass, renewable, abundantly available and a good source of energy. The conversion of biomass waste into valuable products has received wide attention. In this study, an empty fruit bunch (oil palm EFB) supported magnetic acid catalyst for esterification reaction was successfully prepared via the one-step impregnation process. The new magnetic catalyst achieved a higher surface area of 188.87 m2/g with a total acidity of 2.4 mmol/g and identified iron oxide as g-Fe2O3. The magnetization value of 24.97 emu/g demonstrated that the superparamagnetic catalyst could be easily recovered and separated after the reaction using an external magnet. The catalytic performance of oil palm EFB supported magnetic acid catalyst was examined by esterification of oleic acid. Esterification process parameters were optimized via Response Surface Methodology (RSM) optimization tool with Box-Behnken design (BBD). The following optimum parameters were determined: an amount of 9 wt% catalyst, molar ratio of methanol to oleic acid of 12:1, reaction time of 2 h and reaction temperature of 60 °C with a maximum conversion of 94.91% was achieved. The catalyst can be recycled up to five cycles with minimal loss in its activity. The oil palm waste-based magnetic acid catalyst indicates its potential replacement to the existing solid catalysts that are economical and environmentally friendly for the esterification process in biofuel applications. Copyright © 2021 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).

Alginate-based poly ionic liquids for the efficient demulsification of water in heavy crude oil emulsions

This work deals with the synthesis, characterization, and application of alginate-based poly ionic liquids for efficient demulsification of water in oil emulsions. For the formation of renewable poly ionic liquid (PIL), sodium alginate (S.ALG) was converted to alginic acid (H.ALG), followed by an esterification process to produce corresponding polyester, (N.ALG). In the later stages, the formed N.ALG was subjected to a quaternization reaction using either 1-bromohexadecane or 1-bromononane in order to produce PILs (BH-ALG) and (BN-ALG), respectively. Then, the two formed PILs (BH-ALG and BN-ALG) were evaluated in terms of the chemical structure, surface and interfacial tensions, thermal stability, relative solubility number (RSN), and micelle size. While testing the efficiency of as-synthesized two PILs towards the demulsification of water in heavy crude oil (W/O) emulsions, both PILs were found to be efficient. Furthermore, an increase in efficiency was observed with the increase of PIL concentration and ratio of water in the emulsions. Among the two PILs, the BH-ALG displayed higher demulsification efficiency as against the BN-ALG, and this can be due to its higher hydrophobicity, and hence its ability to disperse in heavy crude oil as a continuous phase.

Characterization and Conversion of Sludge Palm Oil (SPO) into Biodiesel

Sludge Palm Oil (SPO) is a potential low-cost feedstock for biodiesel production. The conversion efficiency and the quality of biodiesel produced is governed by the feedstock and the conversion reaction. To our knowledge, the potential of SPO produced by palm oil mills in Sarawak has yet to be explored. Hence, this paper aims to characterize the SPO obtained from Sarawak palm oil mills and to optimize the predominant conversion reaction. The SPO was converted into biodiesel via a sulphuric acid catalyzed esterification reaction, followed by transesterification using potassium hydroxide and methanol.  This SPO contained 1.30 - 10.15% moisture, 2.91 - 7.63% sediment and 47.05 – 87.86% free fatty acids (FFA). The optimum esterification conditions identified were: SPO:methanol ratio (1:10), sulphuric acid concentration (1.84%) and reaction time (3.25 hr). Under these conditions, the biodiesel yield was 74% with an FFA conversion efficiency of 79.87%. The water produced during the esterification process was found to hinder the reaction, reducing both conversion efficiency and biodiesel yield. The findings of this study offer important insights about the challenges and feasibility of biodiesel conversion from SPO, where esterification is inevitable due to its high FFA content. &nbsp

Spray analysis of Palm-Based biodiesel to correlate performance and combustion analysis of a compression ignition engine

Palm oil diesel (POD) is derived from palm oil using an esterification process. POD has similar physicochemical properties to fossil diesel, and this allows POD to be the primary substitute to diesel. However, existing research has found that the combustion of POD in CI engines produce lower performance standards than pure diesel. This is due to POD having a higher viscosity, density and presence of heavier molecules resulting in poor evaporation and mixing with the air leading to higher brake specific fuel consumption (BSFC) and reduced power. This research aims to observe the fuel spray behaviors inside the combustion chamber and corelate these with the lower performance of POD than diesel. POD is tested at 100% (B100) and, blended with diesel at a ratio of 50/50 (B50) by volume to reduce the viscosity. The study of spray properties in real engines is expensive and difficult, with most studies being performed in constant volume transparent chambers using Mie-scattering and Schlieren imaging techniques. Therefore, the engine simulation is conducted using ANSYS Forte software to observe the in-cylinder spray behaviors. A 26-kW diesel engine used in a generator is modelled using SolidWorks with respective performance parameters noted from simulation data. The CHEMKIN-PRO software is used to create POD by solving thousands of reaction combinations. Spray analysis of fuels shows longer penetration lengths with POD, higher Sauter Mean Diameter (SMD) and heavier mass of fuel molecules than diesel. These along with a lower calorific value of POD resulted in lower power and a higher brake specific fuel consumption than diesel. Furthermore, B50 performs better than B100.

Integrated bioconversion process for biodiesel production utilizing waste from the palm oil industry

This study was focused on utilizing palm oil industry waste to produce biodiesel. Palm acid oil and bioethanol partially concentrated from the distillation of artificial palm sap served as the feedstock. Thermomyces lanuginosus lipase (TLL) immobilized on the charcoal of coconut shells served as the biocatalyst in the trans-esterification reaction. After 48 h in bioethanol (63% v/v) obtained from the distillation of artificial palm sap, 500 mg of TLL, esterification at 40 ºC and 35 rpm yielded 98.1% w/w fatty acid ethyl ester. The evaluation of the Gibbs free energy (−10.1 kJ mol−1) showed that the reaction system proceeded spontaneously for producing biodiesel, and the activation energy (Ea) of this esterification process was 58.9 kJ mol−1. This evaluation of biodiesel synthesis utilizing residual oil from palm oil mill effluent and the bioethanol from palm sap could establish the sustainability of an integrated approach to biorefinery operations and reduce the cost of the process. Further, a kinetic study on TAG and FFA was performed to elucidate the superiority of oil with a high FFA content for faster reactions than that with a high TAG in using bioethanol as the acyl acceptor.

Temperature and water activity control in a lipase catalyzed esterification process using nonlinear model predictive control

AbstractControlling the batch esterification process is a difficult task because the kinetics of the process incorporate intrinsic nonlinearity, process uncertainty, and model mismatch. The model predictive control (MPC) was created and used in the lipase‐catalyzed esterification process in this study. The Autoregressive with Exogenous Input (ARX) and Nonlinear Autoregressive with Exogenous Input (NARX) models were embedded in the MPC. The controller's goal is to manipulate the jacket flow rate and air flow rate, respectively, to control reactor temperature and water activity. To identify the best controller performance, the ARX‐MPC and NARX‐MPC parameters of horizon time (P), number of control moves (M), and weighting factor (wk and rk) were tuned in tracking set point. In terms of set point tracking, disturbance rejection, and robustness test, the best‐tuned ARX‐MPC and NARX‐MPC controllers were assessed and compared. Due to smaller integral square error (ISE), quicker settling time, streamlined response, and manipulated variables remaining within their permitted constraints, the NARX‐MPC controller outperformed the ARX‐MPC controller.

Utilization Of Methyl Ester Sulfonate As a Surfactant Raw Material in the Scouring, Bleaching and Dyeing Process of Rayon Fabric

The use of surfactants from palm oil as a wetting agent can be applied in the textile wet processes. Used cooking oil that has been through esterification and transesterification processes can be used as a raw material for surfactants. During this process, methyl ester sulfonate has been formed as a surfactant raw material. MES surfactant as an active ingredient in detergents has a detergency ability in water with a high hardness level, has a tolerance property to Ca 2+ ions, has a low foaming rate, and has good stability to pH. The purpose of this research is to utilize used cooking oil that has been processed through esterification, transesterification, and sulfonation for the surfactant manufacturing process which will later be used for wet textile processes and to determine the optimum concentration of surfactant produced in the cooking and dyeing process of rayon compared to commercial surfactants (teepol). The experiments carried out were the process of making surfactants from methyl esters into sulfonate methyl esters, through the processes of sulfonation, purification and neutralization. Then, testing the wetting time, absorbency of the fabric and testing the resistance of acid, base, and hardness. Then the surfactant product is applied to the cooking and bleaching processes simultaneously, then the dyeing process is continued with the surfactant as a cloth wetting agent in the dyeing process. Then tested the age and evenness of the dyed fabric color. The results showed that MES surfactant has almost the same properties as a teepol, which holds it hard and not resistant to acids and bases. It has a good wetting ability and can reduce surface tension so that the fabric can absorb water in 23,36 seconds. The optimum conditions were achieved in MES surfactant concentrations using 2 ml / L in the scouring bleaching process (simultaneous) and 2 ml / L in the dyeing process. The color saturation is 25.6148 and the color evenness results in a standard deviation of 0.395.

Optimized Biodiesel Production from Madhuca Longifolia using Two Stage Transesterification Process

Optimization biodiesel production from tree borne, non-edible Madhuca longifolia oil was experimentally investigated in the present study. Madhuca longifolia, categorised under second generation of feedstock for biodiesel production, has wide scope in the future. As the Free Fatty Acid (FFA) content of Madhuca longifolia oil was 19% the biodiesel production was carried out by using two stage esterification and transesterification processes. In the first stage acid catalysed esterification was done using H2SO4 and the FFA content of Madhuca longifolia oil was brought down to less than 2%. The second stage of transesterification was carried out using NaOH as base catalyst. During the transesterification, the observation was made on various operating parameters like reaction time, catalyst concentration and methanol to oil molar ratio at three different reaction temperatures 55C, 60C and 65C. The optimised process parameters for the maximum yield of 87.8% of Madhuca longifolia biodiesel were methanol to oil molar ratio of 1:6 % weight of catalyst to oil of 3.00 for a reaction time of 60 minutes at reaction temperature 60C. In order to use the produced Madhuca longifolia biodiesel in the existing engines, the physiochemical properties were measured for its compliance with American Standard for Testing Materials and found to be in accordance with ASTM D6751 standards.

Thermal Hydraulics and Thermochemical Design of Fatty Acid Methyl Ester (Biodiesel) Esterification Reactor by Heating with High Boiling Point Phenyl-Naphthalene Liquid

FAME (biodiesel) is an alternative fuel that can be produced from vegetable oils. There is growing interest in the research and development of renewable energy sources. A possible solution is a biofuel usable in compression-ignition engines (diesel engines) produced from biomass rich in fats and oils. This paper contains a new and safer design of an esterification reactor for producing FAME (biodiesel) by utilizing high boiling point fluid (called phenyl-naphthalene). CFD simulation of biodiesel production by using methyl imidazolium hydrogen sulfate ionic liquid has been carried out. Ionic liquids (ILs) are composed of anions and cations that exist as liquids at relatively low temperatures. They have many advantages, such as chemical and thermal stability, low flammability, and low vapor pressures. In this work, the ionic liquids have been applied in organic reactions as solvents and catalysts of the esterification reaction. The great qualities of high boiling temperature fluids, along with advances in the oil and gas industries, make the organic concept more suitable and safer (water coming into contact with liquid metal may cause a steam explosion hazard) for heating the esterification reactor. The COMSOL Multiphysics code has been employed and simultaneously solves the continuity, fluid flow, heat transfer, and diffusion with chemical reaction kinetics equations. It was shown that the heat flux could provide the necessary heat flux required for maintaining the esterification process. It was found that the mass fractions of methanol and oleic acid decrease along the reactor axis. The FAME mass fraction increased along the reactor axis. The maximal biodiesel yield obtained in the esterification reactor was 86%. This value is very similar to the experimental results obtained by Elsheikh et al.

Preparation and application of an environmentally friendly compound lubricant based biological oil for drilling fluids

As the basic raw material of bio-oil based eco-friendly lubricant, a special selected by-product vegetable acidified oil (AO) was modified by vulcanization, esterification, or vulcanization followed by esterification. The optimized vulcanization process conditions are 1% sulfur powder catalyzed, temperature 130 ℃, reaction time 2 h, while the optimized esterification process requires 20% glycerol and 1% H2SO4 catalysis, reaction temperature 220 ℃, reaction time 3 h. We compounded modified AO, diluent, pour point depressant and emulsifier into an advanced drilling lubricant F-1. F-1 has excellent performances in bentonite drilling fluids, the extreme pressure lubrication coefficient reduction rate (Δf) in fresh water mud is 86.84%, and 85.76% in 4% NaCl salt water mud. After aging at 150 ℃ for 16 h, its Δf is improved compared with room temperature. Adding F-1 to the basic bentonite mud system, the filtration loss of drilling fluids decreased from 10 mL to 6.5 mL, the apparent viscosity and plastic viscosity experienced little change before and after aging. The new bio-oil compound lubricant has an excellent temperature resistance, a high salt contamination resistance and cost-effective. Vulcanization and esterification processes help to improve the lubricity and reduce foaming rates.

12-Tungstophosphoric acid-encapsulated metal-organic framework UiO-66: A promising catalyst for the esterification of acetic acid with n-butanol

BackgroundThe synthesis of highly efficient and stable heteropolyacids catalysts for the esterification of acetic acid with n-butanol is an urgent task. In this work, a novel series of 12-tungstophosphoric acid-encapsulated metal-organic framework UiO-66 materials (HPW@UiO-66) with different HPW loadings were successfully prepared via a one-pot hydrothermal method. MethodsThe synthesized materials were systematically studied by FT-IR, PXRD, N2 adsorption, ICP-OES, SEM, TEM, TGA-DTG, NH3-TPD and XPS. Under the optimum reaction conditions of 120°C temperature, 2:1 n-butanol/acetic acid molar ratio, 3.0 wt% catalyst amount, and 3 h reaction time, the highest conversion of acetic acid (80.2%) was achieved over 30HPW@UiO-66. Significant findingsThe highest activity of 30HPW@UiO-66 could be attributed to its high dispersion of HPW, suitable specific surface area, total volume and total acidity. Meanwhile, the 30HPW@UiO-66 cycled to the fourth time still exhibited good catalytic activity. Moreover, an Eley-Rideal mechanism for the esterification reaction over the HPW@UiO-66 was proposed. Overall, the results demonstrated the potential of HPW@UiO-66 for the esterification process.

Synthesis and characterization of new bifunctional SnZrSi oxide catalysts for biodiesel production

A set of unprecedented (mesoporous SnO2/ZrSiO4) solids has been synthesized via the ultrasound-assisted co-precipitation path. The impact of silica dopant content (ranged between 0.05 and 0.4 mol%) on the characterization evolution of the sonicated ZrSnO4 interface and their biodiesel production efficiency were examined. Physio-chemical characteristics of the synthesized catalysts were analyzed by XRD, SEM-EDS, TEM, TGA-DTG, N2 adsorption–desorption analysis, NH3-TPD, UV–Visible/ DR, and FT-IR before and after pyridine adsorption. The obtained results revealed the formation of reconstructed rutile-SnO2 and zircon as new active phases by calcination at 500 °C, good morphology with mesoporous structure, and significant increase in the SBET, pore volume, interesting optical behavior, and exhibited different acidic properties. The impacts of reaction temperature, silica dopant content, fatty acid type and calcination temperature on the biodiesel % were examined. The tertiary oxide catalysts were gainful for the biodiesel production. The optimum catalyst (0.2 % SiO2/ZrSnO4) had the biggest number of both strong Brönsted and Lewis acid sites compared to the doped and undoped catalysts, so, its maximum yield at optimum conditions for esterification of palmitic acid reaction was 90.2 % and can be reused until the fifth run with giving excellent yield for biodiesel production. But, for the transesterification of soybean oil reaction with methanol was maxima at 88% for (0.4 % SiO2/ZrSnO4) sample. The kinetic, mechanism studies and thermodynamic parameters were estimated. The important role of the doped silica molecules in the mechanism of the esterification process was emphasized by the computational chemistry study.

Process optimization of esterification for deacidification in waste cooking oil: RSM approach and for biodiesel production assisted with ultrasonic and solvent

This study investigated the use of waste cooking oil, as a raw material for biodiesel production, solves its treatment problem, and provides additional value. The low acid value is achieved by the esterification process with H2SO4 as a catalyst for deacidification of FFAs which was optimized using response surface design to invest the effect of the operating parameters in this work. The effects of reaction time, catalyst concentration, temperature, and the molar ratio of methanol to oil on the deacidification were analyzed by the regression model equation in detail. The optimum conditions of the ratio of methanol to oil ratio (8), H2SO4 catalysis concentration (5 wt%), reaction temperature (60℃), and reaction time (108 min) were obtained and an acid value of 0.42 was achieved. The pre-esterified oil was used to produce biodiesel through transesterification with ultrasonic and solvent, and 98.5% FAME yield was achieved under the optimal condition that catalyst dosage of 2 wt%, the molar ratio of oil to methanol of 1:6, reaction temperature of 40℃, solvent type of n-hexane, the solvent dosage of 8: 1, pulse time of 7 s on/1s off, and ultrasonic power of 130 W. Therefore, this study clearly showed the necessity of pre-esterification of WCO as raw material, and assisted measures of ultrasound and co-solvent for biodiesel production, which is more efficient, less time-consuming, and more helpful than the usual process because it reduces the optimal conditions needed to achieve high FAME% yield.