جستجوی مقالات مرتبط با کلیدواژه « transesterification » در نشریات گروه « شیمی »

Glycerol Carbonate (GC) is a green chemical that could replace fuel in lithium-ion batteries in electric vehicles and the energy industry. This study focuses on transesterifying glycerol and dimethyl carbonate using microwave power and a frequency range of 2.45 GHz. The experiment uses Gypsum Board Waste (GBW) and Oil Palm Fuel Ash  (OPFA), two industrial waste catalysts, to produce GC, a sustainable energy source, and explore its potential in EVs and the energy industry. XRD and EDX analysis revealed that the GBW catalyst outperformed the OPFA catalyst in terms of GC yield and cost, achieving a 69.81% GC yield for glycerol carbonate synthesis, with a production cost of 3.05 baht per gram, making it the better choice for glycerol carbonate synthesis.

MgO/γ-alumina and CaO/γ-alumina heterogeneous base catalysts have been prepared by wet impregnation, using 10 wt.% of metal oxide precursors, and used in the transesterification reaction of castor oil (Riccinus communis) into biodiesel. Catalyst characterization includes X-Ray Diffraction (XRD), Fourie Transform InfraRed (FT-IR) spectroscopy, X-Ray Fluorescence (XRF), Surface Area Analyzer (SAA), average pore radius (BJH), and basicity. The catalyst performance was observed from the activity and selectivity of the catalyst in converting castor oil into methyl ester with batch system at 60°C for 2 hours. The castor oil biodiesel was analyzed using GC-MS to determine the selectivity of the catalyst towards methyl ricinoleate. The results showed that the addition of MgO and CaO to γ-alumina increased the basicity and average pore radius but decreased the specific surface area of γ-alumina. The FAME yields of γ-alumina, MgO/γ-alumina, CaO/γ-alumina, MgO, CaO, and KOH catalysts with 3 wt.% ratio were 81.15%, 82.17%, 82.45%, 82.02%, 82.16%, and 84.57%. The selectivity to methyl ricinoleate was the highest for CaO/γ-alumina catalyst which was 87.57% area GC. The yield of FAME at various weight ratios of CaO/γ-alumina (1, 2, 3, 4, and 5 wt.%) were 81.81%, 82.13%, 82.45%, 83.57%, and 83.96% and the selectivity to methyl ricinoleate was the largest at 4 wt.% CaO/γ-alumina catalyst which was 90.20% GC area. Castor oil biodiesel was analyzed according to the American Standard of Testing Materials (ASTM) method for biodiesel eligibility. ASTM test results for castor oil biodiesel showed a kinematic viscosity (40°C) of 15.76 mm2/s which is above the biodiesel standard because the kinematic viscosity of castor oil was also high. The flash point of 222.5°C, pour point <27°C, and cloud point of 15°C have fulfilled the requirements of the biodiesel standard.

Petroleum resources are limited on a global scale. Due to non-renewability, these fossil-fuels are projected to be depleted in next 40-60 years if consumption continues at the current pace. Moreover, the price instability of crude oil poses a significant threat to nations with constrained financial and economic resources. To address these challenges, alternative energy sources are being explored, and there is ongoing emphasis on further progress in these areas. As an alternative fuel, biodiesel can be used in neat form or mixed with petroleum-based diesel. Therefore, we need to move towards alternative fuel like bio-diesel. Several alternative fuels have been studies among which biodiesel from waste soybean oil having great importance. Bio-diesel could be easily prepared from waste soybean oil, by the process of transesterification with alcohol in presence of sodium hydroxide or potassium hydroxide. India is the fourth largest producer of soybean in the world, and from last few decades, soybean oil is exclusively use as edible oil. In different food industries, several million tonnes of soybean oil uses every year. Therefore, huge amount of waste soybean oil is produced every year. In the present work, we attempt to synthesize biodiesel using waste soybean oil via transesterification, and characterize by physical, chemical, and spectroscopic instruments, and found the characteristics properties of this biodiesel is quite similar to petroleum diesel . Therefore, this synthesis may use biodiesel as an alternative for petroleum diesel.

Excessive use of petroleum-based lubricants and their hazardous disposal has increased environmental pollution; hence the need for eco-friendly lubricants has been increased to meet the requirements of industry and automotive. Due to the oil crisis, the world’s attention has been diverted to producing bio-lubricants from non-edible sources. The use of non-edible sources can overcome the problems of toxicity, hazardous nature, and non-biodegradability. This study discusses the effect of various parameters on transesterification reaction to produce bio lubricant from Neem oil. The dried neem seeds were crushed, and the oil was extracted using the Soxhlet extraction method using n-hexane. The bio lube was produced by a double transesterification process using CaO as a catalyst. The effect of temperature, the molar ratio of ethylene glycol to oil, and catalyst wt% on yield bio lubricant was observed. The temperature varied from 110 to 140 °C, molar ratios of ethylene glycol to oil varied from 2:1 to 8:1, and the catalyst wt% was 0.8 to 1.6%, keeping the reaction time and other conditions constant. During the experimentation, it was observed that the yield was low at 110°C, but as the temperature increased, yield also increased, but no significant change in yield was observed beyond 130°C. The maximum yield observed at 130°C, and 140°C was 93.7% and 94.37%, respectively. Similarly, as the molar ratio increases, the yield of bio lube also increases, and the maximum conversion was 94.3% achieved at ethylene glycol to oil molar ratio of 8:1, but a molar ratio 6:1 may be considered optimum because there is no substantial increase in conversion after 8:1. Moreover, the profile was observed by varying the amount of catalyst and it is evident from the results, as the amount of catalyst increases as the conversion increases from 66% to 95%; however, at a catalyst ratio of 1.6 wt %, a yield was decreased slightly to 94.2. It has been observed that the temperature significantly impacts the production yield of Biolube.

Methyl ester is the name given to monoalkyl esters of vegetable and animal oils. Since methyl ester has fuel properties that are comparable to those of diesel fuel, it is becoming more popular as a substitute fuel for use in diesel engines. The amount of free fatty acids (FFA) in the oil determines how methyl ester is produced. In this study, the titration method was used to calculate the FFA values of the crude cottonseed oil (CCSO) and one-time Used Cottonseed Oil (UCSO), with values 0.56 % and 1.26 %, respectively. The UCSO is transformed into methyl ester by employing a heterogeneous alkali catalyzed transesterification reaction. It involves the addition of methanol to bleach and degummed UCSO in the presence of heterogeneous catalysts CaO-blend derived from calcinated eggshells and coconut shell blend. Reaction variables including the methanol-to-oil ratio, reaction temperature, reaction time and catalyst concentration control the transesterification process. The Box-Behnken design was employed to optimize the aforementioned parameters using the response surface methodology (RSM). Numerous factors that affect the generation of biodiesel have been plotted using the response surface plot and contour plot. An optimized UCSO methyl ester yield of 92.00 % was obtained at a 1:10.80 molar ratio, 2.5 wt. % catalyst concentration, 80 minute reaction time, and 60 °C reaction temperature. The experimental yield was 92.10 %, as determined by the optimized yield based on these parameters. This shows that the response surface methodology is a successful strategy for increasing the yield. The regression model proved successful, as observed by the error values between the predicted and actual outcomes being less than 1 % UCSOME conversion. For this study, adequate precision was 8.9518. As a result, the model can be utilized to explore the design space. Each succeeding cycle of reuse produced 91.60 %, 85.50 %, 81.60 %, 78.60 %, 74.20 %, and 72.87 % of the biodiesel. The measurements for viscosity, density, and flash point of UCSO were 33-36 mm2/s at 311 K, 911-916 kg/m3 at 288 K, and 504-510 K, respectively. UCSO methyl ester (UCSOME) had a viscosity between 3.6 and 3.7 mm2/s and a density between 875 and 880 at 311 K. While the flash points of the UCSOME are measured at 435–440 K as opposed to 504-510 K. The saponification value of cottonseed oil was 188.32 mg/g while that of biodiesel was 165.87 mg/g. Thus, biodiesel fatty acid methyl ester possesses a distinctive FTIR absorption of carbonyl (C=0) stretching vibrations near 1740-1744 cm-1 and C-O bending vibrations in the range of 1196 cm-1.

In the present study the production of biodiesel was performed by using raw material like soybean oil by trans-esterification process. According to the American Society for Testing and Materials (ASTM), the international specification free glycerol in biodiesel should not be more than 0.02 mass %. To achieve the biodiesel with the ASTM specification, biodiesel was separated using prepared PAN ultrafiltration membranes. The polyacronitrile ultra filtration membranes were prepared on supporting material of woven fabric by phase inversion technique of membrane casting. The prepared membranes were characterized in terms of its molecular weight cut off and flux of the membranes. Different molecular weights of the BSA solutions were used to determine the molecular weight cut off of the membranes. Then the obtained 6KDa and 15KDa Ultra filtration PAN membranes were used to separate the glycerol from (FAME) free acid methyl ester. It was observed that the both membranes were separated glycerol from the biodiesel below 0.02 mass % which meets the requirements of the ASTM specification of glycerol. The permeate side of the 6KDa membrane was estimated to be 0.017 mass % of glycerol, whereas, 15 KDa membrane was 0.02 mass % . The glycerol percentage in retained side membranes were increased with time.

In this study, in order to produce biodiesel fuel from mixture of crop mustard and edible waste oil, ester exchange method with heterogeneous calcium oxide catalyst prepared from fish bones was used as a catalyst. Then, the effect of the contribution of important and effective factors on the molar ratio of oil to methanol, catalyst percentage, reaction temperature and reaction time on the amount of biodiesel production was investigated using Taguchi experiment design method. In biodiesel production method the optimum reaction, it can be seen that the effect of this parameter is strongly effective in the production of biodiesel with a ratio of (1:12), that this molar ratio of oil to methanol (1:12) has the best efficiency. According to the results, the amount of (0.3%) calcium oxide catalyst prepared from fish bones can be considered as the maximum value in biodiesel production. It was observed that, with increasing the reaction temperature from (55°C to 65°C), the amount of biodiesel production increases by about 8% and with the continuation of increasing the temperature from (65°C to 75°C), with a sharp decrease in production (about 30%) We face. As a result, temperature for biodiesel production is (65°C), and best efficiency and maximum percentage of biodiesel production occur in (5 h) of reaction time. The thermophysical properties of biodiesel produced from these oils were compared with standard biodiesel and all its properties were within the allowable range of standard ASTM D-6751.

Worldwide interest in biofuels, such as biodiesel and biogas as alternatives to fossil fuels, is growing. The transesterification method is usually applied in the production processes of biodiesel because of its numerous advantages. The viscosity of the oil sample was decreased by utilizing this technique. The production procedure of methyl ester is determined by the amount of free fatty acids (FFA) in the sample. The titration technique was employed to evaluate this for the crude cottonseed oil (CCSO) and used cottonseed oil (UCSO), with the following results 0.56 % and 1.26 %. Heterogeneous alkali (calcined commercial CaO) catalyzed transesterification was used to convert UCSO into used cottonseed oil methyl ester (UCSOME). It involves the reaction of methanol with UCSO in the presence of the catalysts. Some of the reaction parameters that control the transesterification process were; the methanol-oil ratio, reaction temperature, reaction time, and catalyst concentration. The aforementioned parameters were optimized through the response surface approach; Box-Behnken Design (BBD). The response surface yield has been plotted graphically as part of the various parameters that improve biodiesel yield. An optimized UCSOME yield of 93.60 % was obtained at a 1:10 molar ratio, 2.5 wt.% catalyst concentration, 80-min reaction time, and 60 °C reaction temperature. 94.50 % was the experimental yield obtained based on these parameters, which shows that the response surface methodology is a successful technique for optimizing the yield. The purity of the methyl ester was determined using GC-MS and FTIR.

The growing energy demand and depletion of conventional energy resources presented a need for an alternative reliable source of energy that can readily replace conventional fuels like diesel and petrol. In the current work, biodiesel is synthesized from Karanja oil by using transesterification. The yield is obtained at varying KOH concentrations (1 wt %, 1.5 wt %, 2 wt %), varying molar ratios of methanol: oil (3:1, 4.5:1, 6:1), and varying times (15 min, 30 min, 45 min, 60 min). The optimal conditions from the experiment are obtained as a temperature of 50° C, a reaction time of 45 minutes, a methanol-oil ratio of 4.5:1, and a catalyst concentration of 1.5 %. The viscosity of biodiesel is found to be between 0.036 - 0.038 stokes. The optimum conditions obtained were compared with the statistics available in the literature. The produced biodiesel from Karanja oil conforms to the ASTM D6751 standards. The produced biodiesel is characterized using Fourier Transform Infra Red (FT-IR) Analysis and Gas Chromatography-Mass Spectrometry (GC-MS). Further Artificial Intelligence techniques namely Support Vector Machine, Genetic Algorithm, and Particle Swarm Optimization have been used for predicting the optimum conditions of biodiesel production. The predicted yield with the Support Vector Machine is compared with the yield obtained from experiments. The SVM accurately predicted the experimental results with R2 = 0.999. PSO and GA can effectively be used as a tool for predicting the optimum parameters for biodiesel production.

New Ni(II) complexes were synthesized from the coordination of the ligands derived from benzo[1,2-c]isoxazoles with Ni(II) cation.. The structure of the new complexes was characterized by elemental analyses, mass, and IR spectra. To gain a deeper insight into the geometry of Ni(II) complexes, a quantum chemical investigation was performed. The obtained results from experimental and theoretical arguments confirmed a square-planar geometry for Ni(II) complexes. These complexes were examined as homogeneous catalysts for the transesterification of corn oil with methanol. The structure of the obtained product was confirmed by 1H NMR analysis. The catalytic results showed that the new Ni(II) complexes can be considered potential candidates for the development of a new catalytic system for biodiesel production.

The aim of this study was to investigate the feasibility of using alumina-zirconia catalysts in energy production. In recent years, the use of liquid biofuels in the transportation sector has grown significantly. Sustainability is a key principle in natural resource management, which includes considering operational efficiency to minimize destructive environmental impacts and socio-economic considerations. Given the depletion of global reserves of fossil fuels and the emission of greenhouse gases from their use, it does not seem wise to trust and rely on the continued use of fossil fuel energy sources. The first-generation biofuels, which have now reached the economic level of production, are often extracted from food and oil products such as rapeseed, sugarcane, sugar beet, corn, as well as vegetable oils and animal fats using conventional technologies. The use of first-generation biofuels has caused much controversy, often because of their impact on the global food market and food security, especially in countries with vulnerable economies, and as a result there is much ambiguity about their potential to replace fossil fuels and sustain production. They have been created.

To make the biodiesel competitive with petroleum diesel, cheap and abundant materials can be utilized as a catalyst and waste oils can be used as resources. In this research study, the potential of waste chicken eggshells was used as a catalyst to produce biodiesel from the rendered chicken fats (RCF). The calcium methoxide catalyst was prepared by calcining the waste eggshells at 900 °C in air for 4 h followed by treatment with methanol under reflux condition. The physico-chemical properties of the prepared catalyst were characterized using the X-ray diffraction (XRD) analysis, Brunner-Emmet-Teller (BET), field emission scanning electron microscopy (FE-SEM), and temperature programmed desorption of carbon dioxide (CO2-TPD). Two-step process including, esterification and transesterification were employed to convert the RCF to fatty acid methyl ester (FAME). Esterification pretreatment with ferric sulfate successfully reduced 75.1% of the FFA content in RCF which enables high biodiesel production. Under the optimal reaction condition, the highest conversion of biodiesel was found to be 90.04% at 1:15 oil to methanol molar ratio, 3 wt% catalyst loading, and 2 h reaction time at 65 °C. The catalyst was successfully used for 4 consecutive cycles with less than 2 mg/kg of Ca was detected in the product.

Biodiesel is one of the sources of renewable fuel. Due to increasing environmental pollution, global warming caused by fossil fuels and limited fossil fuel resources, its production has been increased. Nowadays, low prices renewable sources are used to produce biodiesel. In this study, biodiesel is produced from edible oil wastes, such as goat fat, chicken fat and palm kernel-derived oil using the transesterification process. The produced biodiesel is mixed with different ratios of petroleum diesel to improve the physical properties of the produced biodiesel, such as flash point, kinematic viscosity, density, cloud point and pour point. The physical properties are measured according to the ASTM D6751 standard. The results show that some of the properties, such as density, viscosity and flash point are improved with the addition of biodiesel to diesel fuel. The other properties, such as pour point and cloud point are increased with the higher proportion of the biodiesel in the mixture. This causes a bad effect on the consumption of fuel and cannot be used in cold weather. Generally, adding biodiesel to diesel enhance the fuel properties.

Hydrophobic magnetic silica aerogel was used as a support to immobilize Candida rugosa lipase by adsorption method. Physical and chemical properties of the support and immobilized lipase were determined by Field Emission Scanning Electron Microscope (FESEM), Brunauer–Emmett–Teller (BET) analysis and Fourier Transform InfraRed (FT-IR) spectroscopy and the results showed that the lipase was successfully immobilized onto the support. Biodiesel production from sunflower oil using immobilized lipase was investigated. Response Surface Methodology (RSM) was employed to evaluate the effect of process variables namely methanol/oil molar ratio (4:1-6:1), enzyme concentration (4-10 % mass fraction of oil) and water concentration (3-10 % mass fraction of oil) on biodiesel yield and predict the optimal reaction conditions. A second-order regression model with a high coefficient determination value (R2= 0.99) was fitted to predict the response as a function of reaction parameters. The results indicated that optimum values for methanol/oil molar ratio, enzyme concentration, and water concentration were obtained at 4.5:1, 9.4% and 7.4 %, respectively, in which biodiesel yield was predicted at 72.3%. As the difference between the experimental and predicted values were shown as non-significant, the response surface model employed could be considered as adequate.

Kinetics of lipase-catalyzed esterification of hexanoic acid and ethyl alcohol using the solvent-free system, surface coated lipase from Candida rugosa, had been studied. The effect of various parameters such as reaction time, reaction temperature, reaction kinetics, water removal and feasibility of solvent-free system had been focused. Candida Rugosa lipase was more effective than other lipases when ethyl hexanoate was synthesized in n-hexane. The highest esterification yield after 72 h (93 %) was achieved at a pH of 5.2 and the esterification yield was reduced to 73% at pH 4.0. The values of the apparent kinetic parameters were computed as Vmax= 0.146 μmol/min/mg enzyme; KM, Acid = 0.296 M; KM, Alcohol = 0.1388 M; Ki, Acid = 0.40 M; and Ki, Alcohol = 0.309 M. The reaction rate could be described in terms of the Michaelis–Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both the substrates.

Calcium oxide is one of the appropriate catalysts for biodiesel production. In this study, cheap and compatible with environment catalyst has been used. Mussel shell of Persian Gulf coast is one of the sources of calcium carbonate that is converted to calcium oxide at calcination temperature up to 950°C. Transesterification reaction was carried out at optimum condition of our previous study (calcination temperature of 1050°C, methanol to oil ratio of 24:1 and catalyst to oil ratio of to 12 wt.%) in a 250mL two-necked flask. In this study, the effects of stirrer speed (250 and 350rpm), the reaction temperature (328.15, 333.15, and 338.15K) and reaction time (1, 3, 5, 7 and 8h) on the methyl ester conversion were investigated. The methyl ester conversion, in stirrer speed of 250rpm, reaction temperatures of 328.15 and 333.15K and reaction times of less than 5h is too low. But at the reaction temperature of 338.15K (near to methanol boiling point), the mixing is increased slightly and the reaction occurs at a higher rate and the methyl ester conversion is increased. These results indicate that diffusion has a significant role in the methyl ester conversion rate in the heterogeneously catalyzed reaction. In stirrer speed of 350rpm, the diffusion problem has been solved somewhat and the reaction in the catalyst surface is the controller of the overall reaction rate. In this stirrer speed (350rpm) the methyl ester conversion versus time in all temperature shows pseudo-first-order kinetics. Firstly, the rate was determined at the various temperatures and then the activation energy for the transesterification reaction of soybean oil with methanol was obtained in the presence of mussel shell as the catalyst. Results demonstrate the high precision of the pseudo-first-order kinetics model regard to methyl esters concentration.

In this research, biodiesel was produced using chicken fat in the presence of calcium oxide nano-catalyst. To do so, the effect of various parameters like temperature, reaction time, catalyst amount and methanol to oil ratio was investigated on the biodiesel production. The results showed that the best conditions for biodiesel production were obtained such as the temperature of 65oC, methanol to oil ratio of 1:9, the catalyst amount of 1 wt.% and reaction time of 5 h which in these conditions the biodiesel efficiency was determined 94.4%. Then, for improvement of fuel properties, they were mixed with diesel in different ratios (B25, B50, and B75) and their properties such as flash point, cloud point, pour point, kinematic viscosity and density were analyzed according to international standards. The results showed that the mixture ratio of B75 and B100 had density and viscosity in the range of standard. Additionally, this fuel should not be used in cold weather since its pour point is greater than zero.