جستجوی مقالات مرتبط با کلیدواژه « trans-esterification » در نشریات گروه « شیمی »

Alkaline earth metal oxides (CaO–MgO) are employed as a heterogeneous catalyst in the manufacture of biodiesel from non-edible oils such as olive, sunflower, and corn. The purpose of this research is to examine the effect of temperatures on the catalytic conversion of biodiesel from waste cooking oil using CaO–MgO. The catalyst was used to investigate the temperatures effect on the trans-esterification reaction. The best circumstances were studied a methanol to oil ratio of 6:1 and temperatures of 30-60 °C. The temperatures of the reaction has a considerable influence on the trans-esterification reaction, with optimum biodiesel conversion occurring at 60 °C and a yield 99%, with R2 values larger than 0.70. CaO–MgO catalyst exhibited 99% yield and strong catalytic activity. According to the experimental results, the CaO–MgO heterogeneous catalyst can obtain biodiesel of high yields that are comparable to those cited in the citations.

The negative environmental impact generated by fossil fuel has resulted in the demand to search for alternative routes of renewable sources of energy, such as biodiesel, that have unlimited duration while having little or no hazardous impact. In this study, trans-esterification of palm kernel oil and groundnut oil was carried out using sodium methoxide (CH3ONa) as a catalyst. The effect of varying Sodium Methoxide (CH3ONa) catalyst concentrations of (0.25, 0.5, 1.0, 1.5, and 2.0) % w/v at trans-esterification temperatures of (50, 55, and 60) oC on the yield of biodiesel from groundnut oil and palm kernel oil was determined. This was to identify the catalyst concentration and trans-esterification temperature with optimal process yield. The process gave optimum biodiesel yields of 98% and 84% by volume of groundnut oil and palm kernel oil at reaction conditions of 0.5%w/v CH3ONa as catalyst, trans-esterification temperature of 55oC, 360 rpm mixing rate and a reaction time of 90 minutes. The biodiesel produced was analyzed for fuel properties using the American Society of Testing and Materials (ASTM) standard, and the results obtained were as follows; specific gravity (0.8835, 0.8815 at 15oC), flash point (98, 124) oC, viscosity (5.2, 7.6) mm2S-1at 40oC, pour point (9, -1)oC, iodine value (8.04, 17.11) /100, acid value (0.67, 0.48) mg/KOH/g, peroxide value (28, 60) mg Kg-1, fire point (108,136)oC for palm kernel oil and groundnut oil respectively.

Bis(2-ethylheptyl) phthalate is an anti-oxidant and anticancer compound that was extracted from the Cynodon dactylon plant stem extract and fully identified and characterized by FTIR, CHN, 1HNMR, 13CNMR, along with various 2D NMR techniques. The phthalate compound was modified and functionalized by polyethylene glycol (PEG) chains followed by complexation to Cu(II) ions. The resultant complex was applied as an efficient and strong recyclable homogeneous catalyst for the preparation of 1,8-dioxo-octahydroxanthenes under mild conditions. The homogeneous catalyst could be recovered and reused for several times.

As a green material, used date pits oil is increasingly utilized as inexpensive feedstock for ethyl ester (biodiesel) production. Waste date pits as a raw material are one of the highly produced agricultural wastes in Iran. This study investigated the effect of several procedure parameters including the ethanol/oil molar ratio, reaction temperature and amount of catalysts on the yield of the produced ethyl ester. The activity of date pits oil can be considered a method of second-generation biofuels production including green diesel fractions. Efficient from waste date pits and synthesis of ethyl ester have made a breakthrough in biodiesel production. Gas chromatography/mass spectrometry (GC-MS) and Fourier Transform Infrared (FT-IR) were employed to determine the composition of production. The optimized ethyl ester yield obtained was 92% when the procedure temperature was 65 ℃, within 6h, with 7:1 ethanol/oil molar ratio with 0.75 wt.% of catalyst (KOH). Waste date pits oil as feedstock can be an efficient platform for ethyl ester production. The purified ethyl ester satisfies the stringent quality standards imposed by ASTM D-6751 (USA standard) and EN-14214 (European standard).

The present research investigated the impact assessment of modified rice bran as a heterogeneous catalyst and production of biodiesel from rice bran oil (RBO). Several variables including temperature, catalyst concentration, amount of methanol and reaction time were optimized in order to produce high quality RBO biodiesel with maximum yield. The results showed that obtained conditions for trans-esterification of RBO with methanol and carbon-based acidic heterogeneous catalyst were 65℃ reaction temperature, 6h reaction time, 10:1 molar ratio of RBO to methanol and 1.5%(w/w) catalyst. The produced rice bran oil methyl ester was suitable to be used as a fuel in engines. Considering the availability and renewability, methyl ester rice bran can be easily produced in large quantities as a sustainable and reliable energy resource for multi-functional applications.