Transesterification Time Research Articles

Transesterification catalyzed by industrial waste—Lime mud doped with potassium fluoride and the kinetic calculation

Lime mud (LM), a solid waste from paper mill, is doped with potassium fluoride to prepare heterogeneous base transesterification catalyst. The catalyst is characterized by Hammett indicator method, Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The experimental results show that the basic strength of catalyst is the main reason for high catalytic activity. After doped with 20wt.% KF and activated at 600°C (KF/LM-600), the effects of catalyst addition percentage, molar ratio of methanol to oil, transesterification time, and transesterification temperature are concerned to examine the catalytic activity of KF/LM-600 and the reusability of KF/LM-600 is also investigated. Oil conversion of 99.09% could be achieved with catalyst addition percentage 5wt.%, molar ratio of methanol to oil 12, transesterification time 2h and transesterification temperature 64°C. Furthermore, the kinetic parameters of transesterification catalyzed by KF/LM-600 are calculated.

Biodiesel synthesis with alkaline catalysts: A new refractometric monitoring and kinetic study

In this work, an experimental system was designed to allow the online monitoring of a chemical reaction in continuous flow leading to biodiesel synthesis using a portable digital refractometer. The proposed method was applied to the monitoring of the methanolysis of soybean oil using KOCH3 as the catalyst at temperatures from 30 to 60°C, allowing data acquisition in a relatively simple, reliable and cheap fashion. It was also possible to identify, discriminate and monitor the mixing (emulsification) and the reaction steps, with the former being the rate determinant. The methanolysis reaction is better represented by a zero-order kinetic scheme than by a pseudo-first-order scheme; the activation energy was determined to be (31.3±1.8)kJmol−1. This behavior suggests that methanolysis with alkaline catalysts, usually considered as a homogeneous process, should in fact be assumed to be heterogeneous. Therefore, the rate of mixing controls the reaction kinetics and is a key factor in decreasing the transesterification time.

An investigation on the catalytic capacity of dolomite in transesterification and the calculation of kinetic parameters

The catalytic capacity of dolomite in transesterification was investigated and the kinetic parameters were calculated. The activated dolomites as transesterification catalyst were characterized by X-ray diffraction, nitrogen adsorption and desorption and Hammett indicator method, where the original dolomite was analyzed by thermogravimetric and X-ray fluorescence in advance. Its potential catalytic capacity was validated from aspects of the activated temperature and the reused property, where the reliability of the experimental system was also examined. Then, influences of the catalyst added amount, the mole ratio of methanol to oil, the transesterification temperature and the transesterification time on the catalytic capacity were investigated. Finally, kinetic parameters of the transesterification catalyzed by the activated dolomite were calculated.

Optimization and characterization of biodiesel produced from vegetable oil

The world faces several issues of energy crisis and environmental deterioration due to over-dependence on single source of which is fossil fuel. Though, fuel is needed as ingredients for industrial development and growth of any country, however the fossil fuel which is a major source of energy for this purpose has always been terrifying thus the need for alternative and renewable energy sources. The search for alternative energy sources resulted into the acceptance of a biofuel as a reliable alternative energy source. This work presents the study of optimization of process of transesterification of vegetable oil to biodiesel using NaOH as catalyst. A <TEX>$2^4$</TEX> factorial design method was employed to investigate the influence of ratio of oil to methanol, temperature, NaOH concentration, and transesterification time on the yield of biodiesel from vegetable oil. Low and high levels of the key factors considered were 4:1 and 6:1 mole ratio, 30 and <TEX>$60^{\circ}C$</TEX> temperatures, 0.5 and 1.0 wt% catalyst concentration, and 30 and 60 min reaction time. Results obtained revealed that oil to methanol molar ratio of 6:1, tranesetrification temperature of <TEX>$60^{\circ}C$</TEX>, catalyst concentration of 1.0wt % and reaction time of 30 min are the best operating conditions for the optimum yield of biofuel from vegetable oil, with optimum yield of 95.8%. Results obtained on the characterizzation of the produced biodiesel indicate that the specific gravity, cloud point, flash point, sulphur content, viscosity, diesel index, centane number, acid value, free glycerine, total glycerine and total recovery are 0.8899, 4, 13, 0.0087%, 4.83, 25, 54.6. 0.228mgKOH/g, 0.018, 0.23% and 96% respectively. Results also indicate that the qualities of the biodiesel tested for are in conformity with the set standard. A model equation was developed based on the results obtained using a statistical tool. Analysis of variance (ANOVA) of data shows that mole ratio of ground nut oil to methanol and transesterification time have the most pronounced effect on the biodiesel yield with contributions of 55.06% and 9.22% respectively. It can be inferred from the results various conducted that vegetable oil locally produced from groundnut oil can be utilized as a feedstock for biodiesel production.

A TECHNO-ECONOMIC ANALYSIS OF BIODIESEL PRODUCTION FROM MICROALGAE

The preliminary assessment of a cost-effective flow-sheet for the production of biodiesel from microalgae lipid fraction was carried out. The study was based on approximated cost-estimation methods integrated with the simulation software Aspen Plus (R). Several scenarios were investigated to compare costs regarding the main steps of the biodiesel production process. Ranges of input variables from downstream literature and experimental data were used to simulate the sections that define concrete process routes for production of algal biofuels: the extraction of the lipid fraction from aqueous solution, the lipid transesterification, and the methyl esters (FAMEs) and glycerol recover. The design variables were selected so as to correspond to the main degrees of freedom of the process: number of equilibrium stages, solvent recycle flow rate, transesterification time, methanol to triacylglycerols ratio, plate number and reflux ratio of the distillation unit for methanol recovery. The cost estimation for the conceptual design of the flowsheet dedicated to the FAMEs production from microalgae was carried out according to Happel's method. Data were worked out to assess the venture profit and the selling price (s) for mass unit of FAMEs. The minimization of s was adopted as the objective function. A preliminary determination of plausible values of the cost for unit of mass of biodiesel was attempted as a function of operating conditions.

Optimización del proceso de obtención de biodiesel a partir de colza silvestre (Brassica Campestris)

The objectives of this study were, to optimize the performance of biodiesel from rapeseed wild oil depending on the molar ratio methanol / oil, the concentration of NaOH and KOH homogeneous catalysts, temperature and time of transesterification through the response surface methodology, and determining the physicochemical characteristics of biodiesel obtained under optimized conditions. A Plackett and Burman (PB12) design was applied for the screening stage and a rotatable central composite design (DCCR) for the final optimization. The conditions that maximize the yield of biodiesel (77.8%) were obtained at concentrations of 0 to 0.2% NaOH and 0.4 to 0.6% KOH, with time from 77 to 81 minutes, keeping constant the molar ratio of methanol/oil in 6/1 and a temperature of 60 °C. The physicochemical properties of biodiesel obtained under optimized conditions meet the technical specifications given by ASTM D6751 - 07 and EN14214.

Effect of karawila (Momordica charantia) seed oil on synthesizing the alkyd resins based on soya bean (Glycine max) oil

Air drying long oil alkyd resins of 65% oil length were synthesized from a blend of soya bean (Glycine max) oil and karawila (Momordica charantia) seed oil. Different proportions of karawila seed oil (w/w% 10, 20, 30, 40 and 50) were blended with soya bean oil to examine the effect of karawila seed oil on the drying behavior of alkyds synthesized from soya bean oil. A sharp variation of viscosity is only observed for alkyd resins having more than 40% (w/w) of karawila seed oil. The polyesterification time was reduced and correspondingly the extent of polymerization was also reduced up to 30% (w/w). Significant variation in transesterification time was also observed for 30% (w/w). However, further increase in karawila seed oil above 40% (w/w) had only a marginal effect on the polyesterification reaction. The drying properties of the alkyd resins had been significantly improved with the increase of karawila seed oil up to 30% (w/w) but further increase in karawila seed oil resulted in poor drying characteristics. The film properties (drying time, hardness, adhesion, chemical resistance and gloss) of the alkyd resins were determined. The optimum film properties were recorded for the oil blend with 30% (w/w) karawila seed oil and 70% (w/w) soya bean oil.

Critical factors of indirect determination of 3‐chloropropane‐1,2‐diol esters

AbstractSeveral indirect methods have been developed for the determination of 3‐chloropropane‐1,2‐diol (3‐MCPD) esters in fat matrices, but the variation between these methods leads to an uncertainty about the comparison of the results. All the indirect methods are based on the conversion of 3‐MCPD esters into free 3‐MCPD upon transesterification (either in acid or alkaline solution), its purification, derivatisation and instrumental analysis. In this study, major critical factors of the methodology, particularly transesterification, salting out and the choice of internal standard, were evaluated. 3‐MCPD showed low stability under the conditions of alkaline transesterification (only around 40% recovery) affecting the sensitivity of the method. Furthermore, the results obtained within the first 1–2 min were 10–20% higher than those obtained at longer (5–10 min) transesterification time. A comparison of results obtained by using two different internal standards (free or esterified form of deuterated 3‐MCPD) revealed a slight overestimation (7–15%) when free deuterated 3‐MCPD was used, which may be possibly explained by the different behaviour of the both forms during alkaline transesterification. The use of different salts and pH values of the reaction medium during salting out step had a major impact on the results due to the formation of additional 3‐MCPD. Other compounds, like glycidyl esters, present in oil samples may be converted to 3‐MCPD during this step, however, the conversion was not complete and varied substantially (12–93%) in dependence on the pH value of the medium. The method based on acid transesterification showed better selectivity and robustness.

Biodiesel production in a jet flow stirred reactor

The rate of biodiesel formation was assessed in a transesterification reactor stirred with a dual jet flow close loop. A blend of 85% of soybean and 15% of sunflower oil, methanol and NaOH were used to study the rate of conversion from vegetable oil to methyl esters. A 9 l cylindrical reactor with conical bottom discharge connected to two centrifugal pumps for fluid recirculation through dual opposite radial jet flows in its upper part was developed for the experiment. The system did not require a heating supply due that the frictional effect inside the recirculation hoses and nozzles produced self heating of the inlet fluid to the reactor. Four different diameters of ejector corresponding to initial Reynolds Number (Re) ranging between 1300 and 6470 were tested to assess the reactor heating profile along with the kinetics of biodiesel formation. Clear performance differences among ejector diameters and Reynolds Number values were observed showing that higher Re result in low relative conversion times along with higher final temperature in the reactor. For 98% of relative conversion to biodiesel, the ejector with Re = 6470 showed 88% reduction in transesterification time with respect to an ejector delivering a Re = 1300 and without requiring any external heat source.

Efecto de la temperatura y tiempo de transesterificación en el rendimiento y poder calórico de biodiesel a partir de grasa refinada de pollo

The main objective of this research was to determine through the response surface methodology conditions of temperature and time of transesterification which could achieve the higher yield and calorific value in the biodiesel obtained. We used the Central Composite Rotational Design type 22 +2*2, including 4 repetitions at the central point. Chicken fat passed through refining processes, esterification and transesterification weather conditions and temperature of each experiment. The best conditions of temperature were between 50 and 70 oC and time of transesterification between 60 and 120 min, we have obtained an average yield of 94.5% and calorific value in the biodiesel obtained from 40.2 MJ / Kg. We conclude that using the temperature of 56 oC and time of 108.4 minutes, biodiesel is obtained with characteristics required by the ASTM D6751-07, EN 14214 and NTP 321.003.2005 standards.

Compatibilizing effect of transesterification product between components in bisphenol‐A polycarbonate/poly(ethylene terephthalate) blend

The compatibilizing effect of a random copolymer, which is the transesterification product, on its corresponding blend system of bisphenol-A polycarbonate/poly(ethylene terephthalate) (PC/PET) has been studied using a Differential Scanning Calorimeter and a Phase Contrast Microscope. It was found that after a long time of transesterification between PET and PC (50/50, wt %), the obtained product, that is, TCET random copolymer, is miscible with individual homopolymers of PC and PET. The addition of the TCET copolymer into the immiscible PC/PET blend can make the glass transitions of the PC-rich phase and PET-rich phase approach each other, and eventually merge into a single glass transition when the content of TCET in the ternary mixture reaches 60 wt %. Meanwhile, the phase structure images showed that with the increasing content of the TCET copolymer in the ternary blends, the size of the phase domains decreases and the phase domains further diminish at 60 wt % TCET. All these results proved the compatibilizing effect of TCET copolymer on the PC/PET blends in their ternary mixture. The mechanism of the compatibilizing effect is directly related to the reduction of the interfacial tension between PC-rich and PET-rich phase domains in the presence of increasing amounts of TCET copolymer in the ternary blends. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2960–2972, 1999

Compatibilizing effect of transesterification product between components in bisphenol-A polycarbonate/poly(ethylene terephthalate) blend

The compatibilizing effect of a random copolymer, which is the transesterification product, on its corresponding blend system of bisphenol-A polycarbonate/poly(ethylene terephthalate) (PC/PET) has been studied using a Differential Scanning Calorimeter and a Phase Contrast Microscope. It was found that after a long time of transesterification between PET and PC (50/50, wt %), the obtained product, that is, TCET random copolymer, is miscible with individual homopolymers of PC and PET. The addition of the TCET copolymer into the immiscible PC/PET blend can make the glass transitions of the PC-rich phase and PET-rich phase approach each other, and eventually merge into a single glass transition when the content of TCET in the ternary mixture reaches 60 wt %. Meanwhile, the phase structure images showed that with the increasing content of the TCET copolymer in the ternary blends, the size of the phase domains decreases and the phase domains further diminish at 60 wt % TCET. All these results proved the compatibilizing effect of TCET copolymer on the PC/PET blends in their ternary mixture. The mechanism of the compatibilizing effect is directly related to the reduction of the interfacial tension between PC-rich and PET-rich phase domains in the presence of increasing amounts of TCET copolymer in the ternary blends. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2960–2972, 1999

OPTIMIZATION OF CHEMICAL TRANSESTERIFICATION OF PALM OIL USING RESPONSE SURFACE METHODOLOGY

The effect of catalyst concentration (0.1–0.5% methoxide powder), temperature (50–92C), and time (30–480 min) of chemical transesterification was studied to determine the optimum condition for maximizing concentration of triunsaturated and trisaturated triacylglycerols (TG) in palm oil. TG compositions of the oil were analysed using high-performance liquid chromatography. The optimum condition of the process was determined using statistical response surface methodology. The results showed that the triunsaturated and trisaturated TG responses followed a second order form of the treatments with R2= 0.83 and 0.85, respectively. The triunsaturated TG reached a maximum concentration by using 0.36% catalyst at 78C and 360 min reaction time, whereas the trisaturated TG with 0.36% catalyst at 81C and 325 min reaction time. Considering the two responses, it was concluded that the overall optimum condition could be achieved at 0.36% of catalyst at 78–81C and 325–360 min reaction time. Such conditions increased trisaturated TG in palm oil by 2.34 times and triunsaturated TG by 1.54 times.

Solid-Phase Synthesis of Selectively Protected Peptides: Use of Thallous Alkoxide as Catalyst in the Transesterification Step

Transesterification with 2-dimethylaminoethanol, in the presence of thallous alkoxide, was found to provide a useful method for the cleavage of protected peptides from the Merrifield resin after solid-phase synthesis. The extent of racemization, at the C-terminal residue, was low (&lt; 1%) in the case of peptides containing C-terminal alanine or valine residues. The method was also found to provide good yields of the protected peptide derivative even in the case of the severely sterically hindered C-terminal valine peptides. A study of the α → β aspartyl transpeptidation, showed that the extent of this side reaction was low (&lt; 1% β-isomer) in the case of the labile α-aspartylglycine sequence, when a short transesterification time was employed. The t-butyl ester group was shown to be stable under the conditions of transesterification and this group is recommended for the protection of carboxylic acid side chains. Hydrolysis of the 2-dimethylaminoethyl esters was accomplished by treatment with water or dilute base, to yield the selectively protected peptide acids, suitable for use as building units in the synthesis of large molecules by solid-phase or solution techniques.