Complete Transesterification Research Articles

Phosphonomethylated acetoxymethyl derivatives of acetylfurans and alkyl furoates with the remote location of substituents: synthesis and further transformations

Methods of synthesis of phosphonomethylated acetoxymethyl derivatives of acetylfurans and alkyl furoates with the remote location of functional groups were developed. Investigation of methanolysis of these compounds in presence of sodium methylate showed that complete transesterification of acetates is achived when the equimolar amount of base is used. It takes place due to high acidity of furan alcohols. If acetoxymethyl group is located in the position 3 of the furan ring, and diethoxyphosphorylmethyl one - in the position 2, cleavage of P-C bond takes place. If phosphonomethyl group is located in the position 3, and acetoxymethyl one occupies position 2 or 4, transesterification of ester groups of phosphonate takes place, but P-C bond is not touched. The ester group of carbonic acid is transesterified in any case. The alcohols formed are oxidized according to Kollins to give the corresponding aldehydes. 2-Furylbenzo[ d ]thiazole having ester and diethoxyphosphorylmethyl groups in the furan ring was synthesized by reacting methyl 2-(diethoxyphosphorylmethyl)-5-formylfuran-3-carboxylate with 2-aminothiophenol.

Hydrated metal salt pretreatment and alkali catalyzed reactive distillation: A two-step production of waste cooking oil biodiesel

In this work, a novel method was proposed for the conversion of waste cooking oil into biodiesel. A two-step approach based on a pretreatment with AlCl3•6H2O to convert FFA into the relevant methyl esters, followed by the complete transesterification of glycerides, under KOH catalysis in a reactive distillation column, was considered. The pretreatment with AlCl3•6H2O allowed to obtain two different phases: an oily phase, rich in FAME and triacylglycerols and with a very limited content of water (100 ppm), and residual FFA (1 mgKOH /goil), and a methanol phase, in which most of the catalyst, water and monoacylglycerols were dissolved in. The esterified stream was characterized by its composition and used to obtain new kinetic parameters to be used in the setting of the reactive distillation. The reactive distillation column was proved to be efficient in obtaining a biodiesel stream with a purity requirement conform to the EN14214 standards. The transesterification step was characterized by a specific heating requirement of 701.3 kJ per kg of biodiesel produced.

Biodiesel production through transesterification of Chlorella vulgaris: Synthesis and characterization of CaO nanocatalyst

Current research deals with the effective, economic and ecofriendly conversion of algal oil into biodiesel using Calcium oxide (CaO) nanocatalyast. CaO nanoparticles were used as an alkaline catalyst for the transesterification of the indigenous green alga, Chlorella vulgaris oil into biodiesel. The catalyst was subjected to different calcination temperatures and their effect on complete transesterification of algal oil at different concentrations was also studied. The characteristics of the nanocatalyst were investigated using UV–Vis spectrophotometer, Fourier-Transform Infrared spectroscopy (FTIR), powder X-ray Diffractometer (XRD) and Field Emission Scanning Electron Microscopy (FESEM) equipped with Energy Dispersive Spectroscopy (EDS). It was found that various parameters such as reaction time, temperature and catalyst amount influences the fatty acid methyl esters (FAME) yield. The ideal conditions for transesterification process were optimized as a methanol to oil molar ratio of 9:0.6, a reaction period of 4 h, a catalyst loading at 4% and a reaction temperature of 80 °C. Gas chromatographic analysis revealed a fatty acid profile highly suitable for biodiesel production. A catalyst concentration of 3 mg.L-1 of CaO synthesized at 400 °C was found to be ideal for the transesterification process. These approaches could make massive impact on the large scale biodiesel production minimizing the hefty capital costs.

Applications of Biodiesel in Drilling Fluids

Biodiesel, referred to as the monoalkyl ester of long-chain fatty acid ester that is synthesized by the complete transesterification of triglycerides, has captured the attention of drilling researchers attributing to its magnificent characteristics such as the high flash point, excellent lubricity, nontoxicity, high biodegradability, and abundant feedstock resources, which make it ecofriendly and technically and economically feasible for a sustainable drilling operation. There are several studies that reported and documented the usage of biodiesel in drilling fluids on laboratory and field scales. In this paper, the production and the key physical and chemical properties of biodiesel are thoroughly reviewed. Moreover, the applications of biodiesel in drilling muds either as base fluids or additives were comprehensively surveyed. The literature review revealed that the challenges of biodiesel applications in drilling mud systems are related to its chemical reactivity and adverse interactions with some additives, along with its performance deficiency at temperature above 120°C. Therefore, further investigation on temperature stability and additive compatibility is recommended. In addition, as a new approach, it is recommended to study the potentiality of using crude waste oils in drilling mud formulations. The lessons learned and recommendations stated in this paper will assist in enhancing the proved use of biodiesel and drilling fluid optimization.

Quantification of fatty acids in erythrocytes and plasma by fast gas chromatography.

As a result of the heterogeneous nature of lipid classes in complex biological matrices such as plasma and erythrocytes, it is imperative to have a robust and validated methodology for fatty acid quantification. The effective method presented here combines available methodology of fast gas chromatography and an improvement of the sample preparation methodology before injection into the gas chromatograph. This methodology ensures complete transesterification and quantification of total and individual fatty acids (and not only in relative amounts) by addition of internal standards. We considered sample preparation key, and we established the use of lysis buffer and ethanol for erythrocytes and plasma sample preparation, respectively. Fatty acid profile was determined by acid methylation and fast gas chromatography equipped with a flame ionization detector. The triacylglycerol 13:0, phosphatidylcholine 23:0, and methyl esters 21:0 were used as internal standards. Within the linearity of the calibration, the ratio of the peak area of each fatty acid over the peak area of the internal standard was constant (coefficient of variation≤2.5). Satisfactory repeatability <15% and intermediate reproducibility <15% were observed. Finally, this validated method was applied to a pre-clinical trial that investigated the impact of dietary fats on accretion of specific fatty acids in plasma and erythrocytes.

Biorefinery of Safflower Seeds in a Sequential Process for Effective Use of the Substrate for Biofuel Production

Biofuels are a promising alternative to fossil fuels that addresses the associated environmental concerns and satisfies growing global energy demand. In this study, safflower seeds were used to produce multiple biofuels with an integrated biorefinery perspective. The safflower oil was used for biodiesel production while the resultant seed cake was employed in subsequent ethanol production. Pretreatment of the residual solid is necessary in order to improve the ethanol production yield. Contrasting costly chemical pretreatments, the seed cake was instead pretreated using incomplete anaerobic digestion to remove hemicellulose, increase cellulose accessibility for fermentation, and produce methane. The seed cake produced 124.8 ml/g-VS of methane after 20 days of anaerobic digestion. The digestate (biologically pretreated seed cake) produced 92 g ethanol/kg solid, in stark contrast to 42 g ethanol/kg solid from untreated seed cake. This ethanol was later utilized in biodiesel production. The safflower oil produced 85.9% biodiesel via ethanolic transesterification at optimum conditions. From the integrated biorefinery perspective, the seed cake from 1 kg of safflower seeds produced 70 l of methane at NTP and 51.0 g of ethanol—surpassing the 47.6 g of ethanol stoichiometrically necessary to complete transesterification of safflower oil. Thus, this ethanol could be recycled, largely decreasing the need for an external stream of ethanol for biodiesel production. The incomplete anaerobic digestion is an effective and environmentally friendly way to improve the ethanol production from the safflower seed cake with biomethane as an additional valuable byproduct.

Fatty acid methyl esters yield and phorbol esters degradation during transesterification ofJatropha curcasoil by alkaline, acid and enzyme catalyzed method

Jatropha curcas has recently been the focus of intense research as a raw material of biomass fuel. However, the carcinogenesis promoter action of the phorbol esters in the Jatropha raises concerns for health and environmental risk. The purpose of the present study is to determine the relationship between the fatty acid methyl esters yield and the phorbol esters degradation ratio during the transesterification of the Jatropha oil by alkaline, acid and enzyme catalyzed method, respectively. The phorbol esters in Jatropha oil were degraded during the transesterification of the Jatropha curcas oil by alkaline and acid catalyzed methanol methods. The degradation ratio was significantly correlated with the fatty acid methyl esters yields in alkaline catalyzed transesterification. The results obtained in this study suggest that the health and environmental risk of the phorbol esters in a Jatropha BDF can be significantly reduced by a complete transesterification of the crude oil by controlling the transesterification condition appropriately.

Sodium Impregnated Zinc Oxide as a Solid Catalyst for Biodiesel Preparation from a Variety of Triglycerides

In the present work, a series of sodium impregnated zinc oxide catalysts were prepared by a wet impregnation method followed by calcinations at different temperatures. The prepared catalysts were characterized by powder X-ray diffraction, Hammett indicator test, scanning electron, and transmission electron microscopic studies. The catalysts prepared by impregnating 5 wt% of sodium in ZnO and calcined at 400°C were used for the virgin cotton seed oil transesterification with methanol. The selected catalysts were able to yield the complete transesterification of the oil to biodiesel, and the catalytic activity was found to depend on (i) the impregnated sodium amount, (ii) the calcination temperature, (iii) methanol to oil molar ratio, (iv) reaction temperature, and (v) the amount of free fatty acid contents in feedstock. The selected catalyst was also used for the transesterification of a variety of feedstock (virgin cottonseed oil, used cotton seed oil, mutton fat, karanja oil, and jatropha oil) having free fatty acid contents in the range of 0.1–8.5 wt% and found to complete the transesterification when free fatty acids were less than 1 wt% in feedstock used.

Potassium Ion Impregnated Calcium Oxide as a Nanocrystalline Solid Catalyst for Biodiesel Production from Waste Cotton Seed Oil

Vegetable oil and animal fat derived fatty acid methyl esters are commonly known as biodiesel and provide an environment friendly and renewable substitute for the conventional diesel fuel. The present work demonstrates an easy preparation of potassium ion impregnated calcium oxide in nano crystalline form (supported by powder X-ray diffraction and transmission electron microscopic studies) and its application as a solid catalyst for the transesterification of waste cottonseed oil with methanol. The catalyst prepared by impregnating 3.5 wt% of potassium in CaO support was found to show the best catalytic activity among the prepared catalysts. The same catalyst was found to be effective for the complete transesterification of less expensive feedstock, waste cotton seed oil, even in the presence of 10.26 wt% moisture and 4.35 wt% free fatty acid contents. The selected catalyst has also been reused successfully for three catalytic cycles. Few physicochemical properties of the prepared biodiesel sample have been studied and found to be within the acceptable limits of EN 14214 standards.

Potassium fluoride impregnated CaO/NiO: An efficient heterogeneous catalyst for transesterification of waste cottonseed oil

Potassium fluoride impregnated CaO/NiO has been prepared by wet impregnation method in nano particle form as supported by powder XRD, scanning electron microscopy, and transmission electron microscopy studies. Brunauer–Emmett–Teller surface area and basic sites measurement studies have been performed to establish the effect of potassium fluoride impregnation on catalyst surface morphology and basic strength. CaO/NiO impregnated with 20 wt% potassium fluoride was used as solid catalyst for the transesterification of waste cottonseed oil having up to 5.8 wt% free fatty acid content. The variables used for the transesterification were, KF impregnated on CaO/NiO, catalyst concentration, reaction temperature, and methanol to oil molar ratio. Reaction parameters have been optimized to achieve the least reaction period for the completion of the reaction. Complete transesterification (&gt;99% FAMEs yield) of waste cottonseed oil with methanol (1:15 molar ratio) required 4 h in the presence of 5 wt% catalyst (with respect to oil) at 65°C. Reusability study suggests that catalyst could be recycled for four successive runs without significant loss in activity. A pseudo first order kinetic equation was applied to evaluate the kinetic parameters and under optimized conditions first order rate constant and activation energy was found to be 0.023 min−1 and 41.2 kJ/mol, respectively. Few physicochemical properties of the prepared biodiesel sample have also been studied and compared with standard values.Practical applications: In India, application of edible vegetable oils for biodiesel production is prohibited to avoid food versus fuel situation. Application of waste cottonseed oil (WCO) for biodiesel production could circumvent this problem. However, homogeneous alkali catalyst could not be employed due to the presence of high free fatty acid contents in such feedstock. In this context present study demonstrates the impregnation preparation of KF impregnated CaO/NiO and its application as reusable solid catalyst for the transesterification of WCO.

Lithium ion impregnated calcium oxide as nano catalyst for the biodiesel production from karanja and jatropha oils

Lithium impregnated calcium oxide has been prepared by wet impregnation method in nano particle form as supported by powder X-ray diffraction and transmission electron microscopy. Basic strength of the same was measured by Hammett indicators. Calcium oxide impregnated with 1.75 wt% of lithium was used as solid catalyst for the transesterification karanja and jatropha oil, containing 3.4 and 8.3 wt% of free fatty acids, respectively. The reaction parameters, viz., reaction temperature, alcohol to oil molar ratio, free fatty acid contents, amount of catalyst and amount of impregnated lithium ion in calcium oxide support, have been studied to establish the most suitable condition for the transesterification reaction. The complete transesterification of karanja and jatropha oils was achieved in 1 and 2 h, respectively, at 65 °C, utilizing 12:1 molar ratio of methanol to oil and 5 wt% (catalyst/oil, w/w) of catalyst. Few physicochemical properties of the prepared biodiesel samples have been studied and compared with standard values.

Sequential pressurized liquid extraction to determine brain-originating fatty acids in meat products as markers in bovine spongiform encephalopathy risk assessment studies

A new approach using sequential pressurized liquid extraction described recently [J. Poerschmann, R. Carlson, J. Chromatogr. A, 1127 (2006) 18–25] was applied to determine lipid markers originating from central nervous system (CNS) tissue of cows in heat-processed sausages. These studies are very important in quality control as well as risk assessment studies in the face of the bovine spongiform encephalopathy (BSE) crisis. Diagnostic CNS lipid markers, which should not be present in meat products without CNS addition, were recognized on complete transesterification as polar 2-hydroxy-fatty acids (2OH-24:0, 2OH-24:1, 2OH-22:0, 2OH-18:0, shorthand designation) as well as odd-numbered non-branched fatty acids beyond C 22. An array of other fatty acids including lignoceric acid (24:0), nervonic acid (24:1), arachidonic acid (20:4), and polyunsaturated nC 22-surrogates are strongly related to CNS lipids, but occur as traces in meat products without CNS addition as well, thus reducing their value as diagnostic markers. Samples including meat products without CNS addition, meat with 3% CNS addition, as well as pure CNS homogenates, were subjected to sequential PLE (pressurized liquid extraction) consisting of two steps: n-hexane/acetone 9:1 (v/v) extraction at 50 °C to remove neutral lipids, followed by chloroform/methanol 1:4 (v/v) extraction at 110 °C to isolate polar CNS lipids (two 10 min PLE cycles each). To enhance the fractionation efficiency, cyanopropyl modified silica as well as chemically not modified silica sorbent was used at the outlet of the PLE cartridge to retard polar lipids in the first extraction step. This method proved superior to widely distributed exhaustive lipid extraction followed by solid-phase extraction (SPE) using silica regarding lipid recoveries and clear-cut boundaries between lipid classes. Methodological studies showed that the alcoholysis using trimethylchlorosilane/methanol (1:9, v/v) is an excellent method for the complete transesterification of lipids and quantitative formation of methyl esters.

Stevens rearrangement of ammonium salts containing 2-propynyloxy or tert-butoxycarbonylmethyl groups

The Stevens rearrangement of ammonium salts containing 2-alkenyl, 2-alkynyl, or benzyl groups along with 2-propynyloxy or tert-butoxycarbonylmethyl was studied. Under the action of a suspension of sodium phenolate in benzene the salts containing a 2-propynyloxycarbonylmethyl group form 2-propynyl esters of 2-dialkylamino-4-pentenoic acids, whereas with sodium methylate as the basic reagent, rearrangement is preceded by an almost complete transesterification. The salts containing a tert-butoxycarbonylmethyl group undergo almost no transesterification under the action of sodium methylate. The tert-butyl fragment in the ester group of the salt with a benzyl group exerts a fairly strong effect on the regiochemistry of the rearrangement and on the prototropic isomerization of the 3,2-Stevens rearrangement of the salts with 2-butynyl or 3-phenyl-2-propynyl groups.

Theoretical influence of polyester molecular weight distribution variation on melt viscosity during injection molding and extrusion as influenced by ester‐ester interchange

AbstractIn this study Flory's initial molecular weight derivation involving polyester polymerization and ester‐ester interchange was expanded to address two types of blends relative to both the number average molecular weight and the weight average molecular weight. First, an add blend was considered where the numbers of molecules of the same length were simply added together to calculate new number and weight average molecular weights. Second, the complete transesterification blend was calculated using Flory's most probable distribution with the same number average as the add blend but with a very different weight average molecular weight. The ratio of the weight averages of the add blend to the transesterification blend were found to be significantly larger if the initial blending molecular weights were significantly different from one another. This ratio was also found to go through a maximum that occurred at approximately 50% by weight if the two different molecular weights had the same monomer molecular weight. If the monomer molecular weights were different, the location of this maximum could be quite different from 50% by weight. Since melt viscosity is proportional to the weight average molecular weight to a power ranging from 1 to 3.4, a very large ratio between weight average molecular weight of the add blend and the ester‐ester interchange blend was found to have a significant influence on the melt viscosity. A polyester blend mixture of micro‐domains of both a nearly pure add blend and a nearly complete ester‐ester interchange blend was used to explain how a short shot could be followed a few shots later with a part that flashed the mold in an injection molding application.

Direct transesterification of total fatty acids of adipose tissue, and of freeze-dried muscle and liver with boron-trifluoride in methanol

The purpose of this study was to demonstrate direct transesterification of fatty acids of tissue total lipids with boron-trifluoride in methanol. Adipose tissue, muscle, and liver samples obtained from market-weight lambs, were transesterified with 14% boron-trifluoride in methanol at 80 °C. Total lipids of additional samples were first solvent-extracted and then transesterified with 14% boron-trifluoride in methanol. Thin layer Chromatographic evaluation revealed quantitative conversion of triacylglycerol- and polar lipid-fatty acids to fatty acid methyl esters using direct transesterification. No differences in fatty acid composition were observed for adipose tissue ( p > 0.05); however, for muscle, 20:4 was greater ( p = 0.01) with direct transesterification. For liver, greater concentrations of fatty acids were observed for the direct transesterification method ( p < 0.02). Weight percentages of adipose and muscle fatty acids were unchanged from 15 to 180min of direct transesterification; however, 120 and 90 min of direct transesterification were required for adipose tissue and muscle, respectively, for complete transesterification. It was concluded that for analysis of total fatty acids, one-step direct transesterification with boron-trifluoride in methanol is a useful and acceptable procedure.