Methyl Ester Conversion Research Articles

Intensification of biodiesel synthesis using zigzag micro-channel reactors

Zigzag micro-channel reactors have been fabricated and used for continuous alkali-catalyzed biodiesel synthesis. The influences of the main geometric parameters on the performance of the micro-channel reactors were experimentally studied. It has been found that the zigzag micro-channel reactor with smaller channel size and more turns produces smaller droplets which result in higher efficiency of biodiesel synthesis. Compared to conventional stirred reactors, the time for high methyl ester conversion can be shortened significantly with the methyl ester yield of 99.5% at the residence time of only 28 s by using the optimized zigzag micro-channel reactor, which also exhibits less energy consumption for the same amount of biodiesel during biodiesel synthesis. The results indicate that zigzag micro-channel reactors can be designed as compact and mini-fuel processing plant for distributive applications.

Preparation and Study of Bimetallic Compounds Efficiency in the Synthesis of Biodiesel Fuel

In this work, biodiesel was obtained by the transesterification of babassu oil into methanol, employing as catalysts heterogeneous CuO/Al2O3, CoO/Al2O3, and MnO/Al2O3. The catalysts were prepared by the method of co-precipitation, which is a mixture prepared using a solution of nitrate of Al3+ and nitrate of Cu2+, Co2+ and Mn2+. The catalysts were calcined into two temperatures: 400 °C and 650 °C. The best catalytic activity was obtained with the catalysts calcined at 400 °C because at 650 °C, there was a reduction in the amount of nitrates and carbonates in the structures of catalysts. The conditions for the transesterification reaction’s oil babassu using the heterogeneous catalysts were evaluated and the best parameters were: 6:1 (molar ratio oil and methanol time of 24 h. The optimum condition was applied to all biodiesel obtained using the catalysts CuO(0.25)/Al2O3 (CuO400), CoO(0.4)/Al2O3 (CoO400), and MnO(0.4)/Al2O3 (MnO400) with yields of 66.70, 98.23, and 68.10, and for biodiesels transesterified twice obtained with the catalysts CuO(0.25)/Al2O3 (CuO650), CoO(0.4)/Al2O3 (CoO650), and MnO(0.5)/Al2O3 (MnO650) with yields of 83.67, 97.86, and 94.13%,. The use of heterogeneous catalysts was very satisfactory with respect to conversion of methyl esters (biodiesel).

APLIKASI 1H-NMR DALAM PENENTUAN KONVERSI METIL ESTER PADA PEMBUATAN BIODIESEL

Determination of methyl ester conversion on biodiesel processing using 1H-NMR spectrometer has been done. Methoxy spectra from methyl ester would appear at 3,7 ppm (singlet), spectra at 4,2 ppm (doublet of doublet) was glyceridic proton. The spectrum could be used as reference to determine the degree of biodiesel conversion, because spectra at chemical shift 4.2 ppm was characteristic for triglyceride that methyl ester did not have it. Whereas, spectra at chemical shift 3.7 ppm was characteristic for methyl ester that triglyceride did not have it. The extent of both spectrum indicated for incompletness in biodiesel synthesis.

Gas Chromatography/Electron-Capture Negative Ion Mass Spectrometry for the Quantitative Determination of 2- and 3-Hydroxy Fatty Acids in Bovine Milk Fat

2- and 3-hydroxy fatty acids (2- and 3-OH-FAs) are bioactive substances reported in sphingolipids and bacteria. Little is known of their occurrence in food. For this reason, a method suitable for the determination of OH-FAs at trace levels in bovine milk fat was developed. OH-FAs (and conventional fatty acids in samples) were converted into methyl esters and the hydroxyl group was derivatized with pentafluorobenzoyl (PFBO) chloride to give PFBO- O-FA methyl esters. These derivatives with strong electron affinity were determined by gas chromatography interfaced to mass spectrometry using electron-capture negative ion in the selected ion monitoring mode (GC/ECNI-MS-SIM). This method proved to be highly sensitive and selective for PFBO-O-FA methyl esters. For the analysis of samples, two internal standards were used. For this purpose, 9,10-dideutero-2-OH-18:0 methyl ester (ISTD-1) from 2-OH-18:1(9 c) methyl ester as well as the ethyl ester of 3-PFBO-O-12:0 (ISTD-2) was synthesized. ISTD-1 served as a recovery standard whereas ISTD-2 was used for GC/MS measurements. The whole-sample cleanup consisted of accelerated solvent extraction of dry bovine milk, addition of ISTD 1, saponification, conversion of fatty acids into methyl esters by use of boron trifluoride, separation of the methyl esters of OH-FAs from nonsubstituted FAs on activated silica, conversion of OH-FAs methyl esters into PFBO-O-FA methyl esters, addition of ISTD-2, and measurement by GC/ECNI-MS-SIM. By this method, ten OH-FAs were quantified in bovine milk fat with high precision in the range from 0.02 +/- 0.00 to 4.49 +/- 0.29 mg/100 g of milk fat.

Application of factorial design in optimization of anion exchange resin based methylation of vegetable oil and fats

Abstract A simple, rapid and fairly selective method for the preparation of fatty acid methyl esters (FAMEs) based on anion exchange resin Amberlite IRA-904 catalyzed transesterification of vegetable oil/fat with iodomethane has been described. The vegetable oil and animal fats used were sunflower oil, palm oil, vanaspati (hydrogenated vegetable oil), olive oil, tallow and butter. A Plackett–Burman factorial experimental design was used as a multivariate strategy for the evaluation of the effects of varying several variables at once. The effects of five different variables amount of resin, strength of sodium hydroxide, volume of iodomethane, heating time and temperature of thermostatic water bath, on the yield of fatty acid methyl esters (FAMEs) have been investigated. From these studies, certain variable showed up as significant, and they were optimized by a using 23 + star central composite design, which involved 16 experiments. The best conditions for transesterification reaction were as follows: amount of resin 2 g, strength of sodium hydroxide 0.25 N, volume of iodomethane 400 µl, heating time 2 min at 70 °C. A standard IUPAC method was used to prepare FAMEs from vegetable oil/fats for comparative purpose. Finally samples of oil/fat obtained from both methods were analysed by Gas liquid chromatography. Analytical results for the FAMEs by resin based proposed method, and conventional IUPAC method showed a good agreement, thus indicating the possibility of using Amberlite IRA-904 based transesterification instead of intensive treatments inherent with the conventional time-consuming methods. Industrial relevance Fatty acids are the main components of edible oil and fats, therefore determination of fatty acid composition is so far one of the important parameters for quality evaluation and nutritional value determination of edible oil and fats. The analysis of fatty acid is usually carried out by Gas liquid chromatography (GLC) after conversion of volatile fatty acid methyl esters (FAME) although other ester may be prepared for specific purpose. The endeavor of present work was to improve the FAMEs preparation method, proposing the development of anion exchange resin Amberlite IRA-904 based transesterification of edible oil/fat with iodomethane as alkylating reagent. The present method besides being rapid and reproducible avoids the use of classical saponification, washing of esters and solvent extraction step.

Catalytic partial oxidation of methyl acetate as a model to investigate the conversion of methyl esters to hydrogen

Rhodium and rhodium–ceria catalysts were investigated in the catalytic partial oxidation of methyl acetate, the simplest methyl ester, to better understand the conversion of biodiesel to hydrogen. Both catalysts were active in producing carbon monoxide, carbon dioxide, water, and hydrogen, although the rhodium–ceria catalyst demonstrates the higher conversion and the higher hydrogen selectivities at high gas hourly space velocity (GHSV). A low methyl acetate to oxygen feed ratio (C/O) favored the methyl acetate conversion, the hydrogen selectivity, and the carbon monoxide selectivity. Also, a high GHSV also improved the reactor performance. The experimental data show evidence that the oxidation of methyl acetate produces carbon monoxide and water as a primary step, instead of carbon dioxide and water. Overall, methyl acetate did not yield as much synthesis gas as biodiesel. The methyl ester functional group of biodiesel will limit the yield of hydrogen, so new catalysts targeting the decomposition of methyl esters to hydrogen should be investigated.

Intramolecular Diels–Alder reactions of oxazole–olefins: synthesis of the Rauwolfia alkaloids suaveoline and norsuaveoline

A full account of the highly stereoselective total synthesis of two indole alkaloids, suaveoline ( 4) and norsuaveoline ( 5), is presented. Central features of the synthetic strategy include the conversion of l-tryptophan methyl ester ( 12) into the oxazole derivative 11 and the intramolecular Diels–Alder reaction of the oxazole–olefin 19 leading to the pentacyclic pyridine derivative 21.

Effects of process variables for biodiesel production by transesterification

AbstractIn this study, biodiesel production from various vegetable oils by transesterification was studied, to determine the optimum conditions. Experiments were carried out by using different kinds of catalysts (sodium hydroxide, potassium hydroxide, barium hydroxide, pyrolitic coke and wood ash) and feedstocks (corn oil, sunflower oil, soybean oil, olive pomace oil and cottonseed oil) at 65 °C and an agitation speed of 1000 rpm. The neutralization step with controlled pH was performed by treatment with phosphoric acid. An experimental design was used to evaluate the effects of the parameters such as types of vegetable oils, kinds of catalysts, reaction time, alcohol/oil volumetric ratio and amount of catalyst, on the methyl ester conversion. Using response surface methodology, a quadratic polynomial equation was obtained by multiple regression analysis. It was found that catalyst concentration was the most effective parameter. Sodium hydroxide and potassium hydroxide exhibited a superior catalytic behavior, whereas pyrolitic coke and wood ash had to be used in excess amount or for prolonged reaction times. Moreover, the properties such as viscosity, density, calorific value, acid value, and refractive index of the biodiesel were measured. The tri‐, di‐, monoacylglycerols and glycerol residuals in the methyl esters produced were also quantified by GC analysis.

A Study of Residual Oils Recovered from Spent Bleaching Earth: Their Characteristics and Applications

This study described the extraction of residual oils of spent bleaching earth (SBE) from palm oil refining industry, the properties and applications of residual oils obtained there from. Residual oils of SBE (acid-activated, WAC and neutral, NC) were recovered via solvent and supercritical-fluid (SC-CO2) extraction. The yields of residual oils recovered from WAC were higher than those from NC using solvent and SC-CO2 extraction respectively. Both the residual oils recovered from WAC and NC had fatty acids composition (FAC) similar to that of crude palm oil. These oils exhibited poor qualities in terms of free fatty acids (FFA) content and peroxide value (PV). As the residual oils had very high FFA value (more than 10%), they were no longer suitable for food applications. Alternatively, these oils can be converted to their respective methyl esters for biofuel and other non-food applications as they were thermally and chemically stable with induction period of up to 29 h in Rancimat test. The methyl esters conversion via esterification and transesterification gave optimum yields of more than 80%. The methyl esters obtained have comparable fuel properties as petroleum diesel; hence, they can be used as diesel substitute.

Effect of incompletely converted soybean oil on biodiesel quality

Presence of fully converted monoalkyl esters is the major requirement in quality biodiesel. Due to high associated costs with testing and widespread production of biodiesel not only in commercial scale but also in small scale, there is a high propensity of substandard biodiesel entering the market and being used in compression ignition engines. Due to this reason, it is important to understand how low grade biodiesel with a lower methyl ester conversion affects the parameters of quality standards and as a result, engine performance and durability. In this paper, the performance of fatty acid methyl esters with different proportions of unconverted triglycerides has been evaluated. The study has comprehensively evaluated the effect of unconverted triglycerides on flash point, water and sediment, kinematic viscosity, sulfur content, sulfated ash, copper strip corrosion, cetane number, cloud point, carbon residue, acid number, free glycerin, total glycerin, phosphorus content and distillation temperature.

Continuous Production of Biodiesel via Transesterification from Vegetable Oils in Supercritical Methanol

The continuous production of biodiesel (fatty acid methyl esters) by the transesterification reaction of coconut oil and palm kernel oil was studied in supercritical methanol without using any catalyst. Experiments were carried out in a tubular flow reactor, and reactions were studied at 270, 300, and 350 °C at a pressure of 10 and 19 MPa with various molar ratios of methanol-to-oils from 6 to 42. It was found that the best condition to produce methyl esters from coconut oil and palm kernel oil was at a reaction temperature of 350 °C, molar ratio of methanol-to-vegetable oil of 42, and space time 400 s. The % methyl ester conversions were 95 and 96 wt % for coconut oil and palm kernel oil, respectively. The regression models by the least-squares method were adequate to predict % methyl ester conversion with temperature, molar ratio of methanol-to-oil, and space time as the main effects. The produced methyl ester fuel properties met the specification of the ASTM biodiesel standards.

Dimethylaluminum Methyltellurate, a New Reagent for the Cleavage of Hindered Methyl Esters under Exceptionally Mild Conditions by a Novel Mechanism.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Dimethylaluminum methyltellurate, a new reagent for the cleavage of hindered methyl esters under exceptionally mild conditions by a novel mechanism

An efficient and effective new reagent (Me 2AlTeMe) 2 has been developed for the conversion of methyl esters to the corresponding carboxylic acids in toluene solution at 23 °C.

Easy saponification by metal silanolates: application in SPPS and in ( S)-5-hydroxynorvaline preparation

Alkali metal trimethylsilanolates, TMSO −, M +, has been used for efficient conversion of methyl esters into their corresponding anhydrous acid salts under mild non-aqueous conditions. This strategy has been applied to SPPS for the preparation of neurotoxin cyclic analogues and in ( S)-5-hydroxynorvaline synthesis.

Optimized synthesis of lipase‐catalyzed biodiesel by Novozym 435

AbstractThe ability of immobilized lipase from Candida antarctica (Novozym 435) to catalyze the alcoholysis of canola oil and methanol was investigated. Response surface methodology (RSM) and five–level–five–factor central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time, temperature, enzyme concentration, substrate molar ratio of methanol to canola oil, and added water content on percentage weight conversion of canola oil methyl ester by alcoholysis. Reaction temperature and enzyme concentration were the most important variables. High temperature and superabundant methanol inhibited the ability of Novozym 435 to catalyze the synthesis of biodiesel. Based on the analysis of ridge max, the optimum synthesis conditions were as follows: reaction time 12.4 h, temperature 38.0 °C, enzyme concentration 42.3%, substrate molar ratio 3.5:1, and added water 7.2%. The predicted value was 99.4% weight conversion, and the actual experimental value was 97.9% weight conversion. Copyright © 2004 Society of Chemical Industry

Syntheses of surfactants from oleochemical epoxides

Sugar-based surfactants were obtained in good yields (up to 100%) under mild conditions (70°C, methanol or mixtures of methanol and water) by ring-opening of terminal epoxides with aminopolyols, derived from glucose. Reaction of N-methyl glucamine with epoxides from even-numbered C4-C18 alpha-olefins or from terminal unsaturated fatty acid methyl esters leads to linear products, while corresponding reactions with N-dodecyl glucamine or glucamine yield surfactants with different Y-structures. Products obtained by conversion of omega-epoxy fatty acid methyl esters were saponificated with NaOH or hydrolyzed enzymatically to sodium salts or free acids respectively, which are amphoteric surfactants. Studies of the surfactants at different pH-values demonstrate different surface active properties in aqueous solutions. Critical micelle concentrations (c.m.c.) in a range between 2 and 500mg/l and surface tensions of 25-40mN/m were measured for several of the synthesized sugar-based surfactants. The ring-opening products are rather poor foamers, whereas some of the corresponding hydrobromides show good foaming properties.

A Chiral Synthesis of the Strychnos and Ophiorrhiza Alkaloid Normalindine

A full account of the first chiral synthesis of (−)-normalindine [(−)-4], an indolopyridonaphthyridine alkaloid isolated from Strychnos johnsonii and Ophiorrhiza filistipula, is presented. Central features of the synthetic strategy include the conversion of l-alanine methyl ester (13) into the oxazole derivative 12 and the intramolecular Diels–Alder reaction of the oxazole–olefin derivatives 27a and 30a. The correctness of the absolute configuration proposed for normalindine has been unambiguously confirmed by the present synthesis.

Fatty methyl ester hydrogenation to fatty alcohol: Reaction inhibition by glycerine and monoglyceride

AbstractThe present work demonstrates the rate‐limiting effect of varying levels of both glycerine and monoglyceride through a series of batch hydrogenations of fatty dodecyl methyl ester, using copper chromite as the catalyst. Reactions were carried out at 3000 psig H2, 280°C with catalyst levels varying between 1.25 and 1.80%. With increasing contaminant levels of glycerine (0.0, 0.1, 0.5, 5 wt%), conversion of fatty methyl ester to alcohol is correspondingly reduced (95, 89, 80, 2 wt%). On a molar basis of contaminant, monoglyceride equally reduces the conversion of methyl ester to alcohol. In both cases the latent appearance of fatty‐fatty ester results from the slower hydrogenation rate. Chemistry is proposed outlining the thermal decomposition of glycerine or glyceride to intermediate components (acetol and acrolein), leading to the generation of propanediols. Experimental studies indicate that diols effectively deactivate the copper chromite catalyst, limiting the rate of fatty methyl ester hydrogenation. Catalyst deactivation is not permanent, suggesting catalyst site blockage by physical adsorption of the polyhydroxyl components. The complete understanding of this interaction holds promise for the development of glycerine/monoglyceride‐insensitive catalysts. In addition, a brief overview of methyl ester hydrogenation inhibition effects of some heteroelements, water, and soap is presented.

Ester alkoxylation technology

AbstractConventional ethyoxylation technologies, when used on fatty methyl esters, produce poor yields as well as flat ethoxymer distributions. Peaking ethoxylation catalysts have been successful in efficient conversion of methyl esters into the ethoxylates possessing peaked ethoxymer distribution. Surfactant performance of methyl ester ethoxylates was evaluated. Results generally show these to behave similarly to alcohol ethoxylates, with the exception of exhibiting a lower foam profile. This ester ethoxylation technology has been successful in ethoxylating esters of varying steric environments. Triglyceride ethoxylates have been partially saponified as well as glucaminolyzed to produce mild surfactant blends.

Lipase-catalysed synthesis of biosurfactants by transacylation of N-methyl-glucamine and fatty-acid methyl esters

The enzymatic synthesis of a range of amide surfactants by transesterification reactions between various amines and fatty-acid methyl esters (Diester ® ) a low-cost natural and renewable raw material is described. The transacylation reaction catalysed by a commercial lipase from Candida antarctica (Novozym ® ) at 90°C, yielded 100 % conversion of fatty-acid methyl esters with 80 % amide synthesis in less than 20 hours. Yield and chemoselectivity of the reaction are under the control of the fatty-acid methyl ester/amine molar ratio. The enzymatic synthesis of a range of amide surfactants by transesterification reactions between various amines and Fatty-acid methyl esters (Diester®), is described.