Production of Biodiesel Fuel by Transesterification of Triglycerides in the Presence of Sodium Pyrophosphate

The possibility of using anhydrous sodium pyrophosphate and its decahydrate in transesterification of triacyl glycerides (with sunflower and rapeseed oils as examples) with methanol to obtain biodiesel fuel was examined. As shown by gas-chromatographic analysis, at the vegetable oil to methanol ratio of 1: 12, temperature of 65°C, reaction time of 2 h, and catalyst concentration of no less than 6 wt %, the maximal yield of methyl esters of fatty acids (biodiesel) was 93 and 69% when using Na₄P₂O₇ and Na₄P₂O₇·10H₂O, respectively. The catalytic effect of sodium pyrophosphate in the transesterification of triacyl glycerides was attributed to its methanolysis with the formation of sodium methylate. Water present in sodium pyrophosphate decahydrate causes hydrolysis of the formed sodium methylate; therefore, the yield of methyl esters of fatty acids is lower than with anhydrous pyrophosphate. Anhydrous sodium pyrophosphate can be used repeatedly no less than five times without significant decrease in the yield of methyl esters of fatty acids. Sodium pyrophosphate can be recommended for use in transesterification with other esters and alcohols.

     

薄层色谱-热辅助水解甲基化-气相色谱法测定生物柴油中的甘油酯

建立了薄层色谱-热辅助水解甲基化-气相色谱法测定生物柴油中残余甘油酯含量的方法.样品中的甘油酯经薄层色谱分离,萃取后与三甲基氢氧化硫(0.1 mol/L)各3 μL先后加入到样品杯中,在350℃下,于裂解器中进行衍生化反应,气相色谱测定生成的脂肪酸甲酯,确定甘油酯的含量.生物柴油中常见的甘油一酯、二酯、三酯在60～20...     

A comparative study of the reactions of thiophene-2-carboxanilides and related compounds

Thiophene-2-carboxanilide and itsp-chloro andp-bromo derivatives react with chlorosulfonic acid to give the corresponding sulfonyl chlorides, which react with amino acids to give the respective derivatives. Several methyl esters of the latter were prepared. Hydrazinolysis of these methyl esters yielded the hydrazides. Coupling reactions of some sulfonylamino acids with amino acid methyl ester hydrochlorides in THF-Et₃N medium using the dicyclohexylcarbodiimide method give the corresponding dipeptide methyl esters. The spectral data of the compounds are briefly discussed.Chemistry Department, Faculty of Science, Al Azhar University, Nasr City, Cairo, Egypt. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 921–926, July, 1998.     

A study of the tautomerism of the N-butyl-4(2)-methoxycarbonyl-pyrrolid-3-ones and their hydrochlorides

The tautomerism of N-butyl-2-methoxycarbonyl-4-methylpyrrolid-3-one (I), N-butyl-4-methoxycarbonylpyrrolid-3-one (II), N-butyl-4-methoxycarbonyl-2-methylpyrrolid-3-one (III), N-butyl-4-methoxycarbonylpyrrolid-3-one hydrochloride (IV), and N-butyl-4-methoxy-carbonyl-2-methylpyrrolid-3-one hydrochloride (V) has been studied by UV and IR spectroscopy. It has been found that the esters I–V are highly ionized in aqueous and ethanolic solutions at concentrations of 10^–2–10^–3 M. On passing from methyl cyclopentran-1-one-2-carboxylate to the esters II and III the position of the equilibrium in heptane and CCl₄ shifts in the direction of the keto form. On passing from the esters II and III to the esters IV and V, the position of the equilibrium shifts in the direction of the enol. Meyer's relationship is not satisfied for the esters II and III, while it is satisfied for the esters IV and V. Hypotheses have been put forward on the causes of the phenomena mentioned.     

Quality control of vegetable oil methyl esters used as diesel fuel substitutes: Quantitative determination of mono-, di-, and triglycerides by capillary GC

Vegetable oil methyl esters are increasingly being used as substitutes for petroleum-based diesel fuels. Because the presence of triglycerides and partial glycerides in the fuel as a result of incomplete transesterification of vegetable oils can lead to serious engine problems, continuous quality control of the product is essential. A rapid gas chromatographic method has been developed for the quantitative determination of mono-, di-, and triglycerides in vegetable oil methyl esters. Prior to analysis, mono-, and diglycerides were silylated with N,O-bis(trimethylsilyl)trifluoroacetamide; tridecanoin was used as internal standard. Calibration was performed by analysis of standard solutions containing mono-, di-, and triolein: the calibration plots for mono- and diglycerides showed good linearity, whereas for triglycerides no linearity was observed for triolein concentrations below 0.05 mg/ml. When a non-linear multi level calibration was employed for the quantitation of triglycerides, the method gave excellent quantitative results for mono-, di-, and triglycerides in vegetable oil methyl esters.     

Identification of ω-oxocarboxylic acids as acetal esters in aerosols using capillary gas chromatography-mass spectrometry

An homologous series of ω,ω-dimethoxycarboxylic acid methyl esters (acetal esters) has been identified in the most polar methyl ester fraction separated from remote aerosol samples by liquid chromatography. These compounds were separated by silica gel column chromatography and their structures determined by capillary gas chromatography (GC) and GC—mass spectrometry with a synthesized standard. The acetal esters are originally present in the samples as ω-oxocarboxylic acids, which are derivatized to acetal esters during treatment with boron trifluoride in methanol. This method enables the determination of ω-oxocarboxylic acids in environmental samples as their acetal esters.     

The seed oil ofNepeta cataria

Summary In a study of the glyceride and fatty-acid compositions of the neutral lipids ofN. cataria seeds the presence of di- and monoglycerides in the lipids has been established. It has been shown that the predominating acid in all the glycerides is the 18:3 acid and the main types of triglycerides are those in which the position is esterified with the 18:2 acid and, to a smaller extent, the 18:3 acid.Natural fatty acid methyl esters have been isolated from a seed oil of a higher plant for the first time.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 174–176, March–April, 1978.     

Search for bioactive compounds from Cantharellus cibarius

Ground fruit bodies of Cantharellus cibarius (chanterelle) were extracted with dichloromethane and subjected to CC followed by preparative HPLC, which led to the isolation of glycerol 1,2- and 1,3-dilinoleates and glycerol tridehydrocrepenynate. Extraction of C. cibarius fruit bodies with ethanol or methanol afforded fatty acid ethyl or methyl esters as a result of esterification/transesterification reactions. Insecticidal activity of the isolated glycerides and esters was much lower than that of the crude extracts and chromatographic fractions suggesting a synergistic effect of some of the compounds present in the mixture.     

Telomerization of propylene with methyl dichloroacetate

Conclusions The telomerization of propylene with methyl dichloroacetate includes chain transfer via the C-H and C-Cl bonds, and leads to the formation of four series of telomers, the methyl esters of chloro-substituted acids of type X[CH(CH₃)CH₂]_nCClYCO₂CH₃ (X, Y=H, Cl), and also of the telomeric esters of the higher alcohols and dichloroacetic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2150–2152, September, 1977.     

GC-MS analysis of hydroxy and epoxy acids from seed oil of Hippopha? rhamnoides

By the GC-MS method using a packed column, in the mixture of TMS derivatives of hydroxy acid methyl esters obtained from the seed oil of the sea buckthorn, in ten chromatographic peaks (CPs) 13 monohydroxy compounds have been characterized by their mass spectra, the main ones being derivatives of dimorphecolic and coriolic acids. Structures are proposed for four dihydroxy acids of the C₁₇–C₂₀ series. The mixture of methyl esters of di- and tetra-TMS derivatives obtained from the mixture of epoxy acids from the same source has been analyzed by a similar method. In seven CPs, 11 compounds, reflecting the presence of nine epoxy acids in the initial mixture, have been characterized by their mass spectra. The main component of the mixture was 15,16-epoxyoctadeca-9,12-dienoic acid.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 626–634, September–October, 1989.     

Simple synthesis for methyl esters of 7-oxoheptanoic and 9-oxanonanoic acids

Conclusions A simple method was proposed for the synthesis of the methyl esters of 7-oxoheptanoic and 9-oxononanoic acids from 1,1,1,7-tetrachloroheptane and 1,1,1,9-tetrachlorononane, which are products of the telomerization of ethylene with CCl₄.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2809–2810, December, 1984.     

气相色谱法测定生物柴油样品中脂肪酸甲酯和脂肪酸甘油酯的含量

建立了气相色潜测定生物柴油样品中脂肪酸甘油酯的方法、该方法不需对样品进行衍生化处理,以耐高温的毛细管柱作分析柱,采用冷柱头柱上进样,氢火焰离予化检测器检测,内标法定量,直接得到生物柴油制备工艺所得产物中脂肪酸甲酯、脂肪酸甘油单酯、甘油二酯和甘油三酯的含量。     

Hydrocarbomethoxylation of 1-hexene with formic acid and methanol under conditions of phosphoric acid catalysis

Conclusions When the hydrocarbomethoxylation of 1-hexene with formic acid is run at atmospheric pressure and temperatures close to room temperature, in the presence of conc. H₃PO₄, an increase in the relative amount of the latter, as well as an increase in the reaction temperature in the investigated range, both favor an increase in the yields of the methyl esters of the C₇ acids, in particular, those containing two methyl groups on the quaternary carbon atom in the -position. An increase in the relative amount of formic acid also favors an increase in the amounts of these esters in the obtained mixtures of esters.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1116–1118, May, 1971.     

Antiradical activity of the hormonal preparation estrone in lipid models undergoing oxidation

The rate constants and stoichiometric coefficients of chain termination in the oxidation of lipid models (methyl esters of acids of the oleic series: cis-6-, cis-9-, trans-9-, and trans-11-C₁₇H₃₃COOCH₃) by the main representative of the follicular hormones — estrone (313–348 K) — and for comparison by the phenol 2,6-ditert-butyl-4-methylphenol (323.15 K) were measured. The strength of the OH bond in the estrone molecule was estimated.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 29, No. 5, pp. 445–448, September–October, 1993.     

Lipase-catalyzed kinetic resolution of β-borylated carboxylic esters

The kinetic resolution of chiral β-borylated carboxylic esters via lipase-catalyzed hydrolysis and transesterification reactions was studied. The enantioselective hydrolysis catalyzed by CAL-B furnished the β-borylated carboxylic acid with reasonable enantiomeric excess (62% ee), while both methyl and ethyl β-borylated carboxylic esters were recovered with excellent ee (>99%). Meanwhile, the transesterification reaction of β-borylated carboxylic esters and several alcohols, catalyzed by CAL-B, only indicated a high selectivity when ethanol and methyl-(β-pinacolylboronate)-butanoate were used as substrates, which gave ethyl-(β-pinacolylboronate)-butanoate with >99% ee.     

The use of sulfated tin oxide as solid superacid catalyst for heterogeneous transesterification of <Emphasis Type="Italic">Jatropha curcas</Emphasis> oil

This work presents the use of sulfated tin oxide enhanced with SiO₂ (SO₄²⁻/SnO₂-SiO₂) as a superacid solid catalyst to produce methyl esters from Jatropha curcas oil. The study was conducted using the design of experiment (DoE), specifically a response surface methodology based on a threevariable central composite design (CCD) with α = 2. The reaction parameters in the parametric study were: reaction temperature (60°C to 180°C), reaction period (1 h to 3 h), and methanol to oil mole ratio (1: 6 to 1: 24). Production of the esters was conducted using an autoclave nitrogen pressurized reactor equipped with a thermocouple and a magnetic stirrer. The maximum methyl esters yield of 97 mass % was obtained at the reaction conditions: temperature of 180°C, reaction period of 2 h, and methanol to oil mole ratio of 1: 15. The catalyst amount and agitation speed were fixed to 3 mass % and 350–360 min⁻¹, respectively. Properties of the methyl esters obtained fell within the recommended biodiesel standards such as ASTM D6751 (ASTM, 2003).     

A novel method for correlation of substituent constants in some aromatic esters using the shift reagent Eu(fod)3

The lanthanide induced chemical shifts of the ester methyl group were studied in eighteen m-, and p-substituted aromatic methyl esters with varying amounts of added shift reagent, Eu(fod)₃. Each time the lanthanide induced shift (LIS) was plotted against the molar ratio of shift reagent (SR)/substrate and a straight line was obtained upto one mole ratio of added shift reagent. The slopes of these plots correlated well with the Hammett's σ constants and yield a value of ?4.95 for the reaction constant ?. The method is therefore one of the simplest ways of correlating the substituent constants in aromatic esters.     

Reaction of esters of 2-substituted 5-pyrimidinecarboxylic acids with hydrazine hydrate

The reaction of methyl esters of 2-substituted 5-pyrimidinecarboxylic acids with hydrazine hydrate at 0–5°C results in the nucleophilic substitution of readily eliminating groups (Cl, CH₃O, CH₃S) at the position 2 of the pyrimidine ring, and, on the boiling with the 80% aqueous solution of hydrazine hydrate, the reaction is accompanied by the formation of hydrazides. The dimethylamino group at thepposition 2 of the pyrimidine ring is not substituted by hydrazine.Vilnius University, Vilnius 2006, Lithuania Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1528–1530, November, 1999.     

Synthesis of methyl ethers of Nα-arylsulfonylvalylarginines — Thrombin and trypsin substrates

Summary New thrombin substrates — methyl esters of N-arylsulfonylvalylarginines — have been synthesized by the condensation of N-hydroxysuccinimide esters of arylsulfonylvalines with arginines followed by the treatment of the reaction product with thionyl chloride in methanol. The same compounds have been obtained by condensing N-hydroxysuccinimide esters of arylsulfonylvalines with arginine methyl ester.Institute of Molecular Biology and Genetics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 368–373, May–June, 1978.     

Insect pheromones and their analogs III. Synthesis of the sex attractants of some Lepidoptera

A new route to the synthesis of a number of attractants of Lepidoptera(Argyrotaenia velutinana, Mamestra configurata, andLycorea ceres ceres) have been developed. These substances are acetates of enols with the cis configuration: tetradec-11-en-1-ol, hexadec-11-en-1-ol, and octadec-11-en-1-ol, respectively. The constants of the substances obtained agree completely with those given in the literature. The method is based on the coupling of the C₃, C₅, and C₇ aldehydes with methyl 11-bromoundecanoate (I) by the Wittig reaction. To obtain compound (I) from methyl undeca-2E,5E,10-trienoate or methyl undeca-10-enoate we used hydroboration according to Brown followed by hydrogenation and bromination of the alcohol obtained. The advantage of this method is the use as starting materials of esters of unsaturated acids readily obtained by the homogeneous catalytic co-oligomerization of 1,3-dienes with acrylates.Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 97–102, January–February, 1980.