A study of the structures and reactions of some methyl substituted unsaturated C18 ester intermediates in the synthesis of a racemic mixture of 10-methyloctadecanoic acid

Methyl 10-undecenoate was hydrated to methyl 10-hydroxyundecanoate using mercury (II) acetate in aqueous tetrahydrofuran (THF). Chromic acid oxidation of methyl 10-hydroxyundecanoate gave methyl 10-oxoundecanoate, which was hydrolyzed to 10-oxoundecanoic acid. Reaction of n-octyl magnesium bromide complex in THF with 10-oxoundecanoic acid furnished 10-hydroxy-10-methyloctadecanoic acid after hydrolysis. The latter compound was esterified, and dehydration of methyl 10-hydroxy-10-methyloctadecanoate withp-toluenesulfonic acid in benzene gave a mixture of unsaturated branched fatty ester intermediates:viz. methyl 10-methyl-9-octadecenoate, 10-methyl-10-octadecenoate and 10-octyl-10-undecenoate. Treatment of the mixture of unsaturated branched fatty ester intermediates with mercury (II) acetate in methanol gave exclusively methyl 10-methoxy-10-methyloctadecanoate. Epoxidation of the same mixture of unsaturated fatty esters withm-chloroperbenzoic acid provided a mixture of epoxy derivatives: methyl 9,10-epoxy-10-methyloctadecanoate, 10,11-epoxy-10-methyloctadecanoate and 2-octyl-oxirane-nonanoate. Catalytic hydrogenation of the mixture of unsaturated fatty esters gave a racemic mixture of methyl 10-methyloctadecanoate, which was hydrolyzed to 10-methyloctadecanoic acid. The structures of the mixture of unsaturated branched fatty ester intermediates and their derivatives were characterized by chemical and spectroscopic analyses.     

Isolation of pure linolenate as its mercuric acetate adduct

After addition of mercuric acetate to the unsaturated methyl esters obtained from the methanolysis of linseed oil, linolenate of 99% minimum purity was isolated by means of a liquid-liquid continuous extraction technique and subsequent decomposition of the mercurial adduet. The methyl linolenate-mercuric acetate addition compound was extracted with 10% methanol in water from an ether solution of the reaction mixture. Infrared analysis of the regenerated methyl linolenate showed the complete absence oftrans-linkages. The yield, at least 60% of the linolenic acid present in linseed oil, was considerably higher than that obtained by bromination-debromination procedures. The solubility in aqueous solutions of fatty acid derivatives having 3 or more acetoxymer-euri-groups/molecule provides an approach to the fractionation of highly unsaturated oils. For example, a fraction having an iodine value of 395 was isolated readily from the methyl esters of pilchard oil by this technique. Journal Paper No. 1787, Purdue Agricultural Experiment Station.     

苯嗪草酮的合成新工艺

以苯甲酰腈为起始原料,经过水解、酯化、缩合、酯交换、环合5步反应得到标题化合物苯嗪草酮。首先苯甲酰腈水解得到苯甲酰甲酸(Ⅰ);(Ⅰ)与乙醇在催化剂作用下反应得到苯甲酰甲酸乙酯(Ⅱ);(Ⅱ)与乙酰肼反应得到2-乙酰肼基苯甲酰甲酸乙酯(Ⅲ);(Ⅲ)与水合肼反应得到2-乙酰腙-2-苯基-乙酰肼(Ⅳ);然后(Ⅳ)与乙酸钠反应得到苯嗪草酮。反应总收率为66.2%,优化了工艺条件,使生产更加安全,是有利于环境的绿色生产工艺。     

Reaction of Methyl Linoleate with Mercuric Acetate in Acetic Acid

Methyl linoleate was reacted with mercuric acetate in acetic acid at 60°C for 2 hrs to give an oily mixture from which a relatively unstable adduct fraction with the composition close to C₁₉H₃₄O₂(OCOCH₃) (HgOCOCH₃) was separated. The reaction of methyl linoleate with mercuric acetate at 115°C for 30 min. gave an oily mixture which was found to contain isomerized octadecadienoates, monoacetoxy and diacetoxy derivatives, and polymeric substances. It was found that the monoacetoxy derivatives contain 10-acetoxy-8,12-, 12-acetoxy-9,13-, 9-acetoxy-10,12- and 13-acetoxy-9,11-octadecadienoates.     

Solvent-Assisted Crystallization of Fatty Acid Alkyl Esters from Animal Fat

An easy and efficient method for the separation of saturated and unsaturated fatty acid mono alkyl esters, prepared from animal fat, was developed. The most efficient separation was achieved by the use of solvents such as methanol and acetone at low temperatures. The dilution of the alkyl esters with 10 times the amount of solvent (10:1 v/w) and storage of the mixture for 4 h at ?22 °C could be defined as optimum conditions. After filtration of the saturated fraction at the corresponding temperature very pure fractions were obtained. For fatty acid methyl esters deriving from tallow, with an initial content of saturated fatty acids of almost 50 %, a saturated ester fraction with only 5 % unsaturated fatty acids and an unsaturated ester fraction with about 9 % of saturated fatty acids could be obtained. The solvent easily could be recovered by distillation. In addition fatty acid ethyl, 1‐propyl, 2‐propyl, 1‐butyl, tert‐butyl and 3‐methyl‐1‐butyl esters were prepared and separated into saturated and unsaturated fractions. All fractions were analyzed according to the fatty acid compositions and showed similar or slightly worse results compared to the methyl esters. The cold filter plugging points of the unsaturated fractions were measured, showing the lowest value for the unsaturated methyl ester fraction at ?26 °C. The fractionation with the use of solvents is an easy tool in order to obtain fatty acid alkyl esters with excellent cold temperature behavior out of animal fat.     

Evidence of thermal decomposition of fatty acid methyl esters during the synthesis of biodiesel with supercritical methanol

New evidence on the thermal decomposition of fatty acid methyl esters during biodiesel synthesis in supercritical conditions is presented. Thermal decomposition products were detected chromatographically, by applying the UNE-EN 14105:2003 standard, as a broad single peak during the determination of glycerides in the reaction samples. These degradation products could be quantified chromatographically by the above standard because the area of the peak was proportional to the disappearance of the polyunsaturated fatty acid methyl esters, which contain two or more double bonds (methyl linoleate and linolenate), generated during biodiesel synthesis from soybean oil. In the experimental conditions tested, thermal decomposition reactions of these unsaturated fatty acid methyl esters began to appear at 300 °C/26 MPa, and were more intense as the temperature rose. For its part, the main saturated fatty acid methyl ester (methyl palmitate) generated during the reaction was hardly decomposed at all in the experimental conditions tested and only began to disappear at 350 °C/43 MPa.     

Reaction of methyl alpha-eleostearate with mercuric acetate

Summary Methyl alpha-eleostearate has been reacted with mercuric acetate in acetic acid solution. Carrying out the reaction below room temperature gave products having the highest mercury content. Even these products were relatively unstable, gradually decomposing to produce mercury or mercurous acetate or both at room temperature. A typical product obtained at 10°C. is a viscous, pale yellow oil, insoluble in petroleum ether but soluble in alcohol, ether, and chloroform. Each C₁₈ chain contained, on the average, 1.4 acetoxymercuri-groups (CH₃COOHg−), 1.5 acetoxyl groups attached directly to the carbon chain and 0.4 double bonds. For each mole of mercuric acetate added to the methyl eleostearate approximately one mole of mercuric acetate was reduced to mercurous acetate and a double bond in the ester chain was oxidized to an oxygen-containing group of undetermined structure. Treatment of the acetoxymercuri-, acetoxy-ester with aqueous chlorides or bases yielded the corresponding chloromercuri- or hydroxymercuri-derivative. Refluxing the acetoxymercuri-, acetoxy-ester in alcoholic potassium hydroxide saponified all the ester linkages and removed the acetoxymercuri-groups with the formation of an equal number of double bonds, most of which are present in conjugatedtrans-trans systems. The Marvel-Rands chromatographic procedure was modified to permit determination of total acetoxyl groups and of acetoxyl groups attached to mercury atoms. Acetoxyl groups of the latter kind can also be determined by direct titration with standard base. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

气干型水性聚氨酯的合成与表征

将自制的水性聚酯多元醇、异佛尔酮二异氰酸酯在无有机溶剂参与的情况下进行预缩聚,然后将亚油酸与多羟基化合物三羟甲基丙烷进行酯化反应,获得油脂多元醇混合物。将该油脂多元醇混合物作为干性油脂结构的扩链剂引入到聚氨酯预聚体结构中交联分散于水中,合成了气干型的水性聚氨酯分散液,通过红外光谱(FT-IR)对产物结构进行了表征。采用电子万用试验机和热重分析仪对产物的性能进行测试,结果表明:所制备的气干型聚氨酯胶膜具有良好的力学性能、热稳定性以及耐水性。     

生物柴油低温流动改进剂复配研究

采用碱催化法制备菜籽油生物柴油和棕榈油生物柴油,对其主要品质指标进行分析;考察了添加不同的柴油低温流动改进剂及其复配物对生物柴油低温流动性能的影响。结果表明,柴油低温流动改进剂能够改善生物柴油低温流动性能;将其进行复配后,能表现出协同效应,取得更好的降滤效果,尤其能使饱和脂肪酸甲酯含量高的棕榈油生物柴油冷滤点降低8℃;不同生物柴油对柴油低温流动改进剂或其复配物感受性存在较大差异,不饱和脂肪酸甲酯含量高,且脂肪酸甲酯种类较多、分布较广的菜籽油生物柴油对单一低温流动改进剂感受性好,而饱和脂肪酸甲酯含量高,且脂肪酸甲酯种类分布较集中的棕榈油生物柴油对复配物感受性好。     

Isolation of methylcis,cis-5, 13-docosadienoate fromLimnanthes douglasii oil

Methylcis,cis-5,13-docosadienoate has been isolated from the mixed methyl esters of the fatty acid moiety ofLimnanthes douglasii oil by a combination of low temperature fractional crystallization and fractionation of mercuric acetate adducts. The methyl ester and its free acid have been characterized. So. Util. Res. Dev. Div., ARS, USDA.     

Acetoxylation of methyl oleate with a resin catalyst

The reaction of methyl oleate with acetic acid in the presence of a reticulated cation exchange resin produces methyl acetoxystearate. Saponification of this compound and subsequent acidification yields hydroxystearic acid. Time, temperature, acetic acid:ester ratio, and resin:ester ratio were examined for their effect on yield of methyl acetoxystearate. A yield of approximately 45% of theory was reached under the best conditions. The cation exchange resin promoted ester inter-change with the formation of oleic acid, acetoxy-stearic acid, and methyl acetate. An estolide polymer was formed, probably by ester inter-change between acetoxylated methyl oleate and oleic acid. Acetoxy esters were separated from unreacted methyl oleate and ester polymers by fractional distillation. Molecular weight and GLC data substantiate the product structure. Several other short-chain carboxylic acids were reacted with methyl oleate but gave lower yields of acyloxylated product than acetic acid. Presented at the AOCS Meeting in Cincinnati, October 1965. No. Utiliz. Res. Der. Div., ARS, USDA.     

Fractional vacuum distillation of herring oil methyl esters

Methyl esters of a Canadian Atlantic herring oil containing 62% monoethylenic fatty acids were subjected to batch fractional distillation under vacuum on a pilot plant scale, to study the feasibility of fractionating fatty acid esters of marine oils of low iodine value into monounsaturated fractions with increased commercial value for industrial chemical uses. A total of 64 methyl ester fractions were collected and analyzed by gas liquid chromatography. Recoveries of the major saturated and monounsaturated acids were close to 100%, and some fractions contained over 90% of the desired 22:1 long chain monounsaturated acids. The short chain polyunsaturated acids were recovered in good yields, but the long chain highly unsaturated acids were recovered in yields of 60% or less due to oxidative and thermal decomposition in the particular apparatus employed. If small amounts of unsaturated acids are acceptable, fractional distillation of low iodine value marine oils could inexpensively supply fractions with high concentrations of methyl esters of longer chain (C₂₀ and C₂₂) monounsaturated and shorter chain (C₁₄) saturated acid or (C₁₆) saturated-monounsaturated acid mixture.     

Reactions of Methyl Ricinoleate and Methyl Acetylricinoleate with Mercuric Acetate in Hot Acetic Acid

In the reaction of methyl ricinoleate and mercuric acetate in glacial acetic acid at 115°C a acetoxy-acetoxymercuri complex ist formed which decomposes with the progress of the reaction and disappears completely to give non-mercurial products. The latter contain 9-acetoxy-12-hydroxy-10-, 10-acetoxy-12-hydroxy-8- and 12-hydroxy-9-octadecenoates together with a relatively small amount of 10,12-octadecadienoate. The hydroxyl group in these compounds is partially acetylated, and the ethylenic bond is partially trans-isomerized. Methyl ricinoleate as well as methyl acetylricinoleate are less readily acetoxylated as compared with oleate and linoleate, indicating the steric hindrance exerted by the hydroxyl and acetoxyl groups to the reaction of mercuric acetate and the ethylenic bond located near these groups.     

SO42-/TiO2催化合成乙酸环己酯

以固体超强酸SO4^2-／TiO2催化乙酸和环乙醇合成了乙酸环己酯。实验确定最佳反应条件为n（乙酸）：n（环己醇）：1．0：1．2，SO4^2-／TiO2用量为乙酸质量的10％，反应时间90min，酯化率达92．3％，并与其它催化剂作了比较，结果表明，以SO4^2-／TiO2为催化剂，具有催化剂量少、重复使用效果好、反应时间短、酯收率高、方法简单等优点。     

Double bond location in polyenoic fatty esters through partial oxymercuration

A rapid micro-procedure has been developed to locate double bonds in fatty acid methyl esters containing from one to four double bonds. Reaction of the ester with an equal molar amount of mercuric acetate in methanol and reduction with sodium borohydride, followed by hydrogenation, produce a mixture of monomethoxy alkanoates. The mass spectrum of this mixture is simpler and more definitive than that from the completely methoxylated polyenoate. Only one methoxyl group is present per molecule, and the mass spectrum of the mixture is indicative of all olefinic positions. Four intense ions are observed for all double bonds examined, except Δ3, where the double bond is represented, by only two ions. Hydrogenation in a gas chromatograph reduces total analysis time to 1 hr. Presented at the AOCS Meeting, Cincinnati, September 28–October 1, 1975.     

新溶剂体系应用研究(三):在氨基烤漆中的应用研究

新溶剂体系是指由乙酸仲丁酯、甲氧基乙酸甲酯、甲氧基乙酸仲丁酯共同构成的溶剂体系。介绍了该新溶剂体系在醇酸氨基烤漆、丙烯酸氨基烤漆、环氧氨基烤漆、聚酯氨基烤漆4类氨基烤漆制漆与稀释剂配制中的应用研究结果。结果表明:在4类氨基烤漆制漆中,都可以用甲氧基乙酸甲酯完全替代现有二甲苯/丁醇溶剂;在4类氨基烤漆的稀释剂中,都可以用乙酸仲丁酯、甲氧基乙酸甲酯、甲氧基乙酸仲丁酯按一定比例的混合溶剂,替代现有二甲苯/丁醇的稀释剂;作为稀释剂的混合配方,可以同时适应于这4类氨基烤漆的比例是:m(甲氧基乙酸甲酯)∶m(甲氧基乙酸仲丁酯)∶m(乙酸仲丁酯)=8∶2∶2。     

Rodium-catalyzed carbonylation of methyl glycolate and glycolic acid

Catalytic carbonylation of methyl glycolate in the presence of a homogeneous Rh complex and an iodide promoter yields acetoxy methyl acetate and acetic acid. Carbonylation of glycolic acid under the same conditions gives acetic acid and CO₂ probably from decomposition of the malonic acid intermediate. Jae S. Lee is the author to whom correspondence should be addressed.     

Preparation and characterization of bismaleimide (N,N′‐bismaleimido‐4,4′‐diphenyl methane)–vinyl ester oligomer–modified unsaturated polyester interpenetrating matrices for advanced composites

Interpenetrating networks of varying percentages of bismaleimide (BMI) in vinyl ester oligomer (VEO) modified unsaturated polyester (UP) matrices have been developed. Vinyl ester oligomer was prepared by reacting commercially available epoxy resin GY 250 (Ciba‐Geigy) and acrylic acid, and used as a toughening agent for unsaturated polyester resin. Unsaturated polyesters modified with 10, 20, and 30 wt % vinyl ester oligomer were made. The VEO toughened unsaturated polyester matrix systems, further modified with 5, 10, and 15 wt % bismaleimide (BMI). BMI–VEO–UP matrices were characterized using differential scanning calorimetry, thermogravimetric analysis, and heat deflection temperature analysis. The matrices, in the form of castings, were characterized for their mechanical properties according to ASTM methods: tensile strength, flexural strength, and unnotched Izod impact test. Data obtained from mechanical studies and thermal characterization indicate that the introduction of VEO and BMI into unsaturated polyester resin improves thermomechanical properties according to their percentage concentration. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2502–2508, 2002     

Observations on response factors for thermal conductivity detectors in GLC analysis of fatty acid methyl esters

Various correction factors have been proposed for quantitative analysis of fatty acid methyl ester mixtures by isothermal gas-liquid chromatography (GLC) employing thermal conductivity detectors in an effort to obtain more accurate values. These factors include multiplication of the area of each peak by the square root of the molecular weight of each component before calculating the percentage of each compound in the mixture or applying corrections for relative molar response for saturated esters and relative mass response for unsaturated esters. These proposed factors are not valid corrections for detector response but fortuitously are approximate compensations for lack of optimum operating conditions for each component. This is shown from the analysis of a number of standard fatty acid methyl ester mixtures by isothermal and programmed temperature GLC where the detector is maintained under identical conditions. Isothermal GLC requires different factors each time operating conditions are altered appreciably while proper temperature programming required little or no corrections depending on the particular mixture of methyl esters.     

Copolymerization of vinyl acetate with methyl N-(1-cyanopropene-2-yl)itaconamate

Summary Vinyl acetate copolymerized with methyl N-(1-cyanopropene-2-yl)itaconamate(I) forming low molecular weight copolymer containing about 8% of I. I was prepared by methylating potassium N-(1-cyanopropene-2-yl)itaconamate. The amic acid of the last salt as well as N-(1-cyanopropene-2-yl)maleamic and N-(10cyanopropene-2-yl)citraconamic acids could not be dehydrated to the corresponding imides using acetic anhydride-sodium acetate mixture. High melting, water-soluble polymeric products that could not be crystallized were always the products. These results confirm earlier related studies. Therefore, vinyl containing amic acids having allylic substituents on their nitrogen atoms may not be dehydrated to the corresponding imides by acetic anhydride-sodium acetate mixtures.