癸酸甲酯、月桂酸甲酯和肉豆蔻酸甲酯的液相声速测量

癸酸甲酯、月桂酸甲酯和肉豆蔻酸甲酯3种脂肪酸甲酯是生物柴油的主要成分,其声速是喷油系统优化设计和等熵压缩因子计算中所必需的参数之一。针对癸酸甲酯、月桂酸甲脂和肉豆蔻酸甲脂3种物质声速实验数据缺乏的现状,利用布里渊光散射法,沿0.1、2.5、5.5和8.5 MPa 4条等压线,在288.15~498.15 K温度范围内,分别测量了癸酸甲酯、月桂酸甲酯和肉豆蔻酸甲酯的液相声速;分析了声速随温度、压力的变化规律;依据实验数据,给出了在本文p-T热力学区域内,3种物质液相声速与温度和压力的关联式;关联式计算值与实验数据的相对偏差绝对平均值分别为：0.17%（癸酸甲酯）、0.10%（月桂酸甲酯）和0.15%（肉豆蔻酸甲酯）,满足工程应用需求。     

Separation of methyl malvalate from methyl sterculate

Methyl malvalate and sterculate, labile and differing by a single methylene, are difficult to separate completely. They have been separated in our laboratory by high vacuum spinning band distillation. Each of these fatty esters has been prepared completely free of the other.     

Formation of methyl methacrylate from methyl propionate and methanol

The formation of methyl methacrylate (MMA) was studied in a vapor-phase reaction between methyl propionate (MP) and methanol without using any sources of formaldehyde. Silica-supported CsOH doped with a small amount of silver Ag was found to be the best catalyst. The optimum Ag/Cs/Si atomic ratio was 4–10/20–25/1000. When the reaction was performed in the absence of oxygen in the feed, the main product was methyl isobutyrate (MIB) at the beginning of the reaction; MMA was not obtained. As the time-on-stream increased, the formation of MIB fell, while that of MMA increased, showed a maximum, and then decreased gradually. In the case of the reaction performed in the presence of oxygen, the catalytic activity was stable. As the amount of oxygen increased, the yield of MMA increased, while the selectivity fell. The performances were further improved by the combination of a small amount of Ag–Cs/SiO₂ catalyst and a large amount of Cs/SiO₂ catalyst.     

Catalytic dehydrogenation of methyl 12-hydroxystearate to methyl 12-ketostearate

Economically attractive catalytic methods for the conversion of methyl 12-hydroxystearate to methyl 12-ketostearate have been developed on a laboratory scale. With 1.0 wt% copper chromite catalyst, pure methyl 12-hydroxystearate is dehydrogenated at 180–263C to methyl 12-ketostearate in 99% yield and 97% purity. Commercial methyl 12-hydroxystearate required 3% catalyst but gave a 98% conversion to product and 100% crude yield. Presented at the AOCs Meeting in Cincinnati, October, 1965. W. Utiliz. Res. Dev. Div., ARS, USDA.     

Conjugated dienes and trienes from methyl oleate and methyl linoleate

Methyl oleate and methyl linoleate were converted to conjugated dienes and trienes, respectively, by selecting and modifying the conventional procedures usually applied to the generation and characterization of fatty hydroperoxides. Conditions have been studied in the laboratory for: (a) the optimum production of hydroperoxides with a minimum of by-products, (b) the effective separation and concentration of the resulting hydroperoxide, (c) the economic reduction of the hydroperoxide mixture, (d) simple dehydration of the reduced product, and, (e) recovery of the resulting polyene-rich material. If the processing sequence is halted after the reduction step, the resulting product,is a mixture of allylic hydroxy monoene or diene methyl esters. Our investigations have been extended to include studies on the methyl esters of commercial oleic acid and the mixture of methyl esters resulting from alcoholysis of lard oil. Products containing 20–25% conjugated diene and lesser proportions of conjugated triene were obtained. Presented at the AOCS Meeting, Houston, April 1965. E. Utiliz, Res. Dev. Div., ARS, USDA.     

Preparation of deuterated methyl 6,9,12-octadecatrienoates and methyl 6,9,12,15-octadecatetraenoates

Methyl 6,9,12-octadecatrienoate-15,15,16,16-d ₄ was obtained by Wittig coupling between 6,6,7,7-tetradeutero-3-nonenyltriphenylphosphonium iodide, 8, and the aldehyde ester, methyl 9-oxo-6-nonenoate. Methyl 6-oxohexanoate, obtained by ozonolysis of cyclohexene, was coupled in a Wittig reaction with [2-(1,3-dioxan-2-yl)ethyl]triphenylphosphonium bromide to give methyl 8-dioxanyl-6-octenoate. This compound was transacetalized to methyl 9,9-dimethoxy-6-nonenoate, which was then hydrolyzed to the aldehyde ester. For the preparation of compound 8, the tetrahydropyranyl ether of 2-pentynol was deuterated with deuterium gas and tris-(triphenylphosphine)chlororhodium. The tetradeuterated tetrahydropyranyl ether was converted to the bromide with triphenylphosphine dibromide, and the bromide was coupled with 3-butynol by means of lithium amide in liquid ammonia to give 3-nonynol-6,6,7,7-d ₄. Hydrogenation over Lindlar's catalyst converted the deuterated alkynol to 3-nonenol-6,6,7,7-d ₄. This deuterated alkenol was converted to the bromide with triphenylphosphine dibromide, then to the iodide with sodium iodide in acetone, and finally to 8 with triphenylphosphine in acetonitrile. Methyl 6,9,12,15-octadecatetraenoate-12,13,15,16-d ₄ was obtained by Wittig coupling between methyl 9-oxo-6-nonenoate and 3,4,6,7-tetradeutero-3,6-nonadienyltriphenylphosphonium iodide, 15. For the preparation of compound 15, the bromide obtained from the reaction of 2-pentynol with triphenylphosphine dibromide was coupled with 3-butynol with lithium amide in liquid ammonia. The resulting 3,6-nonadiynol was deuterated with deuterium gas in the presence of P-2 nickel, and the resultant deuterated nonadienol was converted to 15 through the bromide and iodide. The final products were separated from isomers formed during the synthetic sequences by silver resin chromatography.     

Studies on synthesis of methyl glycolate and methyl methoxy acetate from the coupling of formaldehyde and methyl formate

Catalytic performance of various acids in the coupling reaction of formaldehyde and methyl formate to produce methyl glycolate and methyl methoxy acetate has been studied. The influence of reaction conditions, such as catalyst amount, reaction temperature, reaction time, and molar ratio of formaldehyde to methyl formate, has also been investigated. The results showed that the acid strength had great influence on the reaction, namely, stronger acids had higher activities. It was also found that the reaction temperature and time had significant effect on the reaction, and the preferable conditions were quite different as different acids were used.     

Hydrogenation of methyl linolenate. I. The formation of methyl isolinoleate on the hydrogenation of methyl linolenate

Summary A highly purified sample of methyl linoleate was prepared from linolenic acid obtained by debromination of hexabromostearic acid. The methyl linolenate was hydrogenated to varying degrees of saturation, using palladium on barium sulfate as the catalyst. Ethyl acetate was used as the solvent and all hydrogenations were conducted at room temperature and atmospheric pressure. The hydrogenated samples were analyzed for their fatty acid composition (as methyl esters). The relative reactivities of the various polyunsaturated acids towards hydrogenation were calculated and may be represented by the following whole numbers: oleic (including isooleic) acid, 1; isolinoleic acid, 5; linoleic, 27; linolenic, 27. A procedure was outlined for effecting a concentration of an isolinoleic acid (methyl ester) by low temperature crystallization. The fraction isolated contained 95.8% methyl isolinoleate. Contribution No. 798 from the Department of Chemistry, University of Pittsburgh.     

The synthesis of methyl lactate and other methyl oxygenates from cellulose

Light oxygenates, such as methyl lactate (MLA), methyl levulinate (MLE), methyl formate (MFO), methyl acetate (MAC), dimethoxymethane (DMM), and methoxyacetaldehyde dimethyl acetal (MADA) were synthesized from cellulose in the presence of promoted SnX₂ (X = Cl⁻, Br⁻, and I⁻) salt catalysts in methanol. The presence of halides in SnX₂-ML_n (ML_n is metal salt) catalysts was found crucial for methyl lactate formation from sugar. The investigation shows that ZnCl₂ is an efficient promoter for SnX₂ catalyst in converting cellulose to light oxygenates. Up to 52.2% of total one-pass oxygenate yield was obtained in the presence of SnCl₂–ZnCl₂ catalyst.     

Conversion of methyl ricinoleate to methyl 12-ketostearate with Raney nickel

A convenient laboratory preparation of methyl 12-ketostearate is described. Methyl ricinoleate is converted to methyl 12-ketostearate in 70–75% yield by Raney nickel. The type and quantity of Raney nickel have a marked influence on the yield as well as on the time and temp required for the conversion. The reaction is not a direct isomerization as previously assumed but appears to be a two-step process. Methyl ricinoleate is hydrogenated rapidly to methyl 12-hydroxystearate which is then dehydrogenated slowly to the product. Hydrogenolysis of the alcohol function is a competing reaction which is minimized by the proper choice of reaction conditions. A laboratory of the W. Utiliz. Res. & Dev. Div., ARS, USDA.     

Autoxidation of methyl linoleate. Separation and analysis of isomeric mixtures of methyl linoleate hydroperoxides and methyl hydroxylinoleates

The mixture of conjugated diene hydroperoxide isomers obtained from autoxidation of methyl linoleate was separated by high performance liquid chromatography (HPLC). Four major isomers were obtained from adsorption chromatography and identified as the 9 and 13 positional isomers having thetrans-trans andcis-trans configurations. The latter geometrical isomers have thetrans double bond adjacent to the hydroperoxide group. The hydroxy compounds (methyl hydroxylinoleates) obtained from the hydroperoxides by NaBH₄ reduction were similarly separated but with improved resolution. This is the first instance of the complete separation of these compounds and provides a rapid method for their analysis. Unlike adsorption chromatography, reversed-phase chromatography separates the mixtures only according to the geometrical isomerism of the double bonds and not according to the position of the hydroxy or hydroperoxide function.     

脂肪酸甲酯乙氧基化物中未反应脂肪酸甲酯的测定

采用气相色谱法(GC)测定了不同脂肪酸甲酯乙氧基化物(MEE)中未反应的脂肪酸甲酯的质量分数。以十三酸甲酯为内标，对不同MEE进行了定性和定量分析，同时以十二酸甲酯为标准考察了回收率。实验结果表明：该法相对标准偏差在1．2％以内，回收率大于96％。由测定结果可知：GC法简便、快速、准确率高、重现性好、能准确测定不同MEE中未反应脂肪酸甲酯的质量分数，可作为MEE产品质量监控的方法，也可为MEE新产品、新配方研究与开发提供有效的参考依据。     

Alternating copolymerization of methyl α-phenylacrylate and methyl methacrylate by n-BuLi

The copolymerization of methyl α-phenylacrylate (MPhA) and methyl methacrylate by n-BuLi was carried out in toluene at various temperatures with an initial monomer ratio of 1:1. At ?78°C the product was a homopolymer of MPhA. The copolymer obtained at ?40°C was a mixture of poly(methyl α-phenylacrylate) and poly(methyl methacrylate) containing a small amount of alternating copolymer of both monomers. With further increase in the polymerization temperature the fraction of alternating copolymer increased and above 30°C all the copolymers obtained were alternate. With varying composition of feed monomers the copolymerization was carried out at 30°C and the alternating copolymer was obtained over a wide range of monomer feed ratios. In tetrahydrofuran the alternate sequence began to form at a lower temperature than in toluene, and all the copolymers obtained above 0°C were alternating ones. The mechanism of the copolymerization is discussed in some detail.     

Photodegradation kinetics of methyl salicylate in poly(methyl methacrylate)

It has been found that methyl salicylate (MS) undergoes a photoinduced decarboxylation to form phenol with a quantum yield of ca. 8 × 10^?5. The reaction is first order and the rate constant is proportional to the irradiance used. An activation energy of 1.2 kcal/mol was determined. Computer simulations were used to predict whether sufficient UV screening would be provided by MS-containing PMMA lenses over the projected lifetime of solar photovoltaic devices. An effective screening lifetime of less than 2 years is predicted.     

丙酮酸甲酯的合成

本文介绍了以丙酮酸和无水甲醇为原料,加入合适的催化剂合成丙酮酸甲酯的过程。通过对反应物配比、带水剂、反应时间等影响因素进行对比试验,确定以四氯化碳为带水剂,最佳反应配比为:丙酮酸∶无水甲醇∶四氯化碳=1∶2.5∶0.28,产物收率可达73.9%。该工艺过程简单,易操作,适合工业化大生产。     

特戊酰乙酸甲酯的合成研究

以频那酮和过量的碳酸二甲酯为原料在二甲苯溶液中，经一步反应，制得了纯度99％以上的特戊酰乙酸甲酯，对合成条件进行了探讨，确定原料配比（频那酮／碳酸二甲酯）为1：5.0，反应温度为120℃，催化剂用量（甲醇钠／频那酮）为1：5：1。在优化条件下，产品的收率（以频那酮计）达77.4%。     

离子色谱法测定脂肪酸甲酯磺酸钠中的甲基硫酸钠

建立了离子色谱法测定脂肪酸甲酯磺酸钠中的甲基硫酸钠的方法。采用AS19 4MM阴离子分析柱,研究选用不同淋洗液对甲基硫酸钠根的保留时间进行选择,得到较佳分析条件为:以13 mmol/L的氢氧化钠溶液作为流动相,流速0.70 mL/min,柱温25℃,进样量20μL。结果表明,此方法采用的参数可以使脂肪酸甲酯磺酸钠中的甲基硫酸钠得到很好分离,标准溶液线性相关系数均为0.998 1,样品回收率较好,平均回收率为95.9%~101.8%。