双环戊二烯在水溶性铑膦络合催化体系中的氢甲酰化反应

研究了采用水溶性铑膦络合催化体系对双环戊二烯的氢甲酰化反应，考查了反应温度、相转移剂ＣＴＡＢ、铑催化剂浓度等对反应的影响。氢甲酰化反应的产物经ＧＣ／ＭＳ鉴定是不饱和的三环癸单醛     

铑基催化剂

近十年来,石油化学工业中羰基合成用的催化剂是一系列铑基络合物。其中著名的、已获工业化应用的有三苯膦羰基氢化铑。化学式为HRh(CO)(PPh_3)_3和氯三苯膦基铑,化学式为Rh(PPh_3)C1。这类铑催化剂属于均相催化体系。它们的特点是稳定性好、反应速度高、反应条件缓和、催化     

硅胶负载硫酸型固体催化剂催化合成没食子酸丙酯的研究

没食子酸丙酯是一种主要用于油脂或油基食品且性能优良的抗氧化剂。通过考察不同的载体、负载酸种类及浓度、焙烧温度等对没食子酸丙酯收率的影响,设计并制备了一种以硅胶为载体的非均相催化剂来高效催化合成没食子酸丙酯。结果表明,在该硅胶负载硫酸型固体催化剂质量为反应原料总质量的6.1%、反应时间为18 h时,可获得没食子酸丙酯的最高收率为93.0%,产品纯度≥98.0%。与传统的均相催化剂相比,硅胶负载硫酸型固体催化剂非均相催化合成没食子酸丙酯具有催化剂易回收、催化效率高、经济绿色、酸排放量小等优点,有潜在的工业应用价值和前景。     

生物技术在油脂化工方面的应用进展

利用微生物产生的脂酶为生物催化剂,在温和条件(常压、常温)下使油脂转化为脂肪酸单甘酯、脂肪酸甲酯、烷基葡萄糖苷脂肪酸等油脂化工产品.与化学工艺相比,生物催化技术选择性好,副反应少,产物纯度高,能源消耗低,尤其是对于多不饱和脂肪酸衍生物,可以避免较高温度下氧化、聚合等副反应,不仅可以简化提纯工艺,而且有助于提高产品收率与质量.本文简要介绍近期国外化学工作者利用商品脂酶制剂为生物催化剂,通过醇解反应制备高产率、高纯度单甘酯;通过酸解反应,制取富含多不饱和脂肪酸的甘油酯;通过酯化反应,合成脂肪酸甲酯、烷基葡萄糖苷脂肪酸酯.     

生物表面活性剂催化合成蔗糖酯及其应用

蔗糖酯是一种有效的食品添加剂,它可由蔗糖与脂肪酸酯或甘油酯在碱性催化条件下由有机溶剂法或无溶剂法合成得到,报道了蔗糖酯的合成,分离和应用进展,还论述了生物表面活性剂作为均相催化剂在蔗糖酯合成中的作用。     

脂肪酸酯的均相催化制备的研究

研究了天然油脂与甲醇、乙醇、丁醇进行酯交换的反应.发现在无水体系中,实现均相催化是反应顺利进行和提高脂肪酸酯收率的关键.棉籽油和甲醇,用1%的NaOH实现均相催化,常温常压下,甲酯收率可达98%;随着油碳链和醇碳链的增长,适当提高反应温度、增加NaOH用量,酯交换反应都可以收到较好效果.讨论了在均相催化条件下,酯交换反应的条件和影响因素.     

脂肪酶催化合成生物表面活性剂

脂肪酸单甘油酯、脂肪酸糖酯、聚甘油脂肪酸酯和长链脂肪酸蜡酯是重要的生物表面活性剂。传统化学法以碱为催化剂在高温下进行,不仅能耗高且产品纯度低。脂肪酶作为一种天然生物催化剂,可以温和条件下催化合成上述生物表面活性剂,能耗低且产品纯度高。综述对脂肪酶催化合成生物表面活笥剂工艺路线、反应体系及操作参数。     

油脂酶催化酯交换制取糖酯

概况 通常,脂酶在水相介质中催化油脂水解,反应产生甘油和游离脂肪酸(FFA)。在微水条件下,或在有机溶剂中,脂酶催化FFA与甘油的酯化反应,催化甘油酯与酸(或醇)的酯交换反应。另外还能催化甘油酯与其它酯之间的酯交换反应。利用脂酶作为生物催化剂,在温和的条件下,可以使油脂转化成各种用途广泛的新产品。例如,作为表面活性剂的单甘酯(MG),双甘酯(DG),烷基糖苷脂肪酸酯,富含多种不饱和脂肪酸的甘油酯、磷脂等。最近,国外     

脂肪酸脂的均相催化制备的研究

研究了天然油脂与甲醇、乙醇,丁醇进行酯交换的反应。发现在无水体系中,实现均相化是反应顺利进行和提高脂肪酸酯收率的关键。棉籽油和甲醇,用１％的ＮａＯＨ实现均相催化,常温常压下,甲酯收率可达９８％,随着油碳链和醇碳链的增长,适当提高反应温度,增加ＮａＯＨ用量,酯交换反应都可以达到较好效果。讨论了在均相催化条件下,酯交换反应的条件和影响因素。     

钨盐催化糠醇高效转化制乙酰丙酸己酯

乙酰丙酸长链酯是一类具有潜力的生物质基液体燃料，但其催化合成并未受到广泛关注。为开发乙酰丙酸长链酯的高效合成工艺，以HL(乙酰丙酸正己酯)为代表性的长链酯，通过糠醇醇解法研究其催化合成。结果表明，WCl₆是催化糠醇与正己醇醇解制HL的优选均相催化剂。当WCl₆加入量为糠醇物质的量的5%,糠醇与正己醇物质的量之比为1∶9时，在140℃下反应90 min, HL的收率最高可达76%。该催化反应体系可循环利用多次，而且也能实现糠醇与其他多种六碳醇有效醇解制乙酰丙酸六碳酯。此研究可为今后生物质合成可再生燃料提供参考。     

Wiederveresterung von Konzentraten mehrfach ungesättigter Fettsäuren

Reesterification of Polyunsaturated Fatty Acid Concentrates Fatty acids of the n-6 series such as γ-linolenic acid (C18:3) and of the n-3 series such as α-linolenic (C18:3), stearidonic (C18:4), eicosapentaenoic (C20:5) and docosahexaenoic acid (C22:6) are of great nutritional interest. These acids can be obtained by urea fractionation in concentrated form from natural sources like blackcurrant seed oil, borage oil, evening primrose oil, linseed oil and fish oil, respectively. Certain dietary applications require a reesterification of these fatty acid concentrates with glycerol to triglycerides. Industrial scale methods of reesterification could not be applied as such for the present polyunsaturated fatty acid systems. Therefore reaction conditions had to be adapted to these highly sensitive substances. A one step reesterification method, using ZnCl₂ as catalyst, was optimized for three different fatty acid concentrates composed of the above mentioned acids. Under the given reaction conditions, it could be observed that α-linolenic acid is much more sensitive to polymerization than γ-linolenic acid. Different purification methods of the crude triglycerides have been evaluated, obtaining best results by liquid chromatography methods, in particular with respect to decoloration of the final products.     

Detection of adulteration of cottonseed oil by gas chromatography

To detect adulterant vegetable oils in cottonseed oil, soybean, rapeseed, and ricebran oils were mixed into cottonseed oil extracted experimentally from seeds. These adulterated oils and the component oils were analyzed for sterols, fatty acids, and triglycerides by gas chromatography. In sterol analysis, stigmasterol was determined for adulteration with soybean and ricebran oils. Brassicasterol content seemed to be reliable as the indicator of adulteration for rapeseed oil. In fatty acid analysis, erucic acid for rapeseed oil and linolenic acid for soybean and ricebran oils were proof of adulteration. Triglyceride analysis was not so reliable as sterol analysis for detecting contamination, except that triglycerides with carbon-58, 60, and 62 indicate adulteration with rapeseed oil. Rapeseed oil (5%) and soybean and ricebran oils (10%) were the limits of detection for adulteration in cottonseed oil. Analysis of cottonseed oil from six refineries did not show positive indications of adulteration.     

Separation of eicosapentaenoic acid and docosahexaenoic acid in fish oil by kinetic resolution using lipase

The objective of this study was to investigate the use of lipases as catalysts for separating eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish oil by kinetic resolution. Transesterification of various fish oil triglycerides with a stoichiometric amount of ethanol by immobilized Rhizomucor miehei lipase under anhydrous solvent-free conditions resulted in a good separation. When free fatty acids from the various fish oils were directly esterified with ethanol under similar conditions, greatly improved results were obtained. By this modification, complications related to regioselectivity of the lipase and nonhomogeneous distribution of EPA and DHA into the various positions of the triglycerides were avoided. As an example, when tuna oil comprising 6% EPA and 23% DHA was transesterified with ethanol, 65% conversion into ethyl esters was obtained after 24 h. The residual glyceride mixture contained 49% DHA and 6% EPA (8:1), with 90% DHA recovery into the glyceride mixture and 60% EPA recovery into the ethyl ester product. When the corresponding tuna oil free fatty acids were directly esterified with ethanol, 68% conversion was obtained after only 8h. The residual free fatty acids comprised 74% DHA and only 3% EPA (25:1). The recovery of both DHA into the residual free fatty acid fraction and EPA into the ethyl ester product remained very high, 83 and 87%, respectively.     

Fatty acid composition of carotenoid esters in soybean and rapeseed oils

The amounts of the different carotenoids (lutein, lutein monoesters and diesters) in soybean and rapeseed oil were determined through a combination of column chromatography and UV spectrometry. The lutein diesters in the oils have been isolated by a combination of column and thin layer chromatography. Identification and determination of the amount of the various fatty acids of the lutein diesters have been carried out by means of gas chromatography after transesterification of the fatty acids to their methyl esters. Comparison of the fatty acids of the lutein diesters with those of the triglycerides of the oils revealed a striking difference. First, the fatty acids of the lutein diesters have shorter chains than the triglycerides acids. Secondly, the lutein fatty acids are more saturated than the fatty acids of the triglycerides of the corresponding oils. However the amount of linoleic acid in the case of the fatty acids of the lutein diesters in rapeseed oil is greater than that in the fatty acids of the triglycerides in rapeseed oil. Deceased, October 26, 1971.     

Unusual lipids II: Head oil of the north Atlantic pilot whale,Globicephala melaena melaena

Pilot whale head oil (blackfish head oil, raw) was analyzed by means of IR spectroscopy, NMR, thin layer chromatography, and gas liquid chromatography-mass spectrometry. The oil consisted of hydrocarbons (mainly pristane) (3%); waxes and cholesterol esters (9%); triglycerides (87%) (i.e. non-11%, mono-19% and di-57% isovalero triglycerides) and cholesterol and diglycerides (1%). By mass spectrometry, the diisovalero triglycerides were shown to be mainly symmetrical. Fatty acids were isobranched or normal (only traces of anteiso acids were found), saturated, or monounsaturated. Isovaleric acid predominated (54 mole % fatty acids), the rest having 10–18 carbon atoms. A 5-carbon fatty acid was the only acid found in the waxes. The alcohol composition qualitatively resembled that of the fatty acids, but major quantitative differences were present. This rules out direct interconversion of all fatty acids and alcohols. The possible role of these lipids in ultrasound transmission is discussed.     

Effect of continuous enteral medium-chain fatty acid infusion on lipid metabolism in rats

This study compared (i) the relative effects of long-chain triglycerides (LCT) and medium-chain triglycerides (MCT), (ii) the influence of amount of MCT, and (iii) the impact of medium-chain fatty acid position, on plasma and lymphatic triglycerides and portal vein free fatty acids. The animals were fed approximately at 250 kcal/kg · day for 20h. The lymph from lymphatic duct and blood from portal vein and systemic circulation were collected. The results showed that feeding 100% MCT for 20h was sufficiently long to reduce significantly the level of linoleic acid in portal vein fatty acids and plasma and lymph triglycerides. However, this alteration induced by MCT feeding was partially prevented by adding LCT to the diet. The level of arachidonic acid was significantly reduced in plasma triglycerides by any of the diets containing medium-chain fatty acids compared to 100% LCT. When feeding MCT only, palmitoleic acid, presumably reflecting de novo lipogenesis, was increased in lymphatic triglycerides and portal vein fatty acids. Total saturated fatty acids as a total percentage of total fatty acids were also significantly increased in plasma and lymphatic triglycerides and portal vein fatty acids. Thus, when linoleic acid is limiting, the conversion of MCT into long-chain fatty acids by de novo lipogenesis is likely to be an important metabolic route. Providing LCT with MCT or 2-monodecanoin appears to limit this pathway.     

Acacia suma Seed Oil-Characterization of a HBr-Reactive Acid

The seed oil of Acacia suma (Leguminosae) was found to have a HBr-reactive fatty acid along with other usual fatty acids. On the basis of chemical, spectroscopic and chromatographic techniques the HBr-reactive acid was identified as cis-9, 10-epoxy-cis-12-octadecenoic (coronaric) acid. This acid makes up 10.6% of the total oil triglycerides.     

The Effects of High Levels of Fats Rich in Erucic Acid (from Rapeseed Oil) or Cetoleic and Cetelaidic Acids (from Partially Hydrogenated Fish Oil) in a Short-Term Study in a Non-Human Primate Species I

Three experimental groups of primates (cynomolgus monkeys Macaca fascicularis) were adapted to high-fat diets and maintained on the diets for four months. One group (control) was fed a diet containing 25% of lard and corn oil in a 3 : 1 mixture and the other groups received either 25% of rapeseed oil or of partially hydrogenated herring oil. Docosenoic acids were approximately 25% of the rapeseed oil (as erucic acid) and of the partially hydrogenated herring oil (as a mixture of cetoleic acid and cetelaidic acid). Monitoring of physiological parameters did not reveal any important differences between groups. Fecal fatty acids and depot fatty acids showed differences in details of composition from the fatty acids in the diets. These are discussed in terms of intestinal microorganism activity, absorption processes, and in vivo alterations in the primates. In the two experimental groups skeletal and cardiac muscle showed lipidosis. This was especially evident in the apexes of the hearts of animals fed the rapeseed oil and partially hydrogenated herring oil. Fatty acid details from depot fat and cardiac apex triglycerides showed differences and further differences were discerned among the isomeric docosenoic and eicosenoic acids of the cardiac triglycerides. The histopathology of the primate hearts showed a few mild foci of inflammation in all groups which could not be associated with diet, whereas the same diets fed to male weanling rats induced the severe necrotic lesions widely associated with such diets. It is concluded that different species of animals show physiologically different responses to fat-based dietary factors and that further experiments with primates and with oils containing docosenoic acids are required to determine what, if any, cardiac problems exist.     

Composition of fatty acids and structure of triglycerides in medium and low erucic acid rapeseed

Total triglycerides in medium (MEAR) and low (LEAR) erucic acid cultivars of rapeseed were fractionated by argentation chromatography into twelve and ten fractions, respectively. Gas liquid chromatography of the fatty acids in the triglyceride fractions and their 2-monoglycerides was used to evaluate the structural characteristics of the individual fractions. Fractionation occurred on the basis of degree of unsaturation, molecular weight and positional characteristics. The most mobile fractions contained 34–50% of saturated fatty acids while the less mobile had 59–65% of polyunsaturated fatty acids. In the medium erucic acid oil, long chain fatty acids (C20–C22) were found in all fractions, but four fractions of low erucic acid oil were essentially free of long chain acids. Two of these fractions in the latter oil, which represented 44% of the total triglycerides, were glycerol trioleate and dioleoyllinoleoylglycerol. The majority of the 2-positions were occupied by unsaturated C18 fatty acids, generally in the order of linoleic ≥linolenic> oleic acids. The saturated and long chain fatty acids occurred predominantly in the 1-and 3-positions. The various fractions of medium and low erucic acid oils were similar in structural composition except that eicosenoic and erucic acids substituted for oleic acid in some external positions. Erucic acid did not appear to substitute directly for oleic acid in the 2-position.     

Black currant seed oil feeding and fatty acids in liver lipid classes of guinea pigs

Guinea pigs were fed one of three diets containing 10% black currant seed oil (a source of gamma-linolenic (18∶3 n−6) and stearidonic (18∶4 n−3) acids), walnut oil or lard for 40 days. The fatty acid composition of liver triglycerides, free fatty acids, cholesteryl esters, phosphatidylinositol, phosphatidylserine, cardiolipin, phosphatidylcholine and phosphatidylethanolamine were determined. Dietary n−3 fatty acids found esterified in liver lipids had been desaturated and elongated to longer chain analogues, notably docosapentaenoic acid (22∶5 n−3) and docosahexaenoic acid (22∶6 n−3). When the diet contained low amounts of n−6 fatty acids, proportionately more of the n−3 fatty acids were transformed. Significantly more eicosapentaenoic acid (EPA) (20∶5 n−3) was incorporated into triglycerides, cholesteryl esters, phosphatidylcholine and phosphatidylethanolamine of the black currant seed oil group compared with the walnut oil group. Feeding black currant seed oil resulted in significant increases of dihomogamma-linolenic acid (20∶3 n−6) in all liver lipid classes examined, whereas the levels of arachidonic acid (20∶4 n−6) remained relatively stable. The ratio dihomo-gamma-linolenic acid/arachidonic acid was significantly (2.5-fold in PI to 17-fold in cholesteryl esters) higher in all lipid classes from the black currant seed oil fed group.