Chromatographic analysis of sucrose esters of long chain fatty acids

The procedure of the quantitative analysis of the components of sucrose ester products is described. By thin-layer chromatography, sucrose ester products have been separated into their components: mono-,di-,tri-, and higher esters. The individual components have been extracted from the plate and determined colorimetrically by using anthrone reagent. Standard substances of monoesters, diesters and triesters, which have been synthesized from gas-chromatographically pure methyl esters of fatty acids, have been isolated by column chromatography and identified by elemental analysis, colorimetric determination and N.M.R. determination.     

DC-Trennung der stellungsisomeren Monoester von Fettsäurepartialestern mehrwertiger Alkohole

TLC Separation of Positional Isomers of Monoesters from Partial Esters of Fatty Acids with Polybasic Alcohols Partial esters of fatty acids with polybasic alcohols are separated by thin-layer chromatography into the theoretically possible number of monoesters (and diesters). TLC separation of partial esters of the homologous series, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid with 1,2,4-butanetriol, 1,2,6-hexanetriol, glycerol, 1,2-propanediol, and 1,3-butanediol into the theoretically possible number of monoester positional isomers is reported. The periodic acid oxidation was found to be useful for the identification of 4-monoesters of 1,2,4-butanetriol, 6-monoesters of 1,2,6-hexanetriol, and 1-monoglycerides.     

Synthesis of polyoxyethylene derivatives of diesters of sucrose with long-chain fatty acids

Summary Since the long-chain fatty acid sucrose diesters inevitably produced in the synthesis of monoesters are only slightly soluble in water, no important use can be found for them at the present time except as oilsoluble emulsifying agents. In order to exploit new uses we have attempted to improve their solubility in water by introducing oxyethylene radicals into the molecule. The addition reaction of ethylene oxide with the sucrose diesters was carried out in an autoclave in the presence of alkaline catalysts. With the reaction temperature maintained between 100–130° the pressure decreased as the reaction proceeded, and one to two hours were required to consume the ethylene oxide used. The addition products are yellow or orange oily materials soluble in water. Aqueous solutions showed good surface-active properties.     

Herstellung,Analyse und DC-Trennung von Fettsäurepartialestern mehrwertiger Alkohole

Preparation, Analysis and TLC-Separation of Partial Esters of Fatty Acids with Polybasic Alcohols Direct esterification of 99% capric acid, lauric acid, myristic acid, palmitic acid and stearic acid with ethyleneglycol, diethyleneglycol, thiodiethyleneglycol, triethyleneglycol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,5-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,2,4-butanetriol, glycerol, 1,2,6-hexanetriol, trimethylolpropane and pentaerythritol in a molar ratio of 1 :1.25 yields 100 different partial esters of fatty acids. These partial esters are extensively freed from the polyhydric alcohols by washing with sodium sulfate solution and recrystallization in ethanol. Chemical constants and TLC-separation into classes and into polyhydric alcohols permit the evaluation of these compounds as emulsifiers, stabilizers and solubilization acids. All the partial esters of the fatty acids are mixtures, which can be separated by TLC according to the polyhydric alcohol moiety into monoester, diester, triester and tetraester; furthermore, the separation of positional isomers of monoesters and diesters is possible. Several observations made during the synthesis and analysis of partial esters of fatty acids are reported.     

蔗糖酯的HPLC-ELSD法分离与测定

用HPLC-ELSD法分离与测定蔗糖酯,考察了蔗糖酯的HPLC-ELSD分析条件。用Hypersil C8色谱柱(250 mm,4.6 mm,5μm),以〔V(甲醇)∶V(四氢呋喃)=90∶10〕-水二元溶剂系统为流动相,梯度洗脱,流动相流速1.0 mL/m in,柱温40℃,对商品蔗糖酯和合成蔗糖酯进行了定性和定量分析。研究结果表明,在该条件下,HPLC-ELSD有效地分离了蔗糖酯产品中的蔗糖、蔗糖单酯、蔗糖二酯、脂肪酸、硬脂酸甲酯和蔗糖多酯,不但可用于蔗糖酯合成中的终点控制,而且可以对精制后的产品进行分析,从而监控产品的质量,也可用于蔗糖酯的结构鉴定,是一种连续、快速、方便、高效的蔗糖酯的定性和定量分析方法。     

Preparation and surfactant properties of diglycerol esters of fatty acids

Fatty acid mono- and diesters of diglycerol constitute the major portion of commercial polyglycerol esters; hence, their composition influences the performance of the latter as emulsifiers. The correlation of structure of the fatty acids in the mono- and diesters with surfactant properties is of interest. Linear diglycerol was isolated from polymerized glycerol by acetonation, fractional distillation and regeneration. Diglycerol mono- and diesters of undecenoic, lauric, stearic, oleic and ricinoleic acids were prepared by reacting diglycerol and fatty acids in a refluxing mixture of acetonitrile-tetrahydrofuran (75:25) in the presence of p-toluenesulfonic acid and molecular sieves. Mono- and diesters were separated by silica gel column chromatography, and their purities were ascertained by thin layer chromatography and determination of saponification value. The structures were confirmed by periodic acid oxidation, chemical-ionization mass spectrometry and 13 C-NMR spectroscopy. Surfactant properties of the esters were determined. Monoesters showed higher ability in surface tension reduction, emulsification and foaming than the diesters. Short-chain fatty acid esters showed better surfactant properties than the long-chain fatty acid esters. The presence of a central double bond in the lipophilic part of the monoesters reduced emulsion stability. The presence of a hydroxy group in acyl chain retarded foaming and surface tension reducing power.     

Improved synthesis of sucrose fatty acid monoesters

The base-catalyzed synthesis of four sucrose fatty acid esters (caprylate, laurate, myristate, and palmitate) was performed in dimethylsulfoxide by transesterification of sucrose with the corresponding vinyl esters using disodium hydrogen phosphate as catalyst. In using a molar ratio sucrose/vinyl ester 4∶1 and mild reaction conditions (40°C and atmospheric pressure), yields were higher than 85%. The isolated sucroesters had a higher percentage of monoesters (≥90%) and a lower content of diesters in comparison with commercial derivatives. In all cases, 2-O-acylsucrose was the major product (≥60%) in the monoester fraction.     

Production of branched-chain fatty acids from sterculia oil

Methyl sterculate was rearranged by use of 0.5% of rhodium catalyst to isomeric conjugated diene fatty acid methyl esters containing both methylene-and methyl-branched isomers. The rearanged products were hydrogenated directly to saturated, methyl-substituted, branched-chain fatty acid methyl esters with the methyl substituent at one of the positions formerly occupied by the cyclopropenoid ring. The crude branched-chain fatty acids from these esters were purified by recrystallization from a mixed solvent of ethanol and water (80:20, v/v) and flash distillation; the product contained about 90% of branched-chain fatty acids (C₁₉:80%, C₁₈:10%). Esters of the branched-chain fatty acid were prepared with 2-ethylhexyl alcohol or trimethylolpropane, and the characteristic properties of these esters were investigated. The branched-chain fatty esters appear to have potential utility in lubricants; other uses may be possible. Presented at the AOCS meeting in New Orleans, May 1981.     

Methyl glucoside fatty acid diesters

Summary and Conclusion Procedures are described for the preparation of methyl glucoside diesters by direct esterification, using a ratio of one mole of methyl glucoside with two moles of fatty acids. Rate studies indicated that lead or stannous soaps are more effective catalysts than the sodium soaps for speeding up tis esterification. With equal molar quantities of methyl glucoside and fatty acid, the lead and the sodium soap catalysts give products containing predominantly diester and half the methyl glucoside remaining unreacted. Under the same conditions stannous soap catalysis gives high yields of monoesters containing only very small percentages of unreacted methyl glucoside. From the standpoint of speed of reaction, color of the final produets, ease of removal of catalyst from the ester products, and catalyst cost, litharge is the preferred cytalyst for the preparation of methyl glucoside diesters. Properties of various methyl glucoside fatty acid diesters, prepared on a laboratory scale, are given. Du Noüy surface-tension measurements indicate that small quantities of the methyl glucoside dilaurate, dicaprate, or dioleate are quite effective in lowering the surface tension of water.     

Application of lipases to the regioselective synthesis of sucrose fatty acid monoesters

A regioselective synthesis of 6′-O-acyl sucrose monoesters has been developed through the lipase-catalyzed esterification of sucrose acetals with fatty acids in both organic solvents and under solvent-free conditions. The products were obtained in overall yields of 20–27% after hydrolysis of the isopropylidene groups with aqueous acids. The strict selectivity of the enzymes used also enabled the preparation of a monoester fraction that was highly enriched in 6-O-acyl sucrose. This was accomplished by lipase-catalyzed transesterification of sucrose monoesters, prepared by conventional chemical methods, in propan-2-ol. After removal of the transesterification products (sucrose and fatty acid isopropyl esters) and column chromatography on silica gel, the obtained monoester product contained 80% of the single regioisomer, 6-O-acyl sucrose.     

Selective Synthesis of Polyoxyethylene–Polyoxypropylene Block Copolymer (Poloxamer) Fatty Acid Monoesters Over Homogeneous Organotin Catalyst

The synthesis of selected polyoxyethylene–polyoxypropylene block copolymer (poloxamer) fatty acid monoesters is presented. Organotin homogeneous catalyst Sn bis(2‐ethylhexanoate) effectively catalyzed the esterification reaction of (EO)–(PO)–(EO) block copolymer (poloxamer) with fatty acids. The reaction proceeded in high yield and high selectivity to monoesters. Content of diesters in final products was below 1 wt%. The new protocol opened up a high yield and high selective method for the synthesis of poloxamer fatty acid monoesters. These products are potentially interesting for industrial applications, e.g. in lubricants, cosmetics and, in particular, as potential emulsifying agents compatible with hydrocarbon bases, such as paraffin.     

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.     

Column types for the chromatographic analysis of oleochemicals

Chromatography has developed into one of the principle methods of analysis of oleochemicals. Gas chromatography has been used extensively for the analysis of long-chain fatty acids as well as for the analysis of triglycerides and plant sterols. In recent years, high pressure liquid chromatography (HPLC) has been used for the analysis of triglycerides as well as for other related materials. Specialized gas chromatography columns have been developed for the separation of long-chain fatty acids such as the methyl esters. These columns have generally used high polarity stationary phases which separate fatty acids by degree of unsaturation. A specialized use of these high polarity stationary phases is separation ofcis-trans isomers as well ascis-cis andtrans-trans isomers. In this paper, packed and capillary columns are compared for the separation of thecis-trans isomers of fatty acid methyl esters prepared from a hydrogenated vegetable oil. For HPLC separations, the presence of a double bond is approximately equivalent chromatographically to shortening the alkyl chain by two carbons. The long-chain polyenic acids or ethyl esters thus elute near but are resolved from the short-chain saturated fatty acids or esters. HPLC is the method of choice for relatively complex, high molecular weight, or labile esters, such as those of retinyl or cholesterol. Glyceryl esters are particularly well resolved by HPLC in terms of both total chain length and degree of unsaturation. This technique is also useful for lipid class separations and for the analysis of modified fatty acid products, such as prostaglandins and related materials. In general, these analyses are conducted with octadecyl bonded phase column packings.     

琥珀酸双酯磺酸钠类反应型表面活性剂的合成

马来酸酐经单酯化、O-烷基化、选择性磺化反应得到了琥珀酸双酯磺酸钠类表面活性剂。马来酸酐与脂肪醇在90℃下反应3 h得到马来酸单酯;在碳酸钠、Et3N和CH3COCH3存在下,单酯与丙烯基氯(50℃)或异丁烯基氯(65℃)反应6 h得到马来酸双酯;双酯与亚硫酸氢钠在120℃下反应3 h得到目标产物。产物经1HNMR和IR表征,符合结构特征。     

Theoretical and Kinetic Analysis of the Esterification of Undecylenic Acid with Glycerol

The synthesis of undecylenic acid partial esters can be performed at mild temperature with a classical esterification reaction catalyzed by dodecylbenzene sulfonic acid (DBSA). A semi-empirical molecular modeling on the different reaction intermediates indicates that DBSA can strongly decrease their heats of formation through hydrogen bonding. Diester formation seems to be thermodynamically favored with a selectivity for alpha, alpha, or alpha, beta forms that depend on the geometry of the catalyst-intermediate configuration. Triesters are not favored but a high selectivity for monoesters requires a kinetic control. Experimental approach, considering different DBSA concentrations and temperature partially confirms the theoretical predictions but surfactant properties of DBSA and monoesters may induce nonpredicted geometries. Global apparent activation energies are calculated, corresponding to the formation and hydrolysis of mono and diesters. If water trapping allows the decrease of hydrolysis reaction constants, the presence of water and subsequent phase separation may explain differences between theoretical and experimental results and could help increasing monoester selectivity.     

Herstellung,Analyse und DC-Trennung von Fettsäure-Erythritpartialestern

Preparation, Analysis and TLC Separation of Partial Esters of Fatty Acids with Erythritol Direct esterification of 99% capric acid, lauric acid, myristic acid, palmitic acid and stearic acid with meso-erythritol (1,2,3,4-butanetetraol) in mole ratio of 1 : 1.25 yielded partial esters of erythritol which were analyzed by chemical values and TLC separation. Using boric acid impregnated silica gel 60 precoated plates all the theoretically possible positional isomers of mono-, di-, tri- and tetraesters of erythritol (9 fractions) and further four 3,4-hydroxy-tetrahydrofuran-mono- and diesters (both cis- and trans compounds), that were formed as side products by dehydration and 1,4 ring closure from 1,2,3,4-butanetetraol, could be detected. Similarly, the unknown TLC fraction of 1,2,4-butanetriol partial ester, as reported earlier, could be identified as 3-hydroxy-tetrahydrofuran fatty ester by chemical values, elementary analysis, molecular weight determination and synthesis. Moreover, erythritol, 1,2,4-butanetriol, 3,4-hydroxy-tetrahydrofuran and 3-hydroxy-tetrahydrofuran were separated by TLC.     

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。     

Polyhydric alcohol esters of α-sulfo fatty acids

Direct esterification of α-sulfopalmitic and α-sulfostearic acids with excess ethylene glycol, glycerol, pentaerythritol and 2-methoxyethanol was carried out in carbon tetrachloride to give products containing essentially monoesters. Surface active properties of these compounds were measured with emphasis on washing ability in combination with soap. The detergency of these esters was compared with those of hexitol and sucrose α-sulfo fatty acid esters. Although the esters had moderate lime soap dispersing ability, their detergency showed synergism when combined with soap. Deceased. East. Market. Nutr. Res. Div., ARS, USDA.     

New esterification method for resin acids

The reaction of tetraalkylammonium salts of resin acids using dehydroabietic acid as the model with various alkyl polychlorides was studied as a method for preparing new ester derivatives of rosins. Of the alkyl halides investigated, methylene chloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethylene and 1,2,3-trichloropropane reacted with tetrabutylammonium dehydroabietate at moderate temperatures in short reaction times. A number of new esters were identified by NMR, IR and CI-MS. Although many of the primary products were the anticipated monoesters and diesters, some dehydrochlorinated esters were also obtained. The reaction with trichloroethylene resulted in appreciable amounts of dehydroabietic acid anhydride.     

A simple capillary column GC method for analysis of palm oil-based polyol esters

A reliable, simultaneous analysis of palm oil polyol esters using capillary column GC is described. The polyol esters were esterified from palm oil methyl esters (POME) and palm kernel oil methyl esters (PKOME) with trimethylolpropane [2-ethyl-2-(hydroxymethyl)-1,3-propanediol; TMP] to produce the biodegradable base oil for lubricant production. Analysis was performed using a high-temperature capillary column, SGE HT5 operated at a temperature gradient of 6°C/min starting from 80 to 340°C. Before injection, the sample was derivatized with N,O-bis (trimethylsilyl)trifluoroacetamide in ethyl acetate at 40°C for at least 10 min. This procedure provides a complete separation of reaction products: TMP, methyl esters, monoesters (ME), diesters (DE), and triesters (TE). As expected, the ME from palm kernel oil was resolved into five major peaks, DE into seven peaks, and TE into 10 peaks. Since no standard was available for this sample, the identities of the peaks were established by a secondary standard that was derived from pure methyl esters. This GC method has made possible the simultaneous determination of reaction product compositions in order to assess the extent of reaction.