Model microemulsions containing vegetable oils part 1: Nonionic surfactant systems

Nonionic microemulsions containing triglycerides and fatty acid esters as lipophilic components have been studied. The phase inversion temperature (PIT) of the systems was determined by a conductometric method. Partial phase diagrams were constructed in the phase inversion temperature range. Water solubilization capacity of the nonionic surfactant systems studied was dependent on surfactant and oil types in analogy to ordinary hydrocarbon systems. The PIT:s increased with increased molecular weight for both esters and triglycerides.     

Alcoholic extraction of vegetable oils. Part IV. Solubilities of vegetable oils in aqueous 2-propanol

Summary Solubilities of 14 vegetable oils in four different concentrations of aqueous 2-propanol at various temperatures were determined by a direct and simple method. Comprehensive solubility data of these oils and the critical solution temperatureversus 2-propanol composition data are presented in tabular form. Solubility of each oil in aqueous 2-propanol increases with temperature until the critical solution temperature is reached, at and above which oil and the solvent are miscible in all proportions. Further the critical solution temperatures of all the oils with aqueous 2-propanol solutions increased with the increase in water content of 2-propanol solutions. There appears to be a general relation between fatty acid contents of the oils and critical solution temperatures which needs further study. Presented at the 30th fall meeting, American Oil Chemists' Society, September 24–26, 1956, Chicago, Ill.     

Formulating middle-phase microemulsions using mixed anionic and cationic surfactant systems

Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby allowing formation of middle-phase microemulsions with mixed anionic-cationic systems. This research investigates the role of surfactant selection in designing alcohol-free anionic-cationic microemulsions. Microemulsion phase behavior was studied for three anionic-cationic surfactant systems and three oils of widely varying hydrophobicity [trichloroethylene (TCE), hexane, and n-hexadecane]. Consistent with our hypothesis, using a branched surfactant and surfactants with varying tail length allowed us to form alcohol-free middle-phase microemulsion using mixed anionic-cationic systems (i.e., liquid crystals did not form). The anionic to cationic molar ratio required to form middle-phase microemulsions approached 1∶1 for univalent surfactants as oil hydrophobicity increased (i.e., TCE to hexane to n-hexadecane); even for these equimolar systems, liquid crystal formation was avoided. To test the use of these anionic-cationic surfactant mixtures in surfactant-enhanced subsurface remediation, we performed soil column studies: Greater than 95% of the oil was extracted in 2.5 pore volumes using an anionic-rich surfactant system. By contrast, cationic-rich systems performed very poorly (<1% oil removal), reflecting significant losses of the cationic-rich surfactant system in the porous media. The results thus suggest that, when properly designed, anionic-rich mixtures of anionic and cationic surfactants can be efficient for environmental remediation. By corollary, other industrial applications and consumer products should also find these mixtures advantageous.     

Hydrogenation of triglycerides containing linolenic acids: II. Continuous hydrogenation of vegetable oils

In this study continuous hydrogenation of neutral oils, especially the selective hydrogenation of soybean oil, is described. The reactor is a column divided by a series of plates into a number of reaction chambers. Oil with suspended catalyst and hydrogen enters the column at the bottom and flows concurrently with hydrogen through it. The pressure in the reactor will adjust itself, depending on the activity and concentration of the catalyst and throughput of oil. The ratio of gas volume in the reactor to volume of the oil is very low, so that the iodine value of the hydrogenated product can be controlled to within 1.5 iodine unit.     

Modification of vegetable oils. XIV. Properties of aceto-oleins

Summary Pure 1,2-diaceto-3-olein was prepared by acetylating mono-olein. A mixture of aceto-oleins was prepared by acetylating a mixture of mono-, di-, and trioleins derived from commercial oleic acid. Several natural oils were acetylated either by ester-ester interchange with triacetin or by glycerolysis followed by acetylation. The various products were examined for cloud and solid points, point of complete melting, and consistency. The 1,2-diaceto-3-olein, which contains 19.5% of acetyl group on a weight basis, has a melting point of −18.3°C. while the mixture of aceto-oleins, which contained 14.3% of acetyl on a weight basis, melted at −24°C. Acetylation of the natural oils raises in most instances their cloud and solid points and point of complete melting, but it also greatly increases their plasticity at lower temperatures. Aceto-compounds were used to plasticize highly hydrogenated cottonseed oil. These mixtures were prepared so that they possessed the consistency of margarine oil at room temperature. These mixtures, when compared with partially hydrogenated oil, butterfat, or a mixture of cottonseed oil and hydrogenated cottonseed oil, were softer below room temperature and firmer above room temperature. A margarine-like product containing 79% of aceto-olein and 18.5% of highly hydrogenated cottonseed oil had a practically constant consistency over the temperature range of −15° to 49°C. (5° to 120°F.). Presented at the 26th Fall Meeting of the American Oil Chemists' Society, Cincinnati, O., Oct. 20–22, 1952. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

New amphoteric surfactant containing a 2-hydroxyalkyl group: III. Performance of binary systems of amphoteric/anionic surfactants

The performance of new amphoteric surfactants, N-(2-hydroxyethyl)-N-(2-hydroxyalkyl)-β-alanines (HAA), and their oxyethylated derivatives (HAA-nEO) was studied in blends with conventional anionic surfactants. Viscosity, ultraviolet (UV) spectroscopy, surface tension, foaming power, dye solubilization and detergency were measured for the blends of various compositions. The interaction between HAA and sodium linear alkylbenzene sulfonate (LAS) was discussed with respect to the deviation of molar extinction coefficient in the UV spectra. A complex formation was assumed. A notable change in viscosity of 1.0% aqueous solutions was observed at pH 8.0 for the compositions of HAA/LAS (3:1) and HAA/sodium lauryl sulfate (4:1). The binary systems exhibited excellent detergency and other surface active properties, and indicated synergistic effects at a certain weight ratio. Human and rabbit skin irritation also was evaluated.     

Glyceride structure of vegetable oils by countercurrent distribution. VI. Corn oil

Corn oil has been fractionated in a 200-tube countereurrent distribution apparatus. Although this technique gives no information about the positional isomers of the glycerides, the fatty acid composition of the fractions and the amounts of the more unsaturated triglycerides are in agreement with an essentially random pattern. Presented at fall meeting. American Oil Chemists’ Society, New York, N.Y,, October 17–19, 1960. This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U.S. Department of Agriculture.     

Possible mechanisms in thermal polymerization of vegetable oils. II. Polymer formation

Summary From molecular distillation data, and information obtained by hydrogenation in dilute solution, extents of reaction have been calculated for the polymerization of linseed, safflower, tung, and oiticica oils. The hydrogenation data indicate that more than one double bond per molecule can be consumed during polymerization. The kinetic order of the polymerization of nonconjugated oils increases from an initial value of unity to approach a value of two. With conjugated oils, second-order characteristics were maintained during the course of the bodying. An explanation of this difference in reaction order based on monomer disappearance is presented. Rate constants and overall energies of activation were calculated and compared with those obtained from viscosity measurements. Agreement between the two sets of values was obtained. Oiticica oil, which gives curved viscosity plots that cannot be resolved, has been treated successfully in this manner. Intraglyceride reactions have been studied, and differences in behavior between nonconjugated and conjugated oils at high and low polymerization temperatures have been observed. Contribution from the Division of Applied Biology, National Research Laboratories, Ottawa, Canada. Issued as N.R.C. No. 4434. Presented at the 29th Fall Meeting, American Oil Chemists' Society, Philadelphia, October, 1955.     

Glyceride structure of vegetable oils by countercurrent distribution. II. Soybean oil

Summary Soybean oil has been fractionated in a 200-tube countercurrent distribution apparatus. Fractions have been obtained with iodine values both too high and too low to conform to an even distribution. From the weight distribution curve, iodine value, and spectrophotometric analyses the oil is estimated to contain 5.2% dilinoleo-linolenin, 13.7% trilinolein, 9.2% oleolinoleo-linolenin, and 25.2% oleo-dilinolein. This composition is in agreement with a random distribution pattern. Also the fatty acid content of the more saturated fractions indicates the presence of disaturates and dioleins which are not permitted under an even distribution. Based upon this type of information, it is concluded that the fatty acids in soybean oil glycerides approach a random type of distribution. Presented at the meeting of the American Oil Chemists’ Society, Chicago, Ill., September 24–26, 1956.     

Bleaching of vegetable oils. II. Conversions of methyl oleate and linoleate

Methyl oleate and linoleate were treated with 10% acid activated clay at 90–100 C for 1–50 hr with and without admission of air. Positional and geometric isomers of fatty acid esters were found. Polar compounds were detected having one or more functional groups with respect to the starting esters. Preparative thin layer chromatography and gas liquid chromatography were used in isolating the compounds, while IR, NMR, mass spectroscopy, and gas liquid chromatography analysis were employed for identification. The unsaturation of the isolated isomers was present at carbon atoms 5–11. The polar compounds were, among others, 9- and 10-keto octadecanoic methyl esters, isomeric keto octadecenoic methyl esters, isomeric epoxy octadecanoic methyl esters, 9- and 10-hydroxy octadecanoic methyl esters, and some mono methyl ester dicarbonic acids. It may be concluded that geometric, as well as positional, isomerization occurs and that small amounts of compounds with one or more functional groups are formed when unsaturated fatty acids were treated with acid-activated clay.     

Glyceride structure of vegetable oils by countercurrent distribution. III. Safflower oil

Summary Safflower oil was fractionated in a 200-tube countercurrent distribution apparatus, and the oil was also fractionated after interesterification with C¹⁴-labelled palmitic acid. The glyceride composition of the interesterified oil was similar to that of the natural oil. The glycerides were separated on the basis of both unsaturation and chain length of the constituent fatty acids, and the palmitoglycerides had only slightly higher partition coefficients than the oleoglycerides. The amounts of trilinolein, oleodilinolein, and palmitodilinolein found were similar to those calculated for a random distribution. Distribution of a mixture of safflower oil and olive oil showed that no mixing or randomization of triglycerides occurred during countercurrent distribution. It is concluded that fatty acids in safflower triglycerides are distributed in an essentially random pattern. Presented at the 49th annual meeting, American Oil Chemists' Society, Memphis, Tenn., April 21–23, 1958.     

Glyceride structure of vegetable oils by countercurrent distribution. IV. Cocoa butter

Summary Cocoa butter has been fractionated by countercurrent distribution between pentane-hexane and furfural-uitroethane solvent phases with the application of 1,100 transfer stages. Except for a small percentage of trisaturates and linoleic acid-containing triglycerides, oleic acid occurs at least once in each glyceride molecule. Cocoa butter is composed principally of mono-oleins: oleodistearin, 22%; oleopalmitostearin, 41%; and oleodipalmitin, 12%. Whereas the latter glyceride is not permitted under a pure even pattern, the low trisaturate content is not consistent with a random pattern. Cocoa butter follows neither a random nor an even pattern of glyceride structure. Presented at Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. Exposition of Modern Laboratory Equipment, Pittsburgh, Pa., March 3, 1958. This paper reports research undertaken in cooperation with the Quartermaster Food and Container Institute for the Armed Forces, QM. Research and Engineering Command, U. S. Army, and has been assigned number 991 in the series of papers approved for publication. The views or conclusions contained in this report are those of the authors. They are not to be construed as necessarily reflecting the views or indorsement of the Department of Defense. This is a laboratory of the Northern Utilization Research and Development Divison, Agricultural Research Service, U. S. Department of Agriculture.     

Glyceride structure of vegetable oils by countercurrent distribution. I. Linseed oil

Summary Linseed oil has been fractionated in a 200-tube countercurrent-distribution apparatus. Iodine values of fractions ranged from 51 to 261. As determined by the weight distribution curve, iodine values and spectrophotometric analyses, 18.2% trilinolenin, 12.3% linoleo-dilinolenin, and 19.5% oleo-dilinolenin combined with 4.1% dilinoleo-linolenin were isolated. Based upon this type of data and upon several methods of analysis and collation of the data, it is concluded that linseed oil glycerides follow essentially the random pattern of distribution. Presented at the meeting of American Oil Chemists’ Society, Minneapolis, Minn., Oct. 11–13, 1954.     

Alcoholic extraction of vegetable oils. II. Solubilities of corn,linseed, and tung oils in aqueous ethanol

Summary Solubilities of corn, linseed, and tung oils in aqueous alcoholic solutions at various temperatures have been determined by a direct and simple method. The solubility curves for the three oils in aqueous alcoholic solutions are presented. The critical solution temperatureversus alcohol composition data have been plotted for the three oils. It is observed that the critical solution temperature increases with the water content of the alcohol and that the relationship is linear in each case. Similar results were obtained for cottonseed, peanut, sesame, and soybean oils previously (1). The pressure in the system, increases with temperature; the maximum is approximately 20 p.s.i.g. Presented at the Philadelphia fall meeting, American Oil Chemists’ Society, October 11, 1955.     

Studies in interesterification. II. Acidolysis of some vegetable oils with lauric acid

Acidolysis reactions of cottonseed oil, peanut oil, mahua oil (Madhuca latifolia), and palm oil with lauric acid were investigated with special reference to the influence of catalysts and the relative proportions of oil and lauric acid on the extent and type of fatty acids displaced from an oil. Catalysts such as sulfuric acid, zinc oxide, calcium oxide, magnesium oxide, aluminum oxide, and mercuric sulfate were used. The reaction generally was carried out by heating oil and lauric acid at 150C±2 for 3 hr. The reaction products were separated and then analyzed by UV spectrophotometry and GLC. Sulfuric acid was found to be the best catalyst with 1 part of oil and 1.2 parts of the displacing acid (lauric acid) for displacement of high-molecular-weight fatty acids from an oil by low-molecular-weight fatty acids. The nature of the displacement of fatty acids varied from oil to oil, depending on their compositions. It was further indicated that linoleic acid was displaced preferentially over oleic acid in an amount dependent on its initial content in an oil with a corresponding increase in saturated acids content. A broad similarity in displacement patterns, in general, was noted; the fatty acids above C₁₈ were not displaced as in the case of peanut oil. The results demonstrate the feasibility of introducing lauric acid in the vegetable oils for the production of interesting oils with vastly different physical and chemical properties.     

Some effects of ionizing radiations on lipids. I. Monocarbonyl production in vegetable oils

Summary and Conclusions Irradiation of refined vegetable oils by high-energy cathode rays resulted in the production of monocarbonyl compounds. The yield was about 0.2 μM per gram per 10⁶ rep. for doses up to about 10⁷ rep. Some of the products were themselves sensitive to the radiations, and the net yield was dependent upon a function of the concentrations and reactivities of the precursors and of the end-products. Concurrently with the formation of the monocarbonyls there was an attack on the conjugated triene systems in the media and an increase in ultraviolet absorption in the 225–240 mμ region. However the irradiation products resulted from other mechanisms in addition to those involving the trienes. Irradiation under reduced temperature or in vacuum or with the addition of antioxidants did not decrease the yield of monocarbonyl compounds. However the use of a vacuum and the inclusion of antioxidants were partially effective in reducing the irradiation attack on triene groups. The net yields of monocarbonyls were dependent upon the concentrations and sensitivities of the products as well as of their precursors. Thus, although methods commonly successful in inhibiting oxidations of oils did not reduce these yields, they did suppress some irradiation-induced reactions, particularly those involving unsaturated compounds. In this respect their action was similar to that which has been demonstrated in inhibition studies of antioxidations in oils. Contribution No. 263 from the Department of Food Technology, Massachusetts Institute of Technology, Cambridge, Mass. Taken in part from a thesis entitled “Effects of Ionizing Radiations on Lipids,” submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology, Cambridge, Mass., August, 1954.     

Alcoholic extraction of vegetable oils. I. Solubilities of cottonseed,peanut, sesame,and soybean oils in aqueous ethanol

Summary Solubilities of cottonseed, peanut, sesame, and soybean oils in aqueous alcoholic solutions at various temperatures were determined directly. Solubility curves for the four oils in aqueous alcoholic solutions are presented. The critical solution temperaturesversus alcoholic concentrations data have been plotted and are in complete agreement with the previously published data of Japanese workers in each case. It is observed that the critical solution temperature increases with the moisture content of the alcohol, and in each case the relationship is linear. The pressure in the system also varies directly with the temperature, the maximum being approximately 20 p.s.i.g.