Showing papers in "Journal of the American Oil Chemists' Society in 1966"
TL;DR: Largely by x-ray diffraction six crystalline states, I–VI, in order of increasing melting point, have been identified for cocoa butter, and it is premature to say that VI is specifically the phase of chocolate “bloom”.
Abstract: Largely by x-ray diffraction six crystalline states, I–VI, in order of increasing melting point, have been identified for cocoa butter. Of these states II, IV, V and VI are pure and identifiable with previously (or presently) identified polymorphs of 2-oleoylpalmitoyl stearin (POS), namelyα-2,β′-2,β-3 (“V”) andβ-3 (“VI”); V and VI representing distinct but very closely related crystalline structures. State I is a definite but fleeting and not readily characterized subα state and may be a phase mixture, as state III may be also.
397 citations
TL;DR: It is proposed that the lipids of membrane subunits are bound by hydrophobic association of the hydrocarbon chains regions within the interior of the protein, and the resulting two-dimensional lipoprotein aggregate would possess the strongly anionic charged groups of the phospholipids on its surface.
Abstract: The widespread recognition of the corpuscular nature of membrane ultrastructure demands re-evaluation of established concepts of their molecular organization. Many aspects of membrane physiology, composition, and metabolism provide support for the proposal that most membranes consist of two-dimensional polymers of lipoprotein subunits. Such a model allows the activity, specificity, and adaptability attributed to biological membranes. Evidence which supports this corpuscular model for membranes and some inadequacies of the bimolecular lipid leaflet model are pointed out. The lamellae of plant chloroplasts are membranes which clearly consist of subunits (quantasomes). Their four surfactant lipids and pigments comprise 50% of the lipoprotein subunits. In each of these surfactant lipids there is found a limited and specific group of fatty ester components. This phenomenon suggests that the hydrocarbon chain of the fatty esters may specifically complement certain hydrophobic amino acid sequences in the membrane protein. The protein, then, would determine the sites where the lipid will be most firmly bound. It is proposed that the lipids of membrane subunits are bound by hydrophobic association of the hydrocarbon chains regions within the interior of the protein. The resulting two-dimensional lipoprotein aggregate would possess the strongly anionic charged groups of the phospholipids on its surface. Metabolically-driven alterations in conformation of such a flexible lipoprotein ion exchange membrane allows a consistent interpretation of biological membrane transport phenomena.
213 citations
TL;DR: In this report techniques which have been applied to the isolation of plant glycero- and sphingolipids are reviewed and a new scheme presented for the separation of several of the plant lipid classes.
Abstract: Procedures for separation of complex plant lipids and results obtained are reviewed. Procedures based on DEAE cellulose and silicic acid chromatography, which may be preceded by countercurrent distribution, are presented for separation of the individual glyceroland sphingolipid classes of spinach leaf and chloroplast lamellae. These procedures appear to be generally applicable to photosynthetic tissue of plants and algae. The separation and infrared spectra of mono-and digalactosyl diglycerides, lecithin, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol, plant sulfolipid, cerebroside, and sterol glycosides from spinach are recorded. Chloroplast lamellae lipids are in the molar ratio monogalactosyl diglyceride (14.0), digalactosyl diglyceride (8.0), phosphatidyl glycerol (5.5), sulfolipid (3.9), lecithin (2.0), phosphatidyl inositol (1.0). Phosphatidyl ethanolamine, cerebrosides, and sterol glycosides were not detected in chloroplast lamellae. Fatty acid composition of individual lamellae lipids have been determined: The galactosyl lipids contain more than 90% trienoic acids.Trans-3- hexadecenoic acid is restricted almost exclusively to phosphatidyl glycerol. In this report techniques which have been applied to the isolation of plant glycero- and sphingolipids are reviewed and a new scheme presented for the separation of several of the plant lipid classes. Results obtained with spinach leaf and its photosynthetic apparatus are presented and discussed.
201 citations
TL;DR: A micro method, adapted from the aqueous acetone procedure recently proposed by Pons and Goldblatt, was developed to permit accurate determination of aflatoxins in individual kernels and kernel sections, and indicated that the toxins are not uniformly distributed within contaminated kernels, even when the kernel contains a high level of a flatoxins.
Abstract: Subsamples of a given lot of peanuts may vary greatly in aflatoxin content due to extreme variability in the degree of contamination of individual kernels. A micro method, adapted from the aqueous acetone procedure recently proposed by Pons and Goldblatt for the determination of aflatoxins in cottonseed products, was developed to permit accurate determination of aflatoxins in individual kernels and kernel sections. Use of this procedure permitted the topographic distribution of aflatoxins within single kernels to be mapped and indicated that the toxins are not uniformly distributed within contaminated kernels, even when the kernel contains a high level of aflatoxins. Although wrinkling or discoloration sometimes indicated that a kernel was contaminated, this type of physical damage was not found to be a reliable indication of aflatoxin content. Also it was noted that a few apparently sound and mature kernels contained high levels of aflatoxins.
110 citations
TL;DR: One of these has been found to resemble the major ganglioside of Tay-Sachs disease, which is a monosialo species lacking the terminal galactose of the major normal brain types.
Abstract: Gangliosides are lipids which are found primarily in gray matter of the brain, with lesser amounts in white matter and in some tissues outside the central nervous system. At least ten different gangliosides have been isolated from brain, four of which are major components accounting for over 90% of the mixture. Three of these and possibly the fourth possess a common asialo unit consisting of ceramide, glucose, galactose, and N-acetylgalactosamine in the molar ratios 1∶1∶2∶1. Structural work emanating from the laboratories of Kuhn, Klenk, Svennerholm, and others has shown the major monosialoganglioside to be
$$\begin{array}{*{20}c} {GAL(1 \to 3)GALNac(1 \to 4)GAL(1 \to 4)GLU(1 \to 1)CERAMIDE} \\ {\left( \begin{gathered} 3 \hfill \\ \uparrow \hfill \\ 2 \hfill \\ \end{gathered} \right)} \\ {NANA} \\ \end{array} $$
The two major disialo species contain this unit plus an additional NANA attached to terminal galactose in one case, and to the first NANA in the other. The major trisialo may also be related to these, though its structure is not yet settled. The minor gangliosides generally contain fewer carbohydrate units. One of these has been found to resemble the major ganglioside of Tay-Sachs disease, which is a monosialo species lacking the terminal galactose of the major normal brain types. A number of neurological disorders, including other sphingolipidoses, have characteristic alterations in both pattern and level of brain gangliosides.
95 citations
TL;DR: The nonfluorescing forms of aflatoxins, capable of being produced during the alkali refining operations, are also absent from the refined vegetable oils; these aflatoxin derivatives are readily converted to their original form on acidification and thereby measurable by fluorescence, if present.
Abstract: The present investigation is the first definitive study of the fate of the aflatoxins in vegetable oils undergoing processing. Crude oils, obtained by solvent extraction or by hydraulic pressing of ground moldy peanuts (not suitable for human consumption), contained only small fractions of the aflatoxin originally present in the peanuts; the meals retained the bulk of the aflatoxin. Conventional alkali refining and washing of the oils reduced aflatoxin content to a range of 10 to 14 ppb. The subsequent bleaching operation essentially eliminated aflatoxin from the oils; the concentrations were now less than 1 ppb. The above results were confirmed using corn oils obtained from corn germ deliberately contaminated in the laboratory withAspergillus flavus. The nonfluorescing forms of aflatoxins, capable of being produced during the alkali refining operations, are also absent from the refined vegetable oils; these aflatoxin derivatives are readily converted to their original form on acidification and thereby measurable by fluorescence, if present.
90 citations
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TL;DR: Some of the lipids known to occur in soil have phytotoxic properties; these may have a depressing effect on seed germination and on root and shoot growth.
Abstract: As much as 20% of soil humus occurs in the form of lipids. High values are characteristic of Podzol soils and highmoor peats. Lipids of the following types are known to be present: paraffin hydrocarbons, phospholipids, fats, waxes, fatty acids, and terpenoids. A long list of compounds have been reported; the identification of many of them require confirmation using modern analytical techniques. Some of the lipids known to occur in soil have phytotoxic properties; these may have a depressing effect on seed germination and on root and shoot growth. Waxes and similar materials may be responsible for the difficultly wettable condition of certain sands.
89 citations
TL;DR: Triterpene alcohols and sterols were separated by thin-layer chromatography and gas-liquid chromatography from the unsaponifiable fractions of the following 18 vegetable oils: linseed, peanut, olive, rice bran, palm kernel, corn, sesame, oiticica, palm, coconut, rapeseed, grape seed, sunflower, poppy seed, castor, tea seed, cocoa butter and soybean as discussed by the authors.
Abstract: Triterpene alcohols and sterols were separated by thin-layer chromatography and gas-liquid chromatography from the unsaponifiable fractions of the following 18 vegetable oils: linseed, peanut, olive, rice bran, palm kernel, corn, sesame, oiticica, palm, coconut, rapeseed, grape seed, sunflower, poppy seed, castor, tea seed, cocoa butter and soybean. Two triterpene alcohols, cycloartenol and 24-methylene cycloartanol, were found in all of the oils except soybean oil, which contained only cycloartenol. Triterpene alcohols such as α- and β-amyrin, euphorbol, butyrospermol and cyclolaudenol also were encountered occasionally. Three sterols, β-sitosterol, stigmasterol and campesterol were present in all of the oils. In addition a fourth sterol, not yet idenfified, was found in oils of palm, palm kernel and sunflower in varying amounts. This unknown sterol and brassicasterol were found in rapeseed oil in addition to the three sterols that were common to all of the oils studied.
89 citations
TL;DR: In this paper, soybean oil was partially hydrogenated at 170 and 200C with 0.5 and 0.1% copper-chromium catalysts, respectively, and conjugated dienes were formed at 200 than at 170C.
Abstract: Soybean oil was partially hydrogenated at 170 and 200C with 0.5 and 0.1% copper-chromium catalysts, respectively. The reaction proceeded selectively at both temperatures, although selectivity was better at the lower temperature. Both commercial and laboratory-prepared catalysts reduced the linolenic acid to less than 1% and with selectivity ratios (KLe/KLo) ranging from 6 to 13. Since stearate did not increase, linoleate selectivity (KLo/KOl) was extremely high. About 80% or more of the original linoleic acid remained in the hydrogenated products as measured by the alkali-isomerization method. More conjugated dienes were formed at 200 than at 170C.
74 citations
TL;DR: In this article, the effect of polyoxyethylene n-dodecanols on the critical micelle concentration (CMC) of sodium n-Dodecyl alcohol sulfate as a function of composition of the mixtures and temperature is described.
Abstract: This paper describes the effect of a homologous series of polyoxyethylene n-dodecanols on the critical micelle concentration (CMC) of sodium n-dodecyl alcohol sulfate as a function of composition of the mixtures and temperature. The CMC of the nonionic component of the mixed micelles is about one-hundredth of that of the anionic. Only a gradual increase in the CMC values of the mixed micelles above the values of the nonionic components was observed in the composition range of 0–90 mole % anionic detergent. This is followed by an abrupt transition to the high CMC values of the anionic component. The gradual increase of the CMC values in the range below 90 mole % anionic detergent of n-dodecanol+ 4 EO exceeds that of the higher homologs containing 7, 23 and 30 ethylene oxide units. It is postulated that the degree of ionic repulsion of the ionic component in mixed micelles is markedly decreased as the proportion of nonionic component reaches a threshold range of 10 mole %. This effect is more pronounced with large ethylene oxide coils operating at the periphery of the micelle core than with short ethylene oxide coils. Thermodynamic data have been included.
72 citations
TL;DR: In some cases, the observed distributions of fatty acids in naturally occurring lecithins and triglycerides are similar to the distributions predicted from in vitro studies of the acyltransferase enzymes.
Abstract: The continued suggestion that the ratio of saturated to unsaturated acids in the diet can influence the general health of a mammal is still not easily explained at a biochemical level. Studies on the metabolism of glycerophosphatides show that the enzymes involved appear to differ in the degree of selectivity toward substrates with different amounts of unsaturation. In general, each individual acid will have its own characteristic metabolic fate. The acyl-CoA:acyl-GPC acyltransferases have a marked specificity for both the position to be acylated and the particular acyl-CoA involved. In some cases, the observed distributions of fatty acids in naturally occurring lecithins and triglycerides are similar to the distributions predicted from in vitro studies of the acyltransferase enzymes. Other enzymatic steps, such as acid activation and N-methylation, can also be shown to influence the fatty acid composition of the glycerolipids. The relative importance of these metabolic processes must now be determined.
TL;DR: In this article, the different possibilities of stacking of layers in long-chain compounds have been analyzed with reference to structural differences between even and odd members of homologous series, and it has been possible to correlate packing differences with alternation of melting points and explain the alternation behavior completely.
Abstract: The different possibilities of stacking of layers in long-chain compounds have been analyzed with reference to structural differences between even and odd members of homologous series. It has been possible to correlate packing differences with alternation of melting points and explain the alternation behavior completely on this basis. The theory can also be applied to surface films and mesomorphous phases. Alternation of en-antiotropic transition temperatures and other physical properties are also discussed.
Abstract: In order to understand more fully the mechanisms by which hydrocarbons may be mobilized for the ultimate formation of oil fields, the n-alkane content of several aqueous systems was measured. Both laboratory and natural systems were studied. Exploratory measurements by gas liquid chromatography of total C20 to C33 n-alkanes accommodated in distilled water, alkaline solutions, and solutions containing surfactants fell in the range of 1 to 10 mg/1. Millipore filtration markedly reduced the alkane content with a filter of 0.05 μ pore size removing as much as 97% of the accommodated alkanes. Alkaline solutions accommodated higher quantities of alkanes than the distilled water, but the addition of surfactants had little further effect. Natural waters had low total C20 to C33 n-alkane content. Samples of surface waters showed values of 0.2 μg/1 in sea water, 0.5 μg/1 in lake waters, and 1.5 μg/1 in a river water. Coproduced oil field waters generally had a slightly higher n-alkane content with values of 1 to 1.4 μg/1. Waters expressed from recent lake sediments contained up to 50 μg/1 of total C20−C33 n-alkanes. Addition of sodium bicarbonate and surfactants to the sediment prior to expressing water had little or no effect. The data presented appear to be of geochemical significance as they indicate that water has the capacity to accommodate significant quantities of n-alkanes in a distribution remarkably similar to that of alkanes in the reference crude oil of A.P.I. Project 6.
TL;DR: In this paper, the authors measured the solid state fluorescence of aflatoxins on silica gel-coated TLC plates on a densitometer equipped for fluorescence measurements.
Abstract: Measurement of the solid state fluorescence of aflatoxins on silica gel-coated TLC plates on a densitometer equipped for fluorescence measurements showed a linear relationship between peak areas and concentration over a range of at least 2 to 105×10−4 μg of aflatoxins per spot. Response of individual aflatoxins was in order of B2>G2>B1>G1. Aflatoxins can be measured with a precision of ±2–4%.
TL;DR: The occurrence of phytane, pristane, and fatty acids in Precambrian sedimentary rocks 2.7 billion years old has been interpreted to indicate the existence of life processes similar to those that are operative today as mentioned in this paper.
Abstract: Lipids, particularly the glycerides, terpenes, sterols, and hydrocarbons, have properties conducive to their preservation either in original or transformed state and are significant constitutents of the geochemical biomass. The occurrence of phytane, pristane, and fatty acids in Precambrian sedimentary rocks 2.7 billion years old has been interpreted to indicate the existence of life processes similar to those that are operative today.
TL;DR: The lipid-protein positional relationship deseribed by the simple Danielli model leads to a concept of the basic structure which is consistent with recent findings and a “particulate” concept which is compatible with the simple model is discussed with regard to transport phenomena and component turnover in membranes.
Abstract: The lipid-protein positional relationship deseribed by the simple Danielli model leads to a concept of the basic structure which is consistent sistent with recent findings. The stability of membranes is insured by internal cohesion forces and by the potential barrier of surrounding water molecules. The properties of cohesional forces are reviewed with reference to membrane stability and order. The existence of a higher degree of organization is discussed in the light of recent electron microscopic data. A “particulate” concept which is compatible with the simple model is discussed with regard to transport phenomena and component turnover in membranes.
TL;DR: In this article, a dynamic viscosity-temperature criterion, log (1.200+log η) = A−S log(1+t/135), was used to characterize the viscosities of saturated fatty acid methyl esters through nonadecanoate.
Abstract: Kinematic viscosities at 20C, 40C and at 70C have been measured for methyl oleate, linoleate, linolenate, erucate, and for the saturated fatty acid methyl esters acetate through nonadecanoate. Using a recently developed dynamic viscosity-temperature criterion, log (1.200+log η)=A−S log (1+t/135), the viscosity-temperature behavior of the saturated compounds could be characterized by one single parameter.
TL;DR: An improved crambe meal has been developed by using an ammonia-heat treatment to give significantly better nutritive value and acceptability and incorporation of the ammonia reaction into desolventizer-toaster operations should be possible to provide an economical means of improving the feeding value of crambe Meal.
Abstract: An improved crambe meal has been developed by using an ammonia-heat treatment to give significantly better nutritive value and acceptability. The quantity of ammonia permanently bound as nitrogen in the processed meal was from 0.5 to 1.5% of the meal weight and varied with conditions of reaction. Destruction of the undesirable thioglucoside fraction of the meal was demonstrated by paper chromatograph changes and by the absence of the thioglucoside conversion product thiooxazolidone. Ultraviolet-absorbing compounds in the meal, at least one of which is associated with bitterness, were also modified. Feeding experiments with chicks and cattle show the improved palatability and nutritional quality. Incorporation of the ammonia reaction into desolventizer-toaster operations should be possible to provide an economical means of improving the feeding value of crambe meal.
TL;DR: In this paper, the role of fatty acid structure on ozonide formation and thin-layer chromatography (TLC) of ozonides of a number of different types of unsaturated fatty acids is discussed.
Abstract: Important factors and new techniques in the application of ozonolysis to the localization of double bond positions in unsaturated fatty acids are elaborated. Solvent polarity was shown to exert a profound influence on the yield and composition of ozonides. The influence of fatty acid structure on ozonide formation and the thin-layer chromatography (TLC) of ozonides of a number of different types of unsaturated fatty acids are illustrated. Simple methods for the ozonization of unsaturated fatty acid esters and the cleavage of ozonides by reduction and pyrolysis are described. Applications of ozonolysis to the determination of the structures of geometric isomers, hydroxy, epoxy and cyclic olefinic fatty acids, and the localization of radioactivity along the chain of unsaturated fatty acids are illustrated.
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TL;DR: In this paper, the solvent extracts of the sea water were separated into eight lipid classes by column chromatography on silicic acid and the fractions eluted with solvents of increasing polarity were characterized by thin-layer chromatography, infrared and ultraviolet absorption and gas chromatography.
Abstract: Acidified and filtered sea water samples which were extracted with petroleum ether and ethyl acetate have been shown to contain a variety of lipid compounds in trace amounts. Concentrations of these solvent-soluble substances ranged from 0.5 to 6.0 mg/liter, the lower concentrations being found in offshore waters. The solvent extracts of the sea water were separated into eight lipid classes by column chromatography on silicic acid. The fractions eluted with solvents of increasing polarity were characterized by thin-layer chromatography, infrared and ultraviolet absorption and gas chromatography. These techniques revealed a complex mixture of alkanes, alkenes, fatty acids, steroids, phospholipids and many as yet unidentified components. Twenty to thirty alkanes were present as indicated by gas chromatography. No aromatic hydrocarbons were detected. Chromatography of the methyl esters of the fatty acids indicated the presence of acids with chain lengths varying from 14 to 22 carbons, both saturated and unsaturated. In many samples the unsaturated fatty acids containing 18 to 22 carbons predominated. The lipid components varied somewhat in composition as well as concentration from location to location and with season and depth.
TL;DR: In this paper, the free lipid of crambe abyssinica C.D. 6619 and the brassica napus varieties Golden and Zero-erucic were collected at different stages of maturity and the free fatty acids extracted with hexane.
Abstract: Seeds ofCrambe abyssinica C.D. 6619 and theBrassica napus varieties Golden and Zero-erucic were collected at different stages of maturity and the free lipid extracted with hexane. The lipid thus obtained was separated into lipid classes by silicic acid column chromatography. The lipid classes were further examined by thin-layer chromatography and the component fatty acids and sterols by gas-liquid chromatography. The relative amounts of the lipid classes in crambe and both rape varieties varied as the seed matured and a period of great change occurred about 10 days after fertilization. The greatest change was in triglycerides and phospholipids plus glycolipids. Free fatty acids, present in immature seeds, has almost disappeared at maturity. The lipid classes of crambe and both types of rape were in similar proportion at maturity. Differences in phospholipid and glycolipid composition were found between crambe and rape and between immature and mature rape. The fatty acid composition differred between lipid classes and changed with maturity. Changes in 18-carbon acids of Zero-erucic rape were concurrent with the development of erucic and eicosenoic acids in Golden rape.
TL;DR: The reaction of metallic salts in aqueous solution with sodium borohydride produces finely divided metals that are catalytically active for hydrogenation of soybean oil as discussed by the authors.
Abstract: The reaction of metallic salts in aqueous solution with sodium borohydride produces finely divided metals that are catalytically active for hydrogenation. Salts of nickel, cobalt, palladium and platinum give active catalysts for the selective hydrogenation of soybean oil. Iron and silver salts, when reduced with sodium borohydride, show no activity at 200C and atmospheric hydrogen pressure. The cobalt catalyst produces the least amount of stearate. Incorporation of palladium, platinum, copper or chromium up to 2% enhance the activity of the nickel catalyst. Copper and chromium salts, when reduced together, form catalysts that hydrogenate linolenyl groups in soybean oil seven times more rapidly than linoleyl groups. No stearate formation is observed with these binary catalysts.
TL;DR: A sample of rapeseed oil of known composition was analyzed by gas chromatography using open tubular columns and two types of polyester coating to illustrate the possibility of using this technique to detect and determine isomeric forms of monoethylenic fatty acids.
Abstract: A sample of rapeseed oil of known composition was analyzed by gas chromatography using open tubular columns and two types of polyester coating. The results confirm the previous analysis in most respects and elearly illustrate the possibility of using this technique to detect and determine isomeric forms of monoethylenic fatty acids. Some hitherto unreported trace components have been provisionally identified in rapeseed oil by linear log plots.
TL;DR: The usual methods of studying enzyme kinetics are not applicable because of the unusual conditions under which the hydrolysis of triglycerides occurs, and these steps can be influenced by such variables as efficiency of agitation, electrolyte concentration, and the presence of surface-active agents.
Abstract: Triglycerides are metabolized by most of the organs and tissues of the body. However, the conditions in the lumen of the intestinal tract are unique, for it is only here that triglycerides are metabolized in the free state. Elsewhere these lipids are associated with water-soluble materials. Since the substrate is water-insoluble and the enzyme is water-soluble, lipase, which brings about the hydrolysis of triglycerides in the intestinal tract, has the special property of being capable of functioning efficiently at an oil/water interface. Any material that can alter the nature of this oil/water interface can markedly influence the digestion of triglycerides.
TL;DR: In this paper, the best conditions for producing diethanolamide directly from linseed oil (1 mole) required adding oil to the sodium alkoxide in Diethanolamine (6 moles) and heating at 110-115C for 35 min.
Abstract: The sodium alkoxide-catalyzed reaction of linseed oil or linseed methyl esters with diethanolamine produces almost exclusively linseed diethanolamides. Reaction conditions, e.g., temperature, amount of excess diethanolamine and mode of adding reactants, are reported. The best conditions for producing diethanolamide directly from linseed oil (1 mole) required adding oil to the sodium alkoxide in diethanolamine (6 moles) and heating at 110–115C for 35 min. The linseed diethanolamide isolated in 93–95% yield was an amber oil. Progress of the reaction, followed by thin-layer chromatography, showed only trace amounts of byproducts.
TL;DR: The major fatty acid of the seed oil ofTrewia nudiflora was shown to be α-kamlolenic acid, not α-eleostearic acid as believed earlier as discussed by the authors.
Abstract: The major fatty acid of the seed oil ofTrewia nudiflora is shown to be α-kamlolenic acid, not α-eleostearic acid as believed earlier. Other conjugated acids were found and identified in seed oils not previously studied, viz., α-eleostearic acid inParinari insularum andRicinodendron rautanenii; trans,8-trans,10-cis,12-octadecatrienoic acid inCalendula stellata.
TL;DR: In this article, high resolution NMR spectra of all the isomeric methyl hydroxystearates have been measured in carbon tetrachloride, pyridine, and quinoline.
Abstract: High resolution NMR spectra of all the isomeric methyl hydroxystearates have been measured in carbon tetrachloride, pyridine, and quinoline. As a result of association with the solvent, spectra in pyridine, and particularly in quinoline, are considerably different from those in carbon tetrachloride. The two pairs of methylene groups on either side of the CHOH grouping are deshielded by the associated solvent molecule giving a new signal at 1.58 ppm in pyridine, and at 1.75 ppm in quinoline. Deshielding of the terminal CH3 occurs in isomers with hydroxyl near the methyl end, and of the methylene alpha to the ester group in isomers with hydroxyl near the ester end of the chain. When the spectra of isomers substituted near the center of the chain are observed in quinoline, the major methylene signal is split into two peaks due to differential shielding by the solvent. The differences between the spectra of each isomer measured in quinoline are sufficiently large for use as a method of identification.
TL;DR: In this article, the cyclopropenoid acid content of oils extracted from 22 commercial varieties and 3 botanical species of cottonseed have been determined, and it was shown that the fatty acid composition can be estimated from the iodine value.
Abstract: The cyclopropenoid acid content of oils extracted from 22 commercial varieties and 3 botanical species of cottonseed have been determined. The malvalic acid content determined by HBr titration varied from a low of 0.56% to a high of 1.17%. Iodine values of the oils ranged from 96.8 to 111.6 No definite correlation could be established between iodine value and malvalic acid content. Equations for regression lines for the major acids have been calculated from plots of fatty acid composition vs. iodine value. The high degree or correlation suggests that for commercial oils the fatty acid composition can be estimated from the iodine value. Oils of the 3 experimental types of different species showed wide variations in fatty acid composition and represented many of the maximum and minimum values reported.
TL;DR: An exploratory study of the aqueous system of dimethyldodecyl amine oxide (DDAO) revealed it to be an interesting and instructive surfactant system showing the unusual occurrence of at least 5 stable phases at room temperature.
Abstract: An exploratory study of the aqueous system of dimethyldodecyl amine oxide (DDAO) revealed it to be an interesting and instructive surfactant system showing the unusual occurrence of at least 5 stable phases at room temperature—crystal (100-about 80% DDAO), neat (about 80-70%), viscous isotropic (70-65%), middle (65-35%) and fluid isotropic or nigre (35-0%) in order of decreasing DDAO content. In many respects the system resembles anionic detergent systems such as that of sodium palmitate, in which, however, viscous isotropic is not observed. The maximum temperatures of existence for crystal, neat and middle are, respectively, 116, 145 and 110C. Neat phase is soft and anisotropic, viscous isotropic is somewhat brittle and isotropic, middle is plastic and anisotropic. The mesomorphic phases are particularly well shown microscopically in “dried-down” samples under circular cover glasses. Middle and neat textures under the microscope are typical. At least four crystalline phases were recognized at various degrees of hydration.