Nonvolatilealpha-branched chain fatty esters. II

A group of nonvolatilealpha-branched esters was prepared by the di-tertiary butyl peroxide-promoted addition of normal esters to terminal olefins containing methyl branches or aryl groups. Methyl stearate was added to 3,7-dimethyl-1-octene, 3,5,5-trimethyl-1-hexene, and 4-phenyl-1-butene. The reaction with 2,4,4-trimethyl-1-pentene, a terminal alkene with a methyl branch at the internal ethylenic carbon, was not successful. Benzyl 2-(4-phenylbutyl) octadecanoate was prepared by transesterification of the corresponding methyl ester. Benzyl 2,2-dimethylpropanoate, which has no α-hydrogen in the acyl portion of the molecule, was added to 1-hexadecene to form α-hexadecylbenzyl 2,2-dimethylpropanoate. Lubricant evaluation data were obtained on the above compounds. Presented at the AOCS Meeting, New Orlenas, May 1967. E. Utiliz. Res. Dev. Div., ARS, USDA.     

Synthesis of deuterated cyclopropene fatty esters structurally related to palmitic and myristic acids

To develop a synthesis of tritiated cyclopropene fatty acids (CPFA), compounds that should prove useful for affinity labeling of desaturases in insect pheromone biosynthetic studies, a series of novel, selectively deuterated CPFA analogues was prepared and characterized. In methyl [16-²H]12,13-methylene-12-hexadecenoate, the incorporation of deuterium was achieved by treatment of the corresponding ω-chloro derivative with sodium borodeuteride in dimethylsulfoxide at 70°C for 24 h (67% yield) following conventional procedures. Alkylation of the tetrahydropyranyl derivative of 13-tridecynol in the presence of lithium diisopropylamide in tetrahydrofuran at −20°C with 1-chloro-3-iodopropane in hexamethylphosphoramide, followed by Jones oxidation of the crude product, yielded 16-chloro-12-hexadecynoic acid (54%), which was esterified to the corresponding methyl ester by treatment with potassium carbonate and methyl iodide in dimethylformamide. Treatment of this acetylenic ester with ethyldiazoacetate in the presence of activated copper-bronze as catalyst followed by hydrolysis in KOH solution at room temperature yielded 16-chloro-12,13-(carboxymethylene)-12-hexadecenoic acid. This diacid was treated with excess oxalyl chloride to give the corresponding diacyl chloride, which was decarbonylated in a diethyl ether solution with zinc chloride, and the cyclopropenium ions thus formed were added at −40°C to a methanolic sodium hydroxide solution of sodium borohydride to give methyl 16-chloro-12,13-methylene-12-hexadecenoate. Analogous procedures were followed to prepare methyl [17-²H]10,11-methylene-10-hexadecenoate, methyl [17-²H]11,12-methylene-11-hexadecenoate and methyl [17-²H]12,13-methylene-12-hexadecenoate from the corresponding diacids using sodium borodeuteride in the reduction of the cyclopropenium ions. Alternatively, methyl [2,2,3,3-²H₄]hexadecynoate, prepared by reaction of methyl 2,11-hexadecadiynoate with magnesium in deuterated methanol at room temperature, was submitted to the above cyclopropenylation and reductive decarbonylation sequence to give methyl [2,2,3,3,17-²H₅]-11,12-methylene-11-hexadecenoate. In summary, complementary methods for the selective incorporation of one to five deuterium atoms into cyclopropene fatty acids, at different sites, in moderate to high yields have been developed. The methods should easily be applicable to the preparation of the corresponding tritiated analogues.     

Glycidyl esters. IV. Hydration of glycidyl stearate

The acid-catalyzed conversion of glycidyl stearate to monostearin has been investigated. By use of au essentially nonaqueous reaction medium and a two-step procedure, high yields of monostearin were obtained at 15–20C in brief reaction periods, while avoiding ester hydrolysis. Distearin was found to be a by-product. The influence of solvent, reaction temperature, and type of acid catalyst upon the relative amounts of monostearin and distearin produced were studied. A possible reaction path leading to the formation of distearin is proposed. Part III in press. Part II, JAOCS,38, 194 (1961). A laboratory of the E. Utiliz. Res. & Dev. Div., ARS, U.S.D.A.     

Sulfonated branched chain fatty acids and esters

In continuation of work reported a year ago describing branched chain fatty acids, a series of monosodium methyl 2-sulfo-2-alkylalkanoates [RR'C (SO₃Na) CO₂CH₃] were synthesized. The surface active properties of these compounds were evaluated and compared with the corresponding disodium 2-sulfo-2-alkylalkanoates [RR'C (SO₃Na)CO₂Na]. Alkaline hydrolysis rates show that the sodium methyl esters are stable. Relative to the disodium salts, these compounds exhibit better wetting properties and more stable foams. Presented at the AOCS Meeting, Cincinnati, October 1965. E. Utiliz. Res. Dev. Div., ARS, USDA.     

Long Chaina-phosphono fatty acids,salts and esters

A series of α-phosphono fatty acids and their salts and esters was prepared from pelargonic, capric, lauric, myristic, palmitic, and stearic acids. In comparison to correspondingα-sulfo fatty acids theα-phosphono fatty acids are white solids of higher melting point, weaker acids, less hygroscopic, have a lower critical micelle concentration and are less resistant to hard water. Methyl, isopropyl, and amyl esters RCH. [PO (OH)₂] CO₂R′, were prepared from the α-phosphono fatty acids ; a sulfuric acid catalyst was required in the case of lower boiling alcohols. Hydrolysis studies with sodium methylα-phosphonomyristate showed the a-phosphono ester to be 50 times as stable towards alkali as the correspondingα-sulfo ester, but only one-tenth as stable toward acid hydrolysis. Wetting, foaming, detergent, and other surface active properties of theα-phosphono fatty acids, salts, and esters were measured and compared with those of analogousα-sulfo compounds.     

Autoxidation kinetics for fatty acids and their esters

The autoxidation kinetics for n-3 and n-6 polyunsaturated fatty acids and their esters, which are collectively referred to as polyunsaturated fatty acids (PUFA), were investigated. Changes in the amounts of unreacted n-6 PUFA during the entire period of autoxidation could be expressed by dY/dt−k ₁ Y(1 −Y), wereY was the fraction of unreacted PUFA,t was the time, andk ₁ was the rate constant. For n-3 PUFA, autoxidation had to be separated into two parts. The first half of autoxidation (Y ≥ 0.5) was expressed by the same equation as above, while the latter half (Y<0.5) relates to dY/dt=−k ₂ Y, wherek ₂ was the rate constant. The apparent activation energies and the frequency factors ofk ₁ andk ₂ were evaluated. The apparent activation energies were in a range of 50 to 60 kJ/mol for bothk ₁ andk ₂. The frequency factor became large as the number of double bonds of PUFA increased.     

Characterization of esters of fatty acids and dicarboxylic acids with Guerbet alcohols

Esters of some common fatty acids and diacids with Guerbet alcohols were prepared by p-toluenesulfonic acid-catalyzed esterification. Such materials are of interest in applications such as additives in various industrial products. Gas chromatography-mass spectrometry with chemical ionization using methane as ionization gas is an efficient characterization method for these Guerbet esters and diesters. Under these conditions, structural features such as molecular weight and site of branching are easily determined. The spectra of the present compounds were compared to those of di-Guerbet esters reported earlier and differences noted. The compounds were also characterized by ¹³C nuclear magnetic resonance spectroscopy.     

Addition of chlorine to unsaturated fatty acids and esters

Summary Methyl oleate, oleic acid, and ethyl linoleate were chlorinated with elemental chlorine at temperatures near −20°C. Approximately quantitative yields of the addition products were obtained, with little or no concurrent substitution. The products prepared in this manner had not previously been reported in the pure state. Two new compounds, ethyl tetrachlorostearate and tetrachlorostearic acid, were prepared. Methyl dichlorostearate was found to distil with no apparent decomposition at 190–200°C. under pressures below 1 mm. Removal of the chlorine atoms required more drastic conditions that removal of bromine atoms from the same positions and was accompanied by complicating side reactions. Journal Paper No. 755 of the Purdue University Agricultural Experiment Station, Lafayette, Ind.     

Autoxidation of methyl esters of cyclopentenyl fatty acids

The early stages of the autoxidation of methyl hydnocarpate, chaulmoograte and gorlate in air have been examined at 40, 60 and 80 C, and the initial products have been compared by several methods with those derived from methyl oleate and linoleate autoxidized at 60 C. To supplement information about oxygen absorption and peroxide development in relation to time, other information about the early products, and some information about the reduced products, have been obtained by ultraviolet (UV) and infrared (IR) spectrophotometry, and by thin layer chromatography (TLC). The kinetic and other data presented in this study strongly support the conclusion that the methyl esters of cyclopentenyl fatty acids yield initial autoxidation products that, although they are primarily peroxides, differ in some ways (as expected) in the kinetics of their formation and their chemical nature, compared to those of oleate and linoleate. Nevertheless, all the data obtained strongly support the surmise that the peroxides are formed autocatalytically by a chain mechanism, and that secondary products not derived from peroxide decomposition, are formed pari passu in lesser, but increasing amounts with increasing temperature, probably from free radical intermediates. The autoxidation of esters of cyclopentenyl fatty acids has potential importance in several ways, 3 of which are mentioned briefly.     

Hexitol and sucrose esters of α-sulfo fatty acids

Use of the α-sulfo acid, the acid chloride and the methyl ester was explored in the preparation of mannitol, sorbitol and sucrose esters of α-sulfopalmitic and α-sulfostearic acids. The products were difficult to purify because of solubilization of reactants. The α-sulfo esters are more soluble and more resistant to hydrolysis than hexitol and sucrose palmitates and stearates. Presented at the AOCS Meeting, New York, October 1968. ARS, USDA.     

Maleyl esters of monoglycerides of saturated fatty acids

Esterification between maleic anhydride and monoglycerides of saturated fatty acid has been studied. The nature of reaction vessels, temperature and reaction time have been evaluated in view of the product distribution in the final product. Concentration of monoesters (half-esters) diesters and dimers has been calculated and related to the reactants’ ratio, time and temperature of the esterification.     

Efficient synthesis of fatty monoglyceride sulfates from fatty acids and fatty acid methyl esters

An efficient high yield synthesis of fatty monoglyceride sulfates from fatty acids or fatty acid methyl esters, glycerine and chlorosulfuric acid in chloroform using stoichiometric amounts of reagents was developed. Sodium coco monoglyceride sulfate was prepared in 79% yield with 93% purity from coco fatty acids. Similarly, sodium palm kernel monoglyceride sulfate in 57% yield and sodium palm monoglyceride sulfate in 71% yield were obtained from palm kernel fatty acid methyl esters and palm fatty acids, respectively. This new synthetic method produced better quality products with higher active ingredients and improved yields without having to use such cost prohibitive, high purity, fatty acid monoglycerides, and it reduced the undesirable aqueous sodium sulfate by-product by 60% over a current commercial process. The product’s composition and purity were confirmed by cationic titration, infrared and C-13 NMR spectroscopy.     

Preparation of pure fatty acid methyl esters by countercurrent distribution

Summary Acetonitrile-pentane-hexane makes a desirable solvent system for preparation of pure methyl esters because of its immiscibility, selectivity toward unsaturation, low boiling point, stability, and ease of recovery. Since separated esters are removed from the apparatus dissolved in the pentane-hexane layer, successive batches may be fractionated without removing the acetonitrile layer from the instrument. Applications have been illustrated for the preparation of methyl linolenate from an 85% linolenate concentrate, methyl linoleate from safflower esters, and methyl arachidonate from pig liver lipids. This procedure provides a source of “natural” fatty acids with the double bond configuration unchanged, in contrast to those from the conventional bromination-debromination process. Automation of the process is completed by use of a recording refractometer which monitors concentration of solutions issuing from the extractor. Resolutions to be anticipated with lesser numbers of extraction tubes than 200 are calculated for an equal mixture of linoleate and linolenate. Presented at the 50th meeting, American Oil Chemists' Society, New Orleans, La., April 20–22, 1959. This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U.S. Department of Agriculture.     

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.     

Selective hydrogenation of fatty acids and methyl esters of fatty acids to obtain fatty alcohols–a review

In this paper, a review is presented of the evolution of different catalytic systems and operating conditions used in the selective hydrogenation of acids and esters of fatty acids to obtain fatty alcohols, which have broad industrial applications in the oleochemical industry. In addition, the current status of the different technologies used industrially (Lurgi, Davy and Henkel) for obtaining fatty alcohols, as well as major global sources of raw materials for the oleochemical industry are put forward. Finally, the reaction mechanisms of the selective hydrogenation process of oleic acid and methyl oleate to obtain the corresponding unsaturated alcohol as well as the new catalysts proposed by researchers are described. © 2016 Society of Chemical Industry