Winfred E. Parker

Application of urea complexes in the purification of fatty acids, esters, and alcohols. III. Concentrates of natural linoleic and linolenic acids

SummaryConcentrates of natural linoleic acid (linoleic acid content, 85–95%) have been prepared in 50–72% yields from corn oil fatty acids by preferential precipitation of the saturated and monounsaturated fatty acids at room temperature as their urea complexes.By a similar procedure, concentrates of natural linolenic acid (linolenic acid content, 87–89%) have been prepared in 55–61% yields from perilla oil fatty acids by preferential precipitation of the saturated, monounsaturated, and diunsaturated fatty acids. Although concentrates of natural linolenic acid containing only 66–70% linolenic acid were obtained from linseed oil fatty acids, yields were 87–90%.A levelling-off effect has been observed in the use of the preferential precipitation technique in raising the purity of concentrates of linoleic and linolenic acid. This parallels the experience in the purification of these acids by low-temperature crystallization.

Application of urea complexes in the purification of fatty acids, esters, and alcohols. II. Oleic acid and methyl oleate from olive oil

SummaryOleic acid and methyl oleate of high purity (97–99%) and substantially free (0.2% or less) of polyunsaturated contaminants have been isolated in 60–70% yield from the fatty acids or methyl esters of olive oil by procedures which require only one precipitation of urea complexes (single dose of urea technique) one low-temperature crystallization, and one fractional distillation. The best yields of the highest purity acids are obtained when saturates are removed by fractional crystallization prior to a final distillation. The urea complex separation technique can be applied directly to olive oil methanolysis reaction mixtures without prior isolation of the mixed methyl esters.Oleic acid or methyl oleate obtained by decomposition of urea complexes contains approximately 1% of polyunsaturated contaminants. After fractional distillation or crystallization to separate saturated acids the oleic content is about 90–97%. Such products are satisfactory for many uses and in their preparation low-temperature (−50° or lower) crystallizations are not required.Solution and slurry techniques have been studied for the preparation of urea complexes from olive oil acids or esters. The former technique is preferred when a maximum of about 1,000 grams of acids or esters are to be processed. The latter is preferred for larger size experiments mainly because the volume of methanol employed is cut in half, the time is shorter, and also because yields are about 5% higher.

Application of urea complexes in the purification of fatty acids, esters, and alcohols. I. Oleic acid from inedible animal fats

SummaryUrea complex formation has been employed in the preparation of purified oleic acid (oleic acid content, 80–95%) from various grades of inedible animal fats and red oils. Since the urea complex of oleic acid forms in good yield at room temperature, low temperatures are not required in the isolation procedure. Yields of oleic acid are equal to or lower than those obtained by conventional low-temperature crystallization procedures, but the preparation of a polyunsaturate-free oleic acid is apparently not possible by urea complex formation alone. The separation of polyunsaturated acids from oleic acid by urea complex formation is more convenient than but not as efficient as by solvent crystallization, but separation of saturated acids from unsaturated acids is less convenient.Advantages and disadvantages in using urea in the preparation of purified oleic acid are briefly discussed.

Acid-catalyzed addition of phenols and phenyl ethers to oleic acid

SummaryPhenols and phenyl ethers have been added to oleic acid, using both sulfuric acid and a strong acid cation exchange resin as condensing agents. By-product formation during the condensations resulted in low yields and products which were difficult to purify. Infrared spectra were used to identify the various products and to show that ring isomers form. Infrared spectra also assisted in identifying by-products and permitted differentiation between the two strong acid condensing agents.

A note on improved isolation of concentrates of linolenic acid and ethyl linolenate from linseed oil

SummaryLinolenic acid and ethyl linolenate concentrates (80–85%) have been obtained from linseed oil fatty acids or ethyl esters in 50–60% yield, based on linolenic recovery, by a single urea complex separation at room temperature.

Lubricants. I. Preparation and properties of benzyl and substituted benzyl esters of dilinoleic acid

Benzyl and substituted benzyl esters of dilinoleic acid and of hydrogenated dilinoleic acid have been prepared in good yield. Some of the chemical characteristics and physical properties of the resulting products have been measured including a study of their thermal stability by thermogravimetry. Also, they have been examined by several of the bench tests used in laboratory evaluation of lubricants. Several of them compare favorably with control materials used in the study.

Rubber swell as a function of fatty acid ester chain length

A study was made of the relationship between the structure of some fatty acid esters of varying chain length and their swelling effect on standard nitrile rubber samples. The esters evaluated were: methyl esters of caprylic, capric, lauric, myristic, palmitic and isostearic acids;n-butyl, isobutyl,n-octyl, octadecyl, “tallow” and 2,2-dimethyl-1,3-propanediol esters of lauric acid and tetradecyl acetate. Federal test methods for aircraft turbine lubricants were used for the evaluations. In the esters the swelling was higher with type L rubber than with type H. The lower the equivalent weight of the ester, the higher the swell with both types of rubber. Branching in the alcohol moiety lowered the swell. Deswelling (desorption) in air of the swelled samples was also investigated. Methyl myristate, methyl palmitate and the long chain laurate esters meet MIL-L-23699 military specifications for type H rubbers. In type L rubbers the swelling is too high to meet specifications.

Bench-scale evaluation of nonvolatilealpha-branched chain fatty esters as potential lubricants

Several nonvolatile esters of α-branched fatty acids have been prepared in a highly purified state and examined by bench-scale tests of the sort usually used in the preliminary evaluation of lubricants. Viscosity characteristics and Shell-Boerlage wear-test results for these compounds are comparable with those of compounds used in the manufacture of modern synthetic lubricants. These esters are substantially superior to one such compound in thermal stability and resistance to acid hydrolysis.