Oil Chemists Hear New Developments A STAFF REPORT
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"ETERGENTS, extraction, flavor problems, and the modification of oils were some of the topics dealt with before the American Oil Chemists Society's twentythird fall meeting in Chicago, Oct. 31 to N o v . 3. Synthetic detergents came in for a strong share of attention. Comparisons were made with soap and suggestions offered for taking advantage of the superior characteristics of both through combinations. A number of test methods were described. Soaps are superior under ideal conditions with soft water, according to the report of H. C. Borghetty and C. A. Bergmann of General Dyestuffs Corp., while the detergents are superior with hard water. Between, the two extremes the competition is strongest. Some of the detergents are so strongly built with alkali, to give them cleansing properties equal to soap, that they are harmful to the skin and may have other undesirable properties, it was stated. This is bad for the indust ry as a whole. The best answer, it was suggested, is combination. The addition of detergents to soap to disperse the lime soaps is very valuable. T h e ternary systems combining soap, detergents. and polyphosphates were suggested as particularly effective. Soap and detergent combinations were also recommended in a report by L. H Flett, O. M. Morgan, and L. S. Hoyt. National Aniline Division of Allied Chemical and D y e Corp. The detergents, it was said, form soluble calcium and magnesium compounds which aid rather than obstruct cleansing. Such combinations were reported also to be very effective in cold water. Certain detergents can be added which give mixtures superior to soap in solubility and
rinsing characteristics, also, while the soap imparts the desirable qualities of lubrication, plasticity, and slipperiness not possessed by the synthetic. Extraction H . B. Coats, Blaw-Knox Division, presented papers in collaboration with George Karnofsky and M. R. Wingard, respectively, of the same company, on solvent extraction. T h e first of these dealt with studies directed toward the understanding of the process by which solvent extracts the oil from oil-bearing materials. It was shown that the theory of molecular diffusion does not explain all the facts, even when allowance it made for complexity of structure. Through experiments in which flakes were soaked in miscellas of differenl concentrations prior to extraction with pure solvent, it was demonstrated that residual oil is primarily a function of total time of extraction and to a smallei degree dependent on the concentration of the extracting solution. An explanation was offered in terms of a reduced solution rate of the oil associated with phosphatides and othrr nonoil extractives. The second paper dealt with the effect of particle size on extraction rate. In this work, both flakes and grits were studied. Extraction rates for the former were correlated with thickness measurements and for the latter with seive opening sizes. It was shown that the extraction rate is inversely proportional t o the "effective extraction size" to a power n. The value of n is characteristic of the type of preparation and of the material. E. B. Moore, Lever Brothers Co., described a commercial installation for the decolorization of tallow by liquid-liquid
Norris Embree, Distillation Products, Inc., with V, C. Mehlenbacher, Swift & Co»9 AOCS president*
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W. and
extraction with propane, concluding that this is a practical commercial process and is more effective than bleaching with chemical agents or color absorbents. W. D. Harris and J. W. Hayward, Texas A&M, described a system wherein a considerable portion of the solvent— isopropyl alcohol or acetone—used in extracting cottonseed oil from uncooked meats, was separated from the oil by cooling and recirculated through the extractor without evaporation. A high yield of oil of superior grade was obtained with the use of less solvent than required in the conventional evaporation system. Flavor Problem T h e problem of the deterioration, oi flavor in soybean oil has been receiving the attention of oil chemists for some rime. C. D . Evans, A. W. Schwab, and Helen Moser, of the Northern Regional Research Laboratory, offered two contributions to this study in collaboration with Patricia Cooney and with J . E. Hawley and E . H. Melvin, respectively. In the first, taste panel studies of the flavor and oxidative characteristics of soybean oils fractionated with furfural indicated that upon storage the rafrinate fractions did not develop the off-flavore typical of soybean oil to the same extent as did the furfural extract or the original unfractionated oil. Although the resistance of the raffinate fractions t o oxidation was low, the addition of stabilizers such as phosphatides, a-tocopherol. and citric acid markedly improved the stability. Citric acid and phosphatides are believed t o function in part as metal scavengers. I n the second N R R L paper on the flavor problem, it was concluded that all
B. White, Food and Drug C. D . Lowry, Universal Oil
CHEMICAL
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Administration, Products Co.
ENGINEERING
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were useful in some cases aa resin-fret* drying oil extenders. When the use of petroleum drying oils in printing inks has been improved to overcome inferiorities in color, odor, and subresistance, with respect t o triglycerides, they will offer strong competition, according to W. C. Walker of the National Printing Ink Institute. Chemicals
H. T. Spannuth, Wilson and Co., program chairman, gives A* F. Kapecki, Wurster and Sanger, registration chairman, a hand with finishing up the meeting figures, as A. A. Kiess, Armour and C o . . hotel arrangements chairman, approves metal contamination is probably detrimental to the stability of soybean oil. Iron was given particular attention and a high degree of correlation was shown between stability and metal content in both laboratory-renm d oils and oils containing added iron and other metals Copper, cobalt, and zinc were all found to promote the formation of off-flavors Taste panel studies indicated iron to be detrimental in the concentration of one part in ten million, while copper was detrimental in one part in 100 million. Ascorbyl palmitate, potassium ascorbyl palmitate, and ascorbic, tartaric, citric, and phosphoric acids were found to be the most effective metal deactivators in lard from among a group of compounds studied by S. G. Morris, J. S. Myers, Mary Kip, and R. W. Riemenschneider of the Eastern Regional Research Laboratory. The more powerful antioxidants, however, were generally poor metal deactivators and in the presence of traces of metallic pro-oxidants became relatively ineffective unless metal deactivators were also added. Modification and Conversion Menhaden oil, the lowest priced glyceride available in commercial quantities was shown by E. H. Pryde, D u Pont, to be a source of excellent yields of high molecular weight unsaturated alcohols, by means of sodium reduction. This method gave 86 t o 88% yields of these alcohols having iodine values in the range of 155 to 170. It was indicated that probably about o n e half of the polyolefinic material could be isomerized during the process to give molecules containing conjugated double bonds. T h e alcohols thus formed could then be V O L U M E
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selectively hydrogenated eatalyticallv to give a colorless product substantially free from odor with an average of one double bond per molecule. Hydrogenation plants were the subject of a paper by F. B. White, FosterWheeler Corp., and S. Faulkner, E. F Drew and Co. Of the types of plants available, it was stated, the one employing gas re-circulation accompained by cooling and rescrubbing of the hydrogen before re-use gives more uniform hardening time, better selectivity, lower free fatty acid content, and generally superior over-all results for selective hydrogenation of refined, bleached oils. Continuous hydrogenation with a fixed catalyst does not produce a uniform selectively hardened product, it was reported, but is satisfactory for nonselective work. Thf type and kind of catalyst were said to affect selectivity. Hydrogen, free from sulfur compounds, and carbon monoxide were recommended but nitrogen up to 5% or higher was considered permissible. A selective esterification of tall oil. which contains 40 to 45% resin acids, related to rosin or abeitic acids, and 35 to 45% fatty acids to get a clean separation of the fatty esters, was reported by L. H . Dunlap, L. V. Hassel, and Jane Maxwell, Armstrong Cork Co. Pentaerythritol was the alcohol used. An appreciable difference in rates of esterification of the two types of acids was found even at high temperatures. At 180° C. the fatty acids were almost completely esterified before any appreciable amount of resin acids was affected. While lead naphthenate drier was used as a catalyst, one study without it indicated n o justification for its use as a n esterification catalyst in this system. T h e fatty esters
NOVEMBER
14,
1949
in
Foods
The Food and Drug Administration if not opposed to the addition of "chemicals" per se to foods, according to W B. White, of the USFDA, but they have always "viewed with a fishy e y e " proposals for indiscriminate use of chemicals where adequate proof of their harmlessness is lacking. The present Food, Drug, and Cosmetic Act places squarely upon the manufacturer the obligation for conducting adequate toxicity studies OD the chemicals he proposes for food use before he sells it to food manufacturers, said Mr. White. H e recommended that all interested should consult the Food, Drug and Cosmetic Law Quarterly, October 1949, for a full discussion of the proper procedure. A paper describing the use of butyl hydroxyanisole as an antioxidant useful in prolonging the shelf life of potato chips fried in vegetable oils was presented by J. E . Magoffin and R. W Bentz, Tennessee Eastman Corp. Data indicated that B H A possesses "carry through" antioxidant properties n o t only in animal fats but also in vegetable oik and shortenings. Data indicated thai the addition of propyl gallate and citricacid as synergists t o B H A increased the carry-through. In commercial batch fryers of 600-pound capacity, up t o 5,000 pounds of potatoes was fried before the frier was emptied and the fat discarded. T h e activities of molecularly distilled monoglycerides, produced by the catalyzed reaction of glycerol with fats or fatty acids, as shortenings were described b y N . H . Kuhrt and E . A. Welch, Distillation Products, Inc. It was said that their activities in this respect, in baked goods, were similar t o but greater than those of mixtures of monoglycerides. Texture, volume, and other properties of cakes were reported improved with quite small amounts of distilled monoglycerides in the presence of a full quantity of shortening of which a triglyceride is the major component. Recent installations for the production of fatty nitriles and amines were described by H. P. Young and Ralph Potts, Armour and Co., and a plant trip was arranged for showing the guests the new Armour plant at McCook, 111., in action. T h e Food and Container Institute, U. S. Quartermaster Depot, was also host t o a plant tour. Announcement was made that the fall meeting of 1950 of the AOCS will b e held in San Francisco. 3353
