Marvin W. Formo

Directed interesterification in glycerides. Reaction in presence of added glycerol

SummaryDirected interesterification, in which ester-ester interchange is carried out in triglyceride mixtures with simultaneous crystallization of solid glycerides, has been applied to glyceride mixtures containing free hydroxyl groups. Solid glycerides precipitated from cottonseed oil with added glycerol were principally saturated diglycerides or saturated monoglycerides.The prineipal varables controlling the kind and proportion of solid precipitated during reaction from glycerides of a given original composition are the proportion of free alcohol groups, the time-temperature schedule for the reaction, and the method of seeding, if any, used to start the crystallization. The method makes it possible to segregate the high-melting and low-melting fatty acids of a fat practically completely into separate ester fractions.

Saponification value determination of difficultly saponifiable drying oil products

ConclusionsThe use of n-butyl alcohol as a solvent for saponification of a representative series of drying oils has been studied. It appears from this work that n-butyl alcoholic potassium hydroxide reagent, containing 5% of water added to the reaction mixture, gives very acceptable results based upon calculated saponification values.With the exception of maleic-modified oils of certain types, the solvent system of ethyl alcohol-pyridine exhibits excellent results based upon calculated values. However it has the disadvantages that it is a two-solvent system, and the pyridine must be of reagent grade to avoid end-point difficulties.The end-point in the butyl alcohol system is not as sharp as the normal saponification end-point in ethyl alcohol. This may be caused by the two-phase nature of the titration mixture. Addition of ethyl alcohol to the n-butyl alcoholic saponification reaction mixture gives improvement, although the end-point is not as sharp as in the regular ethyl alcohol system. Work is continuing on methods for improvement of the end-point.

Aliphatic urethanes. Effect of chain length on some physical properties

During a study of the thixotropic behavior of certain fatty materials a series of alkyl esters of substituted carbamic acids was prepared, and some of the physical properties were examined. Highly purified fatty aleohols and fatty isocyanates were reacted to give urethanes with from 8 to 22 carbon atoms in both the O-alkyl and N-alkyl groups.The melting points of the urethanes were dependent not only on the number of carbon atoms in the molecule but also on the symmetry of the moiety. In an homologous series the melting point increases with the number of carbon atoms. When symmetry is reached, there is a sharp increase in the melting point. After this the increase is less pronounced.The urethanes give thixotropic gels with ethyl alcohol, soybean oil, solvent-thinned resins, and other similar materials at concentrations as low as 0.5%. In general, better-defined crystal structure and poorer thixotropic properties were observed with an increase in symmetry.

Report of the Spectroscopy Committee—1952–1953

ConclusionsAs a result of the work herein reported, several conclusions can be drawn:a)Reasonably reproducible results, using A.O.C.S. Tentative Method Cd 7-48, revised May, 1951, can be obtained in the hands of experienced operators.b)No particular increase in either precision or accuracy is obtained by using a 45-min. isomerization time.c)Background corrections are unnecessary and probably undesirable when k′268 is greater than 1.0 and when k′315 is greater than 1.0.d)The present method is valueless for determining the composition of oils such as fish oils containing unsaturated acids of higher unsaturation than tetraene.e)Because of the presence of cis- and trans-isomers in all hydrogenated oils and the presence of iso-acids (position isomers) in hydrogenated oils which contained higher unsaturation than diene,i.e., linolenic or arachidonic acids, the present method is not satisfactory for the analysis of hydrogenated oils.f)As hydrogenated oils contain a mixture of cis- and trans-isomers, analysis of such samples by the techniques of the present method followed by calculations, using constants obtained from acids prepared by bromination-debromination methods (which have been shown to consist of cis- and trans-mixtures) might afford more satisfactory results than use of the constants prepared from the natural acids (the all cis-isomers). The results of these collaborative studies show that use of the debromination constants for the calculation on hydrogenated soybean oil instead of the recommended natural-acid constants did not give much more satisfactory results.

Segregation of fatty acids by preferential neutralization

SummaryIt has been shown that soybean fatty acids neutralized with a mixture of 40% of sodium hydroxide and 60% of barium hydroxide (on equivalent basis) form about 35% soluble soaps, which after separating from the insoluble soaps and splitting with sulfuric acid, form fatty acids of about 165 iodine number. From these acids a synthetic drying oil was prepared by esterification with glycerol which formed films almost as good as those of linseed oil.It was also shown that the same process applied to fish oil fatty acids, but using in this case 60% of sodium hydroxide and 40% of barium hydroxide, resulted in a yield of about 50% of fatty acids of about 283 iodine number, which when esterified with glycerol gave a very fast drying synthetic drying oil forming tack-free films.

Report of the color committee, 1953–1954

ConclusionsIt may be concluded from the work of the committee during the past year that1.eight of 18 instruments used in reporting requested data do not meet A.O.C.S. specifications. This conclusion is not necessarily a criticism of the instruments since only two of the instruments gave results materially out of line;2.the use of standardizing solutions holds promise;3.the possibility of using readings at only one or two appropriate wave-lengths suggests itself as a practical method of oil grading;4.additional committee work is necessary not only in the direction so far taken but in other directions which may hold promise of giving precise instrumental color values.