Application of the line-width method to the spectrochemical analysis of oils,fats, and related substances

Summary The application of the line-width method to the spectrochemical analysis of oils and fats in conjunction with the use of an improved ashing technique has been shown to permit the quantitative determination of copper, iron, manganese, nickel, and tin in quantities as low as 1 part in 10 million. The procedure has been critically examined by precision tests on commercial and experimental samples, by accuracy tests on synthetic samples, and by recovery tests. Results of actual analysis of 30 vegetable oils and fats indicate the use of the procedure as a research tool. The procedure may be used for the trace element analysis of organic material low in ash content. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Determination of nitrogen in vegetable oils

Summary Hydrolysis with alcoholic hydrochloric acid quantitatively converts the nitrogen of crude soybean lecithin to a water-dispersible form. This alcoholic-acid hydrolysis also converts the nitrogen in large amounts of crude soybean oil to a water-dispersible form which can then be separated and digested with a minimum amount of sulfuric acid by the Kjeldahl procedure. With careful control of both reagents and blank determinations, as little as 0.1 mg. of nitrogen can be measured with a precision of about 10%. The details of the method are given and it is applied to a series of soybean oils after various treatments and to three kinds of salad oils. Presented by Dr. R. T. Milner of the Northern Regional Research Laboratory at the Spring Meeting of the American Oil Chemists' Society at New Orleans, Louisiana, May 20–22, 1947. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry. Agricultural Research Administration, U. S. Department of Agriculture.     

Preparation of hydroxy acids by sulfation of oleic and linoleic acids

Summary Monohydroxystearic acids were prepared by sulfation and subsequent hydrolysis of oleic acid, and the effect of reaction conditions on yield was studied. Monohydroxystearic acids were obtained from commercial oleic acid in 72% yield and from pure oleic acid in 86% yield. Conditions for the best yields apparently gave increased amounts of isomeric hydroxy acids. Hydroxy acids prepared by the sulfation and subsequent hydrolysis of linoleic acid were converted to methyl esters, and purified by fractional distillation and low temperature crystallization. Experimental evidence indicates that sulfuric acid reacts with one double bond of linoleic acid to form isomeric monohydroxyoleic acids and with both double bonds to form dihydroxystearic acids. The by-products formed by the sulfation of linoleic acid include both ester-type polymers and additional polymeric material which cannot be converted to monomers by alkaline saponification. When commercial oleic acid is sulfated and subsequently hydrolyzed, the monohydroxystearic acid thus obtained presumably contains monohydroxyoleic acids and dihydroxystearic acids resulting from the linoleic acid present in the starting material. The formation of an unsaponifiable polymer during the sulfation of linoleic acid accounts in part for the lower yield of hydroxy acids obtained from commercial oleic acid, as compared with that of purified oleic acid. One of the laboratories of the Bureau of Agricultural and Industrial Ohemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

STABILITY OF A KILN STACK*

Mathematical proof is presented that the wind pressure on a round stack is two-thirds that of a square stack with the wind square to one side. A reconsideration is given of a stack section¹ where tension occurred, and a correction is presented. A convenient method and its application is also given for calculating the stability of a kiln stack upon the soil. The application of the “kern” theorem is discussed, using the kern for the worst condition, viz., with wind blowing diagonally against a square stack.