Abstracts

Journal of the American Oil Chemists' Society -     

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.     

UVERITE—A MILL ADDITION OPACIFIER FOR PORCELAIN ENAMEL*

Uverite is the trade name for an antimony-titanium opacifier, having an approximate formula of 7CaO·CaF₂·6TiO₂·2Sb₂O₅. When compared with tin oxide in a range of commercial enamels, it has proved to be equivalent in its effect on opacity, color, gloss, firing range, general workability, and durability.     

NOTES ON REACTION BETWEEN MgO AND VARIOUS TYPES OF REFRACTORIES *

Samples of high-heat duty, superduty, 60% Al₂O₃, 70% Al₂O₃, 90% Al₂O₃, fused-alumina, kaolin base, kyanite base, chrome magnesite, silicon carbide, zircon, and chrome-magnesite compositions were tested for reaction with MgO at temperatures of 2200°, 2600°, and 2800°F. (1205°, 1425°, and 1540°C.). Silicon carbide and zircon refractories showed a slight reaction at 2800°F. and none at 2600°F. or at 2200°F. Commercial grades of firebrick containing 60% or more of Al₂O₃ in contact with powdered magnesia showed no reaction up to 2800°F.     

Comparison of methods for the determination of glycerol by acetylation

Summary A method for the determination of glycerol has been presented in which the acetylation is performed with a reagent consisting of acetic anhydride in pyridine. Typical data obtained by this procedure and other accepted methods are shown. The proposed procedure is simpler, more rapid, and more accurate than the conventional acetin method.     

SOME CHARACTERISTICS OF ILLINOIS POTTERY CLAY*

Four Illinois pottery clays, representing two extreme types and two intermediate types, are described. Porosity and thermal expansion tests were made on the raw and fired clays. The temperature of the inversion of low to high cristobalite in these clays is much lower than is usually accepted for the lower limit of this inversion because cristobalite is formed at low temperatures. A limited amount of data was obtained on the volume changes of raw clays during firing, the organic matter content, and thermal dissociation.