Ethereal Sulfuric Acids

ETHEREAL SULFURIC ACIDS, discovered in urine by Baumann, are esters of sulfuric acid with various phenols, which are products of putrefaction in the intestines. The formation of ethereal sulfuric acids occurs mainly in the liver and can also occur in the spleen, leading to the detoxification of poisonous phenols. Ethereal sulfuric acids are excreted from the body primarily in urine; they have been found in small quantities in human sweat, bile, blood serum, the secretion of sheep skin glands, and in the urine of newborns. The content of ethereal sulfuric acids in urine fluctuates greatly even under normal conditions depending on diet; there are more of them in the urine of herbivores than in carnivores; on average, their content in the daily amount of human urine ranges from 0.1 to 0.6 g; the excretion of ethereal sulfuric acids increases with increased putrefaction in the intestines, in cases of abscesses, gangrene, tumor decay, etc. In their free state, ethereal sulfuric acids are very unstable; in urine, they are found mainly in the form of potassium salts. The latter crystallize well, are easily soluble in water, and are insoluble in cold alcohol. Salts of ethereal sulfuric acids, when boiled with water, especially in the presence of mineral acids, easily hydrolyze to form free H₂SO₄, but brief boiling in a strongly alkaline reaction or in the presence of organic acids causes only insignificant decomposition. The most frequently encountered ethereal sulfuric acids are the salts of cresol-sulfuric (CH₃-C₆H₄O-SO₂OK) and phenol-sulfuric (C₆H₅-O-SO₂OK) acids. Cresol-sulfuric acid predominates in quantity. Phenol-sulfuric acid in the form of a potassium salt is found in negligible quantities in horse urine, and in larger quantities in human urine; it increases with the administration of phenol or lysol per os and with the use of phenol in wound dressings. Cresol-sulfuric acid is found in the urine of humans, horses, and other mammals, predominantly in the form of the para-isomer; the ortho-isomer has also been found in human urine. Pyrocatechol, mono- and disulfuric acids are contained in the urine of horses, and sometimes in human urine; they are absent during a strict meat diet. Indoxyl-sulfuric acid—see Urine. Skatoxyl-sulfuric acid, C₉H₉O₄NS, is found in normal urine and was isolated from the urine of diabetics. An aqueous solution of its potassium salt gives a red color with concentrated HCl, a violet color with a solution of FeCl₃, and a red color with concentrated HNO₃. Regarding methods of detection and quantitative determination of ethereal sulfuric acids—see Urine, Blood.