1911 Encyclopædia Britannica/Mucic Acid

MUCIC ACID, C₆H₁₀O₈ or HOOC⋅(CHOH)₄·COOH, is obtained by the oxidation of milk, sugar, dulcite, galactose, quercite and most varieties of gum by nitric acid. It forms a crystalline powder which melts at 213° C. It is insoluble in alcohol, and nearly insoluble in cold water. When heated with pyridine to 140° C., it is converted into allomucic acid. When digested with fuming hydrochloric acid for some time it is converted into αα′ furfurane dicarboxylic acid (see Furfurane); while on heating with barium sulphide it is transformed into α—thiophene carboxylic acid (see Thiophene). The ammonium salt yields on dry distillation carbon dioxide, ammonia, pyrrol and other substances. The acid when fused with caustic alkalies yields oxalic acid.