Organic acid anhydride Organic acid anhydride An organic acid anhydride is an acid anhydride that is an organic compound. An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. A common type of organic acid anhydride is a carboxylic anhydride, where the parent acid is a carboxylic acid, the formula of the anhydride being (RC(O))O. Symmetrical acid anhydrides of this type are named by replacing the word "acid" in the name of the parent carboxylic acid by the word "anhydride". Thus, (CHCO)O is called "acetic anhydride." Mixed (or unsymmetrical) acid anhydrides, such as acetic formic anhydride
Isophthalic acid Isophthalic acid Isophthalic acid is an organic compound with the formula CH(COH). This colorless solid is an isomer of phthalic acid and terephthalic acid. The main industrial uses of purified isophthalic acid are for the production of polyethylene terephthalate (PET) resin and for the production of unsaturated polyester resin (UPR) and other types of coating resins. Isophthalic acid is produced on the billion kilogram per year scale by oxidizing meta-xylene using oxygen. The process employs a cobalt-manganese catalyst. The world's largest producer of isophthalic acid is Lotte Chemical Corporation. In the laboratory, chromic acid can be used as the oxidant.