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
Glutaconic acid Glutaconic acid "trans"-Glutaconic acid is an organic compound with formula HOCCH=CHCHCOH. This dicarboxylic acid exists as a colorless solid and is related to the saturated chemical glutaric acid, HOCC(CH)COH. Esters and salts of glutaconic acid are called glutaconates. The geometric isomer, "cis"-glutaconic acid, has a noticeably lower melting point (130–132 °C). It can be prepared by bromination of levulinic acid followed by treatment of the dibromoketone with potassium carbonate. Glutaconic anhydride, which forms by dehydration the diacid, exists mainly as the dicarbonyl tautomer in solution. It is a colorless solid melting at 77–82 °C. Either the "cis" or "trans" diacid