Esters are usually synthesized from an alcohol and an acid, most frequently, a carboxylic acid. In some cases, an epoxide is used instead of the alcohol; or an acid halide or anhydride replaces the ...

39 kilograms of Acetic Anhydride, and 3.2 kilograms of a white powder identified as calcium oxide. These chemicals are critical precursors for the synthesis of narcotics like heroin," police said.