The kinetics of acid-catalyzed hydrolysis of 2, 3-dimethoxy-1, 3-butadiene (1) to 3-methoxy-3- buten-2-one (2) and the subsequent 104 times slower conversion of the latter to biacetyl (3): were studied in aqueous solution at 25° C. Both stages of this process give substantial hydrogen ion isotope effects, for Stage I and for Stage II, and Stage I shows general acid catalysis in formic and acetic acid buffers; both stages are therefore assigned the ...