Kinetics of Hydrolysis of Acetaldehyde Ethyl Hemiacetal in Aqueous Solution

Article abstract of DOI:10.1021/jo00225a007

Rates of hydrolysis of acetaldehyde ethyl hemiacetal were measured in aqueous buffer solutions of acetic and formic acids and semicarbazide hydrochloride at 25 deg C.The catalytic coefficients so obtained are all greater than the corresponding rate constants for acetaldehyde diethyl acetal and ethyl vinyl ether hydrolysis, thus supporting the commonly held belief that hemiacetal formation is slow and its subsequent decomposition is fast in these two reactions.A correlation of rate constants for hydrolysis of acetals and the corresponding hemiacetals indicates, however, that the difference between the rates of these reactions decreases with increasing reactivity and that hemiacetal or hemiketal hydrolysis will become the rate-determining step in the hydrolysis of sufficiently reactive vinyl ethers, acetals, and ketals.