39920-84-8Relevant articles and documents
Diazoacetaldehyde: Completion of the rate profile for hydration of its photo-Wolff rearrangement product, ketene, in aqueous solutio and kinetics and mechanism of acid-catalyzed hydrolysis of the diazoaldehyde
Chiang,Kresge,Popik
, p. 1107 - 1109 (2007/10/03)
Ketene was generated flash photolytically by the photo-Wolff reaction of diazoacetaldehyde and rates of its hydration to acetic acid were measured in dilute aqueous sodium hydroxide solution. The results give the isotope effect kHO/kDO = 0.87, on the hydroxide-ion catalytic coefficient for this reaction, and, together with literature information they provide a complete rate law for the hydration of ketene in aqueous solution promoted by solvent related species: kobs/s-1 = 1.01 × 104[H+] + 3.65 × 101 + 5.26 × 104[HO-]. Rates of hydrolysis of diazoacetaldehyde in dilute perchloric acid solution were also measured and an inverse hydronium ion isotope effect was found: kH+/ kD+ = 0.55. That, plus the fact that hydrogen exchange of the diazo hydrogen atom of diazoacetaldehyde takes place more rapidly than its hydrolysis, shows that hydrolysis occurs through a mechanism involving pre-equilibnum protonation of diazo carbon followed by rate-determining loss of nitrogen.
