Studies on the reaction of aromatic bases with epoxides, and anucleophilic buffer for the acid-catalysed hydrolysis of epoxides

Abstract

The rates of nucleophillic reaction of pyridine and pyrazine with propylene and isobutylene oxides have been measured and compared with related data. No nucleophilic activity can be detected for tetramethylpyrazine, and this base forms an effective buffer in the pH range 3–4. A precision of 3–4% may be attained when rates of epoxide hydrolysis are measured in tetramethylpyrazine–perchlorate buffer solutions at pH 3·5. The rate coefficient for the acid-catalysed hydrolysis of 0·1M-aqueous isobutylene oxide at 25·7° is within the range 7·35 ± 0·24 I mol^–1 s^–1.