Kinetics and mechanism of 1,3-dioxolane formation from substituted benzaldehydes with ethylene oxide in the presence of tetrabutylammonium halides

Kinetic measurements of the reaction among eight substituted benzaldehydes and ethylene oxide in the presence of catalytic amounts of tetrabutylammonium halides have been performed. With poor electrophilic aldehydes the rate-determining step of the reaction is the nucleophilic attack of the halogeno ethoxide anion to the carbonyl group while with rich electrophilic aldehydes the rate-determining step becomes the ring opening of ethylene oxide by the halide ion. Hammett correlations and kinetic results confirm these proposed mechanisms.