Selectivity enhancing effects of carbon dioxide in vapour-phase nucleophilic chlorobenzene substitutions, catalysed by copper-containing zeolites

Abstract

The nucleophilic substitutions of chlorobenzene with ammonia and water, leading to aniline and phenol respectively, were investigated using copper-exchanged zeolites. In these reactions, the performance of carbon dioxide as a carrier gas was compared with that of nitrogen. The conversions were slightly influenced; the substitution selectivity, however, increased rapidly with CO₂, as the reduction to benzene was decreased substantially. In amination experiments, the benzene formation was decreased by a factor 2–3 with copper-Y. In hydrolysis experiments, the phenol selectivity increased from 85–90% (using N₂) to 98–100% (using CO₂) with copper mordenite at 400°C.