The Rearrangements of Potassium 1- and 2-Naphthoates

Abstract

The rearrangement of potassium 1- and 2-naphthoates was investigated in the presence of cadmium oxide under the pressure of carbon dioxide. The disproportionation of 1-naphthoate took place after it melted at 400°C. Various naphthalenecarboxylates were initially produced, and as the reaction proceeded the amounts of these carboxylates decreased rapidly, and simultaneously those of 2-naphthoate and 2, 6-naphthalenedicarkoxylate increased. When the reaction was carried out at a lower temperature around 400°C, the rearrangement virtually stopped to produce the 2-naphthoate.
Potassium 2-naphthoate was hardly fusible and thus less reactive. Even at 480°C for 3h, about 20mol% of 2-naphthoate remained unreacted. The poor fusibility of 2-naphthoate was much improved by addition of 1-naphthoate, and the rearrangement reaction proceeded very smoothly. This observation suggests, that the modified fusibility of the starting material is required for the rearrangement to take place.
A possible reaction mechanism for the rearrangement reactions is proposed.