Thoria-Silica Catalysts for Ketimine Synthesis Prepared from Thorium Nitrate and Colloidal Silica

Abstract

Thoria-silica catalysts for the clehydrative condensation of benzophenone with ammonia were prepared from thorium nitrate and colloidal silica. Their physical properties are given in Table 1. Diphenylmethanimine was formed selectively over these catalysts at 280-450° C. Thoria-contents of 3-5% were sufficient to produce the active catalyst as shown in Fig.1. Crushing and attrition loss were minimized at the same region of ThO^2- contents (Table 1). Apparent equilibrium constant for the formation of diphenylmethanimine was estimated to be K=O.059.006 at 365° C for 3% ThO^2-SiO^2- catalyst.