Condensation of diethylfumarate and diethylmalonate to propane-1,1,2,3 tetracarboxylate. Catalyst specifications: Catalytic entity: Ph(CH2)-N+(PhmSO3-)3 · EtO- (1 milieq of EtO-), additive:: Sodium meta silicate 1 gm, Support: Charcoal 5 gm, Group IIA metal salt: Barium hydroxide, Method of preparation: Deposition precipitation. Procedure: in a 100-ml flask fitted with an efficient reflux condenser, magnetic stirrer bar and dropping funnel was charged 5 gm of catalyst. With stirring 1.6 g (0.001 mol) diethylmalonate and 25 ml dry ethanol was added. Reaction mixture was warmed and 1.4 gm (0.0081 mol) diethyl fumarate was added. Mixture was refluxed for 8 hours. Reaction mixture was cooled and suspension was centrifuged to recover catalyst. Analysis of reaction liquid indicated 90 % conversion for diethylmalonate. Product was distilled under vacuum 8 mm at 180-190°C to obtain propane-1,1,2,3 tetracarboxylate 85% yield. Catalyst was recovered and washed with ethanol, diethyl ether and dried under vacuum. Catalyst was recycled to obtain equivalent activity.
