RUTHENIUM(III)-SCHIFF BASE COMPLEX-CATALYZED CARBONYLATION OF NITROBENZENE TO GIVE PHENYLURETHANE

Ruthenium(III)-Schiff base complexes of the type [Ru(III)L X(n = 1 or 2)] where L = Schiff base such as bis(naphthaldehyde)-o-phenylenediimine (naphoph), bis(naphthaldehyde)ethylene-diimine (naphen), bis(naphthaldehyde) propylenediimine (naphprop) and bis( naphthaldehyde)-diethylenetriimine (naphdien); X = Cl; catalyze the carbonylation of nitrobenzene at 160-degrees-C and 15 atm CO partial pressure in ethanol to give a clean product, phenylurethane. The turnover rates observed after a reaction time of 2 h are in the range 5-22 mol product per mol catalyst per hour. The activity of the Ru(III)-Schiff base complexes screened in the carbonylation of nitrobenzene decrease in the following order: K[Ru(naphoph)Cl2] > K[Ru(naphen)Cl2] > K[Ru(naphprop)Cl2] > [Ru(naphdien)Cl].