NEW CATALYTIC-SYSTEM OF N,N'-DIPHENYLUREA SYNTHESIS FROM NITROBENZENE, CARBON-MONOXIDE AND WATER OR ANILINE

The influence of aniline (PhNH(2)) on the reductive carbonylation of n itrobenzene (PhNO(2)) by carbon monoxide and an excess of methanol, ca talyzed by (w/w % with respect to PhNO(2)): sulfur (10), sodium methox ide (2), ammonium metavanadate (0.1), at 423 +/- 2 K and starting pres sure of CO 13 MPa (298 K) was investi gated. Methyl-N-phenylcarbamate (MPC) is formed predominantly, via the formation of the intermediate N ,N'-diphenylurea (DPU) which is subsequently alcoholyzed by methanol. N-Phenylformamide (NPF) is the main by product. In the presence of wat er, PhNO(2) is carbonylatively reduced to PhNH(2), and DPU is formed b y reductive carbonylation from PhNO(2), CO and PhNH(2). Thus, DPU can be obtained directly from PhNO(2) in a one-step process. If an excess of PhNH(2) is applied, the conversion of PhNO(2) is practically total, a small amount of NPF is formed as in the case of the reductive carbo nylation of PhNO(2) in the presence of methanol. The efficiency of oth er tested sulfur compounds increases in the sequence: S < CS2 << Na2S < H2S < COS. The dominant effect of sulfur components, a basic environ ment as well as the promotive effect of vanadium(V) compounds on the r eductive carbonylation and carbonylative reduction of nitrocompounds h as been confirmed.