New catalytic system of N,N′-diphenylurea synthesis from nitrobenzene, carbon monoxide and water or aniline

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 1996-06, Vol.109 (2), p.119-125
• Main Authors: Macho, Vendelín, Králik, Milan, Halmo, František
• Format: Article
• Language: English
• Subjects: Aniline; Carbonylation; Catalysis; Catalysts: preparations and properties; Chemistry; Exact sciences and technology; General and physical chemistry; Methyl- N-phenyl carbamate; N,N′-Diphenylurea; Nitrobenzene; Reduction; Sulfur compounds; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Vanadium
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/1381-1169(96)00006-4

The influence of aniline (PhNH 2) on the reductive carbonylation of nitrobenzene (PhNO 2) by carbon monoxide and an excess of methanol, catalyzed by ( w w % with respect to PhNO 2): sulfur (10), sodium methoxide (2), ammonium metavanadate (0.1), at 423 ± 2 K and starting pressure of CO 13 MPa (298 K) was investigated. 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 water, PhNO 2 is carbonylatively reduced to PhNH 2, and DPU is formed by 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 carbonylation of PhNO 2 in the presence of methanol. The efficiency of other tested sulfur compounds increases in the sequence: S < CS 2 ⪡ Na 2S < H 2S < COS. The dominant effect of sulfur components, a basic environment as well as the promotive effect of vanadium(V) compounds on the reductive carbonylation and carbonylative reduction of nitrocompounds has been confirmed.