Oxidative carbonylation of aromatic amines by selenium compounds

Various factors affecting the oxidative carbonylation of aromatic amines we re investigated in the presence of a catalyst system comprising SeO2 and al kali metal carbonate. An active catalyst, K2SeO3 was obtained from the reac tion of SeO2 and K2CO3 in methanol and the activity was tested. The effects of added alkali metal salts, solvents, aromatic amine substrates, molar ra tio of aniline to catalyst, temperature, and pressure on the catalytic acti vity were studied. The activation energy of the carbonylation of aniline wa s evaluated as 17.0 kcal/mol. The highest turnover frequency was found to b e 2082/h at aniline/catalyst = 12,800. A plausible mechanism for the carbon ylation of aniline to diphenyl urea and phenyl carbamate has also been prop osed. (C) 1999 Academic Press.