Dk. Mukherjee, Soluble rhodium catalyst for carbonylation reaction: Kinetics and mechanism of diphenylurea formation, I J CHEM A, 40(11), 2001, pp. 1176-1181
Citations number
30
Categorie Soggetti
Chemistry
Journal title
INDIAN JOURNAL OF CHEMISTRY SECTION A-INORGANIC BIO-INORGANIC PHYSICAL THEORETICAL & ANALYTICAL CHEMISTRY
The preparation of [RhA(CO)Py], having the same coordination environment as
[RhA(CO)PPh3], has been reported. Its catalytic behaviour under various re
action conditions and methanol concentrations for the carbonylation of nitr
obenzene at low temperature and atmospheric or elevated pressure has been s
tudied. N,N'-diphenylurea (DPU) is the main product under moderate carbon m
onoxide pressure (P-co), while methyl-N-phenyl carbamate (MPC) is formed pr
edominantly as P-co and methanol concentration is increased. Spectroscopic
and kinetic studies show that the reaction proceeds through a species [Rh(A
)(C(O)OCH3)(2)] and the isocyanate formed at an intermediate stage is immed
iately scavenged by excess amine to form N,N'-diphenylurea. A tentative rea
ction mechanism based on the identification of reactive intermediates has b
een proposed for the carbonylation process.