ACTIVITIES OF Co(II) SCHIFF BASE COMPLEXES IN THE REDOX CARBONYLATION OF ANILINE AND NITROBENZENE TO METHYL N-PHENYL CARBAMATE

摘要

The series of cobalt(II) complexes with different Schiff base ligands was synthesized and used as catalyst for the redox carbonylation of aniline and nitrobenzene. Effects of reaction temperature, CO pressure, promoter, and catalyst additions on the conversion of substrate were studied. When Co[(OH)2saloph] — p-toluenesulfonic acid system was used as catalyst, the reaction was carried out at the next conditions: both Co[(OH)_2saloph] and p-toluenesulfonic acid — 0.2 mmol, aniline — 20 mmol, nitrobenzene — 10 mmol, methanol —30 ml, CO —5 MPa, temperature 170°C, reaction time 7 h. The highest conversion of nitrobenzene and selectivity of methyl N-phenyl carbamate were 54.5 and 92.2%, respectively.