US EPA

7450212 

Journal Article 

Carbamate synthesis on Pd/C catalysts: Gas-solid versus slurry processes 

Toochinda, P; Chuang, SSC 

2004 

Yes 

Industrial and Engineering Chemistry Research
ISSN: 0888-5885
EISSN: 1520-5045 

American Chemical Society 

43 

5 

1192-1199 

English 

10.1021/ie0305768 

WOS:000189320100004 

http://://WOS:000189320100004
Exit
 

Carbamate synthesis has been studied over NaI-Pd/C in slurry, gas-solid, and tubular reactors at 373-438 K and 0.41-7.61 MPa. The gas-solid carbamate synthesis process in which the CO, O2, methanol, and aniline reactants are present in the gas phase and the catalyst is in solid form occurs at a significantly higher rate than the slurry-phase synthesis in which CO and O2 dissolve in the liquid methanol/aniline mixture. The high rate of the gas-solid carbamate synthesis compared with that of the slurry-phase synthesis can be attributed to (i) the intimate contact between the NaI promoter and the Pd on the carbon surface, (ii) the absence of solubility limitations in the gas-solid synthesis, and (iii) the slowing of the sintering of the Pd particles. Reaction pathway studies show that the direct oxidative carbonylation of aniline with methanol is the most effective pathway for carbamate synthesis. A low-cost, environmentally benign carbamate synthesis for the replacement of the isocyanate synthesis from phosgene/amine can be developed by coupling the high rate of the gas-solid synthesis with its intrinsic advantage of ease of catalyst recovery. 

Carbon monoxide; Carbonylation; Catalysts; Chemical reactors; Palladium; Slurries; Synthesis (chemical); Catalyst recovery; Gas-solid synthesis; Organic compounds; amine; aniline; carbamic acid; carbon; carbon monoxide; isocyanate; methanol; oxygen; palladium; phosgene; sodium iodide; catalyst; environmentally friendly product; gas-solid separation; reactor; slurry; article; carbonylation; catalyst; cost; drug mixture; gas analysis; oxidative stress; particle size; process monitoring; product recovery; promoter region; reaction analysis; sludge; solid; solubility; statistical significance; synthesis; tubular reactor