反应详情

Following the procedure described in Example 1, 745 g of aniline, 255 g of N,N'-diphenyl urea, 481 g of urea, 1333 g of methanol and 6.0 g of zinc octoate were reacted for 3.5 hours at 200° C. in the pressure apparatus described in Example 1. The mixture was then cooled and, after the apparatus had been vented, another 72 g of urea were added. The mixture was then reheated and reacted for 4 hours at 200° C. After cooling and venting of the apparatus, the mixture was removed, filtered and subjected to fractional distillation. Most of the methanol excess was separated off at atmospheric pressure. The product was then distilled at 0.2 mbar. 1323 g (84.1% of the theoretical yield) of N-phenyl carbamic acid methyl ester melting at from 45° to 47° C. were obtained.

1. customwere reacted for 3.5 hours at 200° C. in the pressure apparatus
2. temperatureThe mixture was then cooled
3. customreacted for 4 hours at 200° C
4. temperatureAfter cooling
5. customthe mixture was removed
6. filtrationfiltered
7. distillationsubjected to fractional distillation
8. customMost of the methanol excess was separated off at atmospheric pressure
9. distillationThe product was then distilled at 0.2 mbar