反应详情

A suspension of 452 g of 2,5-dichlorobenzene sulfonamide, 260 g of cyclohexylisocyanate and 10.0 g of "Dabco" (1,4-diazabicyclo[2,2,2]octane) in 2000 ml chlorobenzene was heated for one hour to reflux in a flask fitted with a water condenser and dry-ice condenser in series, a stirrer and a thermometer. Phosgene was then added into the vapor space of the flask at such a rate that the temperature of the reaction mass was maintained at 123°-125° C. due to refluxing phosgene. During 3 hours of operation a total of 260 g of phosgene was added. The dry-ice condenser was then removed and the reaction mass refluxed to drive off excess phosgene until the temperature reached 134° C. After cooling to room temperature and filtration, the solvent and cyclohexylisocyanate were recovered by distillation at 100 mm pressure. The resulting residue was then distilled at lower pressure. Obtained were 378 g (75% yield) of 2,5-dichlorobenzenesulfonylisocyanate (B.P. 105° C./0.35 mm).

1. temperaturewas heated for one hour
2. temperatureto reflux in a flask
3. customfitted with a water condenser and dry-ice condenser in series, a stirrer
4. temperaturewas maintained at 123°-125° C. due
5. customThe dry-ice condenser was then removed
6. temperaturethe reaction mass refluxed
7. customreached 134° C
8. filtrationfiltration
9. distillationthe solvent and cyclohexylisocyanate were recovered by distillation at 100 mm pressure
10. distillationThe resulting residue was then distilled at lower pressure
11. customObtained