Phosgene → Cyclohexyl isocyanate

Temperature

78.5 °C

500 g of chlorobenzene and 8.7 g of Cyanex® 923 (commercial product from Cytec Industries, a mixture of different tri-C6-C8-alkylphosphine oxides having an average molecular weight of 348 g/mol) (0.025 mol) were placed in the glass vessel and 53 g of gaseous phosgene was introduced at room temperature. The reaction mixture was subsequently heated to 80° C., with vigorous phosgene reflux being established. While stirring vigorously at 77-80° C., a total of 99.2 g of cyclohexylamine (1 mol) dissolved in 200 g of chlorobenzene and at the same time a further 113 g of phosgene were introduced over a period of 3 hours. After addition was complete, the system was maintained at 77-80° C. for a further one hour without introduction of phosgene to allow further reaction to occur and the residual unreacted phosgene was subsequently stripped out at 40° C. by means of nitrogen. The reaction mixture obtained was a fluid suspension from which the solid obtained was separated by filtration. A few milligrams of solid were able to be isolated in this way. The filtered crude product was worked up by distillation. Removal of the solvent and fractional distillation gave 82.8 g of cyclohexyl isocyanate (0.662 mol). This corresponds to 66.2% of the theoretical yield.

1. additionwas introduced at room temperature
2. temperaturereflux
3. additionwere introduced over a period of 3 hours
4. additionAfter addition
5. customreaction
6. customwas subsequently stripped out at 40° C. by means of nitrogen
7. customThe reaction mixture obtained
8. customobtained
9. customwas separated by filtration
10. customto be isolated in this way
11. filtrationThe filtered crude product
12. distillationwas worked up by distillation
13. customRemoval of the solvent and fractional distillation

ORD record

ord-cb08853962264869929d85da1aa516cd

Source dataset

uspto-grants-2009_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07482481B2