Process for distillation of crude isocyanate concentrates
US5786506A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 4, 1992 |
| Grant date | Jul 28, 1998 |
| Priority date | — |
| Expiry date | Dec 4, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C2601/14
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process is described for the separation and recovery of isocyanate monomers from isocyanate concentrates which leaves a residue which is liquid and burnable. The process for the separation and recovery of isocyanate monomers from isocyanate concentrates formed in the production of isocyanates and comprising a volatile isocyanate monomer and by-products comprises the steps of: (A) preparing a mixture comprising PA1 (A-1) the isocyanate concentrate; and PA1 (A-2) an oil solution comprising; PA2 (A-2-a) a major amount of hydrocarbon oil, and PA2 (A-2-b) a minor amount of at least one ashless dispersant; and (B) heating the mixture to an elevated temperature at reduced pressure whereby isocyanate monomer is distilled and recovered leaving a liquid residue. The presence of the oil solution in the mixture facilitates the distillation of the isocyanate concentrate, generally improves the yield of distilled isocyanate monomer, results in a residue which is liquid and easily removed from the distillation apparatus, and the liquid residue can generally be burned without difficulty.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.