Process for the preparation of substantially pure cyclo aliphatic diisocyanate stereoisomers
US4250106A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 15, 1979 |
| Grant date | Feb 10, 1981 |
| Priority date | — |
| Expiry date | Oct 15, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G18/79
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The instant invention is directed to a novel process for the separation of substantially pure cycloaliphatic diisocyanate reactive (cis-form) stereoisomers from cycloaliphatic diisocyanate non-reactive (trans-form) stereoisomers comprising reacting cycloaliphatic diisocyanates of the formula ##STR1## where R can be hydrogen or an aliphatic hydrocarbon group having from 1 to 4 carbon atoms, at least one of said R's being an aliphatic hydrocarbon having from 1 to 4 carbon atoms and wherein the isocyanato groups are both positioned axially or equatorially in the presence of catalysts selected from the group consisting of lead catalysts, tertiary amines, alkali metal hydroxides and sodium methoxide, thereby producing a cyclic nylon-1 type linear polymer having regularly reoccurring bicyclic structural units of the formula ##STR2## precipitating said cyclic nylon-1 type linear polymers, filtering and washing said precipitated cyclic nylon-1 type linear polymers, then decomposing said precipitated polymer using distillation, thereby producing a distillate and collecting said distillate containing a substantially pure monomer consisting of reactive (cis-form) stereoisomers. The instant in…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.