Polyol extraction by high boiling alkanes
US4336406A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 1981 |
| Grant date | Jun 22, 1982 |
| Priority date | — |
| Expiry date | Feb 24, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/62
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Polyol is recovered from polyurethane based polyurethane foam by a process which includes first dissolving the foam in a saturated alcohol, preferably diethylene glycol, having a boiling point between about 225.degree. C. and 280.degree. C. at a temperature between about 185.degree. C. and 220.degree. C. under a non-oxidizing atmosphere. The solution is reacted with water in the presence of an alkali hydroxide catalyst, preferably sodium hydroxide, under a non-oxidizing atmosphere, such as nitrogen. This may be done by refluxing the solution at a temperature between about 175.degree. C. and 220.degree. C. until all the carbamates produced during dissolution have been hydrolyzed to amines and alcohol. Water remaining in solution after hydrolysis is removed. A high boiling alkane is used to extract the polyol from the solution still under a non-oxidizing atmosphere and then the extracted polyol is subjected to vacuum purification at a temperature of less than about 230.degree. C. Substantially pure polyol is recovered which can be used to make new foam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.