Chemical process
US4950787A · kind A · utility
3Cited by
5References
26Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 24, 1988 |
| Grant date | Aug 21, 1990 |
| Priority date | — |
| Expiry date | Aug 24, 2008 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02B2275/18
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
There is disclosed an improved process for preparing 1-hydroxy-3-oxa-1,2,4,5-pentane tetracarboxylic acid and 3,6-dioxa-1,2,4,5,7,8-octane hexacarboxylic acid wherein the unreacted starting acids are recovered in more desirable crystal habit. The acids are precipitated in salt form by lowering the pH of the reaction product to a range of from 4 to below 6 stepwise. The pH is lowered to above 6 in the first step and then relatively rapidly reduced to the desired level in the second step.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.