Process for the preparation of cis-syn-cis-4,4' (5')-[di-t-butyldicyclohexano]-18-crown-6
US5478953A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 1994 |
| Grant date | Dec 26, 1995 |
| Priority date | — |
| Expiry date | Nov 3, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D323/00
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for preparing 4,4'(5')-[di-t-butyldicyclohexano]-18-crown-6 containing an enhanced amount of an isomer that extracts strontium ions from aqueous solution is disclosed. According to the process, an anhydrous reaction mixture is prepared containing 4,4'(5')-[di-t-butyldibenzo]-18-crown-6 as substrate dissolved in a C.sub.2 -C.sub.6 alcohol-containing solvent that can also contain benzene, toluene or xylene, a C.sub.2 -C.sub.6 carboxylic acid or anhydride and a 5 percent of rhodium on alumina particle catalyst. The resulting reaction medium is hydrogenated at about 200-1000 psi, at a temperature of about 35.degree.-120.degree. C. for a time period sufficient to reduce at least 90 percent of the substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.