| 摘要 |
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 C2-C6 alcohol-containing solvent that can also contain benzene, toluene or xylene, a C2-C6 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 DEG -120 DEG C. for a time period sufficient to reduce at least 90 percent of the substrate.
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