A new polymer-bonded β-cyclodextrin was prepared from chloromethylated styrene-divinylbenzene copolymer,sodium salt of β-cyclodextrin (β-CD), KI,and (C4H9)4N+I- in a molar ratio of Cl∶β-CD∶I=1∶1.5∶1.Element analyses showed that β-CD content in the above catalyst was 701 μmolg-1.With the polymer-bonded β-CD as catalyst, 4-hydroxybenzoic acid was synthesized at 97% selectivity and in 90 mol% yield by the reaction of phenol and CCl4. Without the polymer catalyst, however, the selectivity was 56% and the yield was only 15mol%. The β-CD polymer was conveniently recovered from the reaction mixture by filtration and could be repeatedly used without notable decreases in catalytic activity, which indicated that the β-CD polymer compared to the free CDs or the CDs modified by small molecules has the improved industrial applicability. Finally, A possible mechanism catalyzed by the polymer-bonded β-CD was also suggested on the basis of these results.
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