Synthesis of Unconventional Materials Using Chitosan and Crown Ether for Selective Removal of Precious Metal Ions

The polyfunctional and highly reactive bio-polymer, the chitosan was first regioselectively converted into dialkylated chitosan using dimsyl anionic solution(NaH in DMSO) and bromodecane after protecting amino groups by phthalic anhydride. The dibenzo-18-crown-6-ether, on the other hand, was converted into its carbonyl derivatives via Duff reaction prior to incorporate into chitosan by Schiff base formation. Thus formed diformylated dibenzo-18-crown-6-ether was condensed with lipophilic chitosan to prepare the novel solvent extraction reagent. The products were characterized mainly by IR and 1H-NMR. Hence, the multidentate crown ether-embedded polyfunctional bio-material was tested for extraction of Pd(II) and Pt(IV) in aqueous solution.

Authors:

• Rabindra Prasad Dhakal
• Tatsuya Oshima
• Yoshinari Baba

Keywords:

• Lipophilic chitosan
• Duff reaction
• crown ether and precious metal ions extraction.

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