Conversion of Alcohols to Alkyl Halides.....

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Immobilization of HX: [Hmim]X as Halogenating Agent,
Recyclable Catalyst and Medium for Conversion of
Alcohols to Alkyl Halides

WU, Hai-Hong(   ) SUN, Jing(  ) YANG, Fan(  )
TANG, Jie*(  ) HE, Ming-Yuan(   )

Chinese Journal of Chemistry, 2004, 22, 619 621

Abstract   HX is immobilized by reaction of halogen acid with methylimidazole, and the formed ionic liquid [Hmim]X was used as halogenating agent, catalyst as well as medium for conversion of alcohols to alkyl halides. Excellent yields were obtained. The halides produced could be easily separated from the reaction mixture via simple decantation, and the ionic liquid [Hmim]X could be regenerated conveniently by adding equivalent of halogen acids followed by removal of water.

Conclusion.... the halogen acid was immobilized in
methylimidazole forming IL [Hmim]X. With the properties
of Brønsted acidic acid, thermal stability and negligible
vapor pressure, [Hmim]X could be used as halogenating
agent, acidic catalyst as well as medium for
conversion of alcohol to halide. It was very convenient
to prepare and reuse all the time. The procedure is very
practical for the preparation of primary and secondary
halides. The studies on stereochemistry of the halogenation
reactions are underway.

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