The Studies On The Preparation And Properties Of The Rose Bengal-Wool Sensitizer

Using the sensitized photooxygenation reaction could accomplish some organictransformations that could not easily be realized by traditional thermally-promoted way. Theconditions are mild，easy to control，safe and environmentally friendly. It is one of the mostactive fields in organic reaction research. However，the disadvantage for this method is that thedyes as photosensitive reagents are added to the reaction mixture. They have to be separatedfrom the reaction mixture by usually column chromatography. So，it is not easy to be applied inindustry. And the dyes could not be reused. It may be harmful to the environment. In thisresearch， the Rose Bengal(RB) dyes are absorbed in natural wool. After washing by water tomake sure that they are completed retained in wool，the RB-Wool system are applied in theorganic synthesis as photosensitizer. Furan derivatives are used as the substrates for thephotooxygenation reactions. The desired butenolide （5-Hydroxy-5H-2-furanone） and itsderivatives are obtained. The yields are up to70%. The RB-Wool sensitizer could be recoveredby filtration and be reused. It is much more convenient compared to the traditional dyes asphotosensitizer. The wool-supported Rose Bengal as sensitizer could be used repeatedly. It couldwork continuously in the reaction for about40hours.