Synthesis And Study Of 2,3,5,6-tetrafluorobenzyl Alcohol

2,3,5,6-tetrafluorobenzyl alcohol is one of the most important intermediate in synthesis of medical products and pyrethroid insecticides-transfluthrin. It is also useful for pesticide and liquid crystals and photosensitive compounds.In this thesis, 2,3,5,6-tetrachlorophthalonitrile was used as starting material. 2,3,5,6-tetrafluorobenzyl alcohol was prepared by a serial reactions including fluorination, chlorination, hydrolyzation, decarboxylation, esterification and reduction. The conditions of these reactions were also studied. This thesis concerns the synthesises of 2,3,5,6-tetrafluorophthalonitrile, 2,3,5,6-tetrafluorobenzoic acid, methyl 2,3,5,6-tetrafluorobenzoat and 2,3,5,6-tetrafluorobenzyl alcohol. Besides, we synthesized the derivatives of 2,3,5,6-Tetrachloromethylbenzene. All products synthesized have been identified by IR and GC-MS and element analyse and ' H NMR.This thesis provides a new route to synthesize 2,3,5,6-tetrafluorobenzyl alcohol. The route takes the advantages, not only by using the short steps but also by using sodium borohydride, a cheap reductive reagent to replace the expensive, explosive and flammable lithium aluminium hydride. Moreover, hydrolyzation and decarboxylation are finished in a pot process with high yield of 92%. Furthermore, reactive conditions of this route are moderate and safe and a good yield of this product with high purity is achieved. Therefore, the above method is very useful as an industrial scale production method.