The Synthesis And Research Of Tetrafluorobenzene With Four Different Substituents

In the paper,tetrafluorobenzene with four different substituents,such as amidine cyano nitro hydroxyl,were synthesized.2,3,5,6-tetrafluoroaniline is an important intermediate for medication and pesticide industry.It can be used as raw material for synthesis special effective medicine which has good effect on anti-phlogistic and anti-depression.While 2,3,5,6-tetrafluorobenzonitrile has great market demand as the medicine intermediate and the liquid crystal material intermediate.we use 2,3,5,6-tetrafluorobenzoic acid as raw material 2,3,5,6-tetrafiuoroaniline 2,3,5,6-tetrafluorobenzonitrile In the paper,we synthesized 2,3,5,6-tetrafluoroaniline and 2,3,5,6-tetrafluorobenzonitrile take 2,3,5,6- tetrafluorobenzoic acid as the foundation raw material,synthesis condition of laboratory was studied,which provided the basis for in-depth research and industrial production.This topic belongs to pharmaceutical intermediates research field.There are mainly four aspects of the experiment part of this paper.Firstly, 2,3,5,6-tetrafluoroaniline was synthesized by Hoffman degradation and the optimum reaction conditions was determined.Secondly,the dynamics of Hoffman degradation was studied,the activation energy of the Hoffman degradation reaction of 2,3,5,6-tetrafluorobenzoyl amine was determined.Thirdly,2,3,5,6-tetrafluorobenzonitrile was synthesized and the optimum reaction conditions was determined.Fourth,2,3,5,6-tetrafluoronitrobenzene was synthesized; fifthly,2,3,5,6-tetrafluorobenzonitrile was synthesized and the optimum reaction conditions was determined.The results show that:first,in the synthesis of 2,3,5,6-tetrafluoroaniline,the molar ratio of 2,3,5,6-tetrafluorobenzoyl amine,sodium hydroxide and sodium hypochlorite is 1:2:1, the temperature of rearrangement reaction is 0 to 5℃,the temperature of hydrolysis reaction is 70 to 75℃,the time of hydrolysis and decarboxylation is 1 h.The total mass yield of was 76.5%,the purity of the product＞98%.Second,The dynamics of Hoffman degradation reaction was determined during 0℃,20℃,30℃,from the curve we concluded that the order of the reaction is n=1,activation energy Ea=5.42×103 J/mol.Three,in the synthesis of 2,3,5,6-tetrafluorobenzonitrile,2.4g 2,3,5,6-tetrafluorobenzoyl amine,25ml chlorobenzene was used,the molar ratio of thionyl chloride and 2,3,5,6- tetrafluorobenzoyl amine is 1.3:1,thionyl chloride was dropped at 90℃,keeping refluxing for 3 h,obtained 1.49 g,2,3,5,6-tetrafluorobenzonitrile,the yield of was 68%.Four,2,3,5,6-tetrafluoronitrobenzene was synthesized from2,3,5,6-tetrafluorobenzoic acid by nitration and decarboxylation,the yield of was 64.6%five,the optimum reaction condition of synthese 2,3,5,6-tetrafluorophenol by phase transfer catalytic method is 3.36 gram of Pentafluorobenzene,6.44 gram of (Bu)₄N⁺HSO₄^-,1.6 gram of 50%w/w NaOH solution,and 25 mL of cyclohexane as solvent.The reactions were carried out for two hourses,the yield is 65%.In this paper,the structure of the intermediate products,the final product and other related compounds were characterized.