Research On The Synthesis Of 2-(3’,4’,5’-trifluorophenyl)aniline

The biphenyl compounds are widely applied in pesticides,pharmaceuticals,biological materials and liquid crystals,which are structurally made of two phenyl groups and many other compounds are then made from the substitution of the different functional groups.And the compound studied in our article,that is,2-(3’,4’,5’-trifluorophenyl)aniline is an important farm chemical and many new pesticides of excellent performance are synthesized by the reaction between 2-(3’,4’,5’-trifluorophenyl)aniline and other heterocyclic compounds.Hence,the production of 2-(3’,4’,5’-trifluorophenyl)aniline have some advantages such as wide appliance scope,large market demand,small investment risk and high profits.In our article,a synthetic route of 2-(3’,4’,5’-trifluorophenyl)aniline was developed based on the related published works,and the biphenyl group was obtained by the Suzuki reaction which had been widely applied in the field of coupling reaction.And then the best conditions were obtained by the comparative experiments after getting the corresponding intermediate products and product,which is helpful to the industrial appliance of the route and the route development of similar biphenyl compounds in the future.And the synthetic procedures were shown as follows.Firstly,the Grignard reagent was synthesized by trifluoro-bromobenzene and magnesium chips with the Iodine particles as the initiating agent,and then the best experimental conditions(n(trifluoro-bromobenzene):n(magnesium)=1:4,THF as the solvent,3h,30℃)were got with the conversion of 96.5%by doing experiments.Then the trifluorobenzyl boric acid was obtained by acidolysis of the product which was synthesized by the Grignard reagent and trimethyl borate.By analyzing the experimental results,it is believed that the best conditions(n(borate):n(Grignard reagent)=1.2:1,THF as the solvent,2-3h,-5℃)were got and the yield is 91.1%here(based on the trifluoro-bromobenzene).And next,the Suzuki reaction then was used to get the 3,4,5-trifluoro-2’-nitrobiphenyl by reacting the boric acid with 2-nitrochlorobenzene.Based on the experimental results,the best conditions(THF as the solvent,reflux temperature,1.0 mol%PdCl2/TPP,NaOH)were then obtained with the yield of 95.0%.Finally,the desired compound 2-(3’,4’,5’-trifluorophenyl)aniline was obtained by the liquid catalytic hydrogenation of 3,4,5-trifluoro-2’-nitrobiphenyl and the results showed that the yield of 95.0%was achieved under the best conditions(Pd/C,50℃,0.3Mpa).The total conversion of this synthetic route is 82.2%,and the obtained intermediate products and 2-(3’,4’,5’-trifluorophenyl)aniline were all further confirmed by the melting point analysis,GC-MS.Based on the experimental results in laboratory,we did the pilot plant test of the synthestic route.And the process was devided into three parts,that is,synthesis of trifluorobenzyl boric acid,synthesis of 3,4,5-trifluoro-2’-nitrobiphenyl and synthesis of 2-(3’,4’,5’-trifluorophenyl)aniline.At the same time,the pilot process was then designed for the three parts and the operation process was then discussed in details.The experimental results of the pilot plant were similar with the laboratory,which meant that large scale production of target compound was feasible with the use of the route,and the related data were also obtained to sacle up the production process further by the pilot test.