Aromatic Compounds Electrochemical Chlorinated Reaction Technical Study

Aromatic compounds which contain chlorine are the vital members of industryof finey play an important role in medicine and pesticide. According tostatistics,one third of fine chemicals belong to aromatic chlorides. These chlorinatingagents are either highly toxic or expensive, and their production, storage, transportand usage are strictly limited, these shortcomings restrict the production of aromaticchlorides. Therefore seeking a reasonable chlorination process, using the non-toxic,inexpensive chloride reagent are particularly important.This paper systematically studied the electrochemical chlorination of aromaticcompounds,that is using inorganic chloride as the electrolyte, the anode generatechlorine and then in situ electrophilic substitution react with aromatic compounds.Specific research activities include:electrochemical reactor design, the choice of thetype of dielectric,electrolyte concentration, the choice of organic solvent,the effect ofcurrent and voltage,the influnce of the raw material concentration,the impact of theelectrochemical chlorination reaction time and so on.The results show that:1. Using2-chloro-5-(2-chloro-4-(trifluoromethyl)phenoxy)benzoic acid as raw materials,electrochemical method is used to chlorinate in order to generate3-2–chloro-5-(2-chloro-4-(trifluoromethyl) phenoxy) benzoic acid.The optimum reactionconditions as following:under room temperature,using concentrated hydrochloricacid as the chloride electrolyte and acetonitrile as organic solvent, the volume ratioof hydrochloric acid to acetonitrile in anode chamber is30:30, the concentration ofraw materials is0.053M,the cathode chamber contained only concentratedhydrochloric acid, the current is kapt at0.2A, the voltage at this process is1.10-1.27V, the reaction time is4h,the yield reach at86%, the current efficiency is18.06%, and product is characterized by IR,1H NMR.2. Using acetic acid as raw materials,electrochemical method is used to chlorinate in order to generate the targetproduct2,4-dichlorophenoxyacetic acid (2,4-D).The optimum reaction conditionsas following:under room temperature,using concentrated hydrochloric acid as thechloride electrolyte and acetonitrile as organic solvent, the volume ratio ofhydrochloric acid to acetonitrile is60:60, the concentration of raw materials is0.22M,the current was kapt at0.4A, the voltage at this process is1.26-1.44V,thereaction time is8h,the yield reach at95%, the current efficiency is84%, and productis characterized by IR,1H NMR.