摘要麦草畏，商品名百草敌或百草畏，化学名为3,6-二氯-2-甲氧基苯甲酸，纯品为白色晶体，是一种高效内吸传导型的除草剂，主要用于旱地农作物除草。主要几种不同的制备方法，工业生产中应用最广泛的为3,6-二氯水杨酸醚化制备麦草畏的方法。2,5-二氯苯酚是3,6-二氯水杨酸制备中重要的原料。通常由2,5-二氯苯胺重氮化后酸性条件下水解制得，也可由1,4-二氯苯催化氧化制得，此外还有1,2,4-三氯苯碱性醇解等方法。2,5-二氯苯酚在精细化工生产中有重要应用，除用作除草剂麦草畏的中间体，还应用于医药、染料等其他领域，在氮肥增效、皮革防腐方面有着重要的应用。本文以2,5-二氯苯胺重氮化水解制备2,5-二氯苯酚为基础，改进合成工艺，以盐酸代替传统硫酸制备重氮盐，对硫酸与原料配比、反应温度、亚硝酸钠的用量等反应条件进行优化，并尝试催化氧化方法合成2,5-二氯苯酚。当2,5-二氯苯胺与硫酸摩尔比达到5：2，反应温度为145℃，亚硝酸钠与原料摩尔比为1.6-1.8之间，常规蒸馏可得到92.4％的收率，高效液相色谱分析纯度为97.5％。关键词：麦草畏；2,5-二氯苯胺；2,5-二氯苯酚；2,5-二氯苯甲醚TheStudyonSynthesisof2,5-DichlorophenolAbstractDicamba,whichtradenameisBanvelandchemicalnameis3,6-dichloro-2-methoxy-benzoicacid.Dicambaisakindofhighefficiencyintheabsorptionofthetypeofherbicide,anditismainlyusedfordrillandcropweeding.Thereareseveralmajormethodsofpreparation.Inindustrialproduction,themostwidelyusedmethodsisetherifying3,6-dichlorosilicylicacidtoproduceDicamba.2,5-dichlorophenolisanimportantstartingmaterialtoprepare3,6-dichlorosalicylicacid.Generallyusethemethodsofdiazotizingandhydrolyzing2,5-dichloroanilinetoproduceDicamba.1,4-Dichlorobenzenecanbealsooxidizedto2,5-dichlorophenol.Inadditiontothat,themethodofusing1,2,4-trichlorobenzenetooccursalcoholysisreactioninalkalineenvironmentisalsoused.2,5-dichlorophenolinfinechemicalproductionhasimportantapplications,andalsobeusedinmedicine,dyesandotherfields.Itcanbeusedtomakenitrogenfertilizerefficiencyandusedasleatherpreservatives.Inthispaper,2,5-dichloroanilinewasusedtodiazotizeandhydrolyzeinthesolutionofsodiumhydroxidetoproduce2,5-dichlorophenol,andprocesswasimproved.Diazoniumsaltwaspreparedofbyhydrochloricacidinsteadoftraditionalsulfuricacid.Optimizethereactionconditionssuchasthesulfuricacidandrawmaterialsratio,thereactiontemperature,theamountofsodiumnitriteandotherreactionconditions.Andtrytosynthesize2,5-dichlorophenolbycatalyticoxidation.Whenthemolarratioof2,5-dichloroanilineandsulfuricacidreachesto5:2,themolarratioofsodiumnitriteandrawmaterialisbetween1.6and1.8,reactattemperatureof145℃,theyieldcanreachto92.4%.Usehighperformanceliquidchromatographytoanalysisofthepurity,andthepurityoftheresultscanreachto997.5%.KeyWords：Dicamba;2,5-dichloroaniline;2,5-dichlorophenol;2,5-dichloroanisole目录摘要.........................................................................................................................................IAbstract......................................................................................................................................II1文献综述.................................................................................................................................31.1研究背景及目的..........................................................................................................31.22,5-二氯苯酚的制备方法简介...................................................................................31.2.12,5-二氯苯胺重氮化、水解制备2,5-二氯苯酚................................
