间二甲苯生产技术摘要本文概述了间二甲苯的用途，对国内外的生产现状进行了比较详细的描述，着重介绍了间二甲苯的各种生产技术，包括络合法、吸附分离法、磺化法、反应蒸馏法、共沸精馏法，并提及了间二甲苯的回收技术。对比了几种不同选择性硝化方法，实验结果发现，磷酸对硝化反应的选择性效果较好，乙酸酐的选择性不强，Sn改性皂土没有表现出很好的对位选择性，只有添加磷酸的方法可以提高4-硝基间二甲苯的相对含量，原料转化率也比较好。硝酸混酸的转化率最高。高浓度的磷酸在选择性上的表现和低浓度的相差不大，但在转化率上就表现得很突出，磷酸的效果较好。三酸的混合体系对反应没有很明显的效果，20℃时多聚磷酸—硝酸(1:l)体系反应大概要24h才能达到平衡，50℃体系反应大概在6h达到平衡，50℃多聚磷酸—硝酸(1:l)体系转换率和对位选择性要高于20℃时体系。通过国内外间二甲苯市场分析，对间二甲苯的市场前景进行了预测与展望。关键词：间二甲苯；络合法；硝化反应；磷酸iThePRODUCTIONTECHNOLOGYOFM-XYLENEABSTRACTThisarticleoutlinestheuseofmeta-xylene,comparestheproductionstatusathomeandabroadindetail,emphaticallyintroducesallkindsofproductiontechnologyofmeta-xylene,includingcomplexlegal,adsorptionseparation,sulfonatedmethod,reactiondistillation,azeotropicdistillationmethod,andtherecoverytechnologyofmeta-xylenementioned.Comparedthedifferentselectivenitrationmethod,theexperimentalresultsshowthatphosphoricacidforselectivenitrationeffectisgood,theselectivityofaceticanhydrideisnotstrong,Snmodifiedbentonitehasshowngoodparaselectivity,onlyaddingphosphoricacidmethodcanimprovetherelativecontentof4-nitrometa-xylene,rawmaterialconversionrateisbetter.Thehighestconversionrateofsulfurnitratemixedacid.Ahighconcentrationofphosphateontheselectivityandlowconcentrationdifferenceisnotbig,butperformanceisoutstandingontheconversionrate,theeffectofphosphateisbetter.Mixedsystemofthreeacidreactionisnoobviouseffect,reactionofpolyphosphoricacid-nitricacid(1:l)systemin20℃probably24htoreachequilibrium,reactionofpolyphosphoricacid-nitricacid(1:l)systemin50℃probably6htoreachequilibrium,theconversionrateandparaselectivityofpolyphosphoricacid-nitricacid(1:l)systemhigherthan20℃.Byanalyzingmeta-xylenemarketathomeandabroad,themarketprospectofmeta-xylenehascarriedontheforecastandprospect.KEYWORDS:m-xylene;complexmethod;nitration;phosphoricacidii目录第一章前言......................................................11.1概述.........................................................11.2间二甲苯的用途...............................................11.3间二甲苯的国内外研究现状......................................21.3.1国外间二甲苯的研究现状..................................................................................................31.3.2国内间二甲苯的研究现状..........................................41.4研究内容.....................................................6第二章间二甲苯的生产技术.......................................72.1二甲苯的来源.................................................72.2间二甲苯的提纯................................................72.2.1络合法.......................................................82.2.2吸附分离法...................................................82.2.3磺化法.......................................................92.2.4反应蒸馏法..................................................102.2.5共沸精馏法..................................................102.3回收间二甲苯的新工艺.........................................102.4本章小结................
