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1、FromCanadianPatentNo.822,113itisknownthatethylenediamine(1,2-diaminoethane)canbepreparedfrommonoethanolamineorethyleneglycolbyreactionwithammoniaatelevatedpressureandtemperatureinthepresenceofahydrogenationcatalyst.Aftertheremovalofanyorganicby-productsform
2、ed,oneobtainsamixtureofethylenediamineandwater,thewateroriginatingfromhydroxylgroupspresentintherawmaterial.Theseparationoftheethylenediaminefromthewaterformedisadifficultproblemsinceethylenediamineandwaterformanazeotropicmixtureboilingatabout118.5°C.atatmo
3、sphericpressureandhavingtheconstantcompositionof82%ethylenediamine,theremainderwater.Severalmethodsfortheremovalofmorewaterandforthepreparationof"anhydrous"ethylenediaminehavebeendisclosedinthepatentliterature.U.S.Pat.No.3,055,809andGermanAuslegeschriftNo.1
4、,129,160discloseamethodfortherecoveryofanhydrousethylenediaminefromaqueous水solutionsbyextractivedistillationwithhigh-boilingsolvents,suchasethyleneglycol,diethyleneglycoloralkanolmonoamines.Further,itisknownthatthecompositionoftheazeotropicmixturebetweeneth
5、ylenediamineandwaterisdependentuponthedistillationpressure.Thus,whenthepressureisincreasedtheproportionofwaterintheazeotropicmixturedecreases.InGermanAuslegeschriftNo.1,258,413thisconditionisutilizedforthepreparationof"anhydrous"ethylenediaminebycarryingout
6、thedistillationunderelevatedpressure.However,theuseofanyofthesemethodsmeansinpracticethattheseparationbecomescomplicatedandexpensive.Therefore,foralongtimetherehasbeenaneedfornovelandimprovedmethodsfortheseparationofethylenediaminefromwater.Inthecatalyticam
7、inationofmonoethanolamineorethyleneglycolinthepresenceofammoniatherearealsoformed,inadditiontotheethylenediamine,otherethyleneamines,suchaspiperazine,diethylenetriamine,hydroxyethylethylenediamineandaminoethylpiperazine.Ithasnowsurprisinglybeenfoundthatthep
8、resenceofsaidethyleneaminesfavorablyinfluencestheseparationofwaterupondistillationataboutorslightlyaboveatmosphericpressure.Extensiveinvestigationshaveshownthatthepresenceoftheseaminocompoundsasdistill