Talanta79(2009)856–862ContentslistsavailableatScienceDirectTalantajournalhomepage:www.elsevier.com/locate/talantaCombinedon-linetransmissionFTIRmeasurementsandBTEManalysisforthekineticstudyofaconsecutivereactioninaqueous–organicphasemediumMartinTjahjono∗,ChongHuiheng,EffendiWidjaja,KanichaSa-ei,MarcGarlandInstituteofChemicalandEngineeringSciences,AgencyforScience,TechnologyandResearch(A*STAR),1PesekRoad,JurongIsland,Singapore627833,SingaporearticleinfoabstractArticlehistory:Combinedon-linetransmissionFTIRspectroscopyandband-targetentropyminimization(BTEM)anal-Received6March2009ysiswereemployedinordertomonitorandanalyzethekineticsofthealkalinehydrolysisreactionofReceivedinrevisedform11May2009diethylphthalate(DEP)inaqueous–ethanolsolventmixture.ThisreactionisirreversibleandinvolvesAccepted11May2009twoconsecutivestepswiththeformationoftheobservablemono-ionintermediatespecies.ThepureAvailableonline20May2009componentmid-FTIRspectraofthereactivespeciesinvolvedinthisreaction,namelyDEP,mono-ionintermediateanddi-ionproductweresuccessfullyreconstructedusingBTEM.Theircorrespondingcon-Keywords:centrationswerealsocalculatedandsubsequentlyemployedtoderivethekineticrateparameters.TheOn-linereactionmonitoringMultivariateanalysiseffectoftemperatureandthesolventmixturecompositionsonthesetwoconsecutivereactionstepswereSolventeffectalsodiscussed.ThetemperaturevariationstudyshowedthatbothreactionratecoefficientsincreasedwithSpectraldeconvolutiontemperature.Bothratecoefficientswerealsoaffectedbythesolventmixturecompositionsandreachedminimumvaluesatcertainwater–ethanolsolventcomposition(circa60%(v/v)).Thisstudyshowstheutilityofcombinedon-linetransmissionFTIRspectroscopyandchemometrictechniquesforthepresent,rathercomplex,consecutiveorganicreaction.Moreover,thepresenttypeofapproachcouldfacilitatebetterunderstandingofawidevarietyoforganicreactionsthatareperformedinaqueousandmixedaqueous–organicsolvents.©2009ElsevierB.V.Allrightsreserved.1.Introductionregi