Studies Of The Surfactants Chemistry By Various NMR Techniques

Surfactants have been broadly used in several fields of Chemistry. Thestudies of the chemical and physical properties by NMR are relatively scarce. Inthis thesis studies, we tried to used various NMR techniques to explore manydifferent types of surfactants. The surfactants involved containing the hydrogenand fluorine-containing materials, either anionic, cationic, non-ionic orzwitterionic types. The cationic surfactants included carbonate, sulfate orsulfonate types, the anionic included quaterammonium or pyridinium types. TheNMR detections involve spectra of hydrogen, fluorine, carbon, oxygen,deuterium, by measuring the chemical shifts, integration, half width of signals,relaxation time T₁, etc. The study of surfactants involves the following fields:solubility, viscosity, critical micelle concentration （cmc）, micelle conformation,the influences to solution partitions, the influences to the water clusters, theinfluences toe the equilibrium ratio of keto/enol. The investigations containedthe studied the chemical and physical properties of aqueous two phase systemand the detection of unknown surfactant OS.The detections of relaxation time T₁of hydrogen, fluorine or carbon wereused explore the viscosity of surfactant containing solutions. The results showedthat the addition of certain surfactants to the solution induced the increase of T₁at low concentration, indicating the more mobility of molecules in solution andthat fit for the observance that the solution became less viscous. At higherconcentration, the T₁became smaller and the liquid became more viscous.The famous cmc values （critical micelle concentration） were detect byexploring serious concentrations of solution and the change of chemical shifts orrelaxation time T₁were measured. The cmc values of several surfactants werecalculated and compared the valued obtained by other techniques. The values were basically the same. Certain differences were compared and discussed.The influences of surfactants to the water cluster were studies by detectingthe chemical shifts and half bandwidth of¹⁷O NMR. It was noted that theaddition of surfactants decrease the half bandwidth and therefore seemlydecrease the size of water cluster.The influences of surfactants to the keto/enol ratios of certain isomericcompounds were conducted. Ethyl acetoacetate and acetylacetone were wiselyapplied to explore the properties of surfactants and remarkable experimentsresults were noted. Further studies were applied to the aqueous two phasesystem. Observance of sole isomer was obtained in certain solution condition.The quantitative analyses of carbon, proton, fluorine and deuterium spectrawere used to study the solution partition constants. Capillary tube internalstandard was used as reference for quantitative measurements. The resultsshowed that different surfactants induced different partition disribution and theresults were explained from structure points of views.In this thesis work, an unknown source of surfactant were detected to findits origin. The structures were studied by performing several detectingtechniques including NMR, IR, UV, Mass and HPCL and TLC. The NMRdetections contained proton. carbon and fluorine spectra, DEPT, APT, cosy, hsqc,etc. It was concluded that the unknown surfactant was OS （MS-1）, analkypolyehoxy type cationic surfactant.