Study Of Interactions Between Malachite Green And Surfactants In Aqueous And Microemulaion

Malachite green(MG) is a synthetic triphenylmethane dye which has high toxicity and its metabolites in aquatic organism has a great influence to the human health. This thesis select the malachite green and surfactants as the research objects to study the thermodynamics and kinetics of their interaction for development of detection methods, degradation and elimination of malachite green and to study the association in alcohol aqueous solutions and microemulsions for simulating interactions between drugs and cell membranes in the life system.In this paper, the interaction between malachite green and surfactants(cetyl trimethyl ammonium bromide CTAB, sodium dodecyl sulfate SDS, octylphenol polyoxyethylene ether(10) OP-10) has been studied which used the UV-Vis spectrometry by measuring the absorption spectra and absorbance of MG in different solutions, respectively. By measuring the absorption spectra of MG in different solutions at room temperature, it was found that a significant association interaction between MG and surfactants and adopted an appropriate thermodynamics model. The association equilibrium constants and the association Gibbs free energy ΔG of MG with CTAB in aqueous solution were determined. Using the same method to study the influence of methanol, ethanol, propanol, isopropanol, n-butyl alcohol, isoamyl alcohol and ethylene glycol to association interaction between MG and CTAB, it was found that the association reaction have obvious promoting effect that the association equilibrium constants were increased in the ethylene glycol aqueous solution. The absorbance of MG in a series of water/CTAB/isooctane microemulsions which has different value of α has been measured and the association equilibrium constants and the association Gibbs free energy ΔG of MG with SDS or OP-10 have been determined via using the appropriate association models in microemulsion to analyse the experimental data. In order to determine the extent of association reaction speed, the association reaction suitable dynamics model has established according to the characteristics of association reaction and the order and rate constants of association reactions in aqueous solution have determined, respectively. The rate constant of association reactions was significantly different in different surfactant solutions. The rate constant of MG and SDS was the biggest which can be result from the electrostatic interaction between them.It was found that the N atom of CTAB ions which were closer to the MG molecules by means of exploring the mechanism of association reactions between MG and CTAB using hydrogen nuclear magnetic spectra. The configuration and combination mode of malachite green with K+, NH4+, CH3-NH4+ and CTAB have been determined by using the quantum mechanics calculation simulation method to study the change of energy. There was the cation-interaction between them. Further, it was determined the Mullicken-charge, bond length, energy and dihedral angle change data and found that the three benzene rings of MG tend to be more flat when CTAB ions were near to the malachite green molecules, leading to the change of the electron transition energy level which resulted in the color of malachite green solution changing. The result shows that the same conclusion by simulating CTAB-MG-CTAB complex.