Spectrophotometric and thermodynamic study on the dimerization equilibrium of ionic dyes in water by chemometrics method.
نویسندگان
چکیده
The monomer-dimer equilibrium and thermodynamic of several ionic dyes (Neutral Red, Nile Blue A, Safranine T and Thionine) has been investigated by means of spectrophotometric and chemometrics methods. The dimerization constants of these ionic dyes have been determined by studying the dependence of their absorption spectra on the temperature in the range 20-75 degrees C at concentrations of Neutral Red (1.73 x 10(-5) M), Nile Blue A (3.94 x 10(-5) M), Safranine (6.59 x 10(-5) M) and Thionine (6.60 x 10(-5) M). The monomer-dimer equilibrium of these dyes has been determined by chemometrics refinement of the absorption spectra obtained by thermometric titrations performed. The processing of the data carried out for quantitative analysis of undefined mixtures, based on simultaneous resolution of the overlapping bands in the whole set of absorption spectra. The enthalpy and entropy of the dimerization reactions were determined from the dependence of the equilibrium constants to the temperature (van't Hoff equation).
منابع مشابه
Thermodynamic Study of the Ion-Pair Complexation Equilibria of Dye and Surfactant by Spectral Titration and Chemometric Analysis
Surfactant-dye interactions are very important in chemical and dyeing processes. The dyes interact strongly with surfactant and show new spectrophotometric properties, so the UV-vis absorption spectrophotometric method has been used to study this process and extract some thermodynamic parameters. In this work, the association equilibrium between ionic dyes and ionic surfactant were studied by a...
متن کاملThermodynamic Characterization of the Aggregation Phenomena of SafranineT by Spectral Titration and Chemometric Analysis
The dimerization constants of Safranine T have been determined by studying the dependence of its absorption spectra on the temperature in the range 30–70 ◦C at different total concentrations of Safranine T (1.03×10−5, 1.44×10−5 and 1.73×10−5 M). The monomer–dimer equilibrium of Safranine T has been determined by applying MCR-ALS method on the absorpti...
متن کاملThermodynamic Characterization of the Aggregation Phenomena of SafranineT by Spectral Titration and Chemometric Analysis
The dimerization constants of Safranine T have been determined by studying the dependence of its absorption spectra on the temperature in the range 30–70 ◦C at different total concentrations of Safranine T (1.03×10−5, 1.44×10−5 and 1.73×10−5 M). The monomer–dimer equilibrium of Safranine T has been determined by applying MCR-ALS method on the absorpti...
متن کاملApplication of Chemometrics in determination of the effects of ionic and non-ionic surfactants on ac-id dissociation constant (pKa) of Meloxicam using spectrophotometric method
The purpose of this study was to determine the acid dissociation constants (pKa) of meloxicam in the presence of various surfactants including sodium lauryl sulfate (SLS) as an anionic surfactant, cetyltrimethylammonium bromide (CTAB) as a cationic surfactant and Triton® TX-100 (TX-100) as a non-ionic surfactant in different pre-determined concentrations. The related pKa was determined spec...
متن کاملThermodynamic study of ion- association in KNO3 solution in the mixed solvent (water +methanol)
The solubility of KNO3 in the mixed solvent (water 85%+methanol 15%) were determined by using solvent evaporating method at different temperatures (25, 30, 40, 50, 60 ;C). In addition the equilibrium constant of ion pair formation, KIP, for K+NO3 – ion-pair on the basis of Fuoss contact ion pair model was calculated. Upon choosing the extended Debye-Hückel model for estimating the mean activity...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy
دوره 65 1 شماره
صفحات -
تاریخ انتشار 2006