Determination of thermodynamic functions by means of infrared spectroscopy. Complex formation in phenol-aliphatic sulfide and phenol-aliphatic sulfoxide systems

1969 ◽  
Vol 34 (8) ◽  
pp. 2390-2397 ◽  
Author(s):  
V. Šára ◽  
J. Moravec ◽  
V. Horák ◽  
M. Horák
Keyword(s):  
Infrared Spectroscopy ◽  
Complex Formation ◽  
Thermodynamic Functions

Determination of thermodynamic functions by means of infrared spectroscopy. The accuracy in -ΔH determination; Formation of complexes phenol-pyridine and its homologues

1979 ◽  
Vol 44 (1) ◽  
pp. 148-156 ◽  
Author(s):  
Václav Šára ◽  
Jaromír Moravec ◽  
Milan Horák
Keyword(s):  
Infrared Spectroscopy ◽  
Thermodynamic Functions ◽  
Ionization Constants ◽  
Experimental Conditions ◽  
Pyridine Bases ◽  
Methyl Derivatives ◽  
Pyridinic Nitrogen ◽  
Influence Of Substituents ◽  
Formation Of Complexes

Values of thermodynamic functions -ΔH, -ΔG, and -ΔS of the complex formation between molecules of pyridine (and its methyl derivatives) and phenol in CCl4 solutions were determined using infrared spectroscopy. After optimalizing experimental conditions the error in -ΔH determination does not exceed 0.2%; this accuracy is sufficiently high to investigate the influence of substituents on the pyridinic nitrogen basicity. The values of -ΔH determined in this way correlate linearly with values of ionization constants of pyridine bases.

scholarly journals A Novel Spectrophotometric Determination and Kinetic Study of Sulfamethoxazole in Pure and Tablet Formulation using 9-chloroacridine Reagent

2021 ◽  
pp. 1-13
Author(s):  
Alaa A. Ahmed ◽  
Theia’a N. Al-Sabha ◽  
Emad A. S. Al-Hyali
Keyword(s):  
Complex Formation ◽  
Thermodynamic Functions ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Official Method ◽  
First Order ◽  
Pseudo First Order ◽  
Semi Empirical ◽  
Good Detection

A spectrophotometric method has been developed for analysis of Sulfamethoxazole (SMX) in pure and dosage forms. The method is based on the reaction of the SMX with 9-chloroacridine (9-CA) reagent in organic and acidic medium, to produce a yellow product having maximum absorption at 448 nm. Beer’s law was obeyed in the concentration range 1-30 μg.ml-1 with molar absorptivity of 1.63x104 L.mol-1.cm-1 with good detection and quantification limits. Accuracy (Average recovery %) and precision are 98.43% and 0.651, respectively. The proposed method was applied successfully for determination of Sulfamethoxazole in its commercial dosage form as tablet and agree well with the official method. The equilibrium constant and the thermodynamic functions (ΔHo, ΔGº and ΔSº) of the  complex formation were estimated. The study revealed that the complex formation could occur spontaneously, the type of interacting forces between SMX and 9-CA are physical is nature and association increases the order of the studied systems. The results of kinetic parameters indicated that, the reaction is pseudo first order with respect to SMX. The rate constant at various temperatures and the thermodynamic functions of activation were determined. Theoretical parameters were calculated by applying the semi-empirical Austin method (AM1). These parameters are helped to suggest reaction mechanism and supporting other results.

Colorimetric Determination of Fluoride in Drinking Groundwater using a Polymeric Zirconium Complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline

2013 ◽  
Vol 12 (7) ◽  
pp. 460-465
Author(s):  
Sameer Amereih ◽  
Zaher Barghouthi ◽  
Lamees Majjiad
Keyword(s):  
Drinking Water ◽  
Detection Limit ◽  
Complex Formation ◽  
Molar Absorptivity ◽  
Colorimetric Determination ◽  
Zirconium Complex ◽  
Reliable Determination ◽  
Percentage Recovery ◽  
Quantitation Limit

A sensitive colorimetric determination of fluoride in drinking water has been developed using a polymeric zirconium complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline as fluoride reagents. The method allowed a reliable determination of fluoride in range of (0.0-1.5) mg L-1. The molar absorptivity of the complex formation is 7695 ± 27 L mol-1 cm-1 at 460 nm. The sensitivity, detection limit, quantitation limit, and percentage recovery for 1.0 mg L-1 fluoride for the proposed method were found to be 0.353 ± 0.013 μg mL-1, 0.1 mg L-1, 0.3 mg L-1, and 101.7 ± 4.1, respectively.

Near Infrared Spectroscopy Used in Purification and Determination of Pharmaceutical Cocrystal

2013 ◽  
Vol 41 (12) ◽  
pp. 1928
Author(s):  
Zong-Liang CHI ◽  
Miao-Miao WANG ◽  
Xiao-Dong CONG ◽  
Shao-Guang LIU ◽  
Bao-Chang CAI
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Pharmaceutical Cocrystal
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