Derivative Analysis of Potentiometric Titration Data To Obtain Protonation Constants

1996 ◽  
Vol 68 (22) ◽  
pp. 3973-3978 ◽  
Author(s):  
Jian-Feng Chen ◽  
Yuan-Xian Xia ◽  
Gregory R. Choppin
Keyword(s):  
Potentiometric Titration ◽  
Protonation Constants ◽  
Derivative Analysis ◽  
Titration Data

Plotting potentiometric titration data using an Apple II

1982 ◽  
Vol 59 (6) ◽  
pp. 519
Author(s):  
Vinay Kumar ◽  
John I. McAndrews ◽  
Jon W. Mauch
Keyword(s):  
Potentiometric Titration ◽  
Titration Data

scholarly journals COMPLEXATION OF GOLD (III) WITH 1-FURFURYLIDENE AMINO-1,3,4-TRIAZOLE AT 288 – 318 K

2017 ◽  
Vol 60 (5) ◽  
pp. 37
Author(s):  
Safarmamad M. Safarmamadov ◽  
Davron A. Muborakkadamov ◽  
Kimyo S. Mabatkadamova
Keyword(s):  
Potentiometric Titration ◽  
Stability Constants ◽  
Least Squares Method ◽  
Slope Angle ◽  
Organic Ligand ◽  
General Stability ◽  
Wide Ph Range ◽  
Titration Data ◽  
Ph Range ◽  
Number Of Particles

The potentiometric titration method was used to determine the ionization constant of 1-furfurylideneamino-1,3,4-triazole (pKk = 11.83 log.). The dominating region of 1-furfurylideneamino-1,3,4-triazoles (FF) was identified in a wide pH range. It was shown that 1-furfurylideneamino-1,3,4-triazole ion (HL+) predominates in the pH range up to 0.5-2.0. At pH of 5.0 to 10.5, the neutral molecule (L) predominates, and at pH>13.0 1-furfurylideneamino-1,3,4-triazolate ion (L-) predominates in a solution. To determine the number of a particles formed during the interaction of Au (III) with FF from the potentiometric titration data the dependence of ΔE on -lg [FF] was used for 1-furfurylideneamino-1,3,4-triazole gold (III) complexes at 288-318 K. The slope of the curves of the ΔE-lg [FF] with the excess of 1-furfurylideneamino-1,3,4-triazole at temperatures of 288, 298 and 308 K is 0.059, 0.060 and 0.061 V/mol/l-1, which corresponds to the sequential addition of three molecules of 1-furfurylideneamino-1,3,4-triazole to gold (III). At the temperature of 318 K it is not possible to find the slope angle corresponding to the tris complex due to a quick change in the potential with an excess of FF in a solution. General stability constants of 1-furfuryldenoamino-1,3,4-triazole complexes of Au (III) according to potentiometric titration data was determined by the Friedman method and non-linear least squares method. It was shown that as the temperature increases, the general stability constants of gold (III) complexes are reduced. It was shown that the introduction of substituents into the 1,2,4-triazole molecule affects both the number of particles formed in a solution and the stability of the complexes. Thus, in the system Au (III) -1,2,4-triazole-H2O at 298 K four complex particles are formed, and in the Au (III) system, 1-furfurylideneamino-1,3,4-triazole-H2O only three are formed. The general stability constants of 1,2,4-triazole complexes equal to lgβ1 = 6.56, lgβ2 = 11.13, lgβ3 = 14.94 and lg4 = 18.78 log units, and for 1-furfurylideneamino-1,3,4-triazole complexes Igβ1 = 5.92, lgβ2 = 10.14, lgβ3 = 13.80 log units. The thermodynamic functions of complexe formation were calculated by the temperature coefficient method. It was shown that all complex particles are enthalpy-stabilized. The greatest increase in the exothermicity of the reactions is observed when a complex of three organic-ligand molecules is formed. The value of ΔS at all steps of complexation is negative, which is most likely due to the decrease in the number of particles in a system under study. The spontaneous reaction of complexation is determined by the enthalpy factorFor citation:Safarmamadov S.M., Muborakkadamov D.A., Mabatkadamova K.S. Complexation of gold (III) with 1-furfurylidene amino-1,3,4-triazole at 288 – 318 K. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 5. P. 37-43.

scholarly journals Complexation between Molybdenum(VI) and Histidine. Least Squares Treatment of Potentiometric Titration Data.

1981 ◽  
Vol 35a ◽  
pp. 233-237 ◽  
Author(s):  
Erik Sylvest Johansen ◽  
Ole Jøns ◽  
V. Romano ◽  
R. Zingales ◽  
Kastriot Spahiu
Keyword(s):  
Least Squares ◽  
Potentiometric Titration ◽  
Titration Data

scholarly journals Reliability of protonation constants of vildagliptin dimers by the regression analysis of pH-titration data

2013 ◽  
Vol 11 (7) ◽  
pp. 1101-1111 ◽  
Author(s):  
Milan Meloun ◽  
Zuzana Ferenčíková ◽  
Irena Niesnerová ◽  
Tomáš Pekárek
Keyword(s):  
Regression Analysis ◽  
Systematic Error ◽  
Temperature Variation ◽  
Goodness Of Fit ◽  
Formation Constants ◽  
Protonation Constants ◽  
Parameter Estimates ◽  
Regression Diagnostics ◽  
Ph Titration ◽  
Titration Data

AbstractProtonation constants of protonated monomers and dimers of the vildagliptin are determined potentiometrically. For the low concentration c L = 3.3 mmol dm−3 the monomers L and LH dominate, while for a higher concentration c L = 6.3 mmol dm−3 the dimers L2H2, L2H3, L2H4 and L2H are mainly present. The algorithm used has little influence on the precision of the formation constants in comparison with the reproducibility of the titration. The mixed protonation constants of vildagliptin dimers Lq Hr at various temperatures are determined using FBSTAC4 and HYPERQUAD regression analysis of the potentiometric titration data. The accuracy of the protonation constants log10 βqr depends on the accuracy of the group parameters. As two group parameters L 0, H T are ill conditioned in a model, their determination is therefore uncertain; both can significantly cause a systematic error in the estimated common parameters log10 βqr . Using various regression diagnostics the goodness-of-fit proves the reliability of all parameter estimates. A rough estimation of thermodynamic enthalpies ΔH 0 (kJ mol−1) and entropies ΔS 0 (J K−1 mol−1) is determined from the temperature variation of protonation constants. The enthalpy shows the protonation process is exothermic, and the entropy indicates that it is spontaneous.

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