Acid association quotients of tris(hydroxymethyl)aminomethane in aqueous NaCl media to 200/sup 0/C
The molal acid association quotients of tris(hydroxymethyl)aminomethane (Tris, also abbreviated as THAM) were determined potentiometrically in a concentration cell fitted with hydrogen electrodes. The emf was recorded for equimolal Tris/Tris-HCl buffer solutions from 5 to 200/sup 0/C at approximately 25/sup 0/ intervals, and at ionic strengths of 0.0759, 0.2012, 0.7232, 1.9996, 3.5077, and 4.9599. The molal association quotients, as well as those selected from the literature and calorimetrically-determined enthalpies of reaction, were simply described by a six parameter equation which yielded the following thermodynamic quantities at infinite dilution and 25/sup 0/C: logK = 8.701 +/- 0.009, ..delta..H/sup 0/ = -47.53 +/- 0.13 kJ-mol/sup -1/, ..delta..S/sup 0/ = -4.9 +/- 0.5 J-K/sup -1/-mol/sup -1/, and ..delta..C/sup 0//sub p/ = 67 +/- 13 J-K/sup -1/-mol/sup -1/. The fitting equation for this isocoulombic reaction incorporates a four term expression for logK and a linear isothermal dependence on ionic strength.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6977699
- Journal Information:
- J. Solution Chem.; (United States), Journal Name: J. Solution Chem.; (United States) Vol. 16:7; ISSN JSLCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
ALKALI METAL COMPOUNDS
ALKANES
AMINES
AQUEOUS SOLUTIONS
BINDING ENERGY
BUFFERS
CALORIMETRY
CHLORIDES
CHLORINE COMPOUNDS
DILUTION
DISPERSIONS
ELECTROLYTES
ELECTROMOTIVE FORCE
ENERGY
EQUILIBRIUM
HALIDES
HALOGEN COMPOUNDS
HYDROCARBONS
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INORGANIC ACIDS
MIXTURES
ORGANIC COMPOUNDS
PH VALUE
PHYSICAL PROPERTIES
POTENTIOMETRY
SODIUM CHLORIDES
SODIUM COMPOUNDS
SOLUTIONS
TEMPERATURE EFFECTS
THERMODYNAMIC PROPERTIES
TITRATION
VALENCE