The potentiometric determination of stability constants for zinc acetate complexes in aqueous solutions to 295C

Journal Article · Sun Sep 01 04:00:00 EDT 1991 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(91)90362-9· OSTI ID:7235647

Giordano, T H ^[1]; Drummond, S E ^[2]

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1. New Mexico State Univ., Las Cruces (United States)
2. Oak Ridge National Lab., TN (United States)

A potentiometric method was used to determine the formation quotients of zinc acetate complexes in aqueous solutions from 50 to 295C at ionic strengths of 0.03, 0.3, and 1.0 m. The potentiometric titrations were carried out in an externally heated, Teflon-lined concentration cell fitted with hydrogen electrodes. Formal sodium acetate concentrations of the experimental solutions ranged from 0.001 to 0.1 m with acetic acid to sodium acetate ratios ranging from 30 to 300. Sodium trifluoromethanesulfonate (F{sub 3}CSO{sub 3}Na) was used as a supporting electrolyte. Stoichiometries and formation quotients for the complexes ZnCH{sub 3}COO{sup +}, Zn(CH{sub 3}COO){sub 2}, and Zn(CH{sub 3}COO){sub 3}{sup {minus}} were derived from the titration data by regression analysis. Stability constants at infinite dilution (K{sub n}) and other relevant thermodynamic quantities were calculated for these three complexes. Calculations of zinc speciation in acetate-chloride solutions show that zinc acetate complexes should have an importance similar to zinc chloride complexes in high acetate waters where chloride to acetate molal ratios are less than about 10.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7235647
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 55:9; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ACETATES
AQUEOUS SOLUTIONS
CARBOXYLIC ACID SALTS
CHEMICAL ANALYSIS
CHEMISTRY
COMPLEXES
DIAGENESIS
DISPERSIONS
EQUILIBRIUM
GEOCHEMISTRY
MIXTURES
PHYSICAL PROPERTIES
POTENTIOMETRY
QUANTITATIVE CHEMICAL ANALYSIS
ROCK-FLUID INTERACTIONS
SOLUBILITY
SOLUTIONS
STABILITY
TEMPERATURE EFFECTS
THERMODYNAMIC PROPERTIES
TITRATION
ZINC COMPLEXES