ISSN:
1572-8927
Schlagwort(e):
Apparent molar volume
;
apparent molar relative enthalpies
;
enthalpies of dilution
;
electrolyte
;
and ionic association
;
Bjerrum model
;
acetonitrile
;
propylene carbonate
;
n-propanol
;
γ-butyrolactone
;
tetrabutylammonium bromide
;
lithium perchlorate
;
sodium thiocyanate
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract The association theory based on the Bjerrum model, which had been developed for the treatment of apparent and partial molar volumes of electrolyte solutions, is extended to apparent molar relative enthalpies L 2,φ. Experimental enthalpies of dilution for tetrabutylammonium bromide in acetonitrile, propylene carbonate, and γ-butyrolactone and for lithium perchlorate and sodium thiocyanate in acetonitrile were obtained and analyzed with this model. Literature data for various electrolytes in water, acetonitrile, and n-propanol were also reanalyzed. Through the Bjerrum equations, enthalpies of dilution can be extrapolated to infinite dilution and reliable L 2,φ obtained for associated electrolytes. The model can be used to estimate the association constant K A of the electrolyte and these K A are compared with literature values (generally obtained from conductivity). Considering the difference in the concentration ranges investigated in L 2,φ and Λ measurements, K A extracted from L 2,φ generally fall within an expected range of deviation from the ones obtained by conductivity, provided that no specific interactions are present in solution.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1022656122523
Permalink
