Abstract
The traditional method of calculating equilibrium constants in glacial acetic acid medium was developed by Kolthoff and Bruckenstein in 1957; thenceforth, and even presently, few alternatives have been made available to undertake such studies. This paper presents the results obtained with the use of the program Superquad to assess the equilibrium constants of various bases and their protonated perchlorate salts in glacial acetic media. A model of formation equilibria is proposed and fed into the program, considering the species present during an acid–base titration. The calculations of the equilibrium constants using Superquad for pyridine and diethylamine are statistically in agreement with those reported in the literature, (for pyridine: pKB=5.98±0.02, pK PyHClO4=5.47±0.02 and for diethylamine pKB=5.52±0.04, pK DietHClO4=4.52±0.07). With the use of Superquad, the values found for the aniline were pKB=6.95±0.06 and pK AnilHClO4=4.89±0.06.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
United States Pharmacopeial Convention (2000) USP24-NF19, official from January 1, 2000. United States Pharmacopeial Convention
Kolthoff M, Bruckenstein S (1957) J Am Chem Soc 79:1
Bruckenstein S, Kolthoff M (1956) J Am Chem Soc 78:2974
Shkodin A, Izmailov N, Karkuzaki LI (1961) Ukr Khim Zh 27:155
Shkodin A, Karkuzaki LI (1959) Ukr Khim Zh 33:2795
Shkodin AM, Zadornichova LP, Vysshykh Uchebn. Zavedenii (1964) Khim i Khim Teknol Zh 7:568
Schwarzenbach G, Stenby P (1959) Helv Chim Acta 42:2342
Tanaka M, Nagasuka G (1965) Anal Chim Acta 33:543
Wegmann D, Simon W (1962) Helv Chim Acta 45:962
Barbosa J, Cortina JL, Rosés M (1992) Anal Chim Acta 256:206
Barbosa J, Cortina JL, Rosés M (1992) Anal Chim Acta 256:211
Kolling OW (1976) Anal Chem 48:1221
Gans P, Sabatini A, Vacca A (1985) J Chem Soc Dalton Trans 19:1995
Fritz JS (1952) Acid–base titrations in nonaqueous solutions. GF Smith Chemical Co., Columbia University
Popovych O, Tomkins R (1981) Nonaqueous solution chemistry. Wiley
Biedermann G, Sillén LJ (1953) Ark Kemi 5:425
Miller JN, Miller JC, Miller J (2001) Statistics and chemometrics for analytical chemistry, 4th edn. Prentice Hall
Acknowledgments
The CONACyT Project 35323-E has supported this research work. One of us (GAAR) acknowledges CONACyT for the studentship granted. This work was done in partial fulfilment of GAAR's Ph. D. requirements. The authors wish to thank Dr Mario A. Romero-Romo (from UAM-Azcapotzalco) for fruitful discussions and for the English translation of this paper and to Dr A. Vacca and Dr P. Gans for the authorised use of Superquad.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Álvarez-Romero, G.A., Rojas-Hernández, A., Vázquez, G.A. et al. Potentiometric determination of equilibrium constants of bases and perchlorates of protonated bases in glacial acetic acid using Superquad. Anal Bioanal Chem 375, 826–830 (2003). https://doi.org/10.1007/s00216-003-1785-5
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00216-003-1785-5