Computation of the Krafft temperature value for aqueous solutions of anionic fluorosurfactants
Keywords:
Krafft temperature, fluorosurfactants, anionic surfactants
Summary
The practical usefulness of using surfactants in market products is determined by their chemical structure and solubility of aqueous solutions. In practice, it is important to know the temperature above which a given surfactant is soluble in an aqueous solution. The quantitative parameter characterizing the solubility of ionic surfactants in aqueous solutions is the Krafft temperature. It is a temperature (or more precisely, a narrow temperature range) above which the solubility of a given surfactant in water increases rapidly. Knowledge of Krafft temperature of any surfactant is required to design high quality compositions of new household chemistry products and cosmetic products in which a given surfactant can be used as the active ingredient.
In this paper we present results of our study on the relationship between Krafft temperature for aqueous solutions of anionic fluorosurfactants and their chemical structure. Empirical values of the Krafft temperature available in the literature for aqueous solutions of 27 anionic perfluorosurfactants were correlated with their chemical structure. We developed a set of 11 group contributions for calculating Krafft temperature values for aqueous solutions of anionic perfluorosurfactans. Krafft temperature values calculated using them for aqueous solutions of 27 anionic perfluorosurfactants were compared with experimental data. It has been shown that the newly proposed set of numerical values of the group cotributions assigned to the structural elements of perfluorosurfactants allows for the correct estimation of the Krafft temperature values in aqueous solutions for the test data set with a maximum error of 6.9oC and an mean square error of 4.1oC.
Prof. dr hab. inż. Ryszard ZIELIŃSKI
Poznan University of Economics and Business
Institute of Quality Science
Department of Technology and Instrumental Analysis
Aleja Niepodległości 10, 61-875 Poznań, Poland
tel.: (+48) 61-8569056
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