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Estimation of molecular diffusivity in aqueous solution of acetonitrile by the Wilke–Chang equation
Author(s) -
Miyabe Kanji
Publication year - 2011
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201100385
Subject(s) - acetonitrile , chemistry , benzene , aqueous solution , thermal diffusivity , analytical chemistry (journal) , chromatography , methanol , solubility , diffusion , thermodynamics , organic chemistry , physics
It was tried to estimate the molecular diffusivity ( D m ) of solutes in the mixtures of acetonitrile (ACN) and water by the Wilke–Chang equation. Although the information about association coefficient (α) is necessary for the calculation, it has never been proposed for ACN. The value of α was estimated as 1.37 from D m of benzene in ACN at 303 K experimentally measured by the peak parking method. The values of α, i.e. 2.6, 1.9, 1.5, and 1.0, which have respectively been proposed for four solvents, i.e. water, methanol, ethanol, and benzene, were correlated with two physico‐chemical parameters of the solvents, i.e. solubility parameter and E T value. The α value for ACN was plotted around the two correlations, indicating its appropriateness. The values of D m calculated by the Wilke–Chang equation using the α value for ACN were compared with those measured by the peak parking method and the Aris–Taylor method in aqueous solutions of ACN. The mean square deviation of the estimation of D m was calculated as 8.8 and 14%. It was demonstrated that the Wilke–Chang equation can be used for estimating D m with a reasonable accuracy in the mixtures consisting of ACN and water.