Clarification of the volumetric properties of the (tetrahydrofuran+water) systems [J. Chem. Thermodyn. 41 (2009) 1382–1386]: Author’s statement

Phenomenon of “negative partial molar expansibility” of water in tetrahydrofuran: How plausible is it?

“…at each temperature. Proceeding from this, authors [1] had concluded that V 1 w decreases from 14.22 to 10.51 cm 3 Á mol À1 when temperature increases (in the interval studied). Herewith the specified quantities are found to be smaller than the corresponding molar volumes of pure water, V w , by (8.6 to 40.0) cm 3 Á mol À1 (!).…”

“…Recently my attention has been drawn to the above-mentioned article [1] in which Richon and co-authors estimated the partial molar volumes of water at the infinite dilution, V 1 w in tetrahydrofuran (THF) at nine temperatures from (293.15 to 333.15) K. The V 1 w values were obtained using the Redlich-Kister adjusting coefficients relating to the excess molar volumes, V E (x w ), for (THF + water) mixtures with the initial water content in the THF-rich region being x w = 0.307 m.f. at each temperature.…”

“…At the present time, it has been experimentally established that negative values of ð@V 1 w =@TÞ p ¼ E 1 p;w are typical of dilute solutions of water in MeOH [3][4][5][6][7], tert-butanol (t-BuOH) [6][7][8][9], and tert-pentanol (up to 298.15 K only) [10] as well, too. 1 Up to now, no information is available on the nature of this phenomenon except for results of studying the structural ''peculiarities" of water solutions in MeOH and t-BuOH [6,7]. It was concluded that a physical prerequisite for NPME in these cases is the lack of intermediate alkyl moieties in solvent molecules.…”

“…Therefore, one should be concerned about two aspects of the discussed results. Firstly, are the experimental data [1] (including a solvent quality and density measurements) reliable? Secondly, although there is certain agreement between the experimental and smoothed data on V E (x w ), is a use of the Redlich-Kister adjusting procedure to obtain V 1 w correct?…”

“…Secondly, although there is certain agreement between the experimental and smoothed data on V E (x w ), is a use of the Redlich-Kister adjusting procedure to obtain V 1 w correct? If this is true, how may one interpret the ''unique" results [1]? Unfortunately, published data on V 1 w ðTÞ, which could resolve these questions, are lacking.…”