“Rigorous treatment of linear hydrogen bonded alcohol chains” of M.Szwarc. A reply of the author of the mobile order theory

• Published in: Journal of molecular liquids 1998, Vol.75 (3), p.261-269
• Main Author: Huyskens, Pierre L.
• Format: Article
• Language: English
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/S0167-7322(97)00102-5

The “Rigorous Treatment of Linear Hydrogen Bonded Alcohol Chains” recently published in this Journal by M. Szwarc [1] is a criticism of the Mobile Order and Disorder (MOD) theory of Huyskens et al. [2]. This “rigorous treatment” of Szwarc is identical to an older one of Huyskens [3] which was based on the approximation of Mecke and Kempter [4]. The new MOD theory of Huyskens differs from the older one by the use of time fractions γ instead of ensemble fractions α, as proposed by Einstein in 1911 [5,6]. However different types of time fractions are used in ref.[2]. One considers the fractions of the time γ -OH- ; γ OH- ; γ -OH ; γ OH during which a given OH group is involved in H-bonding at both sides, only at the right, only at the left and not at all. These fractions taken over a long time are equal to the fractions α -OH- ; α OH- ; α -OH ; α OH of the molecules which are, at a given time, in the different bonding states. But the MOD theory also considers another partition of the time γ bonded and γ non-bonded during which a molecule has the ownership of the energy of one H-bond or not. The time fraction γ non-bonded is much larger than γ OH and α OH because the number of molecules involved in H-bonding at a given time is larger than the number of H-bonds. M.Szwarc does not understand the fundamental difference between γ non-bonded and γ OH and presents a completely deformed version of the MOD theory. In many cases the quantitative predictions of experimental data made by this treatment do not appreciably differ from those of classical theories based on ensemble fractions [7,8]. In some cases, however, the predictions diverge completely from each other and the MOD predictions give then always much better results. Examples of such predictions concerning solubilities, ir data and conductivities are taken from our own works [2,9], from the recent work of Ruelle and Kesselring [10] and from the paper of Verheyden, Van Beylen and Huyskens [11]. These few examples constitute the best answer to the attacks of M. Szwarc.