[en] Highlights: ► Molecular geometric factors were found to be important determinants for boiling entropy and thus the boiling temperature. ► Only four molecular geometric factors were used in the study. ► A group contribution method was used to calculate enthalpy of boiling. ► The proposed method is simple and the estimations are in good agreement with experimental values. - Abstract: Boiling related thermodynamic properties are important parameters in research. In this study, a model integrating both additive groups and non-additive molecular geometric factors has been developed for the calculation of boiling enthalpy, entropy and temperature. The calculated values are in good agreement with the measured values of 470 compounds. This model provides a simple and accurate estimation of enthalpy of boiling, entropy of boiling and boiling temperatures with absolute average errors of 0.62 kJ/mol, 1.15 J/K · mol and 7.13 K respectively.

[en] A bottom reflooding experiment in narrow rectangular channels is carried out to investigate the effect of the subcooling and reflooding velocity (U_in) on the minimum film boiling point (MFBP) at atmospheric pressure. In this paper, based on the temperature variation curves of the heating plate during reflooding and the standard definition of minimum film boiling point, the derivative of temperature versus time reaching 11℃/s, the effect of subcooling and U_in on minimum film boiling temperature (T_min) and quench velocity is analyzed. A comparison between experimental T_min and calculated values is made. The results show that T_min and quench velocity will increase with the subcooling and U_in, while the effect is mild for high U_in. The error between experimental T_min and calculated T_min by Henry correlation is within ± 10%, while the values calculated by Peterson and Bajorek correlation are overvalued. (authors)

[en] The method of impulsive heating of a wire probe is used to measure the spontaneous boiling point of commercial synthetic isoprene rubber and its solutions in saturated hydrocarbons, polyethylene glycols, and polyethylsiloxanes with allowance for thermal degradation of the polymer. A formula is obtained to describe the dependence of the boiling point of the polymer solution on heating time. 15 refs., 3 figs., 1 tab

No abstract available

[en] Highlights: • A Claussius–Claperyron equation is obtained in the Pitzer corresponding states scheme. • Some well-known empirical rules for the vapor pressure are rewritten in terms of the Pitzer acentric factor. • The Guggenheim point follows the corresponding state scheme better than the normal boiling point. • The Ambrose–Walton vapor pressure equation yields excellent agreement with NIST data in all considered cases. -- Abstract: A form for the Clausius–Clapeyron vapor-pressure equation is obtained in the Pitzer corresponding states scheme. This equation allows one to rewrite the well-known Trouton, Guldberg, van Laar and Guggenheim rules in terms of the acentric factor ω. The original forms of these empirical rules are recovered for some particular values of ω. The proposed rules are checked by analyzing National Institute of Standards and Technology (NIST) data on the liquid-vapor coexistence curve for 105 fluids. These rules have been also analyzed by using the well-known Ambrose–Walton (AW) vapor pressure equation

[en] The method of impulsive heating of a wire probe is used to study the high-temperature boundary of stability of the condensed state of high-molecular-weight compounds. Measurements are made of the temperatures to which several polymeric liquids can be superheated. The liquids differ in molecular weight. Similar measurements were obtained for polymerizing systems. The effect of dissolved carbon dioxide on the parameters characterizing fluctuation boiling of the systems. The effect of dissolved carbon dioxide on the parameters characterizing fluctuation boiling of the system was examined. 20 refs., 4 figs

[en] Viscosity “η” is one of the most important properties in Newtonian liquids (NLs). It depends on temperature, pressure, molar mass, etc. Its theoretical description is quite complex. For these reasons numerous empirical equations have been suggested, so far. Unfortunately, they have limitation of use. In this regard, firstly we model the relationship between the energy of Arrhenius ($E_a$) and the factor ($\mathit{ln}{A}_s$). Secondly, we deduce a simple empirical model that theoretically describes the viscosity (η). Besides that, we introduce two other interesting models: one relies $E_a$ and the Arrhenius temperature (T_A), by analogy, it looks like the phenomenon of charging a capacitor. The other estimates the boiling temperature “T_b” of an unknown NL. All these suggested models have been validated by using a data set of 157 pure solvents grouped from literature. These models will be useful for engineering data and science community. The model is reduced to a single variable without losing significant accuracy.

[en] A description is made of the physics behind the method of finding the altitude of mountains with the boiling point of water discovered by F.J. de Caldas including results from a test and instructions for an educational experiment

[en] The Wiener polarity index $W_p$ is a topological index that was devised by the chemist Harold Wiener for predicting the boiling points of alkanes. The index $W_p$ for chemical trees (chemical graphs representing alkanes) is defined as the number of unordered pairs of vertices at distance 3. A vertex of a chemical tree with degree at least 3 is called a branching vertex. A segment of a chemical tree $T$ is a nontrivial path $S$ whose end-vertices have degrees different from 2 in $T$ and every other vertex (if exists) of $S$ has degree 2 in $T$. In this paper, sharp upper and lower bounds on the Wiener polarity index $W_p$ are derived for the chemical trees of a fixed order and with a given number of branching vertices or segments, and for every such bound, a class of trees attaining that bound is obtained. As a consequence of the derived results, a vital step towards the complete solution of an existing open problem concerning the maximum $W_p$ value of chemical trees is provided.

[en] The vaporisation behaviour of thorium an uranium halides is being investigated in the solid and liquid region by boiling temperature and transpiration techniques. The two techniques have been used for studies on ThCl₄, UF₄ and UCl₄ in the temperature ranges of 880 to 1161 K, 1169 to 1427 K and 763 to 1008 K respectively. The data from the two techniques agree excellently with each other for these three halides, thereby establishing their vaporisation behaviour. Boiling temperature studies have been completed for ThF₄, ThBr₄, ThI₄ and UBr₄ in the temperature ranges of 1395 to 1554 K, 842 to 1089 K, 790 to 1044 K and 759 to 1004 K respectively. (orig./RW)