Vlastimil Růžička

Recommended vapour and sublimation pressures and related thermal data for chlorobenzenes

Abstract Recommended data on vapour pressures are presented for all dichlorobenzenes, all trichlorobenzenes, and pentachlorobenzene in the temperature range from the triple point up to the normal boiling point. For some chlorobenzenes where reliable sublimation pressures and solid heat capacities are available (1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,3,5-trichlorobenzene, and pentachlorobenzene), recommended sublimation pressures are also given that cover the range from about −40°C (with the exception of 1,4-dichlorobenzene where there are no experimental sublimation pressures below the phase transition at −1.38°C) up to the triple point temperature. The data were developed by a simultaneous multi-property correlation of vapour or sublimation pressures and the related thermal data (heat capacities in the liquid or the solid phase, heat capacities of the ideal gas, enthalpies of vaporisation or sublimation). The data are presented as parameters of the Cox correlation equation which has an identical form for description of vapour–solid (v–s) and vapour–liquid (v–l) equilibria and are consistent at the triple point. Recommendations are based mostly on new experimental vapour and sublimation pressures obtained recently by the authors. Solid and liquid heat capacities required for the simultaneous correlation were provided by merging new experimental data measured using a C80 Setaram heat conduction calorimeter over approximate temperature range from 30 to 160°C (depending on the compound) with the data critically selected from the literature.

Vapor pressure of metal organic precursors

The vapour pressure of four metal organic precursors, diethylzinc, triethylantimony, trimethylgallium and trimethylaluminium, used in the metal organic vapor phase epitaxy processes was measured by a static method in the technologically important temperature range from 238 to 293 K. The experimental data were fitted by the Antoine equation and represent updated values of the present day high-purity materials providing comparison with the previously published data.

Heat capacities of some phthalate esters

Isobaric heat capacities Cp in the liquid phase of dimethyl phthalate, diethyl phthalate, dibutyl phthalate, bis(2-ethylhexyl) phthalate, and benzyl butyl phthalate were measured by commercial SETARAM heat conduction calorimeters. Results obtained cover the following temperature range: dimethyl phthalate 283 to 323 K, diethyl phthalate 306 to 370 K, dibutyl phthalate 313 to 447 K, bis(2-ethylhexyl) phthalate from 313 to 462 K, benzyl butyl phthalate from 313 to 383 K. The heat capacity data obtained in this work were merged with available experimental data from literature, critically assessed and sets of recommended data were developed by correlating selected data as a function of temperature.

Solubility of water in blends of gasoline, methanol and a solubilizer

Abstract Lojkasek M., Růžicka V., Jr., and Kohoutova A., 1992. Solubility of water in blends of gasoline, methanol and a solubilizer. Fluid Phase Equilibria, 71: 113-123. Limited miscibility of blends of gasoline with methanol and of gasoline with methanol and oxygenated octane-boosting components in the presence of water has been investigated. The effect of three solubilizers, tert -amyl methyl ether, methyl tert -butyl ether and isobutanol, on the enhancement of water solubility in a blend of gasoline, methanol and a solubilizer has been compared. Extraction of methanol by water from a blend of gasoline, methanol and tert -amyl methyl ether that contained 4–8 vol.% oxygenated hydrocarbons has been measured and a distribution coefficient of methanol between the water-rich and hydrocarbon-rich phases has been calculated.

Liquid—liquid equilibrium in methanol + gasoline blends

Abstract An investigation has been carried out to study the limited miscibility of methanol and gasoline blends over the temperature range −20 to 20°C. Two liquid phases in equilibrium were analysed by mass spectrometric methods and their composition reported, in addition to the methanol content, in terms of six principal classes of hydrocarbons. Liquid—liquid equilibrium was predicted using the UNIFAC group contribution model. In liquidliquid equilibrium calculations, gasoline was represented by a set of model compounds. The number of the different groups that comprise each model molecule was determined using the result of a distillation analysis and the paraffin—naphthene—aromatic composition. Estimation of conjugate phase composition using the UNIFAC model is reasonable at temperatures above 0°C. To describe correctly the limited miscibility of methanol+gasoline blends over the whole temperature range studied, we found that ‘specific’ UNIFAC interaction parameters were necessary.