Reconciliation of the vapor pressure temperature dependences of poorly studied substances. Part I: Individual compounds

Abstract

Determination of the thermodynamic parameters of vaporization requires expensive equipment and significant financial and time expenditure. On the other hand, obtaining these characteristics for the permanently growing number of organic substances is impossible. In this work, we propose a simple procedure for derivation of the vaporization characteristics from the independent measurements of the reduced and normal pressure boiling points that are often obtained by organic chemists during purification procedures and collected in the databases. The consistency of such p-T measurements was discussed, and expected errors of derived vaporization enthalpies and saturated vapor pressures were evaluated. Applying the methodology proposed, we derived the vaporization characteristics of six compounds: ethyl 4-chlorobutanoate, benzyl methyl ether, 4-methylanisole, ethyl 2-acetyloxypropanoate, 3,3-dimethyl-allyl chloride and ethyl cyclohexanecarboxylate. As a result, this methodology promises obtaining previously unknown vaporization characteristics of hundreds of molecules in a short time without performing the additional measurements. The simplicity of the procedure proposed and existence the data needed in the electronic databases makes possible an automatization of this approach.