Does reference data on physicochemical properties of organic compounds need an additional processing?

Abstract

Using normal boiling points of n-alkyl phosphines it is shown that some of available reference data on the physicochemical properties of organic compounds are unreliable or even erroneous. The use of such data for any practical purposes is undesirable. Among known methods for evaluating physicochemical characteristics of single compounds there are no ones providing a priori required precision. However, such demand can be fulfilled using the methods of comparison of properties of different series of homologues. The predestination of the quality control approach considered is refining physicochemical properties (A) of homologues. It implies their comparison (mutual recalculation) with analogous data for one or few series of analogues characterized by more reliable physicochemical data using three-parameter linear-logarithmic equation lg A(series I)= a lg A(series II) + bY + c, where A is the values of the property under consideration, Y is the additive parameter providing the mutually unambiguous correspondence of homologs of two series under comparison. In this paper the condition Y = nC (number of carbon atoms in the molecules of homologs under consideration) is selected. The following independent step of data processing is the controlling of correspondence of A-values to the recurrent relation A(n + 1) = aA(n) + b, where A(n + 1) is the A-value for homolog containing (n + 1) carbon atoms in the molecule, and A(n) is the A-value for previous homolog. Similar procedures of the quality control of reference data is recommended for different properties of organic compounds. Refs 21. Figs 1. Tables 1.