Background
The group contribution method for the determination
of the Gibbs free energy of formation of organic
compounds is based on the idea that (i) a given
compound is considered to be composed of groups,
that (ii) numerical values can be assigned to these
groups, and that (iii) adding the values of these
groups to a (constant) starting value yields a reliable
estimate of the compound of interest. Table 1.
lists the values for the contributions of a number of
open-chain groups with one or more free bonds as
estimated by Mavrovouniotis (1990). Also given are
the value of origin, i.e. the starting value that is used
in the estimation, and a value to be used if a compound
consists solely of carbon and hydrogen
atoms. These values, as well as the estimates obtained
with these values, are for compounds in
aqueous solution at a concentration of i M.