3.6 Comparison results with existing methods
In Table 2, the ACGC models are
compared with the classical group contribution methods
(Joback: first-order group
technique, C-G: second-order group
technique, M-G: third-order group
technique, M-G+:
third-order group technique) and S-S
(Sun and Sahinidis: third-order group technique). The groups in Joback
method describe part of atomic adjacent relationship, and the AAG method
is more refined than the Joback method, which is theoretically more
accurate than the Joback method. And the groups we have divided are
guaranteed to appear in more than five compounds, thus the ARE for the
critical temperature looks higher than the Joback method. The ARE ofV c in ACGC model was 1.34%, which was lower than
that of Joback (2.30 %), C-G (1.79 %), M-G (1.80 %),
M-G+ (2.05 %) and S-S (3.10 %). These results show
that the ACGC models are accurate. The ARE of critical properties
calculated by ACGC method is lower than M-G+ method
and S-S method. Although ARE of the T c ACGC model
is higher than that of the C-G and M-G methods, we screened the data so
that the number of occurrences of groups in the data set is not less
than 5 times, so the model is more reliable. In addition, this work aims
to develop reliable models with good predictive ability, using 20 % of
the data set as test sets and the rest as training sets to fit the
property model, which is different from the traditional group
contribution method.
Table 2 Comparison of ACGC with GC methods.