Aliphatic alcohols in pure state are associated, after
the addition of aliphatic hydrocarbon follow their gradual dissociation, so
accurate activity coefficient
description in such mixture, e.g. using Wilson equation,
is impossible. Using 9 collections of activity
coefficient literature data (selected as in ATTEMPT TO DESCRIBE) I have checked
(using Wilson equation) how
activity standard deviation is changed along with
increasing of measurement point number, starting from
pure alcohol. It turned out that the standard deviation
has decreased to alcohol mole fraction approximately
0,4-0,6. Perhaps it may show that mixture
characteristics in this concentration range differ from
mixture characteristics in the remaining range, because
the examined range fulfills the condition of solution of
hydrocarbon in alcohol. Could the description with the
aid of two solutions be better than continuous
description of mixture?