Chemistry Reference
In-Depth Information
Fig. 12 Mass average
chemical composition for
every fraction obtained by
cross fractionation using
different fractionation
strategies:
circles
SPF/SPF,
crosses
SPF/SSF,
stars
SSF/
SPF, and
squares
SSF/SSF
0,7
0,6
0,5
0,4
0,3
10
15
20
25
30
35
40
45
50
55
number of fraction
Fig. 13 Nonuniformity for
every fraction obtained by
cross fractionation using
different fractionation
strategies:
circles
SPF/SPF,
crosses
SPF/SSF,
stars
SSF/
SPF, and
squares
SSF/SSF
0,4
0,3
0,2
0,1
10
15
20
25
30
35
40
45
50
55
number of fraction
(stars and squares in Fig.
12
), the mass-average chemical composition of the
intermediate fractions increases with the number of fraction. All fractions, except
the fractions obtained from the last intermediate fractions, show a similar behavior.
If the fractionation of the intermediate fractions in solvent 2 is carried out using the
SPF mechanism (stars in Fig.
12
), the mass-average chemical composition
increases with the number of fraction, whereas the chemical composition decreases
if the second fractionations in the solvent 2 is performed with the SSF method
(squares in Fig.
12
). Using the data in Fig.
12
, it can be concluded the SSF/SSF
strategy leads to the fractionation having the highest effectivity in terms of frac-
tionation according to the chemical composition.
In Fig.
13
, the fractionation results with respect to the molecular weight are
plotted in terms of the nonuniformity of the obtained fractions. Independently of the
fractionation strategy applied, all obtained final fractions have a much smaller
