Handbook of Solvents - George Wypych - ChemTech - Ventech!

172 Christian Wohlfarth
L L s
Ω1 = 1 1 = 1 1 1
L s ( B11 −V1)( P −P1)
⎡
⎤
a / w ( P / w P ) exp ⎢
⎥ [4.4.22c]
⎣⎢
RT
⎦⎥
These relations can be applied to VLE-data from all experimental methods.
The data reduction for infinite dilution IGC starts with the usually obtained terms of
retention volume or net retention volume.
where:
Vnet = Vr− Vdead
[4.4.23]
Vnet Vr Vdead net retention volume
retention volume
retention volume of the (inert) marker gas, dead retention, gas holdup
These retention volumes are reduced to specific ones by division of Equation
[4.4.23] with the mass of the liquid (here the liquid, molten polymer), corrected for the pressure
difference between column inlet and outlet pressure and reduced to T 0 = 273.15K.
where:
V
0
g
V
=
m
⎛
⎜
⎝
0
Vg m2 Pin Pout ( P / P )
( P P )
⎞⎛T
3 1
0 ⎞
−
⎟
⎟⎜
⎟
3
⎠⎝
T ⎠2
/ −1
net in out
2
in out
2
specific retention volume corrected to 0 o C
mass of the polymer in the liquid phase within the column
column inlet pressure
column outlet pressure
[4.4.24]
0
Theory of GLC provides the relation between Vg and thermodynamic data
for the low-molecular component (solvent) 1 at infinite dilution:
∞ ∞
⎛ P ⎞ 1 TR 0
⎜ ⎟
⎜ L
0
⎝x
⎟
1 ⎠ VgM =
2
or
⎛ P ⎞ 1 TR 0
⎜ ⎟
⎜ L
0
⎝w
⎟
1 ⎠ VgM =
1
[4.4.25]
where:
M2 molar mass of the liquid (molten) polymer
M1 molar mass of the low-molecular component (solvent).
The activity coefficients at infinite dilution follow immediately from Equation
[4.4.22] by introducing the above result, if we neglect interactions to and between carrier
gas molecules (which is normally helium):
⎛
∞
= ⎜
⎜
⎝
γ 1
TR
0
0 s
VgM2P1 L s ( B11 −V1)( P −P1)
⎞ ⎡
⎤
⎟exp
⎢
⎥
[4.4.26a]
⎟
⎠ ⎣⎢
RT
⎦⎥