Page 363 - Chemical engineering design

338
CHEMICAL ENGINEERING
(continued)
Table 8.8.
T P V T P V
Sulphur Increments
SH 0.015 0.27 0.055 S (ring) 0.008 Ł 0.24 Ł 0.045 Ł
S (non-ring) 0.015 0.27 0.055 S 0.003 Ł 0.24 Ł 0.047 Ł
Miscellaneous
Si 0.03 0.54 Ł B 0.03 Ł

Dashes represent bonds with atoms other than hydrogen.
Values marked with an asterisk are based on too few experimental points to be reliable.

Fedons (1982) gives a simple method for the estimation of critical temperature, that
does not require a knowledge of the boiling point of the compound.
Example 8.14
Estimate the critical constants for diphenylmethane using Lydersen’s method; normal
boiling point 537.5 K, molecular mass 168.2, structural formula:
H H H H
C C H C C
HC C C C CH
C C H C C
H H H H

Solution

Total contribution
Group No. of
T P V

H C (ring) 10 0.11 1.54 0.37
C (ring) 2 0.022 0.308 0.072
1 0.02 0.227 0.055
CH 2
 0.152 2.075 0.497

537.5
T c D D 772 k
2
0.567 C 0.152 0.152
experimental value 767 K,
168.2
P c D D 28.8atm
0.34 C 2.075 2
experimental value 28.2 atm,
3
V c D 0.04 C 0.497 D 0.537 m /kmol