Figure A2Reduced
vapor-pressure plot12
M is defined as:
\(\frac{\mathrm{d}\mathrm{P}_{\mathrm{r}}}{\mathrm{P}_{\mathrm{r}}}\mathrm{=\ -M}\frac{\mathrm{d}\mathrm{T}_{\mathrm{r}}}{\mathrm{T}_{\mathrm{r}}^{\mathrm{2}}}\)(A37)
The value of M can be achieved by checking Figure A2 and
then m can be calculated by Eq. (16). The value of m also
could be achieved by the following equation while the precision is not
as good as the former method9, 12.
\(\mathrm{m}\mathrm{\ =\ }\)\(\left(\mathrm{5.82+4.92}\mathrm{\omega}\right)\frac{\mathrm{P}_{\mathrm{c}}}{\mathrm{T}_{\mathrm{c}}}\text{\ \ }\)(A38)
ω is the eccentric factor for a given substance.