Joback method: Difference between revisions

Revision as of 01:21, 31 October 2019

Revision as of 01:24, 31 October 2019

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== Formulas ==

In the following formulas ''G''_i'' denotes a group contribution. ''G''_i'' are counted for every single available group. If a group is present multiple times, each occurrence is counted separately.

===Normal boiling point===

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<math>T_\text{c}[\text{K}] = T_\text{b} \left[0.584 + 0.965 \sum T_{\text{c},i} - \left(\sum T_{\text{c},i}\right)^2 \right]^{-1}.</math>

This critical -temperature equation needs a normal boiling point ''T''_b. If an experimental value is available, it is recommended to use this boiling point. It is, on the other hand, also possible to input the normal boiling point estimated by the Joback method. This will lead to a higher error.

===Critical pressure===

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<math>P_\text{c}[\text{bar}] = \left [0.113 + 0.0032 \, N_\text{a} - \sum P_{\text{c},i}\right ]^{-2},</math>

where ''N''_a is the number of atoms in the molecular structure (including hydrogens).

===Critical volume===

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===Liquid dynamic viscosity===

<math>\eta_\text{L}[\text{Pa}\cdot\text{s}] = M_\text{w} e^{ \left([ \left(\sum \eta_a - 597.82 \right]) / T)\right] + \sum \eta_b - 11.202 },</math>

where ''M''_w is the [[molecular weight]].