Joback method: Difference between revisions

Revision as of 14:35, 20 February 2015

Revision as of 08:31, 12 April 2015

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===Normal Boiling Point===

<math>T_b[K] \, = \, 198 + \sum {T_{b,i}}</math>

===Melting Point===

<math>T_m[K] \, = \, 122.5 + \sum {T_{m,i}}</math>

===Critical Temperature===

<math>T_c[K] \, = \, T_b \left[0.584 + 0.965 \sum {T_{c,i}} - \left(\sum {T_{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.

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===Critical Pressure===

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

N_A: Number of atoms in the molecular structure (including hydrogens).

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===Critical Volume===

<math>V_c[cm^{3}/mol] \, = \, 17.5 + \sum {V_{c,i}}</math>

===Heat of Formation (Ideal Gas, 298 K)===

<math>H_{formation}[kJ/mol] \, = \, 68.29 + \sum {H_{form,i}}</math>

===Gibbs Energy of Formation (Ideal Gas, 298 K)===

<math>G_{formation}[kJ/mol] \, = \, 53.88 + \sum {G_{form,i}}</math>

===Heat Capacity (Ideal Gas)===

<math>C_P[J/(mol.K)] \, = \, \sum a_i - 37.93 + \left[ \sum b_i + 0.210 \right] T + \left[ \sum c_i - 3.91 \cdot 10^{-4} \right] T^2 + \left[\sum d_i + 2.06 \cdot 10^{-7}\right] T^3</math>

The Joback method uses a four parameter polynomial to describe the temperature dependency of the ideal gas heat capacity. These parameters are valid from 273 K to approx. 1000 K.

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===Heat of Vaporization at Normal Boiling Point===

<math>\Delta H_{vap}[kJ/mol] \, = \, 15.30 + \sum H_{vap,i}</math>

===Heat of Fusion===

<math>\Delta H_{fus}[kJ/mol] \, = \, -0.88 + \sum H_{fus,i}</math>

===Liquid Dynamic Viscosity===

<math>\eta_L[Pa.s] \, = \, M_w e^{ \left[ \sum \eta_a - 597.82 \right] / T + \sum \eta_b - 11.202 }</math>

M_w: Molecular Weight