Theoretical determination of vapour-liquid equilibrium pressure and vaporisation enthalpy of rubidium in the temperature range of 700 K-2017 K based on a modified Redlich-Kwong equation of state

Based on a four-parameter modified Redlich-Kwong equation of state (m-RK EoS), the vapour-liquid equilibrium pressure of rubidium over a temperature range of 700 K-2017 K is determined using Maxwell's equal area construction. The obtained values of vapour pressure of rubidium agree with the literature values. In this work, the vapour pressure precision is taken as 10(-5) Pa which is, in fact tuneable, depending upon the accuracy requirement. Correlations for the temperature-dependence of vapour pressure of rubidium are obtained through least square analysis based on the obtained vapour pressure data. Also, the curvature of the obtained reduced vapour pressure curve for rubidium is found to have a maximum at 1208.80 K. Moreover, the vaporisation enthalpy of rubidium is determined from the proposed vapour pressure correlation and has reasonable accuracy in the temperature of 700 K-1400 K.

Automated summary

In this study, a modified Redlich-Kwong equation of state (m-RK EoS) with four parameters is used to determine the vapor-liquid equilibrium pressure of rubidium over a temperature range of 700 K to 2017 K. The obtained values are consistent with literature values. Correlations for the temperature-dependence of rubidium vapor pressure are obtained through least square analysis based on the obtained data. It is also found that the curvature of the reduced vapor pressure curve for rubidium has a maximum at 1208.80 K. The vaporization enthalpy of rubidium is determined from the proposed correlation and has reasonable accuracy within the temperature range of 700 K to 1400 K.