Supercritical adsorption data available in the literature for C

_{1}to nC

_{12}n alkanes on 5A zeolite is correlated using the Gaussian Adsorption model. This isotherm model has three parameters:

*q*, the saturation loading; the 50% adsorbate loading pressure P

_{max}_{50}; and the standard deviation

*σ*. The latter two parameters are deduced from a log plot of the isotherm pressure

*P*versus the inverse Gaussian cumulative frequency distribution plot

*Φ*

^{-1}*(*

*q*

*)*. The slope of this plot is

*σ*and the y-intercept is

*log P*. The temperature dependency of P

_{50}_{50}is deduced from a plot of

*log*P

_{50}versus 1/

*T*: this is actually the isosteric heat of adsorption plot at 50 % loading with slope proportional to the heat of adsorption at 50 % loading (4.5 g/100g Z).

The model is tested using 63 supercritical n alkane isotherms from the literature on 5A zeolite. The 63 isotherms from 18 different studies are fitted with the model using a *q _{max}* of 9 g/100g Z applicable to n alkane / 5A isotherms in the supercritical temperature range. The mean standard deviation σ is observed to be 0.960 with a standard deviation of 0.127. All 63 isotherms reduce to one characteristic curve when

*θ*is plotted against (

*P/P*

_{50})^{1/}*.*

^{ϭ}The isosteres of *P _{50}* indicate heats of adsorption

*(-ΔH*that are equal to or greater than literature values at zero loading

_{50})*(-ΔH*; the difference between the two is negligible for low carbon numbers rising to over 10 kcal/mole at higher carbon numbers (nC

_{0})_{10}). This is expected as the heat of adsorption is calculated at 50% loading.

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