# Antoine Equation

on . Posted in Thermodynamics

Antoine equation is used to estimate the vapor pressure of a substance over a range of temperatures.  It's particularly useful for volatile liquids that exhibit a significant vapor pressure at temperatures below their boiling points.  The Antoine equation is particularly useful because it allows you to estimate the vapor pressure of a substance at a specific temperature using only a few constants that can be found in tables or literature.

This equation is valid over a limited temperature range, typically within a few degrees of the substance's boiling point.  It's important to note that the Antoine equation is an empirical model and might not accurately predict vapor pressures for all substances across wide temperature ranges or extreme conditions. For accurate results, it's recommended to use experimental data or more sophisticated thermodynamic models, especially when dealing with critical or unusual substances.

### Antoine equation

$$log_{10} \;p = A - ( B \;/\; C + T )$$
Symbol English Metric
$$p$$ = vapor pressure  $$lbf\;/\;in^2$$ $$Pa$$
$$A, B, C$$ = component specific constants $$dimensionless$$
$$T$$ = temperature $$F$$ $$C$$