What is the Antoine Equation?

The Antoine Equation is a thermodynamic empirical correlation used to calculate the saturation vapor pressure of pure substances as a function of temperature. It is typically expressed as: log10(Psat) = A - B / (T + C), where A, B, and C are substance-specific constants and T is temperature in Celsius.

Can Antoine Equation parameters be extrapolated safely?

No, Antoine constants are only valid within specified minimum (Tmin) and maximum (Tmax) temperature limits. Extrapolating beyond these limits can result in significant design errors, as the empirical model does not accurately represent critical or freezing region behaviors.

How do you convert mmHg to other pressure units?

To convert mmHg (or Torr) to other units, use these factors: Multiply by 133.322 to get Pascals (Pa), multiply by 0.00133322 to get bar, or multiply by 0.0193368 to get psi.

Antoine Equation Coefficient for pure substances

Including water, acetone, methanol, benzene, phenol

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1. How to use Antoine Equation coefficients
2. Table of coefficients of Antoine Equation for pure compounds
3. Interactive Online Antoine Calculator
4. Excel data table

1. How to use Antoine Equation coefficients

The coefficients given in the table below allow to calculate the saturation pressure of the pure substances listed, in mmHg, from the temperature in degree celsius.

They are parameters for a modelisation of the saturation pressure as a function of the temperature following an Antoine Law. Note that the Antoine equation is expressed for the coefficients given in this page as a log in base 10; for a full list of coefficients, see the comprehensive Antoine constants table.

\[ \log_{10}(P^{\text{sat}}) = A - \frac{B}{T + C} \]

Where:
\( P^{\text{sat}} \) = Saturation vapor pressure (\(\text{mmHg}\))
\( T \) = Temperature (\(^\circ\text{C}\))
\( A, B, C \) = Empirical Antoine constants

Antoine law equation for saturation pressure calculation base 10

Equation 1 : Antoine Equation for calculation of saturation pressure - log base 10

It is possible to switch from mmHg - or Torr- to other units by multiplying by the following coefficients :

Base Unit	(Pa)	(bar)	(at)	(atm)	(Torr)	(lbf/in² - psi)
1 Torr (mmHg)	133.322 368 421	0.001 333 224	0.001 359 51	1/760 ≈ 0.001 315 789	1 Torr ≈ 1 mmHg	0.019 336 775

3. Interactive Online Antoine Calculator

⚠️ ENGINEERING NOTICE & EDUCATIONAL DISCLAIMER: This interactive calculator is provided exclusively for preliminary estimation and educational purposes. It is not intended for detailed design or equipment procurement without certified vendor rating. No warranty, expressed or implied, is provided, and no liability is assumed.

Select Compound

Temperature (°C)

Antoine Coefficients (Base 10)

Validity limits: °C

Calculated Saturation Pressure

mmHg / Torr

0.00

bar

0.00

Pascal (Pa)

0.00

atm

0.00

psi (lbf/in²)

0.00

Global Multi-Compound Vapor Pressure Screen at 20 °C

Updates instantly below when you change the input temperature above. Yellow rows indicate compound validity ranges are violated.

Formula	Compound Name	T Min (°C)	T Max (°C)	Psat (mmHg)	Psat (bar)

💡 Plant Engineering Best Practices & Vapor Pressure Rules of Thumb

Avoid Extrapolation: The Antoine Equation is an empirical model. Using the coefficients outside their listed \([T_{MIN}, T_{MAX}]\) limits can yield highly unstable and physical nonsense values. For critical process safety reviews, use the Wagner equation or rigorous thermodynamic models (e.g., Peng-Robinson, NRTL).
Check base notation: Check if your reference coefficients are structured for \(\log_{10}\) or natural logarithm \(\ln\). This page uses base-10 exclusively. Mixing these up causes a structural order of magnitude error (\(2.3026\times\) factor).
Temperature Units: Most standard handbooks list \(C\) offsets assuming \(T\) in °C. If using Kelvin-based databases, the \(C\) offset changes completely (often \(T + C - 273.15\) structure).
Vaporization hazards: When handling volatile solvents like diethyl ether or acetone, verify that standard operating temperatures remain well below their boiling point at atmospheric pressure to prevent tank boiling and vent surges.

2. Table of coefficients of Antoine Equation for pure compounds

Note the domain of validity of the correlation, in between T min and T max. The saturation pressure is in mmHg and the temperature in celsius. The classification in the table is done by alphabetical order of the compound name. No guarantee is given on the data provided; the user is strongly advised to double‑check the information with other sources. For broader reference, see our data tables and diagrams covering viscosity, density, and dimensionless numbers.

Formula	Compound Name	A	B	C	TMIN	TMAX

4. Excel data table

You can download the table above in Excel format here : Excel data table. You can modify the calculation temperature and it calculates the saturation pressure for all the compounds in the table.

Warning : this calculator is provided to illustrate the concepts mentioned in this webpage, it is not intended for detail design. It is not a commercial product, no guarantee is given on the results. Please consult a reputable designer for all detail design you may need.

Screenshot Saturation pressure calculator