Vacuum Vapor Pressure Estimates - Using Antoine Equation

One of the most common uses for vacuum pumps is to cause chemicals to evaporate.  But how much vacuum is needed to make a certain chemical evaporate?One way to estimate the vapor pressure of a given chemical compound is to use the Antoine Equation.

The table below provides reference data on Antoine equation coefficients that has been published in the NIST Chemistry WebBook for a variety of common chemicals.  

The form of the Antoine equation used here is:  log10(P) = A – [B / (T + C)],

where P is the calculated vapor pressure in bar (on an absolute scale) and T is the temperature in Kelvin.  Using the reference data assembled by NIST, you can plug in the values for A, B, and C to estimate the vapor pressure, P.

ChemicalCoefficient ‘A’Coefficient ‘B’Coefficient ‘C’Applicable Temp. Range (K)
Acetic Acid4.682061642.54-39.764290.26 – 391.01
Acetic Acid Anhydride4.246551427.77-75.113335.99 – 412.57
Acetone4.424481312.253-32.445259.16 – 507.6
Acetonitrile4.278731355.374-37.853288.3 – 362.3
Benzene4.018141203.835-53.226287.7 – 354.07
iso-Butanol4.431261236.991-101.528353.36 – 388.77
n-Butanol4.546071351.555-93.34295.8 – 391.0
tert-Butanol4.497741174.869-93.92312.66 – 355.56
Carbon Tetrachloride4.022911221.781-45.739293.03 – 350.86
Chlorobenzene4.110831435.675-55.124335.19 – 404.88
Chloroform4.207721233.129-40.953215 – 334.4
Cyclohexane3.969881203.526-50.287293.06 – 354.73
Cyclopentane4.002881119.208-42.412288.86 – 323.18
Dimethyl Acetamide6.094512725.9628.209303 – 363
Dimethyl Formamide3.930681337.716-82.648303 – 363
Dimethyl Sulfoxide5.230392239.161-29.215293 – 323
Dioxane4.581351570.093-31.297293 – 378
Ethanol5.372291670.409-40.191273 – 351.70
Ethyl Acetate4.228091245.702-55.189288.73 – 348.98
Ethyl Ether4.0221062.64-44.93250.04 – 328.57
Ethylene Dichloride4.585181521.789-24.67242.33 – 372.6
Ethylene Glycol4.970121914.951-84.996323 – 473
Heptane4.028321268.636-56.199299.07 – 372.43
n-Hexane4.002661171.53-48.784286.18 – 342.69
Hydrochloric Acid4.57389868.3581.754188.3 – 309.4
Methanol5.204091581.341-33.5288.1 – 356.83
Methylene Chloride4.536911327.016-20.474233 – 313
Pentane3.98921070.617-40.454268.8 – 341.37
iso-Propanol4.577951221.423-87.474395.1 – 508.24
n-Propanol5.313841690.864-51.804292.4 – 370.5
Pyridine4.162721371.358-58.496340.5 – 426.04
Tetrahydrofuran4.121181202.942-46.818296.29 – 372.8
Toluene4.141571377.578-50.507273 – 323
Water6.209632354.7317.559293 – 343

 

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