Solvents that can be Dried Using the Water Azeotropes

 

In a previous blog article, the point was made that drying organic solvents with solid desiccants would contaminate the entire filter train and thereby drastically increase cycle time. Drying using an azeotrope was much preferred. All of the common organic reaction solvents that are not completely miscible with water form azeotropes that can be used for drying. It is only essential that the solute is stable at the azeotrope’s boiling temperature.

Only the common solvents completely miscible with water cannot be dried by azeotropes:  acetone, methanol, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, and propylene carbonate. 

Solvent Water 

Azeotrope

Acetic acid  76.6

Acetonitrile  76.5

Benzene  69.4

1-butanol  93.0

2-butanol  88.5

t-butanol  79.9

Chlorobenzene   90.2

Chloroform  56.3

Cyclohexane  69.8

1,2-dichloroethane  72.0

1,2-dichlorobenzene 91.1

Ethanol  78.2

Ethyl acetate  70.4

Ethyl ether 34.2

n-Heptane  79.2

n-Hexane  61.6

Isopropyl acetate  75.9

Isopropyl alcohol  80.4

Isopropyl ether  62.2

Methylene chloride  38.8

Methyl ethyl ketone  73.4

MTBE  52.6

n-Pentane  34.6

Propanol  88.1

Tetrachloroethylene  88.5

Toluene  85.0

Trichloroethylene  73.1

m-Xylene  94.5