Lab freezing bath temperatures

Freezing mixtures in the lab are often made from a mixture of either liquid nitrogen or dry ice with a solvent. If using liquid nitrogen this forms a slurry. The viscosity of this slurry is dependent on the solvent or mixture of solvents used. If using dry ice, you generally end up with an equilibrium where a small amount of dry ice is sat in a cold bath of solvent. By varying the solvent used, different temperatures can be achieved.

There has been lots of good work done in the past in determing the temperatures of these baths and there are links for further reading in the references below.

Important combinations in a biochemistry laboratory are highlighted.

Mixture Temperature (°C)
p-Xylene/Liquid nitrogen13
p-Dioxane/Liquid nitrogen12
Cyclohexane/Liquid nitrogen6
Benzene/Liquid nitrogen5
Formamide/Liquid nitrogen2
Aniline/Liquid nitrogen-6
Cycloheptane/Liquid nitrogen-12
Benzonitrile/Liquid nitrogen-13
Ethylene glycol/Dry ice-15
o-Dichlorobenzene/Liquid nitrogen-18
Tetrachloroetane/Liquid nitrogen-22
Carbon tetrachloride/Liquid nitrogen-23
Carbon tetrachloride/Dry ice-23
m-Dichlorobenzene/Liquid nitrogen-25
Nitromethane/Liquid nitrogen-29
o-Xylene/Liquid nitrogen-29
Bromobenzene/Liquid nitrogen-30
Iodobenzene/Liquid nitrogen-31
Thiophene/Liquid nitrogen-38
3-Heptanone/Dry ice-38
Acetonitrile/Liquid nitrogen-41
Pyridine/Liquid nitrogen-42
Acetonenitrile/Dry ice-42
Chlorobenzene/Liquid nitrogen-45
Cylcohexanone/Dry ice-46
m-Xylene/Liquid nitrogen-47
n-Butyl amine/Liquid nitrogen-50
Diethyl carbitol/Dry ice-52
n-Octane/Liquid nitrogen-56
Chloroform/Dry ice-61
Chloroform/Liquid nitrogen-63
Methyl iodide/Liquid nitrogen-66
Carbitol acetate/Dry ice-67
t-Butyl amine/Liquid nitrogen-68
Ethanol/Dry ice-72
Trichloroethylene/Liquid nitrogen-73
Butyl acetate/Liquid nitrogen-77
Acetone/Dry ice-78
Isopropanol/Dry ice-78
Isoamyl acetate/Liquid nitrogen-79
Acylonitrile/Liquid nitrogen-82
Sulfur dioxide/Dry ice-82
Ethyl acetate/Liquid nitrogen-84
Ethyl methyl ketone/Liquid nitrogen-86
Acrolein/Liquid nitrogen-88
Nitroethane/Liquid nitrogen-90
Heptane/Liquid nitrogen-91
Cyclopentane/Liquid nitrogen-93
Hexane/Liquid nitrogen-94
Toluene/Liquid nitrogen-95
Methanol/Liquid nitrogen-98
Diethyl ether/Dry ice-100
n-Propyl iodide/Liquid nitrogen-101
n-Butyl iodide/Liquid nitrogen-103
Cyclohexane/Liquid nitrogen-104
Isooctane/Liquid nitrogen-107
Ethyl iodide/Liquid nitrogen-109
Carbon disulfide/Liquid nitrogen-110
Butyl bromide/Liquid nitrogen-112
Ethyl bromide/Liquid nitrogen-119
Acetaldehyde/Liquid nitrogen-124
Methyl cyclohexane/Liquid nitrogen-126
n-Pentane/Liquid nitrogen-131
1,5-Hexadiene/Liquid nitrogen-141
Isopentane/Liquid nitrogen-160

Cooling baths.pdf (below) contains the original Rondeau paper cited below along with other information regarding making cooling baths with liquid nitrogen, dry ice and salt solutions.

Download Cooling baths.pdf (1.04 MB)

Rondeau, R.E. (1966) Slush baths. J. Chem. Eng. Data, 11: 124.

First published on 9th November 2010 and last modified on 25th June 2011.