Cooling bath

Cooling baths are solutions or mixtures that allow for cooling during a reaction or experiment. Many different solutions and mixtures are available to the amateur, often using ice or dry ice (Carbon dioxide) as a chilling source.

Common mixtures

The below list is of basic, common, and easy to use mixtures.

• Ice (0 °C) - Grind ice for best use. Snow (if available) can also be used.
• Ice/NaCl at 1:1 (-20 °C) - Works best if ground. Saltwater and dry ice works well too. This is one of the cheapest and easy to make.
• Acetonitrile/Dry Ice (-40 °C) - Add dry ice slowly.
• Acetone/Dry Ice (-78 °C) - Mix slowly, may produce lots of CO₂.

Other types:

• Liquid nitrogen/Ethanol (-116°C) - Extremely cold, when it forms the surface will rapidly freeze, but the crust is easy to break. Once all the liquid nitrogen will evaporate, the ethanol will have the consistency of a syrup.

List of cooling baths

Cooling agent	Carrier	T (°C)	Notes
Dry ice	p-Xylene	13 °C
Dry ice	Dioxane	12 °C
Dry ice	Cyclohexane	6 °C
Dry ice	Benzene	5 °C
Dry ice	Formamide	2 °C
Crushed ice	Water/ice	0 °C
Ice	Ammonium chloride	-5 °C	1/0.3 ice to salt ratio
Liquid nitrogen	Aniline	-6 °C
Ice	Sodium thiosulfate pentahydrate	-8 °C	1/1.1 ice to salt ratio
Ice	Calcium chloride hexahydrate	-10 °C	2.5/1 ice to salt ratio
Ice	Table salt	-5 → -20 °C
Dry ice	Ethylene glycol	-10.5 °C
Dry ice	Cycloheptane	-12 °C
Dry ice	Benzyl alcohol	-15 °C
Dry ice	Tetrachloroethylene	-22 °C
Dry ice	Carbon tetrachloride	-22.8 °C
Dry ice	1,3-Dichlorobenezene	-25 °C
Dry ice	o-Xylene	-29 °C
Dry ice	m-Toluidine	-32 °C
Dry ice	Acetonitrile	-41 °C
Dry ice	Pyridine	-42 °C
Dry ice	m-Xylene	-47 °C
Dry ice	n-Octane	-56 °C
Dry ice	Diisopropyl ether	-60 °C
Dry ice	Acetone	-77 °C
Dry ice	Butyl acetate	-77 °C
Dry ice	Propyl amine	-83 °C
Liquid nitrogen	Ethyl acetate	-83.6 °C
Liquid nitrogen	Butanol	-89 °C
Liquid nitrogen	Hexane	-94 °C
Liquid nitrogen	Acetone	-94.6 °C
Liquid nitrogen	Toluene	-95.1 °C
Liquid nitrogen	Methanol	-98 °C
Dry ice	Diethyl ether	-100 °C
Liquid nitrogen	Cyclohexane	-104 °C
Liquid nitrogen	Ethanol	-116 °C
Liquid nitrogen	Diethyl ether	-116 °C
Liquid nitrogen	n-Pentane	-131 °C
Liquid nitrogen	Isopentane	-160 °C
Liquid nitrogen	Liquid nitrogen	-196 °C

References

A more complete list of cooling baths can be obtained at the chem-wiki reference.