Below is a list of alternate cooling baths that can be used in place of liquid nitrogen. The notes section describes some of the hazards and precautions for each bath. When selecting a cooling bath, please consider the innate hazards of the cooling bath used, whether the cooling bath will be in a ventilated area such as a fume hood, and the gases that may be inadvertently condensed using the bath (assuming that the pressure inside the system is equal to ambient pressure).
Important Note: The chemicals that may be condensed at any given cooling bath temperature depend on the pressure inside the system. At elevated pressures, more gases will condense. For example, if you have a glass sample flask submerged in a liquid nitrogen bath, and the pressure inside the sample flask is greater than the pressure on the liquid nitrogen cooling bath, the nitrogen inside may start to condense into liquid nitrogen, leading to potential overpressure and explosion if the sample flask is sealed.
It’s also important to be aware of all of the potential gases and vapors that a cooling bath may trap together and to carefully consider what adverse reactions may occur if incompatible chemicals are co-condensed.
| Temperature | Composition | Notes | Other Gases Condensed |
| 13°C | Dry Ice/p-Xylene | Flammable. The isomers of xylene produce very different bath temperatures. | |
| 12°C | Dry Ice/Dioxane | Dioxane is a peroxide former, possible carcinogen, and highly flammable. | |
| 6°C | Dry Ice/Cyclohexane | Cyclohexane is highly flammable and may causes dizziness/drowsiness. | |
| 5°C | Dry Ice/Benzene | Benzene is highly flammable and a known human carcinogen. | |
| 2°C | Dry Ice/Formamide | Formamide is a potential reproductive toxin and corrosive to the eyes. | |
| 0°C | Ice (crushed) | ||
| -5 to -20°C | Ice/Salt | Equal parts ice and NaCl. Brine with dry ice produces an equivalent bath. | Butane |
| -10.5°C | Dry Ice/Ethylene Glycol | Butane | |
| -12°C | Dry Ice/Cycloheptane | Cycloheptane is highly flammable and may causes dizziness/drowsiness. | Butane |
| -15°C | Dry Ice/Benzyl Alcohol | Benzyl alcohol is a peroxide former, a sensitizer, and may cause dizziness/drowsiness. | Butane |
| -22°C | Dry Ice/Tetrachloroethylene | Tetrachloroethylene is a suspected human carcinogen. | Butane |
| -22.8°C | Dry Ice/Carbon Tetrachloride | Carbon tetrachloride is toxic by inhalation and a possible human carcinogen. | Butane |
| -25°C | Dry Ice/1,3-Dichlorobenzene | Dichlorobenzene is a combustible liquid. | Butane |
| -29°C | Dry Ice/o-Xylene | Flammable. The isomers of xylene produce very different bath temperatures. | Butane |
| -32°C | Dry Ice/m-Toluidine | m-Toluidine is toxic; chronic exposure may produce cumulative effects. | Butane |
| -41°C | Dry Ice/Acetonitrile | Acetonitrile is highly flammable and on contact with acids may produce cyanide gas. Put the acetonitrile into the Dewar with your thermocouple, slowly add dry ice until you hit your desired temperature. Do not add too much dry ice or you’ll freeze the acetonitrile solid. | Butane, Ammonia |
| -42°C | Dry Ice/Pyridine | Pyridine is highly flammable and incredibly odiferous with an odor threshold of 0.01ppm. | Butane, Ammonia, Propane |
| -47°C | Dry Ice/m-Xylene | Flammable. The isomers of xylene produce very different bath temperatures. | Butane, Ammonia, Propane |
| -56°C | Dry Ice/n-Octane | n-Octane is highly flammable and may cause dizziness/drowsiness. | Butane, Ammonia, Propane |
| -60°C | Dry Ice/Isopropyl Ether | Isopropyl ether forms explosive levels of peroxides extremely quickly and without concentration. This bath is not recommended. | Butane, Ammonia, Propane |
| -77°C | Dry Ice/Acetone | Acetone is highly flammable and may cause dizziness/drowsiness. Slowly adding acetone to dry ice will minimize the amount of dry ice you need to handle. Alternatively, you must slowly add dry ice to the acetone or the large volumes of carbon dioxide produced will cause rapid bubbling. | Butane, Ammonia, Propane |
| -77°C | Dry Ice/Butyl Acetate | Butyl acetate is flammable and may cause dizziness/drowsiness. | Butane, Ammonia, Propane |
| -83°C | Dry Ice/n-Propyl Amine | n-Propyl amine is highly flammable and corrosive to the skin and eyes. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride |
| -83.6°C | Liquid Nitrogen/Ethyl Acetate | Ethyl acetate is highly flammable and may cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride |
| -89°C | Liquid Nitrogen/n-Butanol | n-Butanol is flammable, corrosive to the eyes, and may cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide |
| -94°C | Liquid Nitrogen/Hexane | n-Hexane is highly flammable, toxic, and may damage fertility; chronic exposure may cause cumulative effects. May cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide |
| -94.6°C | Liquid Nitrogen/Acetone | Acetone is highly flammable and may cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide |
| -95.1°C | Liquid Nitrogen/Toluene | Toluene is highly flammable and a reproductive toxin; chronic exposure by inhalation may cause serious health effects. May cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide |
| -98°C | Liquid Nitrogen/Methanol | Methanol is highly flammable and toxic by inhalation with possible irreversible effects. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide |
| -100°C | Dry Ice/Ethyl Ether | Ethyl ether is extremely flammable, a peroxide former, and may cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide |
| -104°C | Liquid Nitrogen/Cyclohexane | Cyclohexane is highly flammable and may causes dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide |
| -116°C | Liquid Nitrogen/Ethanol | Ethanol is highly flammable and may cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide, Xenon |
| -116°C | Liquid Nitrogen/Ethyl Ether | Ethyl ether is extremely flammable, a peroxide former, and may cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide, Xenon |
| -131°C | Liquid Nitrogen/n-Pentane | n-Pentane is extremely flammable and may cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide, Xenon |
| -160°C | Liquid Nitrogen/Isopentane | Isopentane is extremely flammable and may cause dizziness/drowsiness. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide, Xenon, Krypton |
| -196°C | Liquid Nitrogen | Liquid nitrogen is capable of condensing oxygen, argon, and carbon dioxide. Areas of oxygen enrichment may form near the surface of an open liquid nitrogen bath. | Butane, Ammonia, Propane, Carbon Dioxide, Hydrogen Chloride, Acetylene, Nitrous Oxide, Xenon, Krypton, Methane, Oxygen, Argon, Carbon Dioxide |
Information adapted from: https://www.jove.com/science-education/10224/conducting-reactions-below-room-temperature
