Make a solution of 30%EtOH (by volume) in water. The freezing point of this solution is -15 C. Cool it by slowly adding dry ice under vigorous mixing and control T~ -10C. Use it as your "water bath."

Hi,

Use Ice/acetone mixture (-10 to -15 C) or 100g Ice/33g NaCl (-10 to -15 C).

Good Luck

I think it depends on the time you want to maintain the temperature. If short as one or tow hours, I suggest a mixture of CaCl2 with ice; If longer than that, a cooling machine is better to maintain the temperature.

https://en.wikipedia.org/wiki/Cooling_bath

Water and ice baths[edit]

A bath of ice and water will maintain a temperature 0 °C since the melting point of water is 0 °C. However, adding a salt such as sodium chloride will lower the temperature through the property of melting-point depression. Although the exact temperature can be hard to control, the weight ratio of salt to ice influences the temperature:

• −10 °C can be achieved with a 1 to 2.5 ratio by weight of calcium chloride hexahydrate to ice.
• −20 °C can be achieved with a 1 to 3 ratio by weight of sodium chloride to ice.
• −40 °C can be achieved with a 1 to 0.8 ratio by weight of calcium chloride hexahydrate to ice.[citation needed]

Perform your reaction outdoors here in northern Michigan this winter.

Use dry ice and acetone. This can achieve temperatures up to -80C

Use dry ice along with vacuvum

Dear A. Mukhtar,

You can follow Mr. S. Gupta and Dr. G. Xiang answers for just -10oC. (Ice+Nacl)

Good Luck.

I routinely used methanol poured onto ice to make a -10 to -20 oC bath. This is useful when using larger flasks up to 20L and avoids the mess of cleaning up inorganic salts in the bath container.

Try rocksalt instead of nacl

Use acetone and Dry ice mixture to maintain required temprature (-10 to -15 C)

Use vacuum pump in zero degree

Synthetic organic experiments are conducted at temperatures ranging from -90 degrees to 200 degrees Celsius. It is important to know how to achieve and maintain the correct temperature for a reaction, especially over long time periods. Temperature should be monitored with a low-temperature alcohol thermometer.

Low Temperature Cooling Baths

• Cryocool: If you have access to one, a cryocool can maintain a reaction at a set temperature (typically -40 to 20 degrees) for a long period of time.
• Ice/Salt: -15 to -5 degrees
• Dry Ice/Acetonitrile: -40 degrees
• Dry Ice/Acetone: -78 degrees
• Liquid Nitrogen/Dichloromethane: -92 degrees

See Also: The Complete List on the Hoveyda Group website.

Using liquid nitrogen

This is easy to say " Using liquid nitrogen. " It would be interesting to see how you do this in laboratory. I would say that your answer is useless unless you describe the procedure details. "Nothing personal just a busyness"