# distillation of aqueous CAN solution for the purpose of a reversible and strong endothermic reaction in cool packs

I know calcium ammonium nitrate (CAN) is used for cold packs. By bending a small metal plate the salt gets dissolved in water (separated pack) and this process is endothermic.

I would like to heat this calcium ammonium nitrate solution to get back anhydrous CAN. Is there a way I can do it without safety issues?

• Source 1 advices to heat it up to 210 °C.
• Source 2 mentions the possibility to decompose at 60 °C into nitrogen oxides

Do you think I can heat the mixture up to 100 °C?

• chemistry.stackexchange.com/questions/78776/… – Mithoron Aug 1 '18 at 21:08
• Can I heat this icepack made of calcium ammonium nitrate up to get a reversible process? Are there alternatives with higher reaction enthalpy? – laminin Aug 1 '18 at 21:38
• This is an extremely difficult problem. The answer is worth a lot of money to people who would like to use this for something other than personal comfort cold pack. – ericksonla Aug 2 '18 at 19:34
• What we think is irrelevant. Try heating a very small amount to $100\pu{^\circ C}$ and see what happens. – A.K. Aug 4 '18 at 18:54