7

Shakashiri describes the reaction of solid Ammonium Thiocyanate and solid Barium Hydroxide Octahydrate resulting in an endothermic reaction leading to subzero temperatures. I've performed this experiment and measured temperature as low as about $-10\ ^\circ\text{C}$.

Are there known chemical reactions that can lead to even lower temperatures?

docscience
  • 2,763
  • 4
  • 20
  • 43
  • I attempt to change the title so this question won't seem "primarily opinion-based", hopefully. As for the reaction, I can suggest the formation of ATP form ADP. But since you didn't mention the $\Delta H$ for that reaction, it's really hard to say that to what degree should your reaction be endothermic. – M.A.R. Jan 23 '15 at 16:41
  • it is claimed that temperatures up to -90 may be achieved with precooled ice and magnesium chloride hexahydrate. – permeakra Jan 23 '15 at 18:25
  • @M.A.R i think op meant low temprature spontaneous endothermic reactions. – Kartik Apr 17 '17 at 02:46

1 Answers1

5

Yes there are. In Vogels famous textbook on practical organic chemistry there is a section about the cooling effect of certain salt (mixture) solutions in water.

If ice is temporarily not available, advantage may be taken of the cooling effect attending the solution of certain salts or salt mixtures in water. Thus a mixture produced by dissolving 1 part of NH4C1 and 1 part of NaNO3 in 1-2 parts of water causes a reduction in temperature from 10 to — 15 °C to — 20 °C; 3 parts of NH4C1 in 10 parts of water from 13 to -15°C; 11 parts of Na2S2O3.5H2O in 10 parts of water from 11 to - 8 °C; and 3 parts of NH4NO3 in 5 parts of water from 13 to — 13°C

(Taken from Vogels 5th edition, p. 70)

Jori
  • 6,203
  • 7
  • 32
  • 68