Endothermic cooling

PabloPicasso

PabloPicasso

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What chemicAls could safely be used to cause an endothermic reaction to cool an insulated cool/ice box on a small boat? Please consider the safety of carrying mixing and ease of purchasing? (Edit). Oh yeah, and food safe!
 
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PabloPicasso said:
What chemicAls could safely be used to cause an endothermic reaction to cool an insulated cool/ice box on a small boat? Please consider the safety of carrying mixing and ease of purchasing?
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A solution of 2-hydroxypropane-1,2,3-tricarboxylic acid plus sodium hydrogen carbonate perhaps

Both readily available and relatively safe to handle
 
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Dry ice and Acetone will get you down to -78°C but if you need a little cooler...
Dry ice and Diethyl Ether will get you down to -100°C
after that I thng you need to go down the liquid nitrogen route rather than dry ice.
Acetone is readily available, Diethyl Ether not so readily available to the public.
#would -78°C be cool enough? if so go for the dry ice and acetoneUsed it a lot when I was a yoof.
 
2nd_apprentice said:
See here:

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

http://en.wikipedia.org/wiki/List_of_cooling_baths
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cliff said:
Dry ice and Acetone will get you down to -78°C but if you need a little cooler...
Dry ice and Diethyl Ether will get you down to -100°C
after that I thng you need to go down the liquid nitrogen route rather than dry ice.
Acetone is readily available, Diethyl Ether not so readily available to the public.
#would -78°C be cool enough? if so go for the dry ice and acetoneUsed it a lot when I was a yoof.
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2nd_apprentice said:
Table salt or ammonium chloride with ice?
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Endothermic reaction :confused::rolleyes:
 
elton said:
Endothermic reaction :confused::rolleyes:
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Exactly.

We all know that ice from the freezer is hard to beat for keeping stuff cool for ages (in properly insulated container). Water has a high specific heat capacity and soaks up a lot of energy to lift it each degree, throw in the large amount of energy needed to change from solid ice to liquid water and you can see it's good for keeping things cool.

I wonder if the OP is actually more interested in cooling something down for a short while rather than keeping stuff cold in a fridge for hours or days.

e.g. Sitting in the baking sun with warm beer and no ice on the boat, just warm water and "magic powder" sitting at ambient temperature.

In that case, an endothermic reaction might be just the job. Only thing that comes to mind and hasn't been mentioned is Urea. I seem to remember that the heat of solution is +ve but can't remember by how much. I don't seem to remember it being a great temp drop but it still might be worth checking.
 
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I was under the impression that melting ice, which is a endothermic reaction, adds to the endothermic reaction of dissolving salts in water. Wikipedia seems to agree but please do correct me if I'm wrong.

IIRC Napoleon's soldiers used cooled water and gun powder in Egypt btw but that's probably less helpful
 
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2nd_apprentice said:
I was under the impression that melting ice, which is a endothermic reaction, adds to the endothermic reaction of dissolving salts in water. Wikipedia seems to agree but please do correct me if I'm wrong.
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Probably better to describe them as endothermic processes rather than reactions

Nothing involving liquid nitrogen, dry ice or even ordinary ice is of any interest. If the OP could store or even obtain them he'd have no problems anyway. He could just stick his cans of beer in a box with one of them.

What he wants is a couple of common substances , that are easy to obtain, can be stored without requiring refrigeration themselves, are safe to handle and when mixed will undergo a endothermic chemical reaction.

Since posting I have tried my suggestion in #2. It works but the amount of heat absorbed is not very great and the result, although interesting, is unspectacular.
 
VicS said:
Probably better to describe them as endothermic processes rather than reactions

Nothing involving liquid nitrogen, dry ice or even ordinary ice is of any interest. If the OP could store or even obtain them he'd have no problems anyway. He could just stick his cans of beer in a box with one of them.
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Fair enough. I still think a cooling box at -5°C could be more useful than +3°C (and ice should be available at any port) but you do have a point. I'd be genuinely interested in a recipe not requiring ice or cooled water however.
 
I seem to recall from school that sherbet creation is endothermic so you could keep the ingredients for that on board and make sherbet when you need a cold beer :D
 
lustyd said:
I seem to recall from school that sherbet creation is endothermic so you could keep the ingredients for that on board and make sherbet when you need a cold beer :D
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Sherbet = Post #2 + icing sugar
 
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Ammonium nitrate and water? Commonly used in instant cold packs. Ammonium nitrate is pretty harmless stuff, although it does have ... explosive possibilities in combination.
 
I do remember what must be 35 years ago I saw someone had bought a pack of 2 chemicals presumabley separated in some way designed for just this purpose. Remove the separation, mix the ingredients and put the bag into an insulated box for instant cold. Now I never saw it work just knew it could be bought. I have never seen it since so presumably it was not a hot seller. Probably not a lot of cooling power. My guess is that ordinary people find it just as easy to freeze a bottle of water to put in the insulated box. Even so it could be handy for emergency cooling. olewill
 
Its easy enough to buy emergency cooling packs from Chemists for use stopping nose bleeds or keeping drugs cold. They last for years without problems. Probably not much use for cooling beer.
 
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