[GrumpyOldFart]

I'm neither a student nor a professional, in fact I am woefully ignorant of chemistry and I know it, which is why I'm here. As part of a personal project, I'm looking for a reaction between two or more compounds which:

1) Can all be produced by biological processes
2) Have an endothermic reaction when mixed, the more extreme the better
3) Yield a product which is flammable, again the more extreme the better.

It would be nice if the product were also extremely volatile to increase the endothermic process still further, and if it were toxic into the bargain that would be a nice bonus. Keep in mind this is strictly hypothetical, I promise not to blow anything up.

[nj_bartel]

Your first requirement is severely limiting here, to those conditions.  Can't think of anything offhand.  Methane maybe?

[GrumpyOldFart]

I can't claim to know. Please understand, the compounds involved don't have to be anything that a living creature demonstrably produces in today's world. It has to be something a biological system (ie a living creature) *could* produce.

Just so you know (and in the interests of setting people's minds at ease about safety), this is a potential plot element for a story I am writing.

[macman104]

I can't claim to know. Please understand, the compounds involved don't have to be anything that a living creature demonstrably produces in today's world. It has to be something a biological system (ie a living creature) *could* produce.

Well, if that's the case, the biological system COULD produce anything.  Make up whatever biological process you feel like.  Also, you say you want an endothermic reaction, you mean exothermic?  Why don't you have the biological process make the components for thermite, lol?

Your best way to go about this is to decide on a reaction you want, and then just make up a biological process.

[GrumpyOldFart]

Well, if that's the case, the biological system COULD produce anything. Make up whatever biological process you feel like.

Well there is that, but some of the weirdnesses that seem to be produced as part of "normal" life chemistry, I didn't think I would have to go that far afield. I mean, bombardier beetles for cryin out loud. I would have felt stupid if there was some oddball thing that, precisely *because*it's so odd, gets taught to biochemistry students the world over, and I missed it because I never thought to ask.

Also, you say you want an endothermic reaction, you mean exothermic?

Nope. The idea is you mix the compounds, the reaction is endothermic, preferably extreme enough to cause frostbite if you touch the reaction vessel. The resulting compound may or may not be stable, may or may not be toxic, but *is* highly flammable.

Keep in mind, this is for a story. Yes I could just make something up, but the idea is to immerse the reader in the setting. The more the setting connects with the world the reader experiences, the easier it is to do that.

Why don't you have the biological process make the components for thermite, lol?
Your best way to go about this is to decide on a reaction you want, and then just make up a biological process.

Okay. The creature in question has ducts in its mouth. If it chooses to spit at you, the compounds mix in the air. The ongoing reaction is highly endothermic, to the point of causing frostbite where it touches the skin. If the yield compound is volatile enough to add to the problem by evaporating quickly, so much the better. If it's toxic as well, better still. But until it DOES evaporate, or until you take detox measures of some sort, you'd do well not to light a match.

Given that as what I want for story purposes, what could the compound be and how could it be produced? Any ideas? Cos I have no foggiest clue, and until I define precisely what the problem *is*, the characters can only deal with the result rather than overcoming the problem. Does that make sense?

Thanks for giving this your attention, btw...

[nj_bartel]

acetonitrile?  If enough of that evaporates on you would it cause frostbite?  I know acetone gets you pretty chilly, and I've heard acetonitrile is worse.

[GrumpyOldFart]

Don't know but I'll find out what I can. A lot of the ketones seem to be promising.

[GrumpyOldFart]

Hmmm... could a biological process produce diborane?