exothermic reaction

just a single compound that must react with the atmosphere (but not react with the oxygen), or could it be more than a single compound, e.g. Conc Sulfuric Acid and Water for instance.

Thanks for the reply; I guess it would be overrestrictive to say a single compound. The obective would be to heat the air inside a container without the initiation of a flame and without degrading the container itself which is a rubber compound. Two or more substances which could be mixed in the presence of air (oxygen or nitrogen) - the ensuing reaction would release heat and fairly stable products. Thanks again for any ideas.

Do you really need just a compound? Would your application permit some sort of a resistive (or any other form of) electrical heating?

How about a plastic packet containing a mixture of finely divided iron / aluminum / magnesium and water in separate compartments, divided by a plastic membrane. (They should be enclosed to prevent the oxidation of the metal.) Break the membrane to allow the two to mix and you get enough heat. The resulting H2 gas can be vented off from the packet using a valve or allowed to mix with the air if that is okay with you. I vaguely remember hearing about a version of this is used in portable heat and eat lunches.

Look for buffer chemicals that slow the reaction process also used in rocket fuels similar to the ones mentioned, mono propellants bi-propellants and solid propellants can use buffer materials to enhance performance and slow the reaction. Much like water injection in piston engines.

Limit the reaction below the combustion level while heating the air from the chemical process.

Just an Idea

Brad

Thanks guys. You have been helpful. Considering the care taken in handling these products it seems problematic in environments less than optimal such as those controlled by NASA. Cheers

How about using the heat of crystallization of sodium acetate? See:

http://home.howstuffworks.com/question290.htm

Tad