Sciencemadness Discussion Board

Whistle mix with potassium persulfate and potassium benzoate?

mirgp - 5-11-2016 at 01:49

Potassium perchlorate is illegal where I live and i was wondering if potassium persulfate would be a suitable alternative. I have used potassium persulfate in magnesium flash powder before and its suprisingly stable.

Dornier 335A - 5-11-2016 at 14:31

No. Persulfate is not a good oxidizer for organic fuels. It's not even very good for aluminium, only magnesium and magnalium works well.

mirgp - 5-11-2016 at 14:44

Quote: Originally posted by Dornier 335A  
No. Persulfate is not a good oxidizer for organic fuels. It's not even very good for aluminium, only magnesium and magnalium works well.

Oh ok that some interesting information. Do you know what could be a suitable oxidizer for potassium benzoate?

PHILOU Zrealone - 6-11-2016 at 08:23

Na-O-SO2-O-O-SO2-O-Na is a relavively strong oxydiser ...
but a weak oxygen provider except with a strong reducer what is able to take the oxygen out of the sulfate (like Mg and eventually Al if very (ultra-nano)fine and dendritic for very intimate mixing of fuel (reducer) and oxydiser).

Most organic reducer will play with the following
Na2S2O8 --> Na2SO4 + SO2 + O2 <==> Na2SO4 + SO3 + 1/2 O2
Thus 1 to 2 mole equivalent O/mole

Strong reducers will play ultimately with the following
Na2S2O8 --> Na2S + SO2 + 3 O2 <==> Na2S + S(2-) + 4 O2
Thus 6 to 8 mole equivalent O2/mole...but it needs high initiation temperature (see sulfate thermites).

I have eard of an incident into a tiny plant (hair products factory) I was working in; about NH4 persulfate powder mixed with other ingredients (for hair bleaching or for oxydation after thiol (thioacetic acid, thioglycol, thiopropanoic acid) hair "permanent treatment") that was comprimed after years into discrete part of an automatic filler and thus mixed with greases...metals... and it suddently deflagrated and initiated a strong fire into the machine and the powder it was working with...the fire was very localized and stopped once the 500g powder bag (the unarmed worker was busy with) had burned off.

So for K or Na benzoate, only the first route will prevail and it would require a lot of oxydiser vs fuel to acheive a combustion/deflagration...and this is bad news since this means less heat per volume/weight and a lot of dead weight to heat up.

Whistle mix needs a lot of heat for benzoate break down and it uses chlorates what combines good and fast O2 release/mole at moderate temperature.