frogy Posted June 5, 2008 Posted June 5, 2008 I was thinking that a dedicated Chemistry thread for help with the synthesis of chemicals used strictly in pyrotechnics would be a good idea. My question is rather easy if the synthesis has been performed by any others, if not, it may just take someone who knows what they're doing . I'm trying to synth NH4Cl to use in the "Negative-X" composition...At first, I added ~11 grams of HCl (31.5%) to ~30 grams of NH4OH (~4%).This yielded a large amount of white fumes or suspended white "mist", which I presume was NH4Cl formed from the HCl fumes reaching with the NH4 fumes... The solution looked nearly 100% clear, except for some small strand-like crystals, that looked very similar to extracted DNA, if you are familiar with that... The solution was boiled for about an hour at 300°F or so, until I got tired of heating it... After over an hour at a rolling boil, nearly any moisture had been driven off, even though the mixture was fuming extensively throughout the whole duration of heating. After cooling, a yellow-tinged solid mush was left over... The product smells very pungent, definitely containing some chlorine or chlorides... I'm really wondering what my final product is... Throughout cooking the aroma was very sweet smelling... Similar to recrystallizing KNO3 and making RCandy... Edit:Apparently small amount of liquids left were very acidic, because just a few mL that were decanted off reacted very violently with some aluminum foil. Maybe too little NH4OH was used... http://img247.imageshack.us/img247/9263/nh4clpi4.jpgHere's an image of the mush... I would have it smaller, but it's only 42 KB as it is...
Sylar Posted June 6, 2008 Posted June 6, 2008 In my opinion, it's allways better to add a bit too much NH4OH then a bit too much HCl. Sure, they're both gasses and /should/ evaporate off completely. But keeping the excess of NH4OH to a minimum effectively speeds up drying (it evaporates faster then HCl*) and decreased the waste of good acid. When thouroughly dried it shouldn't make much extra incompatibilities. Everybody knows about ammoniumchlorate, right? I wouldn't know what's best for the enviroment (HCl or NH3 vapor), but when making and shooting fireworks, one has to face the fact that the whole deal is not very friendly towards the enviroment anyway. Something I stumbled upon while checking my facts in ullmanns ecyclopedia of industrial chemistry:"Ammonium chloride has two modifications. The transformation between the two is reversible at 457.6 K (184.5 °C): a-NH4Cl (cubic, CsCl type) A b-NH4Cl (cubic, NaCl type) B DH = + 4.3 kJ/molThe a modification is the one stable at room temperature. b-NH4Cl melts at 793.2 K under 3.45 MPa; it sublimes at atmospheric pressure. In fact, NH4Cl is quite volatile at lower temperatures, dissociating into NH3 and HCl."So never let production temperatures rise above 150°C! * I know ammonia's boiling point is alot higher then that of hydrochloric acid (-33°C vs -85°C for HCl), but the density of the vapor/gas phase seems to play a more significant role at room temperature drying then the actual boiling point. HCl vapor is twice as heavy as NH3 vapor.
psyco_1322 Posted June 7, 2008 Posted June 7, 2008 Frogy, im not sure if you know this but NaCl will work equally as well with the negative-x formula. Carefull, the slightest humidity gives about enough time to dump and stir before boiling starts and it bursts to flames.
frogy Posted June 7, 2008 Author Posted June 7, 2008 Haha I didn't know that at all... I should have taken time to figure the reaction out... The HCl seems to have evaporated off, leaves a slightly acidic Ammonium salt.... Hopefully chloride Though I have no real use for it now, other than cleaning my soldering iron.
Recommended Posts