5 replies to this topic

[Creepin_pyro]

I've just seen Ammonium Chloride listed as a possible pyro chlorine donor. As I don't really want to order parlon from the states, would like to give it a go. Anyone heard of Ammonium Chloride being used in this way, or had any success?

[BigG]

Ammonium Chloride can not be used as a chlorine dounor. I know Kentish was trying to use it – but those formulas incorporating ammonium chloride found not to tbe working by modern writers.

There are two problems with ammonium chloride. First, Kentish used it with chlorate, a practice that today we know if not expectable (he used it with chlorate and sulphur in the same formula!!!). Second – Ammonium chloride decomposes at such low temperature that by the time the composition reaches colour temperature - most of chloride is already gone and is not available for colour production.

Edited by BigG, 10 February 2004 - 09:41 AM.

[Phoenix]

BigG said,

Ammonium chloride decomposes at such low temperature that by the time the composition reaches colour temperature - most of chloride is already gone and is not available for colour production.

I believe you about the formulas not working, but I thought chlorine donors were meant to decompose, and the resultant HCl or elemental Cl would react with the metal to give the metal chloride.

Isn't this what happens in amounium perchlorate colour compositions after the initial decomposition to oxygen and ammonium chloride? I thought that potassium perchlorate benefits from an additional chlorine donor _because_ potassium chloride does not decompose very well at ordinary pyro temperatures.

[BigG]

Your description is quite good Phoenix. Indeed, it is the decomposition that frees the chlorine. However, in order for the chlorine to be available for colour production, the temperature of the decomposition need to be close to the temperature required for colour production. For chlorine to be available, we say that the decomposing needs to be at least in ?the flame temperature?. Ammonium chloride decomposes much earlier then temperature required for colour production. By the time the temperature is high enough, the chlorine is not ?close enough? to the flame to help in colour production.

In that sense, there is a big difference between ammonium chloride and ammonium perclorate. Ammonium perchlorate decomposes upon combustion, releasing the ammonium chloride, which immediately decomposes itself ? but at that point the temperature is already high enough! (This is because ammonium perchlorate decomposes at temperature that is enough for colour creation). So the released chlorine is immediately used in the flame. Ammonium perchlorate is unique in that sense. None of the other oxidizers release chlorine containing compounds, which immediately decomposes themselves ? not even chlorates.

PVC, Parlon, Seran and others, decomposes at the right flame temperature, to allow most of the available chlorine to be used by the flame.

Well, not dead accurate, but I hope the idea is more or less clear.

[BurlHorse]

Excellent Dissertation, accurate too!

Regads, Stay Green,

Bear

[Phoenix]

Thanks BigG, I hadn't thought of that.