Sciencemadness Discussion Board

How does terephtalic acid work in smoke grenades?

John paul III - 7-6-2018 at 05:09

How does terephthalic acid work as a smoking agent? Does it need added oxidizer? (it's always listed alone) Does it react in contact with air? How does its efficiency compare with C2Cl6+Zn?

[Edited on 7-6-2018 by John paul III]

softbeard - 8-6-2018 at 03:49

I'm not sure specifically for terephthalic acid, but usually materials like this generate a light-obscuring aerosol by first being vaporized in a 'low temperature' pyrotechnic reaction.
Usually, the pyrotechnic is something like a KClO3 / sugar mixture with NaHCO3 added. The terephthalic acid is added as a component and vaporized when this mixture 'burns'. The terephthalic acid then re-condenses as an aerosol 'smoke'.
The point is, terephthalic-acid-smoke should be relatively innocuous to breath in concentrations that still make a good light obscurant.

greenlight - 8-6-2018 at 10:39

Sofbeard is correct I am quite sure.

Terephthalic acid can be used in the mixture with potassium chlorate and lactose. Yes, it needs an oxidizer and a fuel.
In a mixture with an oxidizer and a fuel it is s vaporized and the particles form the obscuring smoke in a similar fashion to the coloured dyes used in KClO3 compositions.

I think it is quite similar to HC smoke but without the toxicity baggage.
The HC smoke is a better obscurant due to the darker colour and ?thickness? of the smoke cloud. It is less likely moved by the wind or breeze I as well I think because it is more dense and heavier.
Then there is always that toxicity problem raising it's head again though;) and the military is always trying to phase anything out that is toxic.



That took 30 seconds...

Bert - 9-6-2018 at 02:43

I have never made this. Don't need smoke too often- But:
Quote:

This Terephthalic Acid is very fine and ready to use. Mixed with Potassium Chlorate and Lactose (or Confectioners Sugar) it produces a dense white smoke.

KClO3 23
Lactose 16
TPA 61

Used in military smoke gernades as a replacement for HC smoke.




Mixture information provided by an online supplier-