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Why does NH4ClO4 contribute Cl but KClO4 does not?


FlaMtnBkr

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How come AP contributes chlorine to a formula so that a chlorine donor is not needed but KClO3/KClO4 does not and requires a chlorine donor?

 

Guess it's not important why but I'm curious if there is an (somewhat) easy explanation.

 

Thanks!

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When AP decomposes you get free chlorine, or at least hydrochloric acid than can easily react with something else to form copper chloride ect.

 

With the potassium salts you get KCl. So the chlorine is already part of a very stable compound.

Another slight disadvantage is that KCl produces it's own lavender like flame colour, which interferes with your desired one.

Edited by mabuse00
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That makes sense. I guess KCl must have a high decomposition temp.

 

If a formula contains a potassium salt would it tend to make KCl instead of the desired color/metal chloride? It seems like I've seen formulas with both AP and perc.

 

Again, just curious.

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My best guess is that it's sort of a secondary reaction. Both perchlorates will decompose to the resulting chloride. In this case potassium chloride and ammonium chloride. The difference being that ammonium chloride is not particularly stable. It decomposes in hot water, and will decompose in the solid state at a few hundred degrees celcius. A burning star is more than hot enough to decompose it into ammonia and HCl gas. Potassium chloride is quite stable on the other hand. Standing too close to a poorly formulated AP star will give you all the proof you need there is HCl being released.

 

As a mild aside, you can force potassium perchlorate (or the chloride really) to give up it's chlorine by using sulfur as part of the fuel source. It will force it to make potassium sulfide and sulfates instead of chlorides.

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Also to remember, perc does contribute Cl, but not too much. But it contains much less chlorone (by weight) compared to ammonium perchlorate. It's just sufficient enough. On the contray chlorate decomposes into the chloride too, but most chlorate formulas allready work good without a chlorine donor.
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  • 1 year later...

Some people have experimented with chlorides as the colorant. The biggest issue is that chlorides of the common colorant salts we use tend to be hygroscopic or corrosive. It works fine for alcohol flames or ghost mines since they can be mixed quickly before use and are not as sensitive to water, but in stars they are not particularly useful.

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Mumbles' reasoning for ap donating more cl than perchlorate sound most reasonable to me.

 

That said, From my experience with ap comps, ap still doesn't donate a considerable amount of cl to any color reaction especially those with metals. I still end up having to add additional parlon, pvc, or hcb to get a stronger color. I would go as far as to say the cl donation from either oxidizers is negligible. As I don't know of any ap color comps which don't require additional chlorine donors.

Edited by CrossOut
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Now that we have modern binders I think there should be a renewed interest in the use of metal chlorides. I agree with you mumbles that traditionally they are not at all useful, however, In the right composition, for the right purpose, with the right binder I think they really could be.

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I mean the hygroscopic drawbacks can be eliminated ( I can do this using Ixan as an example, I suspect PVB in combination with other binders too ). with Copper (ii) chloride it's more difficult as it is corrosive, especially to aluminium and stainless steel but I suspect not to brass.

 

As an example I am working on - Guanadine Nitrate + Ammonium Perchlorate + Dextrin will strobe beautifully, the drawback comes when adding sufficient chlorine donor / colourant as this tends to either destroy the strobe or turn it into a vibrational burn. Using Copper (ii) chloride for a blue strobe resolves this issue with an astoundingly bright and saturated flame with a large flame envelope - if it could be suitably bound then it might be stable.

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I would imagine the best way to bind then would be using a solvent binder like phenolic resin or nc for example. Then make sure your prime coat uses the same binding method and get a nice thick layer to isolate the star from the environment.

 

Worth a try. Let us know how it goes. Ive been looking for better color strobes.

Edited by CrossOut
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Mumbles' reasoning for ap donating more cl than perchlorate sound most reasonable to me.

 

That said, From my experience with ap comps, ap still doesn't donate a considerable amount of cl to any color reaction especially those with metals. I still end up having to add additional parlon, pvc, or hcb to get a stronger color. I would go as far as to say the cl donation from either oxidizers is negligible. As I don't know of any ap color comps which don't require additional chlorine donors.

Don't forget Dave Bleser's New Blue! It's old now though :)

82- ammonium perchlorate

18- copper benzoate

4- dextrin

 

It's the bluest blue I've ever seen.

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Don't forget Dave Bleser's New Blue! It's old now though :)

82- ammonium perchlorate

18- copper benzoate

4- dextrin

 

It's the bluest blue I've ever seen.

 

And also the very reason I don't have or use Chlorate. They also lend themselves well to using phenolic resin or NC lacquer for binding.

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Dave, I completely agree with you, apart from a bromate blue it's the bluest blue I've seen that's why I've turned it into a strobe ! Can't quite get up to the same amount of Copper Benzoate to fully saturate the colour without killing the strobe but I can do it with Copper (ii) Chloride dihydrate. I'll look at resorcinol and phenolic binding. I have a good working star with Ixan but will let you all know how it goes, my biggest worry is not the corrosive or hygroscopic properties but stability with AP.

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How do you manage to bind those AP stars with dextrin?.. Doesn't the AP break down on you with water?

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Why would you think that AP would break down with water?

 

Admittedly, AP, water and, say, magnesium together IS a problem. That's because a solution of AP is acidic (because perchloric acid is a strong acid and ammonium hydroxide is a weak base). It is sufficiently acidic to react with the magnesium. In a mixture that does not contain anything that is sensitive to acids (such as Dave Bleser's New Blue), using a water-activated binder is not going to be a problem.

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Makes sense.

 

All of the comps I've ever used with ap stress solvent binding. And I've had a friend mention it breaks down similar to ammonium nitrate. Admittedly I just took his word for it and never tested my self.

 

Checking wiki shows a rather low solubility so I guess there you have it.

 

Thanks

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  • 2 weeks later...

I've been away from the forums for a while between my 20 month old daughter and my health problems so my membership to passfire and Fireworking have lapsed and I don't have access to an easily searchable database. But from what I remember and the formulas I do have in my notes, most AP based colors don't have a chlorine donor.

 

Is this not the case or are people starting to add chlorine donors to AP comps now?

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As a mild aside, you can force potassium perchlorate (or the chloride really) to give up it's chlorine by using sulfur as part of the fuel source. It will force it to make potassium sulfide and sulfates instead of chlorides.

 

Mumbles, I take this to mean that a chlorine donor is not necessary if you use the right amount of sulfur. If this is the case, then would this be an example of such a reaction?:

2KClO4 + S + 2CuO → K2SO4 + 2CuCl + 3O2

 

If so, then:

KClO4 = 138.55g/mol, S = 32.06g/mol

2 mol KClO4 * 138.55g/mol = 277.10g KClO4

1 mol S = 32.06g S

32.06g S / 277.10g KClO4 = 0.1157g S / g KClO4

So for 60.5g of KClO4, you'd want to use at least 7g of sulfur (this is not taking into account use of sulfur by other reactions in the comp).

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I suppose theoretically yes, that is true. I would also like to point out that chlorine also is important to metal fueled colors as well. It helps to form magnesium and aluminum chlorides in the flame, instead of the oxides. The oxides are what wash out colors, while the chlorides tend to emit outside the visible region.

 

Flame chemistry is complicated. There are no hard and fast rules since dozens of products are formed in varying amounts.

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I suppose theoretically yes, that is true. I would also like to point out that chlorine also is important to metal fueled colors as well. It helps to form magnesium and aluminum chlorides in the flame, instead of the oxides. The oxides are what wash out colors, while the chlorides tend to emit outside the visible region.

 

Flame chemistry is complicated. There are no hard and fast rules since dozens of products are formed in varying amounts.

 

yep, except in the case of LIthium - halides are detrimental in that circumstance which is not normally the case as Mumbles says.

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  • 2 weeks later...
Thanks, this is helpful. Got into an argument once about someone saying Na chlorate was not as strong as Na perchlorat because of oxygen.
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