Exotic Whistle Catalysts

[Mumbles]

Being the chemistry nerd that I am, I'm always on the lookout for new chemicals to make. Being the synthetic inorganic chemistry nerd that I am, I have a fondness for exotic whistle cataysts, despite making less than a handful of whistle rockets in my life. It's pretty commonly accepted (I think) that copper oxychloride makes the most thrust from the commonly available pyro chems. According to Danny Creagan, copper chromite outpreforms copper oxychloride somewhat. This has always made me think, if copper chromite is great, what's better?

 

As of late I have been doing some research. If I go through with any of it, I'm going to try to pawn it off on a few people to do the actual testing for me.

 

The first thing I've been looking at are transition metal salts of transition metal ions. Pretty much Copper Chromite analogues with other transition metals.

 

Copper Manganite

Nickel Manganite

Cobalt Ferrite

 

You get the idea, but those are the ones I have patents/proceedures for. It's all pretty standard stuff. You have a mixture of soluble salts (normally chloride or nitrate) of both metal ions, and you rapidly precipitate them together with sodium or potassium hydroxide. You then roast it, and you get these transition metal salts. By varying the ratios, you can determine which is the "anion" and which is the "cation". I think this has the best chance of finding something new.

 

I've also been looking into Iron Oxide nanoparticles. They really aren't as hard to make as it sounds. Nano particles are generally what are used when it's a catalyst in bigger rockets or commercial boosters. Why not go for the best right?

 

As a third avenue, I've been perusing the Inorganic Syntheses database. Many of you will be familiar with www.orgsyn.org. It is the inorganic equivalent, only it's isn't free and open to the public unfortunately. I've seen a few interesting things in there. I had a few thoughts, such as what would happen upon replacing the metal oxides with metal sulfides, or high oxygen ligands.

 

-Potassium dioxalatocuprate (II) 2-hydrate - It dehydrates at an easily obtainable temperature. When copper oxalate decomposes, it produces nano-scale pyrophoric copper, which may have an interesting effect. It is really easy to make too.

-Potassium Dithioferrate

-Transition metal Acac complexes. These can be made into ions as well, with appropriate oxidation state selection. Copper bis[triacetylacetonate chromium(II)] would be interesting

-Maybe metal formates or oxalates. They both are highly oxygen based. They also decompose in nano-particles upon pyrolysis in the flame.

-The last thing I was looking at were nitrogen donating ligands instead of oxygen.

 

I'm not sure why I am posting this. I just felt like sharing, and potentially getting some input. I can share syntheses of the above if anyone is interested. It can just serve as a place for discussion of all the fun in talking about whistle catalysts.

[Lagrange]

That is very interesting, do you have any physical theory about whistle composition? this would help find good candidate for whistle producing agent. For the production of manganite you can read a little description here http://www.springerlink.com/content/x04315m841000528/. it is largely the same as you explained but there is quantitative information of the end composition of the product.

I would be very interested in reading about whistle. I think it can be possible to change the resonator factor by designing a choked nozzle or the reverse. A resonating box placed at the end of your casing should work to "concentrate and communicate"the sound to the air a lot more. Pitch is either determine partly by the volume of the free chamber if it is a "resonator" phenomenon, or not, if the volume of the chamber doesn't change the pitch you can class this phenomenon as unfitted forced oscillator witch would make the effect a lot more composition dependent. check wikipedia for this.

It doesn't seem possible to try lot's of chemicals without theory but if you have time it's event more fun and lead to possibly more discovery!

[Mumbles]

Oh yeah, I have plenty of practical experimental details for the production of these compounds. Their preparation is not a problem. I am aware that they often don't have stoichiometric ratios in many cases as well.

 

My interest in this project primarily lies on the synthesis side of things. I made some copper chromite for a few people, and they really love it. It's also rather time consuming to make though. Many of the above are structurally related, so that is my thinking with them. There really are few benefits to these types of things given their laborious preparation, but who knows, maybe it will win me some PGI competitions with my whistle on steroids, or unexpectedly create some unique sound.

 

There are relatively few papers out on the chemistry and physics of whistle mix. It is fairly well understood that the aromatic ring seems pretty critical. It is also fairly well understood that there is an extremely fast "strobe" type reaction where there is a smolder phase, and a bright phase. This cycles so fast that it is in the human hearing range. Given it's pitch, possibly over 1000 Hz. All of the current papers out on the mechanism are of course unavailable with my journal access. Without knowing that, it's hard to put some theory behind the design of new high powered catalysts. Outside of knowing that transition metals catalyze the decomposition of chlorates and perchlorate, and the empirical data I have, I have very few insights into this. This is part of the reason I proposed and am interested in a wide variety of classes.

 

You can actually tune pitch and thrust somewhat by redesigning the core.

[Rosco]

Aromatic ring(s) needed huh ? Okay here's an idea for an experiment.

 

There is one hypothetical material which I have been thinking may be possible, a double salt or complex salt of manganese with benzoic acid and picric acid. It could possibly be made easily, if it exists, by slowly adding manganese carbonate to a stirred hot or maybe a boiling equimolar solution of benzoic acid and picric acid. Copper carbonate may work the same way to form a copper benzoate picrate similarly as the manganese benzoate picrate. Strontium and Barium may also work.

 

Of course it's possible that a hydrated salt or two separate hydrate salts in mixture could result instead of a neat anhydrous complex salt. Never tried these so I couldn't say, nor can I guess how these materials may behave as fuels in combination with oxidizers.

Edited April 14, 2010 by Rosco

[Mumbles]

The problem I see with that is the different coordinating environment of both carboxylic acids and phenols. Carboxylates coordinate through both oxygens, while phenol goes through one. I would use potassium salts of both benzoic acid and TNP. These will have to be warm due to solubility concerns. I would mix a soluble copper or manganese salt (chloride, nitrate, sulfate, etc) with the warm mixed acid solution.

 

Honestly, complex salt or not, I wouldn't feel comfortable making picric salts of any of those metals. Copper picrate is quite sensitive and not all that stable.

[Rosco]

IIRC potassium picrate has been used in whistles and it is a lot more sensitive and energetic than the copper salt, which would ordinarily be a hydrated salt. The dehydrated copper salt is probably another story. Metal Acetate/Picrate complex salts do form and so do complex basic picrates, additive with acetate, lactate, glycinate, formate. The acid hydrogen on an end of an aliphatic acid is not vastly different from the acidity of the hydrogen of the hydroxyl on a ring compound, and there are parallel reactions of various kinds where there is a parallel for the aromatic and aliphatic compounds. The idea that a complex phenolate could be possible similarly as known complex carboxylate phenolates doesn't seem implausible. Salicylate could do the same thing. I don't know for certain, but I wouldn't rule it out without testing it by experiment. Also, because of the unknown solubility factors for an unknown product, the

suggested route from a carbonate precursor having only one byproduct which would be the CO2 that effervesces seems more straightforward. The potassium salts may not drive the reaction

in the same way. For example a potassium salt added to a solution of TNP or soluble TNP salt

will produce a precipitate of potassium picrate, since it has low solubility. Sodium salts would

probably work better if a metathesis was attempted, but really the carbonate route proposed

is more direct and free from byproducts.

Edited April 14, 2010 by Rosco

[Mumbles]

Potassium picrate is still somewhat soluble in warm solution. There is no reason sodium could not be used instead. Just from the general aversion to sodium for color purity reasons, I have an automatic aversion to sodium in pyrotechnic applications. As a catalyst, there isn't any issues though.

 

The reason I was trying to shy away from the use of carbonates is to prevent preferential reaction. My thoughts, analogous to the mixed metal oxides above, was that by using solutions of all the precursors could allow a potentially more like formation of a complex salt. I also was unaware of these complex salts between picrates and various carboxylates. I've done a bit of research on them this morning, and this seems much more plausible. I was used to the preparation of copper benzoate, where the salt immediately precipitates upon mixing. It sounds like it could be done it two steps even from the following paper, where the transition metal picrate is mixed with a hot solution of benzoic acid (or benzoates) instead of amino acids or other carboxylates.

 

http://www.jbc.org/content/227/2/871.full.pdf

http://www.jbc.org/content/230/1/157.full.pdf

 

Potassium picrate certainly is somewhat sensitive, but I've been under the impression that in the grand scheme of metal benzoates, it is one of the more benign. Just the fact that it could be made into functional whistles is saying something. As a side note, it makes a black smoke trail that I bet would be quite a sight.

[Rosco]

Maybe there is also potential here for making colorant containing fuels which could be combined with the associated colorant oxidizer

to produce a more intensely colored fire. So even if such complex picrates prove not to be valuable in whistle mixes, there could still be some value for their use in flares or stars. For example, the strontium glycinate picrate in mixture with strontium nitrate could be very intensely red, and likewise green for the barium, and blue for the copper, ect. Zinc might also give a blue. Somewhere I think I have seen a military red flare composition that was based upon a similar complex where the colorant was bound in an energetic fuel oxidizer complex and it reportedly does work to do this approach sometimes for coloring fires, so I thought it might have parallel usefulness for the catalytic oxides desirable with chlorate and other oxidizers in a whistle mix. Possibly you could find properties useful for whistles or colors or even both at the same time. Different pitches for different colored whistles could be interesting.

[asilentbob]

Psyco_1322 and I are going to mess around with cobalt compounds as possible whistle catalysts at some point. I have some cobalt(II) sulfate that I got cheap as part of a lot of ceramic grade chems.

 

Not that they would necessarily be anything special. Just that there are many possible transition metals.

 

I have wondered about using ferrocerium to make salts to use for catalysts before. I have also wondered about alloying ferrocerium with various other cheaper metals for DIY metal hydride hydrogen storage, because of the lanthanum present. I remember something along the lines of a lanthanum/iron/? alloy used like this.

 

Not too helpful, but still...

[crazyboy25]

I would have thought you have seen this page Mumbles, they tested a large number of whistle catalysts: http://www.wichitabuggywhip.com/fireworks/rockets/whistletests.html

 

Or perhaps you knew about it and were inspired?

Edited April 19, 2010 by crazyboy25

[Mumbles]

Cobalt does some cool catalytic stuff, so why not? Rhodium has a personal place in my heart (probably literally), so I have confidence in it's little brother too. I plan to play a little bit too.

 

Another one I was reading about was one with more aeronautical influences is Ferrocene, and the analogues.

 

As far as Danny's website, it is mostly inspiration. If I ever get around to it, Danny will likely be getting samples. Anything I could do would be strictly qualitative.

[Rosco]

The chloranilate salts of copper, strontium, and barium could also have interest in experimental pyrotechnic mixtures,

as they would contain an aromatic ring, the colorant metal, and would be a chlorine donor. This would be of interest

in experiments with stars generally, but in the case of the copper salt would also have interest in whistles

[Mumbles]

Related to the chloroanilates are chlorobenzoate salts. From a respected individual, he said that it worked fine as a star or a colorant, but it wouldn't make a blue whistle. It apparently doesn't do it's thing in the audible range of humans.

 

In any case, I don't know if I would call it aromatic. Benzoquinone is not aromatic.

[Rosco]

There's also the possibility of it forming complexes and double salts or even polymer linkages

 

check this jazz and fireworks

 

Edited May 2, 2010 by Rosco

[MadMax]

Mumbles,

 

According to what you are saying iron oxide nanoparticles aren't that hard to make. Would you please elaborate on this?

 

I have attempted this with both the red and the black iron oxide. The method I used was ball milling for many days with a very high milling media to powder ratio. It did make a very fine powder in deed. I tested it to see if it would react any faster in a thermite comp with my finest grade of Al (and included about 10% of fine MgAl to boost it). The end result was a decent thermite that ignites via lighter even in small quantities and did burn faster but I have no way of knowing if the powder was in deed truly nanoscale. I heard something about it taking on some weird magnetic properties but I believe that Fe3O4 is already magnetic (hence the name magnetite). I did not try it as a catalyst but that's mainly because I wasn't sure if it was what I had hoped it was.

 

Is there a different (better) way that you might know to make and test this?

 

Thanks buddy

 

I've also been looking into Iron Oxide nanoparticles. They really aren't as hard to make as it sounds. Nano particles are generally what are used when it's a catalyst in bigger rockets or commercial boosters. Why not go for the best right?

[Mumbles]

Hate to burst your bubble, but you can't mechanically make nano particles. You may have approached single digit to teen microns, but that is still orders of magnitude larger than nanoparticles. I'll try to look up the synthesis I have in mind. The one I found with a quick search isn't quite as easy as I had thought. Typically they're made by thermal decomposition of soluble iron sources.

[pillyg]

I saw a video on youtube about making fine aluminum powder. They boiled the Al and then sprayed the vapor with liquid nitrogen. What size particles would that make?