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Rsambo
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Copper Oxybromide
I have been following this forum for sometime but this is my first post here, I apologise in advance for any poor etiquette.
I have been working with Potassium Bromate / Copper (i) bromide / Nitrocellulose / Nitroguanadine pyrotechnic blues. I have some interesting results
but I am finding that Copper (i) bromide oxidises in air readily to the Copper (ii) form ( which is deliquescent ) and so within a short 24 hour
period the effect is lost.
I'm trying to think of ways around the problem and wondered if the analogue of Copper Oxychloride might be suitable, namely : Copper Oxybromide. I
can find little information regarding the latter. Copper Oxychloride can be made by the aeration of copper metal in hydrochloric acid. Is it
plausible that the oxybromide might be produced by the aeration of copper in hydrobromic acid?
[Edited on 9-6-2016 by Rsambo]
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myristicinaldehyde
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A pre cursory search of my books didn't turn up any hits for oxybromide, but I can't imagine why not. Here's a synth. of oxychloride. It might work
for the bromide version.
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myristicinaldehyde
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From JSTOR- an actual preparation seems like.
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Rsambo
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Thanks very much, I'm quite tempted to give the calcium carbonate metathesis a go. I need to re-distill my hydrobromic acid and then I might have
some results to show for it !
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myristicinaldehyde
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Good luck! I might just try it myself.
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Rsambo
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If you're at all into colours you should DEFINITELY try potassium bromate / copper (i) bromide with NC. It truly is an incredible blue, even if it
doesn't keep. It's like a powder blue.
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myristicinaldehyde
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Quote: Originally posted by Rsambo | If you're at all into colours you should DEFINITELY try potassium bromate / copper (i) bromide with NC. It truly is an incredible blue, even if it
doesn't keep. It's like a powder blue. |
I DO like colors, but NC is nitrocelluose, right? Chemical acronyms bother me. Am I right in guessing it burns green? Sounds like fun stuff! (^-^)
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Rsambo
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Sorry yes, Nitrocellulose. It burns with a very nice powder blue. % by weight :
KBrO3 58%
CuBr 18%
Hexamine 10%
Nitrocellulose 14%
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Rsambo
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Well I'm not having much luck here so far. I have tried reacting CuO with my hydrobromic acid and all I get is a dark brown liquid which when I
dilute to re-crystallize just seems to form what looks like Copper Sulphate crystals. Either something is majorly wrong with my hydrobromic acid
synthesis or something else ? ! ?
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PHILOU Zrealone
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Quote: Originally posted by Rsambo | Well I'm not having much luck here so far. I have tried reacting CuO with my hydrobromic acid and all I get is a dark brown liquid which when I
dilute to re-crystallize just seems to form what looks like Copper Sulphate crystals. Either something is majorly wrong with my hydrobromic acid
synthesis or something else ? ! ? |
If you get sulfate anion (SO4(2-)) from bromhydric acid (HBr); then indeed you are in big troubles...
Then run for life ... thermonuclear fusion and fission are occuring into your reactor!
[Edited on 14-6-2016 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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PHILOU Zrealone
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Quote: Originally posted by Rsambo | Sorry yes, Nitrocellulose. It burns with a very nice powder blue. % by weight :
KBrO3 58%
CuBr 18%
Hexamine 10%
Nitrocellulose 14% |
What is the benefit over cheaper CuCl, KClO3, Hexamine, NC?
What also makes a wonderful blue colour...
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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woelen
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Quote: Originally posted by Rsambo | Well I'm not having much luck here so far. I have tried reacting CuO with my hydrobromic acid and all I get is a dark brown liquid which when I
dilute to re-crystallize just seems to form what looks like Copper Sulphate crystals. Either something is majorly wrong with my hydrobromic acid
synthesis or something else ? ! ? |
"Het probleem is niet het spulleke, maar het knulleke"
There is no issue with your HBr. When you dissolve CuO in aqueous CuBr, then you get the dark brown red complex CuBr4(2-) in excess HBr. On
evaporation, however, you lose water and HBr and what is left behind is hydrated CuBr2.2H2O. A better description is CuBr2(H2O)2. This is a blue
compound with a greenish hue. Anhydrous CuBr2 is black, very much looking like iodine.
If the HBr is impure and also contains H2SO4, then you'll lose even more HBr on evaporation and CuSO4.5H2O remains behind, with a small amount of
CuBr2(H2O)2 in it as well.
Making oxybromide of copper in this way is not possible. For that you need a more basic solution.
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Rsambo
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The benefit is the blue is substantially more saturated and "cleaner". Not only that but this is an indirect and intriguing route to an alternative
blue strobe. Aside from that, it's just fun and I'm learning here.
Thanks Woelen. Google translate didn't quite get there for me on that one unfortunately. I see, so it forms a dihydrate analogous to Copper (ii)
chloride dihydrate formed using Copper (ii) Carbonate and HCl. I'm rather embarrassed to say I have pondered on your last point for the last half
hour but I can't quite get there.
I had wondered about the water of crystallization and in my first run I took some of the crystals and heated them and they were definitely copper
sulphate as they behave exactly as such when anhydrous; and are white when dehydrated. In my second run I re-distilled my hydrobromic acid and it
came over consistently at 126 degrees C, so I'll go and dry again and see if I can dehydrate these crystals to check they are black and not white when
anhydrous.
I'd really love to figure 90% of this out for myself and not be spoon fed, especially with my first post but I'm feeling like I need a bump in the
right direction.
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PHILOU Zrealone
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Then maybe go for CuI, KIO3, hexamine and NC ... to get another shade of blue?
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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Rsambo
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Veering off topic, but since you ask :
"Recently, some of us reported copper(I) iodide as a potential “green” blue light emitter for perchlorate-free compositions. These compositions
are based on a pyrotechnic formulation that involves copper iodate, guanidinium nitrate, and magnesium. The main drawback is a low burning rate of the
compositions. In turn, they produce ash when burned and a blue flame of low intensity"
Dominykas Juknelevicius et al., Chemistry - A European Journal 21(43):15354 · September 2015
[Edited on 14-6-2016 by Rsambo]
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PHILOU Zrealone
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Not off topic ...
CuCl, CuBr and CuI are Cu(+) halides and as such responsible of the blue-green flame colour...in principle the blue green colour also works with
Cu(2+) if halide is present into the pyrotechnic mix (via PVC glue, powder or intrinsically from the oxydiser (chlorate/perchlorate)...but Cu(2+) and
chlorate anion generates storage troubles.
Nothing is thus against the use of CuCl2, CuBr2 or CuI2 into pyro comp except eventual reactivity with an ingredient of the pyro compo --> storage
stability.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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Rsambo
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Hi Philou,
I didn't mean to offend. This thread is really supposed to be about how to synthesize Copper Oxybromide CuCl2 with nitrocellulose makes an extremely beautiful blue
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woelen
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My words are hard to translate. I think PHILOU may be able to understand them and smile
What I meant with my last sentence is that making oxybromide (and also oxychloride) from CuO and the corresponding acid is not possible in those
acidic solutions.
If you use excess acid, then all CuO dissolves to form the halide and the strongly colored tetrahalogen complex of copper (which is deep yellow/brown
for chloride and nice purple/red/brown for bromide). If you use excess CuO, then you get a solution of the copper halide and some CuO remains
undissolved.
Making oxyhalide can be done by preparing a solution of the copper halide and then carefully adding (under constant strong stirring) hydroxide. This
will give you a compound of ill-defined composition, with halide ions and hydroxide ions mixed in the compound. Heating this stuff drives off water
and leaves behind a mixed halide/oxide.
Another option is to prepare wet CuCl or CuBr. These are white solids and can be prepared from HCl/HBr, copper oxide and a sulfite or metabisulfite.
The wet solid must be rinsed with water and then the humid compound must be put aside in contact with air. It will oxidize quickly and lose its white
color. When it is dry, you need to grind very well and allow to stand in contact with air for another few days. Finally you end up with a dry,
non-hygroscopic powder. The mixed oxide/chloride is green (not blue at all), I expect the mixed oxide/bromide to be green as well, probably a somewhat
darker shade, green like olives. But this is my educated guess, I have no personal experience with that. If you use a sulfite/metabisulfite, use the
potassium salt, such as K2S2O5. If you use the sodium salt, then the resulting copper oxide/halide also has some sodium ions in it, which spoils the
blue color of the flame.
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Rsambo
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Ah ha. Thank you very much for an incredibly clear explanation. Just to make absolutely sure Philou I very much appreciate your comments, it's one
of the problems with forums to worry that you aren't offending anyone ! Hey, I might just try your iodate anyway !
Woelen, I can certainly expand on your suggestion as I have synthesised the Copper (i) halide using both potassium metabisulfite and sodium sulfite so
I'm going to run with that and see what I can do. Thanks enormously !
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PHILOU Zrealone
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@Woelen,
I don't know that idiom (maybe more from The Netherlands than from The Flanders?) but I think I get the feeling of it/ the idea.
"Het probleem is niet het spulleke, maar het knulleke"
-->
The problem doesn't resides into the material, but more into the operator/the process.
Correct understanding? (A la Dutch way: Is dit wel de meening ervan of ben ik compleet ernaast?)
@Rsambo,
Not offended at all, just saying it looks off the line, but stil into the debate because strongly (cor)related.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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Rsambo
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Cool.
I think the English phrase is something like "A lousy workman blames his tools" ! ?
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DraconicAcid
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I hear it phrased as "It's a wet-ware problem, not a software problem."
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Bert
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I am more oriented towards storage stability and easily repeatable affects sufficiently good for display work... An absolutely beautiful blue effects
that that does not last a week in storage is a sad failure to me.
I recall watching G.H. of P. Pyrotechnics exhibit a lovely purple strobe star from air mine/horse tail shells some years back. But the stars would not
keep looking good (or safely!) long enough to be an article of commerce. So, a tease and a great disappointment, however fine they looked that day.
By all means, do experiment on with the atypical halogen chemistry, but always keep in mind the requirements for a PRACTICAL mixture: Safe of
formulate and handle. Stable under real world storage conditions. Easily repeatable in effect. Sufficiently cheap and widely available components...
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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woelen
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All of you got the meaning of that phrase quite well
It is not meant really seriously, it has a humoristic undertone.
-------------------------------------------------------
Bert also has an important point. Some compositions may be unstable and even dangerous. I would be reluctant to use a bromate in a pyrotechnic
composition, unless it is used as a lab curiousity at small scale for a fun demo (I once did, I made CsBrO3 and used that as oxidizer to get really
good blue colors, but this was only meant as a nice chemistry demo at microscale, not for practical use).
In the old times (2004 or so) I once read somewhere on Google Groups sci.chem the following:
"Playing with chlorates in pyrotechnics is like playing with a deadly poisonous snake, playing with bromates in pyrotechnics is like playing with a
deadly poisonous snake, which is slightly pissed off."
Bromates are more sensitive to friction and easier to ignite. In general, the bromate ion is more reactive than the chlorate ion. I know this from
experience with microscale experiments.
[Edited on 16-6-16 by woelen]
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PHILOU Zrealone
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Quote: Originally posted by woelen | All of you got the meaning of that phrase quite well
It is not meant really seriously, it has a humoristic undertone.
-------------------------------------------------------
In the old times (2004 or so) I once read somewhere on Google Groups sci.chem the following:
"Playing with chlorates in pyrotechnics is like playing with a deadly poisonous snake, playing with bromates in pyrotechnics is like playing with a
deadly poisonous snake, which is slightly pissed off."
Bromates are more sensitive to friction and easier to ignite. In general, the bromate ion is more reactive than the chlorate ion. I know this from
experience with microscale experiments.
[Edited on 16-6-16 by woelen] |
1°) Great.
2°) Yes bromates have a more oxydant power than chlorates as such their activation energy is lower and they are more prone to react with a reducer
and more fiercely.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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