Ammonium Perchlorate Plastique

[ALENGOSVIG1]

I was browsing though KIPE2 and came across "Silicone Oil/ Ammonium Perchlorate plastique". It contains ammonium perchlorate and copper chromate. it uses silicone oil as a plasticizer. Does anyone know wher copper chromite can be aquired? if anyone has any information about this explosives and its properties please respond.

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[FadeToBlackened]

thanks kingspaz.. thats what i though

[This message has been edited by FadeToBlackened (edited August 07, 2001).]

[Lagen]

deleting post - not relevant to copper chromite (http://www.rhodium.ws/chemistry/copperchromite.txt) preparation

[This message has been edited by Lagen (edited August 07, 2001).]

[kingspaz]

there is such thing as Cu2SO4 - copper has a variable oxidation sate http://theforum.virtualave.net/ubb/smilies/smile.gif

[Lagen]

not in a water solution. If any Cu2SO4 existed in the solution, it would quickly change to CuSO4 and metallic copper.

[This message has been edited by Lagen (edited August 07, 2001).]

[cutefix]

I am not very familiar with this particular explosive formulation but it has similarity with the rocket propellant techniques,however I give my opinon as well.:

I was thinking about the importance of copper chromite in ammonium perchlorate ….
I think that this chromium compound has this formula- Cu(CrO2)2.It should contain chromium oxide about 40% and copper oxide 60%and and is a black material used as catalyst in industrial chemistry,and in paint pigment industry/alternative for black color..It was made by calcining copper oxide and chromium oxide.As far as I know
It is used in solid propellants as burn rate modifier/catalyst..It was claimed that it can accelerate the decomposition of ammonium perchlorate in propellant combustion.
.In industrial setting ,this copper chromite is to be ground in ultrafine particle size in the same manner as ammonium perchlorate and they are intimately blended,before added to other propellant ingredients.Lately its function was said to be replaced by ferrocene derivatives.
In your explosive formulation from kipe it contains a a maximum of 5% copper chromite and 95% ammonium perchlorate;then added to a gel made by combining specific silicon oils and silicon paste,in ratios of 85/15 oxidant to binder ratio.Somehow I was thinking that the initiation was centered on the ammonium perchlorate that was sensitized by this combination.I think by replacing that chromate with aluminum powder it will do the same job buts its VOD might be slightly lower,but would create a sizable blast.I don’t believe in the claim that the copper chromite combination will have good VOD as standard explosives like RDX and the like….I recommend that you use a powerful primer to set this off…

[Lagen]

I have the official spec for copper chromite and the formula there is 2 CuO . Cr2O3, this would lead to a 60:57 weight ratio CuO:Cr2O3.

[cutefix]

Why such and odd ratio?

[Lagen]

I calculated it...
MM(CuO)=79.5454 MM(Cr2O3)=151.9904 so CuO:Cr2O3=159.0908:151.9904
Why those numbers: I simply put 60g 2moles CuO in my chem program and the equimolar amount of Cr2O3 was 57.322g. I did that to quickly verify the 60/40 ratio you have given, to see if I get 40g. Translated into % it's 51.14% and 48.86%.

I found another spec (http://www.nikki-chem.co.jp/eng/products/syokubai/e200-2.html) for it, this does not quote the chemical formula and it is probably the "barium promoted" variety (generally this contains up to 10% BaO). But the CuO:Cr2O3 ratios are much the same.

[This message has been edited by Lagen (edited August 11, 2001).]

[cutefix]

There is copper chromate link for UK military use which has higher content of copper oxide than chromium oxide.check this out:
http://www.dstan.mod.uk/data/68/099/00000100.pdf
Copper chromite is used by U.S before(until replaced by ferrocene derivatives)and the Chinese for propellant compositions.
I think for simple purpose of initiating that plastic explosive combination,the composition doesn’t affect the performance;therefore any source of copper chromite will suffice.
I think copper chromate can be improvised by reacting chromic acid with copper hydroxide.The chromic acid can be obtained by the reaction of sodium dichromate and sulfuric acid.Then this copper chromate is heated at 400C to form copper chromite.
According to the Merck Index “,This copper chromite or known also as cupric chromite(lV)-CuO4Cr2 is different from cupric chromate(lll)-CrCuO4.The former is grayish black to black while the latter is reddish brown.
Elemental analysis;
E lements Cupric Chromate Cupric Chromite
Chromium 28.96% 44.91%
Copper 35.39% 27.45%
Oxygen 35.65% 27.64%
Molecular Weight 179.54 231.54





[This message has been edited by cutefix (edited August 12, 2001).]

[Lagen]

Regarding copper chromate manufacture: Yes, but if you improvise everything including the dichromate then it's easier to switch to copper chromate in the early stages of dichromate preparation. Just add a soluble Cu(II) salt at the point where there is sodium chromate in solution and the insoluble copper chromate precipitates.

Edit: Hey, that spec sheet is for basic copper chromate, CuCrO4.2Cu(OH)2, which of course has totally different percentages! This contains Cr(VI). As to the oxidation states of chromium in the other compounds, I believe you must be mistaken as CuCrO4 would be Cr(VI) and CuCr2O4 would be Cr(III). I think copper chromite can be both CuCr2O4 and 2CuO.Cr2O3, depending on the method of preparation. The method you gave would probably lead to CuCr2O4, but I have never seen a mention of it being used as catalyst. (You probably assume an analogy with the mineral chromite, FeCr2O4, right?) What matters here is the surface area - 2CuO.Cr2O3 has ca 35 sq.m./gram.

[This message has been edited by Lagen (edited August 12, 2001).]

[cutefix]

All the information about that copper chromate,copper chromite comparison were from the Merck Index.To my knowledge,the copper chromate are used as fungicides,and the the copper chromite are used as industrial catalysts.The latter was applicable for rocket propellants also(it is a burning rate accelerator in solid propellants)If you will see in the search,there is this catalyst that is part of the importance of this copper chromite material,I think it was hydrogenation and similar things in industrial chemistry.Regarding the catalysis of ammonium perchlorate by copper chromite in propellants,its very difficult to find in the web.
Some websites that supply copper chromite as catalyst check these:
http://www.filtrandia.com/znocatalyst1.htm
http://criepe.denken.or.ip/RD/nenpo/1996E/96scika47.html


[This message has been edited by cutefix (edited August 13, 2001).]

[cutefix]

I found some relevant information related to this topic:
Process of preparing copper chromite catalyst.U.S.Patent 3,935,128
“A copper chromite catalyst was prepared according to the technique as set forth below. 900cc of a solution containing 260 grams of copper nitrate trihydrate in deionized water was heated to 80.degree. C and added with stirring into 900cc of a solution at 25.degree.C containing 178 grams of sodium dichromate dihydrate and 225cc of 28% ammonium hydroxide in deionized water resulting in the formation of a precipitate. The reaction mixture which had a pH of 6.4 was digested for 45 minutes under agitation after which it was filtered, washed twice on the filter with 100cc portions of deionized water, dried at 110.degree.C overnight and calcined at 360.degree.C for 45 minutes”

Perchlorate Sensitizing Agent-U.S.Patent 4,040,880
“An inorganic perchlorate is sensitized by adding about 1-8 percent by weight of copper chromite to said perchlorate. The mixture of inorganic perchlorate-copper chromite can be used as a substitute for RDX. “

This perchlorate is the ammonium perchlorate,and 4-5% of that chromite is sufficient to sensitize it to be a powerful explosive,which is preferable if some quantities of another explosive is added to it to boost its power;such as 5-10%RDX or PETN plus aluminum powder. When bound by as suitable polymer like silicon gel or similar materials,it will make agood plastic explosive.
I anticipate that potassium/sodium perchlorate will work the same.

[Hex]

Chromium can be a fairly potent carcinogen depending on it's oxidation state - don't suck your thumb. Is the chromium mentioned in the patent acting catalytically, or is it sensitizing the mixture in some other way? Certain chromium (VII) salts are borderline primary explosives.

[This message has been edited by Hex (edited August 15, 2001).]

[Mr Cool]

Hexavalent chromium compounds are the worst, but all are carcinogens I think. But nowadays it seems that most things are! Barbequed meat, wood smoke, MDF...

[cutefix]

Chromium in copper chromite was acting catalytically.To attain optimum performance, a portion of ammonium perchlorate is ground to micron sizes(about 20mu).Then this copper chromite is ground in the ball mill to almost the same size;then this two are blended to form a uniform mixture.This will be the igniting mixture,and this is further blended with higher particle size ammonium perchlorate before other ingredients are incorporated for solid propellant composition.The minimum amount of copper chromite will be 1% based on totalammonium perchlorate contentin formulation for propellants; but a content of at least 4% will be reasonable for explosive composition using this principle.Another burn rate catalyst that was effective for solid rocket propellants is ferric oxide which has equivalent performance(there was no data if it works in this particular plastic explosive composition).I think it is a potential replacement if there is difficulty of procuring this double oxide of copper and chromium.
Ordinarily this composite solid propellants burn slower than nitrocellulose propellants.The incorporation of this catalyst to the composite formulation,enabled this mixtures to equal the burn rate of the single or maybe even double base propellants.

[Mr Cool]

I think I've heard of copper chromite being sold as a pigment for ceramics. Copper oxide and chromium oxide both are, so there's a possible source.
Also, what about other chromium compounds, like K2Cr2O7?

[cutefix]

There is another reactive chromium compound called Guignet’s green which is also used in pigment industry.This is a hydrated chromium oxide pigment with the following stated formulae: CrO3.2H2O, CrO3.4H2O ,Cr2O(OH) and Cr2O(OH)4.This is an aggregate of hydrated chromium oxides.This is made by calcining potassium dichromate with boric acid and washing with water to leave a very finely divided intensely green acid/base resistant pigment.Other chromium compounds suitable for catalytic purposes are: chromium sesquioxide,zinc chromate,chromium dioxide.Even copper chromate had some catalytic activity but not as active as the copper chromite.I ‘ve heard that potassium dichromate will also catalyze potassium perchlorate based mixture.

[This message has been edited by cutefix (edited August 17, 2001).]