Sciencemadness Discussion Board - chlorinating one of the most chemical resistan element.

chlorinating one of the most chemical resistan element.

plante1999 - 12-1-2011 at 13:59

I ave arround 5g of zirconium and i want to chlorinate it to zirconium tetrachloride , i ave read that it can be done with zinc chloride wath is your opinion?

[Edited on 13-1-2011 by plante1999]

bbartlog - 12-1-2011 at 18:16

I don't think zinc chloride by itself is much of a chlorinating agent (unless you want to say that it will 'chlorinate' elemental sodium or some such), so I wonder where you read that. Too bad you didn't tell us. I suppose that at temperatures sufficient to vaporize ZrCl4 there might be some way to drive some reaction, but I'd think the oxide seems like a more likely candidate... ZrO2 + 2ZnCl2 -> ZrCl4 + 2ZnO, maybe around 400C could work since the tetrachloride would gas off. Sounds hard to do at home.

plante1999 - 13-1-2011 at 04:55

this is the document.

Attachment: 30123025-Zirconium-and-Zirconium-Compounds.pdf (313kB)
This file has been downloaded 475 times

Lab prep

The WiZard is In - 13-1-2011 at 08:24

Quote: Originally posted by plante1999

I ave arround 5g of zirconium and i want to chlorinate it to zirconium tetrachloride , i ave read that it can be done with zinc chloride wath is your opinion?

In English there are two books commonly referenced for the
laboratory preparation of inorganic chemicals —

Brauer's (translated from the German) 2-volume Handbook of
Preparative Chemistry, and the multi-volume continuously
added to - Inorganic Synthesis.

Brauer can be found in the Forms Library.

Both Brauer p.1203-1204 and Inorganic Synthesis. 4:121-126 use this method.

ZrO2 + 2 C + 2 Cl2 = Zr4Cl + 2 CO

IS notes —This procedure is not easily adaptable to laboratory
use, since an arc furnace is used to produce zirconium carbide.
Furthermore, the chlorination of zirconium carbide is a strongly
exothermic reaction requiring apparatus that will withstand
temperatures of of at least 1000o. [And Cl2 at 1000o!]

IS notes in passing some have suggested —

Chlorinating Z22S3
Zr oxide & P chloride/S monochloride/thionyl chloride/carbonal
chloride/carbon tetrachloride

A method for the synthesis of Hf chloride using CCl4 that can
also be used for Zr "which proceeds at a desirable rate and
involves easily constructed Pyrex apparatus" is given.

djh
----
Edible Experimentalism

The Economist 18i10 http://tinyurl.com/4uw3dnn
Fire in the hole
Barbecue navigates the twin perils of mass appeal and nostalgia

IT IS a noun, not a verb. You do not barbecue meat; you smoke it
until it becomes barbecue. And it is not a meal so much as a
meditative process, perched somewhere between science and art,
dependent on reserves of judgment. The science lies in building a
fire that will smoulder steadily without flaring, and in constructing a
vessel that will bathe the meat in smoke without subjecting it to
too much heat. The art lies in the butchering and seasoning. The
judgment comes in knowing precisely when a cooking process that
may last as long as 18 or 24 hours should end. Barbecue is the art
of turning tough cuts tender (“Need no teef to eat my beef” is a
popular boast among smokemasters). None of these facts brook
disagreement, but here the unity ends.

ScienceSquirrel - 13-1-2011 at 08:45

Quote: Originally posted by The WiZard is In

A method for the synthesis of Hf chloride using CCl4 that can
also be used for Zr "which proceeds at a desirable rate and
involves easily constructed Pyrex apparatus" is given.

That sounds like the well known method that produces phosgene as byproduct.

http://www.colutron.com/products/chargeprep.html

Useful stuff phosgene

blogfast25 - 13-1-2011 at 10:00

I really wonder if direct chlorination of fine zirconium (or turnings) in hot Cl2 is impossible. There are a number of d-block elements in that area of the PT that are, such as Nb (a direct neighbour) or W, directly chlorinatable. In both cases chlorides are obtained which are somewhere between ionic and covalent substances (solids with low MPs and very prone to hydrolysis), much like ZrCl4 itself. Certainly thermodynamically it is possible. And it doesn’t sound more difficult than the Kroll process…

Heat dry Zr in a (very) dry stream of pure (no O2!) Cl2 in a long, dry pyrex or quartz tube: if reaction occurs, ZrCl4 should sublime somewhere downstream in the cooler part of the tube.

[Edited on 13-1-2011 by blogfast25]

bbartlog - 13-1-2011 at 10:19

Hm, sure enough. Thanks for the reference. So zirconium can reduce zinc, then. It also sounds like ZrO2 is chemically resistant enough that my suggested reaction wouldn't work. If you do try to react ZnCl2 and Zr I expect that the main difficulty will be keeping oxygen out of the mix, whether in the form of atmospheric O2 or water/hydroxy contaminants in your ZnCl2. Putting together an apparatus that will melt ZnCl2, boil off ZrCl4, and condense it isn't exactly trivial either, but at least the temperatures involved are low enough that you could do it in glass.

ScienceSquirrel - 13-1-2011 at 10:20

Quite a good summary of the chemistry of zirconium may be found here.
It seems that direct chlorination of the metal will work as will heating it with iron II chloride.
http://upetd.up.ac.za/thesis/submitted/etd-09082005-113709/u...

plante1999 - 13-1-2011 at 11:17

so of i can make simply pure iron II chloride?

i

blogfast25 - 13-1-2011 at 11:22

Quote: Originally posted by plante1999

so of i can make simply pure iron II chloride?

i

It has to be ANHYDROUS, plante, that's harder to achieve. Also, Fe(II) chloride is notorious for it's tendency to oxidise to Fe(III) chloride...

Quote: Originally posted by bbartlog

It also sounds like ZrO2 is chemically resistant enough that my suggested reaction wouldn't work.

Again, just check the HoF's. ZrO2's HoF is insanely high, even Al isn't capable of reducing it... Which is why Zr is produced by reducing the chloride with Mg.

[Edited on 13-1-2011 by blogfast25]

The WiZard is In - 13-1-2011 at 11:30

Quote: Originally posted by The WiZard is In

In English there are two books commonly referenced for the
laboratory preparation of inorganic chemicals —

IS 4:122

"Since zirconium wire is now widely available [1953] zirconium
tetrachloride has been prepared by one of the authors (Yolles).
The reaction difficlut to control and was discarded in favor of the
following which proceeds at a desirable rate and involves easily
constructed pyrex apparatus."

The WiZard is In - 13-1-2011 at 12:17

Quote: Originally posted by plante1999

I ave arround 5g of zirconium and i want to chlorinate it to zirconium tetrachloride , i ave read that it can be done with zinc chloride wath is your opinion?
[Edited on 13-1-2011 by plante1999]

Early attempts 1894.

http://tinyurl.com/47wngew

Mellor Volume VII

plante1999 - 14-1-2011 at 04:55

do you think with 1cubic cm of zirconium could be totaly chlorinaed by chlorine?

plante1999 - 14-1-2011 at 05:18

sorry for the double post.

I dont know if its thermodicaly fesible but some imagination reaction.
thincked with reactivity sery,and idea y ave read in the forum.

2ZnCl2 + Zr-> ZrCl4 + 2Zn

2CuCl2+Zr->2Cu+ZrCl4

Zr+2Cl2->ZrCl4

FeCl2+Zr->ZrCl4+2Fe

which i should use?

[Edited on 14-1-2011 by plante1999]

[Edited on 14-1-2011 by plante1999]

bbartlog - 14-1-2011 at 07:23

The problem with the iron and copper, I expect, is that on being reduced they will tend to coat the zirconium and bring the reaction to a halt. Now in the case of CuCl2, you could address this by using a twofold excess of CuCl2 and keeping things heated above 400C (I expect this would actually be a thermite-like reaction once it got going, anyway...). That would result molten CuCl rather than elemental copper.
But anyway, it seems like the main problem here is defeating the passivating oxide layer. Just because the overall thermodynamics look good doesn't mean the reaction will proceed.
The reference the Wiz gives, above, suggests that the reaction with chlorine requires dull red heat.

blogfast25 - 14-1-2011 at 07:42

Quote: Originally posted by plante1999

do you think with 1cubic cm of zirconium could be totaly chlorinaed by chlorine?

If you mean the metal is solid, then forget it: it would be a slow boat to China. The metal has to be powdered or at least in the form of turnings or shavings. That holds true also of any reduction reactions you want to use it for.

I hadn't thought of CuCl2 but it has some distinct advantages. Firstly it can be obtained from direct dehydration, no fuss: heating the CuCl2 dihydrate in air dehydrates it, see here:

http://www.amazingrust.com/Experiments/background_knowledge/...

But dehydrating ZnCl2 or FeCl2 is harder to do with hydrolysis or oxidation or both (in the case of FeCl2).

CuCl2 has another advantage that like all Cu (II) binary compounds it has a very low heat of formation (- 206 kJ/mol for CuCl2) and thus is relatively easy to reduce. In fact the reaction CuCl2 + ½ Zr === > Cu + ½ ZrCl4 is possibly fairly easy to initiate (because CuCl2 thermally dissociates quite a bit). The heat of formation of ZrCl4 is – 980.5 kJ/mol, and thus the heat of reaction (@ 298 K) for the reduction reaction is a cool +206 + ½ (- 980.5) = - 284 kJ/mol, quite a respectable value…

The heat of reaction strongly suggests that the ZrCl4 will form in the gaseous (vapour) state, you’d have to heat the mixture in a ceramic boat inside a pyrex or quartz tube, with some argon carrier gas to carry the ZrCl4 off to a cooler place.

Note that on the CuCl2 page is also described the experimental reduction of CuCl2 with Al:

CuCl2 +2/3 Al === > Cu + 2/3 AlCl3 with a heat of reaction of – 265 kJ/mol (@ 298 K). It proceeds effortlessly albeit kind of slowly, once initiated. My worry though would be that the hot, gaseous AlCl3 formed would tend to carry with it also some CuCl2. That could explain the rather strange colour of the smoke.

ZrCl4 obtained from reduction of a choride with Zr would almost certainly have to be purified by means of sublimation.

[Edited on 14-1-2011 by blogfast25]

blogfast25 - 14-1-2011 at 08:13

Quote: Originally posted by bbartlog

The problem with the iron and copper, I expect, is that on being reduced they will tend to coat the zirconium and bring the reaction to a halt. Now in the case of CuCl2, you could address this by using a twofold excess of CuCl2 and keeping things heated above 400C (I expect this would actually be a thermite-like reaction once it got going, anyway...). That would result molten CuCl rather than elemental copper.
But anyway, it seems like the main problem here is defeating the passivating oxide layer. Just because the overall thermodynamics look good doesn't mean the reaction will proceed.
The reference the Wiz gives, above, suggests that the reaction with chlorine requires dull red heat.

Very unlikely bbart. The reaction enthalpy points to the copper being produced in the solid state, thus not being capable of ‘coating’ anything. But in classic thermites and analogues (‘aluminothermic reactions’) the formed metal does form in the molten state, yet the reaction proceeds nonetheless, no coating takes place. That is because the reaction equilibria ARE WHAT THEY ARE.

No need for doubling the amount of CuCl2. Also even if you did do, that doesn’t mean CuCl would be formed: thermodynamical calculations would show what the end products are, the path of lowest ΔG being the chosen one.

Re. passivation, the most passivated metal of all is probably aluminium, because of it’s affinity for oxygen due to the insanely high value of the HoF of alumina (- 1,676 kJ/mol, from memeory). Yet it never stops Al from taking part in reduction reactions of whatever kind, as long as they are thermodynamically favourable.

The same is true for other ‘passivators’ like Ti or Zr. The passivated ‘skin’ is at best a few atoms thick and rarely withstands a sustained thermal attack. It just protects the metal from further oxidation at room temperature, that’s all.

[Edited on 14-1-2011 by blogfast25]

plante1999 - 16-1-2011 at 08:14

so , i will try anydrous copper chloride.

solution

1Passing dry chlorine or HCl on copper heated at 700degree celius.

2copper carbonate in HCl and precipitate crystal, haet the crystal to the anydrous

i think i will do the choise 2.

[Edited on 16-1-2011 by plante1999]

blogfast25 - 16-1-2011 at 09:42

Quote: Originally posted by plante1999

so , i will try anydrous copper chloride.

solution

1Passing dry chlorine or HCl on copper heated at 700degree celius.

2copper carbonate in HCl and precipitate crystal, haet the crystal to the anydrous

i think i will do the choise 2.

[Edited on 16-1-2011 by plante1999]

Oh, definitely 2....

Or... buy this and decompose thermally:

http://cgi.ebay.co.uk/Copper-II-Diammonium-Chloride-dihydrat...

plante1999 - 16-1-2011 at 10:30

Cu(NH4)2Cl4·2H2O

i think this is best if it can be anydrous, ammonium ion react with zirconium easly.

blogfast25 - 16-1-2011 at 11:23

When you blow off the NH4Cl in there, it will actually help protect the CuCl2 against oxygen. It’s a classic trick to protect ‘vulnerable’ chlorides: anhydrous MnCl2 for instance can be made by heating a mixture of MnCl2 hydrate and NH4Cl in inert atmosphere (argon or CO2). The NH4Cl dissociates into NH3 + HCl, the latter protecting the chloride against hydrolysis. But it seems possible to directly dehydrate CuCl2.2H2O without any fuss...

The cheapest option remains using CuSO4 or Cu(NO3)2, precipitate as CuCO3 with soda or as Cu(OH)2 with NaOH, wash with plentiful cold water (CuCO3 is quite prone to pyrolysis) until pH of wash water is close to 7 and dissolve in equivalent amount of HCl. Boil in to dryness and heat to drive off water, as per AmazingRust.com.

[Edited on 16-1-2011 by blogfast25]

plante1999 - 16-1-2011 at 11:37

those CuCl2 + NH4OHorNH4Cl= teramine copper chloride?

if it yes , do you think it could be used in the place of Cu(NH4)2Cl4·2H2O.

[Edited on 16-1-2011 by plante1999]

blogfast25 - 17-1-2011 at 09:40

Quote: Originally posted by plante1999

those CuCl2 + NH4OHorNH4Cl= teramine copper chloride?

if it yes , do you think it could be used in the place of Cu(NH4)2Cl4·2H2O.

[Edited on 16-1-2011 by plante1999]

Not sure what you’re asking here. The product on offer on eBay is a double salt of NH4Cl and CuCl2, hydrated. It’s not a copper tetramine complex. Here’s an interesting YouTube on the synth. of copper (II) tetramine sulphate hydrate:

http://www.youtube.com/watch?v=bwDKDc3W6BE

Copper (II) tetramine complexes must decompose by heat, much like hydrates. I’ve no idea at what temperature they start losing their liganded ammonia molecules though. Could be higher than for the hydrates, the amine complexes are very stable (high complexing K). A simple heating test should tell you…

I’m still not convinced that direct chlorination of Zr is more complicated than using a halide/zirconium reduction reaction though…

plante1999 - 5-2-2011 at 16:55

so i made copper chloride anydrous , y will post the result tomorrow.

i will also post picture.

plante1999 - 5-2-2011 at 18:05

i have great news today, so i ad 3g of copper chloride to a pelet of 0.5g of Zr and i heat , first evolved grean fume, than the copper chloride melt to a black slury at around 500 degree c a very hot reation ocured and the test tube go to white hot and greatly melted, a withe cloud of probably zrcl4 formed , i stop heating and i looked to the products, crystal of CuCl2 , some copper oxide and a withe stuf!!!!! probably ZrCl4.

[Edited on 6-2-2011 by plante1999]

[Edited on 6-2-2011 by plante1999]

blogfast25 - 6-2-2011 at 08:46

Interesting. You used a pellet of Zr, not Zr powder, right?

So did the reaction appear self-sustaining after initial heating and initiation?

Did you test for copper (add a little nitric acid: fumes of NOx indicate copper is being oxidised. CuCl2/CuO won’t do that…)?

All in all it seems to prove that CuCl2 + ½ Zr === > Cu + ½ ZrCl4 does proceed as predicted.

Be aware that even if you master an apparatus to capture the ZrCl4, the product will still be highly contaminated with CuCl2, possibly also Cu, and will require re-sublimation at about 500 C for required purity! This re-sublimation will have to be carried out in the absence of oxygen, as ZrCl4 + O2 === > ZrO2 + 2 Cl2 is thermodynamically very favourable...

[Edited on 6-2-2011 by blogfast25]

plante1999 - 6-2-2011 at 09:19

the reation appear to be self sustaining , i do not test for copper but i will test today.

[Edited on 6-2-2011 by plante1999]

bbartlog - 6-2-2011 at 16:49

The white stuff could also be CuCl. Some CuCl is likely to be present given that you have both Cu and CuCl2 in your residue. And at white heat it's entirely possible that most of your ZrCl4 escaped as vapor...

blogfast25 - 7-2-2011 at 09:04

Nope. There is no reason at all why the reduction should stop at CuCl: CuCl + ¼ Zr === > Cu + ¼ ZrZl4 is also very exothermic and is further driven by ZrCl4 being driven off.

In a closed system, with a stoichio mix of CuCl2 + ¼ Zr < === > CuCl + ¼ ZrCl4, heated at high temp you would find some CuCl in the reaction mix (but still mainly Cu and ZrCl4) but not here…

bbartlog - 8-2-2011 at 07:44

I'm sure that's true, but in this case we have
- molar excess of cupric chloride (~22mmol CuCl2 versus 5-6mmol Zr)
- unreacted CuCl2 (as we might expect given the above)

So it seems to me that it's not so much a question of whether the reduction would stop at CuCl if more Zr were available (clearly it wouldn't) but whether the Zr reacts preferentially with CuCl to such a degree that it would always be consumed before the remaining CuCl2. Of course with the whole thing open to air CuCl would also tend to be oxidized by atmospheric oxygen, but I don't think its existence here is all that implausible.

blogfast25 - 8-2-2011 at 09:46

Hmmm… because the reduction of CuCl2 is much more energetic to Cu than to CuCl, the only real way for CuCl to form is from Cu(s) + CuCl2(s, l?) === > 2 CuCl(s), from formed Cu and the excess CuCl2. I don’t know if ΔG < 0 for that reaction. In watery solution CuCl can be made by boiling a Cu (II) salt with copper wire, and with salt (NaCl) in the solution, so it probably is thermodynamically favourable (driven by the lattice energy of CuCl). But CuCl oxidises very quickly in air (slower when it’s perfectly dry). No, the white bits he saw was ZrCl4, I’m sure of it…