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Velzee
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Any way to prepare anhydrous ZnCl2 without using gaseous Cl2 or HCl?
In an attempt to make anhydrous AlCl3 as a catalyst (following some of ChemPlayer's videos), I would like to prepare some zinc chloride. A few
searches on the site and the wiki didn't come up with much, so I figured I'd ask you all if you alternative methods of preparing it without dealing
with gaseous HCl or Cl2.
Thank you,
—V
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Pumukli
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Drying hydrated ZnCl2 is possible by melting. (Strong heating required, in a stainless steel pot maybe.)
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clearly_not_atara
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Lol wut? ZnCl*6H2O decomposes thermally to zinc oxychlorides.
Instead, I think you can react Zn with anhydrous CuCl2, which can be dried by heating. To expedite the rxn, CuCl2 can be dissolved in a polar aprotic
solvent such as acetonitrile or propylene carbonate.
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unionised
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If you can get FeCl3....
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lordcookies24
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Do you have any other chloride salts on hand?
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Chem Science
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I have dried ZnCl2 by melting without any problems. Maybe decomposition is slow.
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Velzee
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Yes, and I can prepare most of them if needed. What did you have in mind?
I do NOT have Zn powder, rather I have Zn battery casings, some Zn pieces I melted from coins, and some ZnCO3 I recently prepared.
[Edited on 6/11/2019 by Velzee]
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Pumukli
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I've seen people who made relatively big ammounts (circa 200g) ZnCl2 melt on a strong gas flame in an iron "pan". Then this stuff was good
enough for whatever they required anhydrous ZnCl2.
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happyfooddance
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Quote: Originally posted by Pumukli | I've seen people who made relatively big ammounts (circa 200g) ZnCl2 melt on a strong gas flame in an iron "pan". Then this stuff was good
enough for whatever they required anhydrous ZnCl2.
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If it is anhydrous it will fuse without decomp. The hydrate decomposes significantly, and vacuum dessication doesn't work either.
There are other threads on this, Velzee, you should UTSE before starting a new thread. This clutters search results and makes it harder for other
people to find the information if they search for this subject in the future.
Anhydrous zinc sulfate dry distilled with calcium chloride (or table salt but prob. requires higher temps) was used commercially for many years, you
might be able to pull that off. At any rate, you will have to search.
Hope this helps
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walruslover69
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Could you possibly produce anhydrous ZnCl2 by the reduction/displacment of CuCl2 with zinc metal in a suitable solvent like either?
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fusso
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Anhydrous MnCl2 and CoCl2 can be dehydrated by heating the hydrate.
[Edited on 190611 by fusso]
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unionised
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Not really, no.
They can be prepared by heating the hydrated salts.
It's also unlikely to be relevant.
[Edited on 11-6-19 by unionised]
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walruslover69
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I believe the hydrates of MnCl2 and CoCl2 can be dehydrated by heating. I know for sure that CuCl2 can be made by dehydration of hydrated CuCl2 made
by dissolving basic Copper carbonate or hydroxide in aqueous HCl.
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fusso
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So I think these anhydrous salt can react with Al in organic solvents to make anhydrous AlCl3.
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Tsjerk
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[Edited on 11-6-2019 by Tsjerk]
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lordcookies24
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Quote: Originally posted by Velzee |
Yes, and I can prepare most of them if needed. What did you have in mind?
I do NOT have Zn powder, rather I have Zn battery casings, some Zn pieces I melted from coins, and some ZnCO3 I recently prepared.
[Edited on 6/11/2019 by Velzee] |
i was thinking about having Zn powder mixed in a solution of CuCl2 and filter of the copper ,but since you do not have zinc powder, that wouldn't be a
good option... Tell me again why you cannot just mix HCl with the zinc cassings?
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clearly_not_atara
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Velzee, if you do not have zinc powder, the next question you should ask is "how do I make zinc powder"? Because I do not see the distillation of
gaseous ZnCl2 in your future. And the available methods are this one and that one.
There are so many threads which have a question like "how do i make triflic anhydride but without knowing anything or buying anything or doing
anything difficult or time-consuming".
Anyway if you dissolve the zinc in some alkali and add some Al, you should see zinc powder forming.
Quote: | Anhydrous zinc sulfate dry distilled with calcium chloride (or table salt but prob. requires higher temps) was used commercially for many years, you
might be able to pull that off. At any rate, you will have to search.
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This is popular because CaCl2 is a common industrial waste product (Solvay process, others), not because it's practical :p
According to this paper:
https://scripts.iucr.org/cgi-bin/paper?a17499
potassium tetrachlorozincate is obtained by evaporation of a solution containing the appropriate proportions of KCl and ZnCl2. Possibly heating the
salt will liberate ZnCl2 gas. Although this is a fool's errand because OP cannot prepare or capture gases as he has already informed us.
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walruslover69
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if you cut it up into strips or pieces and clean it just alittle bit with steel wool or sand paper then reflux it with CuCl2 in ether you might be
able to get it to work. Since the zinc chloride product is very soluble in ether the surface won't be covered/passivated by product like it work be if
you were doing it in the solid state with Cl2 or HCL. This might allow you to get by with not having a huge surface area. Still probably have to
reflux it potentially over night, but that isn't to much trouble.
I am really interested in this synthesis now, I might have to try it whenever I can find the time.
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Pumukli
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OK, I'm stand corrected!
I asked around and someone told me that those guys I mentioned in my previous post were not preparing anhydrous ZnCl2 by melting the
hydrate. They were purifying (I think drying would be a better verb) the originally anhydrous ZnCl2 which was stored in an opened bottle
and some humidity found the way into that bottle.
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Velzee
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Quote: Originally posted by clearly_not_atara | Velzee, if you do not have zinc powder, the next question you should ask is "how do I make zinc powder"? Because I do not see the distillation of
gaseous ZnCl2 in your future. And the available methods are this one and that one.
There are so many threads which have a question like "how do i make triflic anhydride but without knowing anything or buying anything or doing
anything difficult or time-consuming".
Anyway if you dissolve the zinc in some alkali and add some Al, you should see zinc powder forming. |
Thank you. I will try this shortly.
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WGTR
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I was wondering if heating with ammonium chloride would do the trick. Here is a document referencing a similar approach:
Attachment: cdc_10599_DS1.pdf (343kB) This file has been downloaded 808 times
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S.C. Wack
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In the old lab manuals the water can indeed be removed with heat and some care, perhaps not perfectly.
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Metacelsus
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Yes, I have done this. Adding a little excess HCl helps to avoid decomposition to the oxychloride. The resulting ZnCl2 isn't absolutely dry but it is
good enough for most purposes.
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fusso
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Can azeotropic distillation work?
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hacker
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I don't know if azeotropic distillation would work.
This method looks easy. I believe it would produce a superior product.
Quote: | To develop technology to assure an ample supply of zinc and to reduce environmental pollution, the U.S. Bureau of Mines investigated alternatives to
the roast-leach process for treating complex sulfide concentrates. Previous studies proved that low-grade zinc sulfide (ZnS) concentrates could be
leached using chlorine-oxygen to produce zinc chloride (ZnCl2). The process involves high energy requirements for evaporating the pregnant solution to
produce anhydrous ZnCl2 needed for electrolytic cell feed. An efficient hydrometallurgical process would facilitate treatment of lower grade ores than
can be used in conventional processing and would render roasting unnecessary.
An alternative method was devised for recovering ZnCl2 from solution. Zinc diammine chloride [Zn(NH3)2Cl2] was precipitated from solution by adding
ammonium chloride (NH4Cl) and sparging with ammonia (NH3) to a pH of 6 to 7.5. The spent solution was treated with calcium hydroxide [Ca(OH)2] at 60°
to 80° C for 1 to 4 h to remove remaining zinc and NH3. The Zn(NH3)2Cl2 was heated to 300° to 400° C to remove NH3 and produce anhydrous ZnCl2. A
possible flowsheet was devised and is included.
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