Hello netters, I would like to know if anybody in this newsgroup has
any pointers to any type of a simple process that would yield gaseous
chlorine from preferably solid precursors. In particular I am looking
at a process that would be very temperature sensitive, so that I could
control the amount of chlorine emitted just by using a servo loop on the
pressure of the gas. The amounts of gas needed are tiny, since 1g of the
gas would probably last a long time.
The gas will be injected into a vacuum chamber where it will be used to
etch various materials.
Of course I could just buy a bottle of Cl2 and a regulator, but then the
presence of so much Chlorine around our system would raise plenty of safety
issues.
Thank you for any information in this matter.
Stefano Concina
- Hide quoted text — Show quoted text -
In article <2oko1e$…@k2.San-Jose.ate.slb.com> stef…@sj.ate.slb.com (Stefano Concina) writes:
> Hello netters, I would like to know if anybody in this newsgroup has
> any pointers to any type of a simple process that would yield gaseous
> chlorine from preferably solid precursors. In particular I am looking
> at a process that would be very temperature sensitive, so that I could
> control the amount of chlorine emitted just by using a servo loop on the
> pressure of the gas. The amounts of gas needed are tiny, since 1g of the
> gas would probably last a long time.
> The gas will be injected into a vacuum chamber where it will be used to
> etch various materials.
> Of course I could just buy a bottle of Cl2 and a regulator, but then the
> presence of so much Chlorine around our system would raise plenty of safety
> issues.
> Thank you for any information in this matter.
Try dribbling aqueous HCl onto solid MnO2 whenever you need more Cl2 gas.
I believe the reaction is:
MnO2 + 4H+ + 4Cl- -> Mn++ + 2Cl- + 2H2O + Cl2
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Triphenly phosphine forms an addition compound with chlorine which might
dissociate with heat. If the addition product is a solid, this may work.
Regards, Mike
Electrolosis of a weak solution of sodium chloride using
graphite electrodes will produce some chlorine gas, I am not, however,
certain of the stoichiometry, so I can’t tell you how much.
Best of luck,
–
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* "Cloquet hated reality, but he realized it * Aaron Benner *
* was the only place to get a good steak." * -benwah *
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I once made medium sized quantities of Cl2 quite simply and cheaply:
to a medium sized Schlenk flask with some MnO2 (or other strong and
available oxidizing agent) add via syringe common bleach (NaOCl). You
control the generation of Cl2 by the addition of bleach. Then pass the gas
through a column of NaOH and another column of Dri-Rite and then pass the
gas through your reaction mixture or whatever… It’s pretty easy, safe,
cheap, and gives pretty good results, and it looks impressive. Two other
things that come to mind – it is murder on your hoses, so be prepared to
throw them away. And if you are really trying to be careful, it is not
difficult to deoxygenate your system (and place under an Ar or N2 atmosphere)
by the standard means.
- ted
An alternative to dripping aqueous HCl to MnO2 could be the
application of an mixture of half-concentrated H2SO4, salt (NaCl) and
an oxidation agent, e.g. MnO2, PbO2, KMnO4. This would offer the
advantage of an HCl-free Cl2, as in the reaction mixture there is at
no time a surplus of HCl.
Oliver
In article 2pbvggINN1…@rs1.rrz.Uni-Koeln.DE, a2270…@rrz.Uni-Koeln.DE (Oliver Bedford) writes:
> An alternative to dripping aqueous HCl to MnO2 could be the
> application of an mixture of half-concentrated H2SO4, salt (NaCl) and
> an oxidation agent, e.g. MnO2, PbO2, KMnO4. This would offer the
> advantage of an HCl-free Cl2, as in the reaction mixture there is at
> no time a surplus of HCl.
> Oliver
It is a long, long time since I did any inorganic, or even practical, chemistry
but I would be very, very wary of using KMn04 in the above mixture. Remember
KMnO4 and conc sulphuric make the interesting oily green liquid Mn207. Apart
from being interesting, it is also extremely unstable, decomposing explosively
above around 270K. And I mean explosively ( know someone who lost an eye because
of it ). I know it says half conc above but I would still be very unsure
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