Making chlorine

[johnheritage]

Making chlorine via electrolysis needs a selectively permeable membrane. If you check out the wiki page on chlorine there's some more information on there. One of the materials is asbestos (so a no go) and the other you may also find difficult to obtain. Electrolysis of hydrochloric acid may be the only easy electro method.

 

Storing chlorine is also not really a good idea unless you can seal it in an ampoule, as it will of coarse be a gas at room temperature, and a corrosive one which will try to get back out of the tube over time. To store gases like that, they really need to be dry, if only so the sample looks nice. In laboratories, they tend to buy cylinders of gases like this, with the gas having been dried before being pushed in. They will usually rot the regulators, valves and even the cylinder it's self over time, so they use special metal alloys that are Nickel based instead of Iron - called Hastealloy and Monel. Both of these are extremely expensive and usually only available from laboratory suppliers. To be extra sure, the regulators are attached to a manifold that goes between them and the cylinder. After use, the cylinder is closed and dry, inert gas is blown through the manifold and regulator, to blow out any moisture and the remaining corrosive gas. Such a manifold & regulator will set you back over $1k.

 

Dripping concentrated hydrochloric on manganese dioxide (which is one of the main components of most none rechargeable batteries) is one way to make it. However, you may have seen the Nurd Rage video about manganese dioxide, in which he receives a bag of it apparently cut with sand. Similarly, I have bought "99%" pure powder before and discovered a significant amount of it unreacted at the bottom of a flask. Meaning mine is also likely cut with something (like activated carbon). This is only really important if you need a precise amount from the gas generator.

 

You can also make it, probably more reliably, by dripping HCl(aq) onto TCCA, which is used in some pool tablets.

 

As someone pointed out earlier, the serious danger with chlorine is not really how you feel on inhaling it, but how you feel three hours later. Provided you make very small amounts, it's not going to hurt you. The trick being, start with a tiny, tiny quantity. Using just a few drips of acid onto less than a teaspoon of your powder. And get used to it from there.

 

Concentrated chlorine can overpower your ability to determine whether or not it's still at a dangerous concentration immediately afterwards. Inhaling a concentrated amount of it feels like inhaling bleach. It burns and causes voluntary coughing.

 

Around two or three hours later, if you have inhaled any significant amount, it will feels as though your being suffocated (as you are being suffocated); you'll continue coughing and producing phlegm. Feeling out of breath / dizzy / chest feels like it's been hit. With severe exposure, you will die in this period of time. So you really need to be able to judge whether or not it's time to make a hospital visit. I have experienced this myself, and it's not pleasant at all. It is worse than SO2 or HCl(g) in my opinion. Numerous people have died as a result of mixing incompatible cleaning products; in one report I read, they had to start locking the cleaning equipment away in a hospital because more than one person managed it in the same building.

 

With that said, here are some photos of glassware setup to generate chlorine, along with it's (not particularly intense) lime / yellow colour. The first imagine is before I set the generator off;

 

 

 

 

 

 

 

This a flask of water it has been bubbling through for about 6-9h

 

 

 

For fun... here's some Iodine as well. A far easier halogen to collect and use given that it is solid at room temperature. This flask is hot, so some of it is floating around as a faint purple tinge

 

 

 

And there's some in ethanol. That's 25g in 45ml, with a fair amount still sat at the bottom as a solid. The solution is currently boiling, without any heat applied, as the iodine is quite violently reacting with some aluminium powder that is also in there. The colour of iodine changes depending on it's concentration, from faint yellow / amber / orange, to purple, to what looks like black (but is in fact extremely dark purple).

 

 

Edited April 23, 2011 by johnheritage

[walkingreject]

In my opinion, the simplest way to make relatively pure Cl₂ gas is to obtain MnO₂ from a zinc-carbon battery (its that brown-black paste-like stuff between the outer shell and the carbon electrode), pour in a little hydrochloric acid, and set up a simple apparatus in order to bubble the Cl₂ gas produced through some water into a test tube. Voila. Isolated chlorine gas.

 

The chemical equation of this reaction is: 4 HCl + MnO₂ → MnCl₂ + 2 H₂O + Cl₂

For those of you who are curious, this method of creating chlorine gas was actually how chlorine was discovered. It was discovered in 1774 by Carl Wilhelm Scheele.