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[The Lycaeum Forums]

 The Lycaeum Forums » Integrate » The Alchemist's Den (Moderator: tryp2fun)Topic:
 Generating anhydrous HCl (gassing)

[pylkko]

temporarily down for update purpose

[tryp2fun]

Very clever idea!  I will have to give this a try in my lab next time I need some HCl gas.  I usually use the H₂SO₄/HCl method, and it works fine, but cleaning up the spent H₂SO₄ is a hassle.

[pylkko]

Are you saying that a method invented on the net by clandestine chemists is going to be used in a real uni lab? LOL

[farmerjack]

sounds simple enough.

how long would the plastic last in that pure acid environment? it's so cheap that money isn't an issue so if it would work through ten cycles it would be perfect!

to spread the gas out in the bottom of the target container would it help to plug the tubing into an airstone? or an array of airstones to better distrubute the gas around the bottom of the container? or could this whole idea be replaced by placing the container on a stirring plate to cause  all the liquid to pass over the acid-bubbling tube?

or perforate a foot of the tubing and coil it in the bottom of the container. plug the submerged end of the tube and hopelly the gas would evenly distrubute itself through the liquid? but what happens to the precipitates? would they stick to the plastic tube and make a whole new problem?

[pylkko]

It depends on the nature of the plastic.
http://www.millerplastics.net/chemical_resistance_chart.html

This setup could be modified as wanted. The idea of this one is to create gas in little bursts. For other setups one might want a more stable flow of gas.

[pharmanimal78]

Sweet. Thanks. :p

[trylobeet]

i was looking for some such thing.

thanks a bunch.

[Moriarty]

Ever notice how a 24/40 to 19/22 bushing (adapter) fits into the top of a standard 1.5 liter bottle of water?  If one were so inclined he might make that observation.  Fill said (empty) bottle with CaCl2 and add the bushing adapter.  Now use electrical tape to make it air tight.  Fit a 3-way adapter (19/22) with a glass plug on top.  Now take a West condenser and add some glass wool or paper or whatever.  The West condenser is sort of like a drying tube.  It has three glass prongs inside so you can pack it with stuff.  So the West condenser is versatile as it can be used for distillation, a fractionating column or drying tube.  Fill the 19/22 West condenser with CaCl2.  Now take some PP tubing and tape it to the end of the condenser.  Now add ~100ml 31% HCl(aq) and you'll notice gas right away.  So the HCl is at the bottom of a bottle filled with CaCl2.  As the water is absorbed the gas has to pass through the entire bottle and then your drying tube.  So it gets an opportunity to get dried twice before being directed to the non-polar/amine mixture.  It's a pretty simple and easy way to make dry HCl gas.

[farmerjack]

I've seen similar teks which all  use this  one improvement:

by adding tubing of x length you can insert the tube down into the bottom of whatever you're gassing and get the benefit of the gas floating up through the entirety of the nonpolar. by waving  the tube all around the bottom of the nonpolar the entirety of the nonpolar very quickly gets exposed to the gas. very efficient.

one tek cleverly calls this tube a "wand"

[Moriarty]

Umm...yeah, I sort of thought that might be implied or that after trying it once the operator might just inherently understand as much.  The length if tubing I used to use when I was active was just long enough to reach the bottom of the 1-liter beaker.  Since the tubing comes in a roll, it is already curving down.  The tube has to be, obviously, polypropylene or the non-polar will start to dissolve it.  In addition, one might like the plastic bottle as squeezing the bottle to produce bursts of HCl(g) for the impatient chemist can be employed .

[farmerjack]

Yes sir oh ChemGod  (jack averts eyes) .  I assumed you knew as much but thought that the average, never has extracted, reader might have benefited from the clarification.

Let's turn on the black lights and watch the crystals precipitate

[Moriarty]

Funny.  Hey farmerjack, I didn't give myself that title.  One of the moderators here did.  There are, no doubt, more proficient chemists here than I and I can assure you I meant not to take a tone with you that was intended to undermine any of your comments.  If it came off that way I apologize.

[farmerjack]

No no no. don't even think it. I was having fun with you.

Actually for this crowd to give you that title is quite an honor.

[pharmanimal78]

That would be my doing....