Sciencemadness Discussion Board

Bottling hcl gas?

bmays - 8-6-2016 at 15:25

Setting up a gas generator isn't hard but its still annoying when you do many small experiments, especially if you need dry hcl.

I've wanted to bottle some hcl gas for a while, i was thinking how to do it. Maybe add a liter of muriatic acid into an old propane cylinder and a few bags of damprid. After a few days the CaCl2 should have all the water held. I havn't had much luck with this method in flasks. H2SO4 and NaCl works better. Then use my fridge compressor to fill an old iron paintball CO2 tank.

I assume iron, brass are ok? Maybe i should be looking at all stainless steel apparatus? Just thinking, future project. Maybe this is just a bad idea.

myristicinaldehyde - 8-6-2016 at 15:37

It's a bad idea.

j_sum1 - 8-6-2016 at 16:34

If you are not pressurising then you are very limited in what you can store.
If you are pressurising then you are asking for trouble.

Making it as needed is safer and ultimately more convenient.

Orenousername - 8-6-2016 at 16:36

Quote: Originally posted by myristicinaldehyde  
It's a bad idea.


I agree. Most (if not all) tanks you will find that will hold any significant amount of pressure are going to metal. If you do try anything leave it for a few days in a ventilated area with some NaCO3 or something else to neutralize it on hand and ready. The vapor pressure is 43ish bar so a CO2 cylinder or something will handle the pressure (keep in mind corrosion) but a propane cylinder is likely to fail under those pressures. That is of course in liquid state though. Most CO2 cylinders you might run across are going to be aluminum or steel (both of which HCl will attack).

Dr.Bob - 8-6-2016 at 17:53

Yes, wet HCl is very corrosive. It will attack metal quickly when wet. Trying to bottle it without proper equipment is not a good idea. Just make it as needed or even make a solution of it in a solvent if you really want to store it. But use a glass bottle. HCl gas will dissolve in MeOH, dioxane, and even ether to a degree. You can even generate a ~2M solution in ether by mixing conc. aq. HCl in ether and drying with MgSO4, there was an article about that somewhere years ago, maybe Journal of Chem Ed. The solutions are not long lasting, they slowly lose their molarity. But still better than trying to deal with bad cylinders of HCl. I have access to them, and still prefer to use solutions of it or generate it as needed. It is also easy to make from acetyl chloride and methanol or ethanol, that is one of my favorite ways to generate it in situ.

macckone - 8-6-2016 at 22:43

Commercial HCl cylinders are steel. Absolutely dry HCl will not attack steel. Commercially HCl is dried by condensing out water vapor and followed with calcium chloride followed by aluminum chloride.

vmelkon - 15-6-2016 at 18:37

I imagine the HCl solution that you put in your propane tank will react with the steel and weaken it.

I recommend making a polyethylene bag and fill it with HCl gas.
That is what I am going to do for a reaction chamber thing that I am doing.

careysub - 15-6-2016 at 19:30

If you want to store dry HCl for future use, perhaps you could dissolve it in a dry organic solvent, like the alcohol of your choice.

zed - 17-6-2016 at 16:47

Easy to make, and hard to store. In my opinion; storing is a bad idea. Not worth the trouble, and possibly dangerous.

Yeah, some of the guys do it, but doubt I ever will.

DraconicAcid - 17-6-2016 at 17:13

Quote: Originally posted by careysub  
If you want to store dry HCl for future use, perhaps you could dissolve it in a dry organic solvent, like the alcohol of your choice.


I think alcohols can react with dry HCl to give water and chloroalkanes. I'd use chloroform or dichloromethane.

DJF90 - 18-6-2016 at 03:19

Quote: Originally posted by DraconicAcid  
Quote: Originally posted by careysub  
If you want to store dry HCl for future use, perhaps you could dissolve it in a dry organic solvent, like the alcohol of your choice.


I think alcohols can react with dry HCl to give water and chloroalkanes. I'd use chloroform or dichloromethane.


Thats not true of the lower primary or even secondary alcohols to any significant extent. 2M HCl in iPrOH is surprisingly stable. We used to use it for salt formation and due to the potential for chloropropane formation/contamination of API product it had to be investigated. I had the same concerns as you, initially, but it turned out to ne fine.

CaptainPike - 18-6-2016 at 12:23

Quote: Originally posted by vmelkon  


I recommend making a polyethylene bag and fill it with HCl gas.
That is what I am going to do for a reaction chamber thing that I am doing.


I've thought of this idea too, but how to force it through a solution in any controlled, constant manner? I imagined hugging the bag (sounds like some new sex thing, right?); but it seemed kind of silly, trying to squeeze it, just a little.
Maybe some huge spring-loaded syringe (like a fuel injection pressure accumulator), with the bag in it– but that's so ghetto and probably harder than just generating HCl in one of the many serviceable methods.

A crazy idea I had once,I hesitate even to type here: any synthesis I do is pretty much on a micro scale. I thought about evacuating a spent Bic lighter, and backfilling it with dry gas at a moderate pressure, to provide millimoles of HCL– take one down off the shelf, attach some tubing, bubble bubble bubble! A safe amount (a known amount). The hardware is brass (I think) and the "cylinder" is polly. No suck-back worries. There is even an adjustment valve, to set flow rate!!:cool:

I'll sell them on eBay – make big money…
(Well, I said it was a crazy idea):D

vmelkon - 20-6-2016 at 08:25

Quote: Originally posted by CaptainPike  

I've thought of this idea too, but how to force it through a solution in any controlled, constant manner? I imagined hugging the bag (sounds like some new sex thing, right?); but it seemed kind of silly, trying to squeeze it, just a little.


"I've thought of this idea too, but how to force it through a solution in any controlled, constant manner?"

==Yes, that is a problem I have considered. I guess a regulator is needed but you need to buy it from somewhere.
Perhaps putting some weights of the proper value + having a very thin tube (or large tube with a small diameter somewhere to restrict the flow.

I have also done the BIC lighter thing long ago. I put in H2SO4 + Al to see what would happen. It did not blow. Pressing the button releases the hydrogen and I burned the hydrogen. It's fun! I only did it once.

CaptainPike - 3-9-2016 at 08:47

I thought of another "ghetto gas cylinder", which might be appropriate for HCl.

Cans of starting fluid. The ones that contain ether. They are made rugged – ruggeder than a typical aerosol can AND some of them have an innet (I think) flexible lining. I saw this on a YouTube video by Doug's Lab. The one about preparing diethyl ether. He's probably on this board as well.

He's got some cool stuff – his ketene generator is really cool, and he discusses the practical aspects of glacial acetic acid and acetic anhydride production. Check him out.

Maker - 3-9-2016 at 09:02

If you're in the UK you could buy a 5 kg cylinder of liquid hydrogen chloride from BOC. Okay so it won't be cheap but it will definitely be safe. It may even work out cheaper than the chemicals for a gas generator.

Sulaiman - 3-9-2016 at 11:15

never tried, just an idea (I doubt that it is original) for dispensing gas from a bag,
a glass syringe connected to a Tee=piece with a valve either side.
close valve to experiment,open valve to bag, suck gas into syringe
close valve to bag, open valve to experiment, force gas into experiment.
Repeat as required
Scale determines syringe capacity.

[Edited on 3-9-2016 by Sulaiman]

aga - 3-9-2016 at 12:31

Quote: Originally posted by Sulaiman  
Scale determines syringe capacity.

Seems you can get 'em Large ...

syringe.png - 73kB

Fulmen - 3-9-2016 at 12:45

If you can liquefy the gas, it can be done. The gas can then be measured out by weight or volume and added to a pre-chilled tank. Add a slight excess for flushing and seal up. You will off course have to monitor the pressure as it heats up and release any excess pressure. One possible problem could be the cold-properties of the tank, I will have to read up a bit on that one. But it should be doable for gasses that can be liquefied at moderate temperatures.

bmays - 3-9-2016 at 14:06

Quote: Originally posted by aga  

Seems you can get 'em Large ...

lmfao

[Edited on 3-9-2016 by bmays]