Sciencemadness Discussion Board

Filling gas flasks at home using a fridge compressor

garage chemist - 28-9-2005 at 13:05

I bought a very old and quite large fridge compressor which originally ran with R12 (CF2Cl2).
I wanted to know how much pressure this thing can develop.

With some hard solder, copper pressure piping, a 60 bar manometer and some bought parts I threw together an adapter that allows the pressurizing of common gas flasks and displays the current pressure.

I turned on the compressor with closed valve first and couldn't believe my eyes: the manometer climbed straight to 50 bar!
I filled the gas flask to 40 bar (at this pressure the pump volume stream becomes very small and pressure rises extremely slowly, also leaks started to show at such a pressure- the parts were originally designed for 15 bar), which took 5 minutes (volume of the flask was 0,5 L).
Then I released a hurricane in my garage by opening the valve. :D

That thing is awesome, I can now fill my gas flask with gases like hydrogen (gonna have to purge the pump and flask with hydrogen first before letting it build up pressure to eliminate explosion risk) and ammonia (this would actually liquefy inside the flask and allow for huge amounts to be stored).

To fill the flask with gas, I would collect the gas inside a freezer bag (after washing and drying), turn on the compressor (also connected to the bag) as soon as the bag is full until the bag is empty. Then wait again until the bag is full and turn on again etc.

I could also make a pipe-bomb autoclave and pressurize with hydrogen to run catalytic hydrogenations- 40 bar should be enough for reactions with raney-nickel if the reaction time is long enough.

Pictures of my setup available here:,4697,0,-Gasflaschen+...

12AX7 - 28-9-2005 at 13:35

Very nice. Yes, refrigeration regularly runs in the 200PSI (low side) to 500-600PSI (high side) range.

1 bar = 1 atm = 14.7 PSI so that's circa 41 bar. Sounds about right :D


Twospoons - 28-9-2005 at 14:22

Compatability of some gases with the compressor oil may be an issue - check each one. I would also suggest an oil mist filter on the outlet - collect the oil and return it to the compressor intake.

Magpie - 28-9-2005 at 18:46

That's pretty impressive. As you say it opens up all kinds of possible syntheses normally considered beyond our scope. ;)

I have some questions: 1) those "gas flasks," - are they what are called lecture bottles? What are they rated for in pressure and volume. Do they come in different styles, wall thickness, etc, depending on the gas to be stored? Where do you get them?

Can compressors be found that are oil-less for compression at these pressures? It seems that would eliminate contamination with oil - if this is indeed a problem.

The_Davster - 28-9-2005 at 19:13

Could empty propane tanks be refilled with the gas of your choice? I do not mean the big white BBQ ones, but the small ones we all have lying around from our torches.

Would chlorine be rather difficult to store as it would react with most metals causing destruction of the bottle, or would the reaction passivate the metal surface stopping all futher reaction?

Very cool(pun intended) indeed.:cool:

12AX7 - 28-9-2005 at 21:46

Throw on some phosphorous pentoxide it looks like. :cool: Or should I say... metaphosphoric acid. ;)

Corrosivity to Metals:
At ordinary temperatures, dry chlorine is not corrosive to most common metals, including steel, stainless steel, cast iron, nickel and its alloys, copper, brass, bronze, lead, platinum and tantalum. Dry chlorine attacks aluminum, tin and titantium at ordinary temperatures and is corrosive to most metals at high temperatures (121 deg C and up). Moist chlorine is strongly corrosive to most common metals. Platinum, tantalum and titanium are resistant. Tantalum is the most stable metal to both dry and wet chlorine.(24,25,28,35)

The irony is, just above it says:
Liquefied chlorine can react violently, explosively or ignite on contact with carbon disulfide and iron, bismuth, dibutyl phthalate, drawing wax, gasoline, glycerol, linseed oil, white phosphorus, polydimethylsiloxane, silicones, sodium hydroxide, tin, titanium and vanadium powder.(33,34)

I guess they emphasize powder, as how aluminum is pyrophoric in 23% O2, particularly when unpassivated.

Don't use small disposable bottles, they aren't meant to be filled. Yeah, so that's just the D.O.T.'s suggestion...well, maybe they know something we don't, or something. I think you can get pretty small "real" tanks though.


[Edited on 9-29-2005 by 12AX7]

garage chemist - 29-9-2005 at 04:03

The bottle is an empty oxygen tank rated for 200 bar. Its original purpose is unknown to me, most likely for welding. I got it on Ebay.
I only have this one flask, and it is only made for oxygen. But I don't think that hydrogen or ammonia will pose problems.
Now that it's contaminated with oil, it cannot be used for oxygen any more.
Chlorine is impossible to compress with this sort of equipment, as it would immediately destroy the compressor.

Oilless resistant compressors might be available, but far beyond our budget.
I want to know what can be done with a fridge compressor and not with a special ultra-expensive pump!

My next step will be to make a new filling apparatus which is airtight (the current construction is highly improvised and has some small leaks).
Then I'm going to try hydrogen, made from NaOH and Al and dried first by condensing most of the water in a dimroth cooler running with icecold water and then with silica gel.

If this works then nitrous oxide could be the next step, this will pose more problems as
proper washing and drying is important.

And then ammonia.

Chris The Great - 1-10-2005 at 15:31

Very cool! Looks like my fridge compressor will soon be going to work :)

I don't think refilling old propane cylinders would be a problem as long as the pressure is stopped at 250psi (17 bar). That is the pressure propane cylinders are designed for, bring it higher is a unneccessary risk in my opinion.

mick - 2-10-2005 at 04:08

I am not sure what CO2 fire extinguishers or pub CO2 cylinders are rated at but I think it is quite high.
I have also read that dry chlorine is OK in steel, there has not been any reports of them failing due to storage. Old fluorine cylinders after about 10 years have been found to build up a pressure over 3000 psi and fail.

mick - 2-10-2005 at 04:26

If you want to pressure test some general gas equipment the way I was shown was to fill the kit with water and use a good quality car brake master cylinder rigged up to a long handle. If you can pressurise to twice the working pressure it should be OK. If it goes when it is full of water there is not a problem, if it goes when it is full of gas that could be a problem.

Magpie - 26-10-2005 at 19:53

I plan to test my homemade black iron (steel) ammonia cylinder hydrostatically 1st and then with air (at a lower pressure) to check for gas tightness.

Following mick's advice I stopped at a brake repair place to ask if they had a used master cylinder. I couldn't believe it - they did and gave it to me for nothing -what luck on the 1st try! :D It even has a vacuum assist which I can hook up to my aspirator if needed.

I don't want to use brake hydraulic fluid as a test liquid and think that leaving water in the master cylinder can't be good as it would rust. So I'm wondering if the denatured alcohol sold at the auto parts place for brake system cleaning would be a good permanent working fluid, something I could just leave in the master cylinder reservoirs.

Magpie - 2-11-2005 at 19:38

I have completed assembly of my hydrostatic testing device. I have 2 jpg pictures that I would like to show but can't get them inserted in my post for some reason.

I've been trying to use the "Attachment:" and "Browse..." at the bottom of the page. This pulls up the photo addresses OK but they don't show up when I "Preview Post." I'm new at this and some guidance from forum members would be much appreciated. ;)

garage chemist - 3-11-2005 at 02:58

Now I have successfully filled my gas bottle with ammonia.
If you tilt the bottle you can feel the liquid sloshing around, very nice!:D

Pics of my setup available here, with detailed description in german:,4697,60,-Gasflaschen...

I used 1,4L 20% NH3 solution, in four portions of 350ml each. Each portion took one hour to extract the ammonia from.
The dimroth condenser was run with icecold water, and the drying column (custom made by a glass blower) is filled with KOH. This worked very well, only the first 10cm of the KOH became wet and the upper 20cm remained dry, indicating complete drying of the ammonia.
The 20% NH3 solution begins to "boil" at 50°C and the boiling temperature gradually rises as ammonia is given off. I boiled until it was at 95°C, at which point the NH3 evolution becomes too slow to be of use.

The bottle got very warm as the ammonia condensed inside it, and the pressure over the liquid which was at 10 bar initially later rised to 20 bar due to this.

A 6L freezer bag was used as the intermediate storing container, it was connected to the gas generator and the compressor via a "T" adapter.

The brass valve of the bottle was attacked somewhat, the filling construction too, as seen in the last two pics.
Copper and its alloys are definately not a good metal for use with ammonia!

When I was done filling, I unscrewed the bottle from the adapter and a huge amount of ammonia came out. The copper pipe and the adapter became cold as ice, and smoke was produced from the intense cold!
The cotton oil mist filter was completely soaked in liquid ammonia and continued to smoke for a while.
My garden must have stunk like hell... but I smelled nothing, thanks to my fume hood.

Now I need dry ice to condense some ammonia and produce some solvated electrons by adding sodium metal!
I also want to make NaNH2 by adding a catalyst (iron compound) to the blue solution.

I have a pressure reducer designed for oxygen, I'll have to see how good it will hold up to ammonia. Maybe add a few drops of oil to minimize corrosion?
I tested it without oil and it produced a blue hue on the brass inlet pipe of the reducer.
I hope the valve doesn't get attacked.

When I bubble ammonia into water, it gets absorbed very vigorously, the bubbles collapse immediately as they form, producing a peculiar sound.

[Edited on 3-11-2005 by garage chemist]

Tacho - 3-11-2005 at 03:14

Magpie, I juste tested the attachment feature and it's working.

- Type your text;
-Click on the browse (edit) button- a window opens;
-Select the file;
-Click on the "open" button in the selection window - the window closes;
- Click on the "Post Reply" button.

Maybe the file was too large. Most digital cameras produce enormous files. If that's the case, do this:

- Put your picture on your screen the size you think is convenient;
- Press the "Print Scrn" key in your keyboard;
- Open the "Paint" program that comes with windows;
- click the paste button;
-An image of your screen should be pasted - cut your image the size you want and paste it in blank page- Make sure the white background is not larger than your picture

- Save in .jpg format

Now you have a much smaller file.

[Edited on 3-11-2005 by Tacho]

Magpie - 3-11-2005 at 08:32

Congratulations garage chemist on your good work. I hope to have similar results very soon as all my parts & pieces have arrived. I will be constructing and pressure testing (hydrostatic to 300 psi) my gas cylinders today.

Thanks very much Tacho. I shall give your procedures a try pronto. FYI the file sizes are 99KB and 539KB. I didn't think these would be too large as the FAQ guideline says only that they must be <1MB.

Tacho - 3-11-2005 at 08:58

Garage chemist, I'm very impressed with your work too. Congratulations.

Don't forget to post your results with pictures!

Magpie - 3-11-2005 at 12:47

Here's the 2 pictures of my hydrostatic testing device made from a brake master cylinder. Turning the 3/8" nuts gets me about 200 psi/rev. Although my pressure guage only goes up to 1000 psig I'm sure the device is good for at least 2000 psig.

I have it loaded with DOT3 brake fluid and will likely keep it that way and just fill my cylinders with water. The when done I'll just bleed some brake fluid through to purge the device of any water.

Thanks Tacho for your help with the attachments - it seems I had them all along but was faked out as I did not see them on the "Preview Post."

[Edited on 30-1-2007 by chemoleo]

example.jpg - 56kB

Magpie - 3-11-2005 at 13:04

Oops! Here's the 2nd picture for the above post.

I wanted to mention that the vacuum assist (that big bell shaped item) is really not needed for this application. You get plenty of force with the clamp like affair that I assembled from 1/4" (6mm) steel plate on the right side. This is driven (against itself) with 2 each 3/8" nuts on bolts about 5" (12.5 cm) long. As the screws are tightened the far right plate drives the 1/4" rod attached to the brake pistons.

[Edited on 3-11-2005 by Magpie]

master cylinder hydrostatic test device.jpg - 55kB

Magpie - 3-11-2005 at 19:59

Sorry for so many posts on this thread but I'm imbedded here by now. Be sure to see garage chemists last post where he has great pictures of his successful liquid NH3 bottling.

The picture below is a pressure test of my homemade high pressure reaction vessel. The fittings are "150 lb" which are normally considered good to 300 psig at room temperature. I inadvertantly tested it at 350 psig. Messing with high pressures is a little exciting. Makes you feel like a kewl again. :D

[Edited on 30-1-2007 by chemoleo]

reaction.jpg - 100kB

Tacho - 5-11-2005 at 06:32

Forgive my car mechanics ignorance, but let me see if I got it straight:

If you press the axis of the brake master cilinder (on the right of your picture) with nuts and bolts, you end up with 350 psi in those copper tubes coming out of it?

That sounds very interesting. A flexible capsule inside your test vessel would be under 350 psi of pressure!

Nice place you have BTW Magpie!Clean and tidy... so far.

Magpie - 5-11-2005 at 07:39

Yes Tacho you have it straight. The tubes are steel brake lines. I had a hydraulic shop fabricate the manifold. The fittings are hydraulic and not available at a hardware store. Same for the hydraulic hose.

Thanks for the comment about my shop/lab. I was talked out of building a stand-alone lab in my backyard so compromised by using my garage. I have been working all summer on it. I probably owe the forum a lab tour now that I have a camera.

Magpie - 8-11-2005 at 20:04

Here's a final picture of my hydrostatic pressure testing: the testing of my gas (NH3) storage cylinder. As you will note I had to add a check valve (right before the pressure guage) to build pressure. With the other vessel I could do this with the in-line ball valve.

I accidently ran this one up to 430 psig.
Will now test to 150 psi with air to test for gas tightness.

[Edited on 9-11-2005 by Magpie]

[Edited on 30-1-2007 by chemoleo]

hydrostatic.jpg - 63kB

IrC - 11-11-2005 at 13:57

Maybe this could help liquify a gas?

Magpie - 11-11-2005 at 16:21

That's a neat project IrC. In my research on NH3 I noticed that RV refrigerators use NH3 as refrigerant as well as do many cold storage facilities. The RV systems looked pretty simple. The vapor pressure of ammonia at room temperature is around 120 psig whereas that for propane is around 200 psig. Also NH3 is almost non-flammable compared to propane. So if I was to build a refrigerator I would likely try NH3.

As you probably know garage chemist liquified his NH3 using a fridge compressor. I have chosen a different route - I'm going to liquify it using an acetone/solid CO2 bath in a dewar flask. Then I'll just pour the liquid into my pre-cooled gas cylinder and screw on the cap. That's the plan, anyway.

[Edited on 12-11-2005 by Magpie]

garage chemist - 12-11-2005 at 02:10

When you immerse the cylinder in the CO2/acetone bath to precool it, won't the acetone dissolve the plastic sealant in the threads of the pipe?
Or is this teflon tape?

I'm asking because the blue tape in your pipe threads looks strange to me.

My teflon tape is white.

Magpie - 12-11-2005 at 08:38

It is a good question Garage Chemist. For my normal household (water) pipefitting I use Ace's TFE (Teflon) dope. I've stopped leaks with it that Teflon tape wouldn't.

But for the ammonia I talked to a technician who maintains a large ammonia cooling system for an ice-rink. He said not to use the PTFE dope but get a dope especially made for ammonia. So I asked my industrial supplier and he recommended Leak Lock, which is blue. IIRC it is good for acetone also - it better be :o. I have also found a supplier of valves and guages specifically sold for ammonia - good prices too (agricultural supplier - not scientific). But I think any steel will be good. The main thing is to avoid copper and its alloys (brass) for any long term use.

[Edited on 12-11-2005 by Magpie]

I have an inquiry into Highline (who makes Leak Lock) about compatibility with acetone. Perhaps I should have used my own research conclusion which was that Gasoila-100 pipe joint compound would have been the best. Its specifications are pretty impressive.

[Edited on 12-11-2005 by Magpie]

garage chemist - 12-11-2005 at 09:35

Very strange. PTFE not suitable for ammonia?
PTFE is resisrant to every chemical except molten alkali metals and elemental fluorine (it breaky C-C bonds, making CF4).
I'm absolutely sure that teflon will work for your ammonia cylinder.

What did he say about copper? The valve of my gas bottle is made of brass. It turned black/blue from exposure to the ammonia.
Is the attack only superficial and will eventually come to a halt (passivation of the surface) or will the brass slowly be eaten away and turn my ammonia cylinder into a toxic time bomb?

Magpie - 12-11-2005 at 09:54

I agree that the PTFE (Teflon) particles themselves are inert as you say to ammonia and almost everything else. So the tape would be OK. I have just not had good luck sealing with Teflon tape on relatively coarse steel pipe threads. Brass would probably seal better as it is softer and will deform better as you tighten the connection.

I think for the dope (paste) it is the carrier liquid that is vulnerable to ammonia attack - not the Teflon particles.

As for the brass - well, I went out of my way not to use it. I can't answer your question directly. You should research that. I don't think you'll find any brass in commercial ammonia systems.

I can tell you a story about a brass fitting that corroded through overnite. It was a drain valve on a tank holding some acidic concoction. It caused a significant discharge of Cr+6 to the soil environment. The poor young engineer who specified that valve did not work there much longer. I felt very sorry for him. He should have had more support from his senior mentors.

Tacho - 12-11-2005 at 12:39

I think teflon tapes resist chemically to ammonia, but are permeable to most gases, including ammonia. In fact, teflon tapes seem to be permeable even to lighter solvents. I know that from experience.

I liked the project IrC posted! I always wanted to have a cold water generator in my attic, and I have plenty of experience with compressors.

-propane, specially compressed, makes me worry about explosions or fires. I would worry a lot really;
-ammonia may corrode the compressor mechanics, specially if it has a chance to absorb moisture from air;
- I would think of home-made methyl bromide, widely used in the past as fumigant, but a methylating agent nevetheless.


Sorry to be off-topic.

garage chemist - 12-11-2005 at 12:58

Methyl bromide is very toxic and also damages the brain and nervous system. Plus it's odorless, increasing the danger. Using it in a refrigeration unit sounds like a terrible idea.
Methyl chloride, on the other hand, would be a better idea. The toxicity is much lower.

A different refrigerant, also used in the pre-CFC days, is, besides ammonia (which is very good as a refrigerant, extremely effective systems can be made with it), sulfur dioxide.
Its boiling point is remarkably high and the pressure above it at room temperature is only 3,5 bar (compared to 9 bar for ammonia). It could actually be stored without risk in a Coke PET bottle (the CO2 from the drink produces a pressure in excess of 3,5 bar).

But the best choice would still be propane.
The advantages outweigh the disadvantages.

Magpie - 12-11-2005 at 13:06

Tacho don't give up on NH3 too quickly. It is used as a refrigerant (R-717) all the time. Yes, you would have to carefully select your materials, but I don't think water would necessarily be a problem. IIRC the RV refrigerators actually use ammonium hydroxide as the refrigerant. I did see stress corrosion cracking as a potential problem with ammonia in steel. The solution: add about 5% water!

Offhand I would much rather have traces of NH3 loose in my living quarters that methyl bromide.

[Edited on 12-11-2005 by Magpie]

IrC - 12-11-2005 at 17:00

I forgot to mention but if you click on his beginning page at the bottom he has more projects, including making your own cheap and simple expansion valves for the refrigerant. He did not mention much about problems using the propane but then again he did take a can and used it to mow his lawn, so he may be a little too cavalier in his experiments.

Magpie - 14-11-2005 at 10:37

Garage chemist asked:


When you immerse the cylinder in the CO2/acetone bath to precool it, won't the acetone dissolve the plastic sealant in the threads of the pipe?

I received a reply from Highline Chemicals on the applicability of Leak Lock (the blue paste) to -80C acetone for 1/2 day at 5"H2O WC pressure. He said that, over time, Leak Lock is affected by ketones. But at my conditions it would be OK. So I will give it a try. (He offered to send me free samples of Leak Lock for testing if I requested them on my letterhead :D ).

Magpie - 15-11-2005 at 16:35

I finally have achieved success in pneumatic (air) testing of my homemade pressure vessels for gas tightness. I learned some things along the way: (1) dope both surfaces and use plenty of it (2) turn the joint down "all the way home".

When the tests were failing I noted that the pressure loss rate was similar on both vessels. This made me think that the leak was in the test manifold. So I replaced a suspect nipple in the manifold and remade other joints on the 1/4" piping.

I think I'm ready to go now and will assemble the equipment in the fume hood for NH3 liquifaction.

Here's a picture of the last test. I kept it in original format so people could read the data in my notebook if desired. Sorry for any seasickness. :D

Lest anyone call foul it is still at 142 psig after 4 hours.

[Edited on 16-11-2005 by Magpie]

[Edited on 30-1-2007 by chemoleo]

[Edited on 30-1-2007 by chemoleo]

reaction.jpg - 187kB

Magpie - 17-11-2005 at 14:14

NH3 liquidfied and stored today!

I knew this experiment was going to teach me a lot about high pressure and cryogenics - I just didn't know how much.

The liquifaction train is shown in the picture below. I used a 30mm glass tube 2 feet long for a drying column per garage chemist. I put 13 " of flake KOH in the tube supported on some SS scrub pad. Probably way too much KOH.

RBF is 500 mL. In the 1 liter dewar is a cold trap used to protect vacuum pumps. Sorry the picture is out of focus.

I used acetone/dry ice to get the temperature down to about -38C in both that dewar and an auxiliary dewar consisting of a wide-mouth Thermos bottle. In the Thermos I had the gas storage cylinder protected by a small poly bag from the acetone. This was at about -45C per #1 son who was helping me.

After about 1/2 hr of gas generation we could see the cold trap gas vent burp occaisionally. This worried me so I terminated the run. We couldn't smell any ammonia in the lab but sure could smell it outside. I conclude that I was generating NH3 too fast and/or didn't have my bath temperature low enough.

There was about 15 mL of crystal clear NH3 in the cold trap. (My target was 50 mL.) I poured this into the gas storage cylinder and screwed in a pressure relief (liquid) valve set at 350 psi. It is shown in the 2nd picture (next message).

The main thing I learned is to have all your acetone and dewars pre-cooled before you even start NH3 generation. I learned this the hard way by frothing over a lot of warm acetone when I added the chunks of solid CO2. Once you get everything cold the dewars do a nice job of keeping them cold.

[Edited on 18-11-2005 by Magpie]

NH3 liquifaction.JPG - 96kB

Magpie - 17-11-2005 at 14:20

In reference to my message above here's the 2nd picture:

stored liquid NH3.JPG - 110kB

garage chemist - 18-11-2005 at 02:32

Nice! Looks good.

First pic is somewhat blurred, could you make another pic of you setup? It's hard to see details there.

Only 15ml of ammonia? That doesn't sound like it was worth the effort.

Was there any dry ice still floating in the acetone? There should be.

How was the ammonia generated? Boiling of 10% aqueous solution?
If I saw that only 15ml were condensed, I'd put another 350ml of solution in the flask and generate more ammonia until I have my desired 50ml.

Will you try it again?

Magpie - 18-11-2005 at 08:26

Garage chemist: I will set up the apparatus (without loading the vessels) and take another picture.

When I first started the NH3 liquifaction I was disappointed as it was messy and high maintenance to get the temperature down. Now I know that my whole problem was due to failure to pre-cool my acetone, dewars, cylinder, funnel, etc. Once you get down to temperature it stays there. If I would have turned my heater down and kept at it I could easily have gotten the 50 mL needed to fill my small cylinder.

Would I do this again. Definitely, once I have a definite need. This was mostly a "proof-of-principle" experiment and to get some NH3 to upgrade my reagent shelf NH4OH. It is too expensive to do casually. I saved the acetone and can reuse it for this again. But I have to buy a minimum 2.5 kg of dry ice at $7.

Keeping the dry ice well insulated (say by wrapping with cloth towels) will keep it from disappearing too fast.

Was there any floating dry ice? Well, I didn't think so but when I poured out the dewar 1.5 hours later there was an active bubbling - so I guess there was floating CO2. Also the temperature was still down at -35C.

When I first started I was thinking how much superior your method is to mine. But then I kept thinking: "But you get to see the liquid NH3!" :D

Magpie - 18-11-2005 at 17:07

Garage chemist here is a picture of the cryogenic components. The NH3 generator and KOH water absorber were pretty much the same as yours so I didn't show them. (If you need info on those let me know.) The cold trap is the smaller glass tube that fits inside the larger (30mm) glass tube and is sealed to it via ground glass fitting. This assembly is inserted into the 1 liter dewar flask. The thermometer has a range of -100C to 50C. Any questions just let me know.

[Edited on 30-1-2007 by chemoleo]

cryogenic.jpg - 71kB

Magpie - 19-11-2005 at 07:26

One last report:

I poured ~40 mL of 7N NH4OH into the iron reaction cylinder. Then connected this to the NH3 storage cylinder via hydraulic hose. When I opened both valves I expected to see about 110 psig on the pressure guage. It spiked up to 50 psig then quickly dropped off to about 20 psig. Over the next 1/2 hr it dropped to 0 psig.

The gas storage cylinder became very cold indicating evaporation of the liquid NH3. The reaction cylinder became warm indicating the heat of dissolution/reaction of NH3 with the NH4OH solution.

I titrated the product NH4OH at 10.9N.
It was rusty colored from reaction with the iron cylinder.

Although smaller quantities than desired were produced, this series of experiments met all of my objectives for "proof-of-principle." 2 pictures follow:

[Edited on 30-1-2007 by chemoleo]

reactor.jpg - 78kB

Magpie - 19-11-2005 at 07:37

2nd picture from post above:

[Edited on 30-1-2007 by chemoleo]

50.jpg - 51kB

Magpie - 21-11-2005 at 14:15

Have you ever noticed that if you back away from a problem for awhile the right (intuitive) side of your brain will often solve the problem? Well, I now know why the liquid ammonia was burping in the cold trap: I had it hooked up backwards! :o

A similar thing happended at work once due to the plant constructor mixing up two 2" pipes. This manifested itself through severe water hammer - lucky no one was hurt.

mick - 8-1-2006 at 14:46

If you want liquid ammonia find an old camper fridge that runs on gas (ammonia). The one I have got still works by lighting the pilot light.


Sorry I think I am a bit of topic having re-read the posting.

[Edited on 8-1-2006 by mick]

neutrino - 8-1-2006 at 17:50

Don’t these refrigerators contain a concentrated ammonia solution instead of liquid ammonia? This is the design I have always seen.