Sciencemadness Discussion Board - Alternative inert gasses

Alternative inert gasses

mr.crow - 24-12-2011 at 13:07

I had a weird idea today, thinking about how to get some sort of inert gas.

1,1-Difluoroethane is available in canned air dusters and looks pretty non reactive. However they include a bitterant to stop glue sniffers from inhaling it. This must be an aerosol that can be filtered out or absorbed.

Butane is also easy to get and use from lighter refill cans. It has a slight odor but not like the sulfides they put in natural gas. The downside is its flammable but at least its chemically inert. Squirt some into your flask to displace all the oxygen.

You can also build a home made liquified gas cylinder. Get some galvanized iron pipes from home depot, an end cap and a ball valve. Fill it up with your cryogenic liquid and then close the valve. Bingo! Attach a needle valve and hose barb to the top for flow regulation. The pipes would easily withstand the pressure of these substances.

What do you think of these ideas?

paulr1234 - 24-12-2011 at 15:00

Helium can be purchased in those party cans for balloons, expensive compared with dry nitrogen but easy to obtain and those pink cylinders have a built-in regulator (of sorts). Given that it is lighter than air, I would use purge the system especially well. Not sure how dry or pure this source is however, plenty inert tho.

AndersHoveland - 24-12-2011 at 15:08

Many of the helium tanks sold at party stores also contain 10-15% oxygen added, to reduce the danger of suffocation if the gas leaks, or when people inhale the helium from balloons.

One good inert gas for most applications is carbon dioxide. It can either be produced by reacting sodium bicarbonate (baking powder) with sodium bisulfate, from the sublimation of a piece of "dry ice" (sold at some supermarkets), or from compressed gas cylinders (one source might possibly be those used for toy guns).

Welding stores can rent tanks of argon (usually expensive). Nitrogen would also be an good gas, but I know not where one could buy compressed nitrogen tanks.

[Edited on 24-12-2011 by AndersHoveland]

Neil - 24-12-2011 at 15:11

Quote: Originally posted by mr.crow

You can also build a home made liquified gas cylinder. Get some galvanized iron pipes from home depot, an end cap and a ball valve. Fill it up with your cryogenic liquid and then close the valve. Bingo! Attach a needle valve and hose barb to the top for flow regulation. The pipes would easily withstand the pressure of these substances.

What do you think of these ideas?

That's a pipe bomb, no way a pipe is going to keep N2 liquid without blowing up. Even CO2 would be pushing the pressure limits on schedule 40 - or did you mean something like R22?

The canned air dusters make sense. You can also buy cylinders of liquid CO2 from brewing stores, welding stores etc.

Some tool/paint/marine shops sell a mixture of inert gasses which are intended to be used in flushing the air out of epoxy cans.

http://www.leevalley.com/en/wood/page.aspx?p=30268&cat=1...

In the past you could get the cans of dusting gas that were Tetrafluoroethane IIRC - non flammable. Not sure if you still can and not certain if it was Tetrafluoroethane but I do remember that you could get ones that were flammable and ones that were not. You can get refrigerants for re-filling a AC unit from most hardware/car stores.

[Edited on 24-12-2011 by Neil]

Neil - 24-12-2011 at 15:13

Quote: Originally posted by AndersHoveland

Many of the helium tanks sold at party stores also contain 10-15% oxygen added, to reduce the danger of suffocation if the gas leaks, or when people inhale the helium from balloons.

Not true, check the MSDS sheets for them; the impurity tends to be N2.

AndersHoveland - 24-12-2011 at 15:16

It really depends on what region of the world you are in, and even then there is much variation between different suppliers.

[Edited on 24-12-2011 by AndersHoveland]

Neil - 24-12-2011 at 15:20

Possibly, I tried to find any that had O2 in them in the past but could find none. The O2 thing seems to be an urban legend, or at least something that was phased out?

All the helium comes from the same place so for one brand to contain O2 it would have to be added by whoever was re-selling it. Anyways, Darwin is much better at watching out for fools.

mr.crow - 24-12-2011 at 15:32

Quote: Originally posted by Neil

That's a pipe bomb, no way a pipe is going to keep N2 liquid without blowing up. Even CO2 would be pushing the pressure limits on schedule 40 - or did you mean something like R22?

You are right, I meant only for Difluoroethane and Butane. Don't put LN2 or dry ice in it!!!

CO2 is also good but watch out for it reacting with things like grignards or NaOH. I have a refillable CO2 tank for inflating tires but I don't know where I can get it refilled

Helium is not good, is lighter than air and has oxygen or other gasses in it.

What got me thinking is these little cheesy spray cans for flushing the air out of wine bottles. Its just a slightly compressed gas so its a total rip off. Just drink the wine or get some friends to help!

Vogelzang - 24-12-2011 at 15:49

After paying over $100 for the nitrogen tank on the left in the picture, it only costs about $11 to refill it. The price might have gone up, though.

Neil - 24-12-2011 at 15:54

Ahh! I thought it weird that you seemed to suggest something like that.

For filling a CO2 canister check out local beer brewing shops, welding shops, or find your local Prax/Air Liquid or whoever sells gas in your area. Every bar goes through a couple bottles of CO2 for their kegs and fast food places for their soda - it is there you just need to dig a bit

Alternatively check your phone book for paint ball places - sometimes the do bulk fills.

Lambda-Eyde - 24-12-2011 at 15:56

1,1-difluoroethane and the other haloethanes are likely to dissolve in organic solvents which may or may not be a drawback. Carbon dioxide, as already mentioned, isn't really that inert and reacts with bases and grignard reagents among other things. Dicking around with butane is borderline suicidal if you ask me (and also smells like shit and will screw with your brain if you breathe large amounts of it), I don't see why you can't go to the nearest welding store that stocks argon cylinders. I can buy one liter of Ar for ~20 €, which is very much worth it.

paulr1234 - 24-12-2011 at 16:11

If you do buy a big cylinder of N2, make sure you secure it properly; knock it over with the regulator in place, and you risk having the thing flying around like a guided missile.

BromicAcid - 24-12-2011 at 16:22

Quote:

If you do buy a big cylinder of N2, make sure you secure it properly; knock it over with the regulator in place, and you risk having the thing flying around like a guided missile.

Don't you mean misguided missile?
[rimshot] [/rimshot]

Really though, there is also a thread around here on using the nitrogen in the air for inerting purposes. It was in an older inorganic syn book and the main component was hot copper wool as a scrubber for the oxygen to make something that was useful for Schlenk line use.

peach - 24-12-2011 at 17:25

My first contact with the net, back before my teens, when the three users were all on dialup and when it took an evening to download one photo of a naked girl, was with welding, casting and laser email groups. The guys from the US would frequently mention buying the cylinders as opposed to renting them. That is something which seems much easier in the US than the UK. If you can buy one and have it refilled, definitely go with that option.

The original inert work, before cylinder gases were as commonly available as they are now, was done under hydrogen.

We're a long way on from there now. The guys over at extreme overclockers (who are well used to working with gases) actually banned entries to one of their competitions if they included propane as one of the refrigerants, due to the risk of the entrants exploding.

Rent or buy one of these:

Or, buy one of these disposables:

I really don't think it's worth messing around with the inert stuff. It is hard and dangerous enough as it is without using air dusters or propane tanks. At best, it is painful to watch something degrade after putting in days worth of loving effort, simply due to trying to go cheapo on the gas. For example, how dost thou intend to make an air tight, regulated seal between said air duster and the glass? LN2 in a DIY cylinder is not a good idea at all. If that goes wrong, which it likely will, it'll go with such an immense bang you may not even remember it.

Renting the cylinders for at home chemistry is generally too expensive. In the UK anyway. The rental is far too much versus the usage rate. You want to buy one and pay for the refills if you're not also using it for welding (which will rape the gas by comparison).

The smallest inert cylinders from British Oxygen are X sizes I think (waist height). The rental is about £70 a year and a single fill will last about a year, making the rental alone double the cost of the gas. I took my last one back with most of the cylinder still full, after a year.

The disposables in the second photo are £10.50 each. The gas is at a premium per unit, but the lack of rental charge makes them very appealing; I would need to buy seven of these things to offset the rental alone on a commercial cylinder, and three to five more to offset one fill.

Welding argon and nitrogen is used by universities. They don't use specialty grades for regular inert work; because they cost an absolute fortune and there's no need.

As I'm already on the beers for Christmas, now might be the time to wish the fiery ship science madness a merry morrow.

[Edited on 25-12-2011 by peach]

mr.crow - 24-12-2011 at 17:59

Yay for Christmas beer

The disposable argon cylinders look like the best bet. Everyone should find a way to get one. I'm unwilling to rent or buy a real cylinder

To get a proper connection to the apparatus I would transfer the liquified gas to the home made pipe cylinder.

Good point about dissolving in organic solvents. At reflux this shouldn't be a problem. How about difluoroethane reacting with NaOH?

Butane sounds really dumb but the risks don't seem that bad compared to diethyl ether. Only do this outside of course

barley81 - 24-12-2011 at 18:22

How about plain old propane? I unscrew my propane torch's 'flame stabilizer' thingy and stick clear vinyl tubing on it to supply my Bunsen burner. Even if it contains some smelly sulfur compound, it's only a trace and shouldn't interfere with most reactions. Of course, it is a good idea to use it as inert gas outside, and far away from sparks or flame.

peach - 24-12-2011 at 18:32

Quote: Originally posted by barley81

How about plain old propane.

barley81 - 24-12-2011 at 18:42

ROFL

Seriously though, if butane can be used in some cases, then why not propane? It's much cheaper and seems like it would do all right for a few (safe!) things.

peach - 24-12-2011 at 19:20

Quote: Originally posted by AndersHoveland

Welding stores can rent tanks of argon (usually expensive). Nitrogen would also be an good gas, but I know not where one could buy compressed nitrogen tanks.

Same place.

The welding yards also sell OFN (oxygen free nitrogen) for pubs and pressure testing.

Quote: Originally posted by barley81

ROFL

Seriously though, if butane can be used in some cases, then why not propane? It's much cheaper and seems like it would do all right for a few (safe!) things.

It's certainly possible.

The question is, why would you want to use a gas that is so much more prone to fire, explosions and side reactions. And it really is so even given the extra cost of argon.

Star Trek analogy on route: It's like cleaning a toilet with a reach around when there's a plunger right there beside you.

Speaking of which, all this air duster talk reminds me...

<iframe sandbox width="640" height="480" src="http://www.youtube.com/embed/C1zzJIWKCMw" frameborder="0" allowfullscreen></iframe>

White Yeti - 24-12-2011 at 19:29

What's wrong with CO2? It's cheap, readily available, inert and denser than air (thus displaces it quite well).

Lambda-Eyde - 24-12-2011 at 19:40

As previously mentioned, carbon dioxide is in fact an acid. It will dissolve in water, react with hydroxides and turn your grignard reagents into carboxylic acids. And it's not that much cheaper than a 1L disposable argon cylinder (Ar will also displace air). But yes, sometimes carbon dioxide will be more than adequate, but it will also interfere with a number of reactions. If you don't have 100 % control (which few of us have all the time) you'll probably have the same problem like this guy one day.

White Yeti - 24-12-2011 at 19:48

Quote: Originally posted by Lambda-Eyde

As previously mentioned, carbon dioxide is in fact an acid. It will dissolve in water, react with hydroxides and turn your grignard reagents into carboxylic acids. And it's not that much cheaper than a 1L disposable argon cylinder (Ar will also displace air). But yes, sometimes carbon dioxide will be more than adequate, but it will also interfere with a number of reactions. If you don't have 100 % control (which few of us have all the time) you'll probably have the same problem like this guy one day.

Right, but for many other, more forgiving reactions, CO2 works just fine. If all else fails, a trip to the local balloon shop will get you a completely inert gas (as previously mentioned). If I were trying out a grignard reaction, I wouldn't be stupid enough to loose sight of the big picture, and to realise that an inert atmosphere should be the least of my worries.

plante1999 - 24-12-2011 at 20:06

With out catalyst hydrogen is an somewath inert gas...

Mr. Wizard - 25-12-2011 at 09:30

Propane and it's higher boiling relative butane can be used to cover some reactions where oxygen would be a problem. Remember that propane and butane are NOT pure when sold for fuel purposes. I always assumed they were, but they are just a combination of gasses that will distill over at a certain pressure and temperature. Propane especially can contain various alkenes and alkynes. I used to use a lot of it, and burned it as motor fuel, and was familiar with it's sale and handling. As time went by I realized it was not a pure substance. In warm weather it was sold with more of an admix of butane to lower it's vapor pressure , to prevent tank venting. Butane is also added to low octane gasoline to boost it's octane rating. This might work well in cooler climates, and where the gasoline is consumed quickly, and be problematic in warmer climates.

Alkenes, and alkynes accidentally added to many reactions could lead to big problems. Be careful using LPG (Liquified Petroleum Gas) as an 'inert' gas. That said, it can be used to flush oxygen out of containers. Perhaps you could test your gas with a permanganate solution or a bromine solution before using it in a critical application. The price is certainly better than argon or compressed N2.

MagicJigPipe - 25-12-2011 at 20:06

"Many of the helium tanks sold at party stores also contain 10-15% oxygen added, to reduce the danger of suffocation if the gas leaks, or when people inhale the helium from balloons.

One good inert gas for most applications is carbon dioxide. It can either be produced by reacting sodium bicarbonate (baking powder) with sodium bisulfate, from the sublimation of a piece of "dry ice" (sold at some supermarkets), or from compressed gas cylinders (one source might possibly be those used for toy guns).

Welding stores can rent tanks of argon (usually expensive). "

Niel is correct about the 20% oxygen thing being an urban legend I think. I have talked to several He tank suppliers and none of them had any idea about it. In fact, one, "Party Time", claimed that their He was 99.99% (possibly one more nine, I can't remember exactly) "pure". I understand that companies have a dubious history of claiming things to be "100%" pure and things of that nature, but I tended to believe them as if he was just reading a label from the huge tank that they fill the small ones from.

Also, 1,1,1,2-tetrafluoroethane is still INSANELY available. It's everywhere. Everywhere you turn SOMETHING has TFE in it. Not to mention it is a common refrigerant (can't remember the "R" number; 134a?).

And I don't consider argon very expensive unless you're comparing it to CO2 or maybe N2. You can buy 20 ft^3 (I assume that's at STP) for about $10. I am constantly surprised at how much that is.

And remember, all this applies to the US only. I can't vouch for anywhere else.

[Edited on 12-26-2011 by MagicJigPipe]

smaerd - 26-12-2011 at 00:15

I fancy the idea of CO2 being a replacement for some reactions. I've often wondered though, in general can it prevent oxidation by the mechanism of O2 + Heat for some of the more prone compounds(provided the purge/blanket/flow is sufficient)? I've assumed yes, however, I've seen very little mention of it in journals, and forums.

White Yeti - 26-12-2011 at 06:31

Quote: Originally posted by MagicJigPipe

And I don't consider argon very expensive unless you're comparing it to CO2 or maybe N2. You can buy 20 ft^3 (I assume that's at STP) for about $10. I am constantly surprised at how much that is.[Edited on 12-26-2011 by MagicJigPipe]

Argon is relatively inexpensive because it's a by-product of the distillation if air. In a sense, it should be cheaper than CO2:

cub_air_lesson01_activity1_fig2.jpg - 17kB

Of course, CO2 is cheaper because it is easily sequestered from localised high volume sources, like chemical plants for example.

paulr1234 - 26-12-2011 at 08:42

Quote: Originally posted by peach

Renting the cylinders for at home chemistry is generally too expensive.

Now relocated to the USA, I'm not sure what I am most jealous about, Peach's bottle of Abbot or his 60lt SIP bottle of Argon, nether of which is easy to find State-side.

Arthur Dent - 26-12-2011 at 10:55

I was not aware of the existence of those disposable argon bottles... strangely, they only seem to be available in Australia/NZ... I've been thinking for a long time about outfitting myself with an argon bottle and regulator, but I was put off by the outrageous prices!

Maybe this could be an interesting alternative. A small disposable cylinder could probably last me one year & +...

Robert

paulr1234 - 26-12-2011 at 22:31

Sold by Halfords in the UK for about 13 quid by the looks of things.

peach - 29-12-2011 at 17:50

If you google, 'disposable argon cylinder', 'disposable mig cylinder' or something along those lines, it'll churn out a load of different places. Toolstation is the only name required.

If I was in the US, I'd definitely grab one of these from Harbor Freight.

20 cubic feet, 5" by 15" (smaller than your monitor) makes it nice and compact but it'll have enough in it to last a long time, all DOT coded to avoid the risk of DIY pressure vessels, $84.99. Perfect. Stick a regular on there and you're flying.

<img src="http://img52.imageshack.us/img52/8452/image13676.jpg" width="200" />

Sign up at CNCZone.com and Weldzone.com. You can also try Weldingweb.com. There'll be loads and loads of guys there who can help you out with cylinders and filling (particularly if you're in the US). A lot of them have the latest gear from ESAB and Miller, and access to plasma / laser / waterjet tables, serious CNC mills and lathes. I think CNCZone has a job section, on which you can list up your required part and find someone to sort it for you.

[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: reduced image size(s)]

[Edited on 17.12.13 by bfesser]

AndersHoveland - 29-12-2011 at 19:08

While we are on the topic of inert gases, I will also mention sulfur hexafluoride . It is surprisingly inert, not even reacting with molten elemental sodium (it does not react until the boiling point is reached). It is also safe to breathe, provided of course that it is premixed with oxygen, otherwise it can easily cause suffocation.

Some of the few things that SF6 does react with at lower temperatures are a solution of sodium in anhydrous liquid ammonia, or sodium in the presence of diphenyl ethylene glycol dimethyl ether. Hydrogen sulfide can suppossedly also reduce it. Hydrogen iodide reduces SF6 at room temperature.
"Reaction between Sulfur Hexafluoride and Hydrogen Iodide", D. K. Padma, A. R. Vasudeva Murthy

Obviously elemental sodium is a stronger reducing agent than HI, but the differences in reaction in this unusual situation are due to steric reasons.

A cylinder of SF6 can be purchased for around 250 euros.

Carbon tetrafluoride is also an inert gas, although it reacts spontaneously with elemental lithium or sodium.

[Edited on 30-12-2011 by AndersHoveland]

peach - 29-12-2011 at 23:26

Quote:

Of course, CO2 is cheaper because it is easily sequestered from localised high volume sources, like chemical plants for example.

It also condenses at a much higher temperature (-78 °C) than argon (−185.85 °C)

In terms of the latent heats of vapourisation, CO2 does involve a larger change (15.326 kJ/mol at –57.5°C) than argon (6.43 kJ·mol−1). But creating and maintaining the temperature differential for argon consumes a lot of energy.

Contrary to the films, it takes about 18h to freeze a human body to liquid nitrogen temperatures because the latent heat for vaporising nitrogen is about 5 kJ / mol. Water is 40.7. Hence the serious burns that result from steam and boiling water contacting skin, versus spilling liquid nitrogen.

The air temperature at lake Vostok has reached -89.2C (making it the coldest place on earth).

Quote: Originally posted by AndersHoveland

A cylinder of SF6 can be purchased for around 250 euros.

Do you get to keep the cylinder, or is that per fill? I seem to remember SF6 being quite expensive. Even if you get to keep the cylinder, a fill of argon is about £50-75.

I just remembered, there are two other places you can try for inert gas and refills.

Paint ball people use CO2. They'll usually have one or more shoulder / head height cylinders and the people there are constantly refilling the cylinders. Some of them also use high pressure air or nitrogen. A 20oz paintball gun cylinder is about £30.

Divers and dive shops also tend to have cylinders near by. Numerous different gas blends exist for different dive profiles, as regular air induces nitrogen narcosis below about 30m. Deeper down, oxygen becomes toxic. The stores will produce blends of gases for technical diving.

Nitrox - Air with extra oxygen and bit of argon, to extend the length of shallow dives
Argox - Argon and oxygen
Heliox - Helium and oxygen
Hydrox - Hydrogen and oxygen
Hydreliox - Hydrogen, helium and oxygen
Trimix - Helium, oxygen and nitrogen (most technical divers use this for 100m dives, which is about the limit)

So the shops will have those cylinders sat around for the blending. As well as high pressure compressors for charging them.

Divers sometimes use argon to pressurise their dry suits, as the lower thermal conductivity of it versus breathable air helps keep the cold away. Or argox, or oxygen, to avoid having nitrogen under pressure in contact with their skin at depth. Armed with one of those harbor freight 20 cuft cylinders, call and ask about gas blending, if they do it or who else to call, then say you've got a small suit filling / bail out sized bottle and ask if they can charge it up with pure nitrogen or argon.

The affectionately named 'yellow box of death' rebreather. Five thousand buttons to press and hoses to tangle in whilst you suffocate in the cold, cold dark - trapped.

A typical technical diver, going for a relaxing swim.

[Edited on 30-12-2011 by peach]

AndersHoveland - 30-12-2011 at 13:14

Even nitrogen gas is not completely chemically inert. Although it will not react with elemental sodium or potassium at any temperature, it will gradually react with metallic calcium at room temperature.

Quote:

At normal temperature, Ca rapidly acquires a layer of nitride and oxide, but forming chiefly nitride. At higher temperature both CaO and Ca3N2 are formed.

"Concise Encyclopedia Chemistry", deGruyter

Quote:

Someone left some calcium in my glovebox in an open container. The glovebox was obviously 100% nitrogen environment. The box also happened to be at ~30 C at the time. By the next day it was all calcium nitride.

"enahs" from "Chemical Forums"

Interestingly, metallic calcium does not actually react with anhydrous ammonia at room temperature, but rather dissolves in the cold liquid. When heated (or with the use of an iron nitrate catalyst) it forms calcium nitride and calcium hydride, which are very different products from the reaction of sodium and NH3.

6 Ca + 2 NH3 --> Ca3N2 + 3 CaH2

2 Na + 2 NH3 --> 2 NaNH2 + H2

Nitrogen is actually soluble (only slightly) in molten sodium. "N-Na (Nitrogen-Sodium) System", James Sangster, Journal of Phase Equilibria and Diffusion
Volume 25, Number 6, 560-563,

peach - 31-12-2011 at 13:26

Interesting note there Anders.

It also underlines what I've been going on about, that if nitrogen can cause issues, you don't want to be messing around with things that are a lot more reactive in search of inert conditions. Argon is the way to go.

Quote:

Argon’s complete octet of electrons indicates full s and p subshells. This full outer energy level makes argon very stable and extremely resistant to bonding with other elements. Before 1962, argon and the other noble gases were considered to be chemically inert and unable to form compounds; however, compounds of the heavier noble gases have since been synthesized. In August 2000, the first argon compounds were formed by researchers at the University of Helsinki. By shining ultraviolet light onto frozen argon containing a small amount of hydrogen fluoride, argon fluorohydride (HArF) was formed.[2][16] It is stable up to 40 kelvin (−233 °C). The ArCF2+
2 metastable dication was also observed.[17]

I'd have to put effort into achieving that. As opposed to hydrogen and propane, which will happily explode with the slightest mistake.

[Edited on 31-12-2011 by peach]

benzylchloride1 - 2-1-2012 at 11:40

i use a Air Liquide cylinder of compressed balloon grade helium for all of my reactions that have to be run under inert gas as well as for my gas chromatographs. I successfully prepared cobaltocene using this gas, this compound is extremely oxygen sensitive and potentially pyrophoric.

Panache - 2-1-2012 at 18:55

No one seemes to mention the degredation of the planets atmosphere by recklessly using copious amounts of co2 and methane, ethane, propane, butane. It may be inert to you but what about the trees and the orangutangs. I think gm is wrong but sometimes i can't afford the organic alternative. How much is organic argon a cylinder?
Well if no one else cares i'm not going to either, ( cue music, 'arsehole' by denis leary)
can't wait for my burger.

peach - 3-1-2012 at 12:50

And how else are we supposed to cool down our swimming pools when they've burnt too much fuel and become too warm?

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[Edited on 3-1-2012 by peach]

AndersHoveland - 28-4-2012 at 13:38

Solubility of nitrogen and the noble gases in molten sodium and potassium:
"Solubility and Diffusivity of Inert Gases in Liquid Sodium, Potassium, and NaK", E.L. Reed, J,J. Droher
http://www.osti.gov/bridge/servlets/purl/4181890-sqUlyW/4181...
Realise that this does not mean nitrogen is unreactive at higher temperatures, just that there are unique chemical reasons that nitrogen does not readily combine with sodium or the alkali metals below it. Magnesium, a less reactive element than sodium, can burn in pure nitrogen. And nitrogen would also not be soluble in an amalgam (liquid mercury alloy) of aluminum or titanium, as it would instead react.

Quote:

"Dinitrogen has been known for many years to react with metals, such as lithium amongst the alkali metals and calcium, under very mild conditions. Such reactions are recognized to be initially surface tarnishing reactions, and the ultimate bulk product is the metal nitride, such as Li3N."
Nitrogen Fixation at the Millennium, edited by G. J. Leigh

[Edited on 28-4-2012 by AndersHoveland]

Digital Hepatitis - 22-7-2012 at 04:49

You can easily get pure argon gas as "wine preserver". This is a much more cost-efficient way of acquiring this than going down the welding canister route, if you are so inclined. If you only need a small amount of inert gas you can easily pick up a canister or two of wine preserver (just ensure that your brand is pure argon gas, as some are a mixture of gases.)

zenosx - 16-12-2013 at 22:16

Refreshing an old thread but better than making a new one eh?

I would love to have an inert atmo available to work under in my lab, however, I have not been able to find very cost effective routes to this.. Yes you can get Ar from Harbor Freight for $84.99 (as of today), but then the regulator is going to cost how much... another $100-$250?

There are welding supplies in my area but they only offer huge tanks (the 5'+ size) and those are not affordable..

I seen someone mentioning R-134A in the thread, and while Not cheap in my area ($11 for a small can minimum), is easily available and regulators are not hard to come by (I have two).

So, for someone that performs maybe 3 (or wants to) inert atmo reactions every year (at this point), what would you guys recommend. I can pick up a big tank of He, but being lighter than air you would start bottom up, but am not sure about reactivity without more research which I can do of course, but am now looking for an overall inert gas.

So TLDR;, is He viable for grignards? CO2 is definitely out for carboxylic acid production. Has anyone found a viable N2 route that doesn't cost $300 US to purchase, same for Ar...

Thanks for any input

DraconicAcid - 16-12-2013 at 23:22

If you're doing your Grignard in ether reflux, the ether vapour is all the inert gas you need.

Dr.Bob - 17-12-2013 at 08:02

If anyone does manage to find a cylinder of argon or helium, I think I have some regulators for them. Since I don't have any cylinders at home, I haven't tested them out yet, but I plan to sort through them one of these days. While they are expensive to buy, there seems to be little demand for used ones, so my price would be low. I always liked argon, but N2 works fine for most things. It is cheap to get cylinders refilled with, once you have a cylinder. (At least it used to be.)

Magpie - 17-12-2013 at 10:25

Here's some more info:

http://www.sciencemadness.org/talk/viewthread.php?tid=10366#...

Refills are cheap in my locale.

TheChemiKid - 17-12-2013 at 14:20

Quote: Originally posted by White Yeti

What's wrong with CO2? It's cheap, readily available, inert and denser than air (thus displaces it quite well).

Yes, just buy some dry ice and sublimate it. It costs $1 per pound, and is easy to get.

Lambda-Eyde - 18-12-2013 at 11:53

Quote: Originally posted by TheChemiKid

Quote: Originally posted by White Yeti

What's wrong with CO2? It's cheap, readily available, inert and denser than air (thus displaces it quite well).

Yes, just buy some dry ice and sublimate it. It costs $1 per pound, and is easy to get.

Please refer to my signature...

Also, CO2 is useless for many reactions, like Grignards. It is also relatively soluble in water and it is acidic. So yeah, dry ice might be viable for those who can get it when you need something for a reaction where it will work. But investing in a CO2 bottle would just be stupid if nitrogen or argon is available at a similar price.

TheChemiKid - 18-12-2013 at 12:11

That is true. I was just adding carbon dioxide as a choice because buying dry ice is cheap, and is better than just plain air for most reactions.