[lutesium]

How is an inert atmosphere set up??? By bubbling Argon gas into the reaction solvent??? And which gases can be used??? Only Argon and Nitrogen???


Lutesium...

[Kryolith]

Heat your flask with a heat gun under vakuum, flush it with argon and repeat this procedure a few times. Argon is the gas of choice in most cases. It's very inert and somewhat cheap. Nitrogen is cheaper but not inert enough for several reactions. Can you imagine why helium isn't used as an inert gas (apart from the price)?

[lutesium]

I'd ask the same question as why He or Ne can't be used as inert atmospheres??? And what's a heat gun and why do we use vacuum??? I only want to do a reflux!!!


Lutesium...

[Kryolith]

If you work under inert gas conditions you want to get rid of oxygen, water etc. right? Evacuation and heating of the flask removes these undesired components of air.

Argon is a good choice because it's heavier than air, thus "sitting" on the surface of your reactants and protecting them.

[lutesium]

Is LiAlH4 so moisture sensitive that warrants its usage under an inert atmosphere. And once the bottle is opened do we have to flush the atmosphere of the bottle with inert gas again??? And while weighing inside an 5Oml beaker do we have to flush the atmosphere over the beaker with Argon???

And for my previous question... If the reaction takes 2-3 days to complete should I watch the reaction for that much time just to open and close the valve??? There must be an easier way!!!

PS: I like watching reactions I can watch a reaction for 4 hours without a stop (other than reading some documents while wathcing) but 2-3 days is a very long time!!!


Lutesium...

[ifuller]

I have worked a fair amount with LiAlH4 and although it is very moisture sensitive, it should be fine in normal air. Pouring water over the compound though will create flame. (Known from experience) A simple dehumidifier for a small room should suffice. Remember also though that if you are combining LiAlH4 and water you are producing hydrogen, so ensure there is nothing in the room which could cause a spark of any type.
As for any rebottling procedures, I do not reseal the bottle with an inert gas. I simply only open the container for the least possible amount of time and leave it at that. This will eventually degrade the compound but depending on the amount the bottle is open it should still last a long time.
Let me know if you need more information.

Just curious, what are you doing with the lithium aluminum hydride?

[lutesium]

Thank you very much ifuller but you must be kidding with me with this question!!! What's LiAlH4??? Its one of the most common rediucing agents in organic chemistry!!! Just out of curioisty
why were you curious???


Lutesium...

[ifuller]

That is just what I was asking. I know that it is a reducing agent but my experimentation with LiAlH4 uses it as a possible hydrogen fuel source. I was simply asking if you were looking to use it for fuel cell applications. That is why I was curious. Sorry about the confusion

[lutesium]

If you had read the post from the beginning you could understand I think


Lutesium...