Sciencemadness Discussion Board

Inert atmosphere :Vacuum as good as Nitrogen ?

BaFuxa - 10-2-2018 at 09:29

Hi,

I need an inert atmosphere to carry out an experiment. I do not have a dinitrogen source but I have a vacuum pump. Can I just put the reactor under vacuum instead of flowing it with N2 ?

I cannot see why this would not be equivalent apart from where intermolecular configuration conservation is crucial, yet, all the papers I read use N2 instead of vacuum so I felt like I would ask.

NEMO-Chemistry - 10-2-2018 at 09:43

is the reactor empty? as in are you wanting to fill the reactor? You might get away with that but unlikely, if it isnt empty then your going to boil what is in it.

What are you actually doing? whats the reactor for, i use bioreactors often is says Nitrogen atmosphere and i read hydrogen or butane :D.

JJay - 10-2-2018 at 10:45

If you believe that a vacuum will substitute for nitrogen, no one is stopping you from trying it and posting your results, but it is unusual to substitute a vacuum for inert gas in a reactor. Many reactions require some amount of pressure, if only regular atmospheric pressure, to proceed at a reasonable rate at normal temperatures, and there could also be issues with the reactants evaporating or subliming.

One thing I have wondered about is whether it is possible to distill benzaldehyde in a stream of inert gas; I have seen several demonstrations that show benzoic acid crystallizing in the condenser when a distillation is attempted in air, but I have not seen any showing it distilled in inert gas, and I don't see offhand why it wouldn't be possible.

BaFuxa - 10-2-2018 at 10:56

Quote: Originally posted by NEMO-Chemistry  
is the reactor empty? as in are you wanting to fill the reactor? You might get away with that but unlikely, if it isnt empty then your going to boil what is in it.

What are you actually doing? whats the reactor for, i use bioreactors often is says Nitrogen atmosphere and i read hydrogen or butane :D.


I want to calcinate Cu Nps on activated carbon, @ 450 ° C for 2 hours.

Trying to avoid oxidation at all costs here, CuO ( the black one) Nps are very carcinogenic ->https://pubs.acs.org/doi/abs/10.1021/tx800064j

JJay - 10-2-2018 at 11:01

Oh, that kind of reactor. I have one. It would be hard to maintain a vacuum in it at those temperatures.

NEMO-Chemistry - 10-2-2018 at 11:17

I had a feeling this was going to be about nano something.......

No sorry in this instance a vac isnt going to do it. Get a second hand oxygen scrubber, a cheap bottle of argon.

zed - 12-2-2018 at 16:53

I would keep in mind, that vacuum is an excellent insulator. Heat distribution may not occur normally.

And also, that atmospheric pressure, might squash your hot-soft apparatus, depending on construction.

Is CO2 sufficiently inert for your purposes? Or, is it too reactive?

Easy to generate! Cheap!

PirateDocBrown - 12-2-2018 at 21:23

N2 is easy to generate. NaNO2 + NH4Cl. Pass the gas through a drying tube, and voila! nearly pure N2.

N2 cylinders are cheap, too, after you pay for the cylinder deposit itself and the regulator.