Information on Sulfur hexafluoride?

[jim mcnamara]

Anybody know more about this? It is in DISCUSSION forums since I do not see any decent references on the subject. Maybe I'm having a bad day...

$SF_{6}$ -
Prevents fires from electrical shorts, used in high kVa distribution lines - at connection points, substations, and "ties" Apparently it has a tremendous greenhouse gas potential - on the order of 20K per molar mass unit (?do not know) greater than methane:

<snip>... It is 23,500 times more warming than carbon dioxide (CO2). ...<snip>

---- https://www.bbc.com/news/science-environment-49567197

https://en.wikipedia.org/wiki/Greenhouse_gas - mentions $SF_{6}$:
https://en.wikipedia.org/wiki/Sulfur_hexafluoride - this states 10000 tons of the gas are synthesized every year.

I've never encountered any of this before.

 

[fresh_42]

I just read on Wiki that it is the most damaging greenhouse gas known, a factor 26,000 worse than carbon dioxide, plus an average atmospheric lifetime of 3,200 years. Wow! And they release it during magnesium production! Next one telling me something about cars gets better prepared for a loud veto.

They also said it had been used in tires, insulated glazing and sport shoes. I wonder which amount is actually released per year.

 

[Bystander]

Mass of atmosphere = 5 x 10∧18 (where in the h*** have the sub/superscripts gone) kg, x 400 ppm carbon dioxide = 2 x 10∧12 tons; got a loonnngggg way to go before 10∧4 tons/a registers.

 

[TeethWhitener]

SF₆ is a low conductivity, inert gas used as a gas insulator in a lot of large-scale electrical applications. Maybe @anorlunda knows more about it.

Fun fact about SF₆: it’s much much heavier than air and non-toxic. As a result, if a large quantity is inhaled (NB—I AM NOT RECOMMENDING THIS), it does essentially the opposite to one’s voice that helium does.

 

[jim mcnamara]

@Bystander I think the total loss due to leakage is not even as great as you mention. Where did you get the $10^4$ tons?
@TeethWhitener - so the density means that residual $SF_{6}$ remains in some lower alveoli displacing $CO_{2}$ ?

 

[jim mcnamara]

@Bystander - you can use latex for subscripts or turn on bbcode to get the "sub" tags.

 

[Bystander]

this states 10000 tons of the gas

the 10410410^4 tons?

From you. It's a reasonable upper limit; switchgear isn't built to collect/recycle the stuff.

turn on bbcode

Thank you.

 

[Bystander]

Now is the time for all good men to come to aid of the sly brown fox jumping quickly over the lazy dog. CO₂ + SF₆, 10¹⁸ kg

 

[snorkack]

Fun fact about SF₆: it’s much much heavier than air and non-toxic. As a result, if a large quantity is inhaled (NB—I AM NOT RECOMMENDING THIS), it does essentially the opposite to one’s voice that helium does.

It´ s suffocating (like all gases other than O₂) and it´ s narcotic (like most heavy gases).
It is not the densest gas (that´ s WF₆, which is reactive and poisonous), but it is the densest common one. The densest nontoxic gases seem to be the isomers of perfluorobutane.

 

[hilbert2]

There are also some other sulfur compounds that are about as nontoxic as $H_2 O$, first ones to come to mind are dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM).

 

[TeethWhitener]

so the density means that residual SF6SF6SF_{6} remains in some lower alveoli displacing CO2CO2CO_{2} ?

I’ve heard this is a myth perpetuated by more senior grad students to get their juniors to stand on their heads to remove residual SF₆, but I really wouldn’t know anything about that...

 

[Tom.G]

There are also some other sulfur compounds that are about as nontoxic as $H_2 O$, first ones to come to mind are dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM).

The problem with DMSO is it acts as a carrier to transport other chemicals thru the skin. Great I suppose if you want an infusion of <?> without a needle stick.

 

[hilbert2]

Yeah, in some organic syntheses a DMSO solution of sodium cyanide is used as a reagent, and then you need double airtight safety gloves and other protective apparel.