Question safe way to give of hydrogen gas?

[mithyl2]

Because hydrogen gas is combustible with the air, what's the best way to deal with hydrogen gas when I'm doing a reaction that produces it? (Apart from using a professional fume hood.)

 

[cesc]

Zinc HCl ?

 

[mithyl2]

could you elaborate?

 

[cesc]

Redox meaning. Notshooting H2 to Space

 

[mithyl2]

ok. so i add zinc hcl to the solution with sodium borohydride in it to reduce its explosivity?

 

[UWe9o12jkied91d]

Run hosing from the top of the condenser to the outside if youre THAT worried.
But if youre just reducing using borohydride for example an open window and a running fan will do just fine

 

[mithyl2]

but isn't hydrogen gas combustible with the air?

 

[archae]

It is, H2 can cause explosion at a minimal concentration of 4%. For it to be a real concern you would have to use quite a lot of it to fill a normal room at this point.

Ventilate your workspace correctly and that shouldn't be a problem.

 

[cesc]

Hi. As far as I know H is flamable with fires Indeed,

 

[HerrHaber]

It really depends on the quantity of gas evolved so if this isn't a great volume you can also put an previously inflated and then emptied baloon at the end of your setup, as it will inflate the pressure in the system will increase (often enough a desired thing in hydrogenation reactions) and instead of letting it pop you change it and empty the full one out. The advantage of H2 is that it's lighter than air so it will rather tend to escape a room with a current of air then accumulate to form explosive mixtures with O2 in the atmosphere (reason for which Et2O is a dangerous solvent is that it accumulates on the floor and by the time it reaches your nose it can be too late). Hope this helps.

 

[mithyl2]

this is exactly what i was thinking, although if the balloon does pop by accident before i change it then perhaps it could cause an explosion through quick pressure release or static.

i was going to put a hose leading from my condenser to outside the window. but i'm still a bit paranoid/worried about explosions. i think i'll just have to do this.

 

[HerrHaber]

you chose the more preffered method, don't worry H2 floats better than He and it will wickly dilute in the outside athmosphere also going up and away from the source (make sure the hose is attached outside from the upper point as not tho hav gas blown back by wind)

 

[sharetea]

The correct way is to pipe it off and have a flashback arrestor on the end.

though hose/pipe to the outside should be sufficient as long as it is no trapped

hydrogen is lighter then air. Think about a helium ballon. sure every1 has experience lossing a helium ballon.

Think about 3 seconds after let go of the ballon.

Where is the ballon now?
Are you able to grab the ballon back.

It the ballon represent danger explosions. How quick did it leave ur perimeter.

It path to the sky would be best unhinderd.

Dont let it accumulate in the room ur working.

Most reactions ur not mesnt to hsve a closed system to avoid preassure build up /explosions..

Unless ur doing a preassure bomb where you hsve preassure vessels.

I wouldnt use s ballon... Use hoses or pipes.. That csnnhsndle pressssure if its small dismeter means you need thick walls

But kf ur exhusst is big ur reslly just directing the flow of gas.

If ur kitchen fan extractor goes straight outside thats okay too.

Some bathrooms only send the air into the roof but unless ur going upto the roof to have a cigerrettte u should be fine.

Fans dont even hsve to be on.. If it leads outside.. Just runn the hose up a little.. Or to the outside where it can go straight up.. Hydrogen doesnt have a smell i dont think .. I could be wrong..

If alot of hydrogen is produced it may carry some lf the liquid solvent wth it. Co vapourise. If that smell yah need to make adjustments to account for on the large scale.

I suggest you dummy run everything to know what ur dealing with

.smaller reaction makes problems smaller. Then you can decide what you actuslly need.

Hydrogen is quite safe outdoors as long as no ignition source.

1910.103 - Hydrogen. | Occupational Safety and Health Administration

www.osha.gov

It the gasses that go down and linger you have to worry about cos u dont even know its there.

If it smells after a small test. You will need to scrub the gas.

Here is a video of a person using a water asporator as make shift scrubber.. You will have to close the lid.. And pipe from the lid to allow you yo direct the hydrogen outside still.

Stay safe

 

[HerrHaber]

also copper sieve has the magical property of stopping flames to pass through

 

[sharetea]

Thanks for that..

 

[sharetea]

How does that work.?. Where can i find a explanation

 

[HerrHaber]

I really don't know but this I heard from a reputable professor with vast experience in industrial chemistry, that putting a fine copper sieve at the gas outlet of inflamable stuff blocks the flame entering the system. I did put this sort of sieve bt I was rather more careful not to have an ignition source so I never had the unfortunate chance of seeing it's effectiveness.

 

[sharetea]

Interesting i do like obsecure pieces of knowedge.. I need to wrap my head around this.

I want to pursue this tangent to whereever it leads.. But i dont know what term to begin this lil journey.. It always the jargon finding the right word to search to get the answers we looking for..

Did he refer to it as sieve..maybe flame retarder..

 

[sharetea]

Im searching and searching... And i realised.. We had wire mesh for highscgool.. And bunsen burners underneath.. And ur right it doesnt go past.. Wtf..

 

[HerrHaber]

it needs to be copper wire mesh

 

[G.Patton]

Hello, my dear forum members. I wrote this topic for such questions: Hydrogen gas (H2) laboratory preparation
Also, there is option to buy Hydrogen gas (H2) generators

 

[HerrHaber]

an electrolytic H2 generator is the best if you use it for heterogenous catalytic reductions like with Pd/C