Always, ALWAYS let the pump run for a few minutes and turning on the vacuum BEFORE you cool the solvent trap. You can get liquid oxygen in it if you do it this way.
Useful video! I agree with what other commenters have said - it is inadvisable to wear non-cryogenic gloves when handling liquid nitrogen as they can freeze to the skin. It is better to either wear cryogenic gloves or no gloves whatsoever. As an addition - there is always a risk when doing a freeze pump thaw that a vessel fails, particularly if there is a structural defect such as a crack that you haven't noticed. I saw that you have performed this with the sash particularly high. I would lower the sash when doing this.
This was brill.Please be careful wearing gloves.They can stick to your skin, if any liquid nitrogen gets between them and your skin....ouch! We have to F.P.T at least 5 times in our lab and then sit the bomb into an adequate volume of ambient water.We also have to turn the pump on first,then the manometer, flush the line with gas and then put on the cold trap.Has anybody else got any good tips.Hope to see more from your channel soon. Irish Chemist.
Hi! I really appreciated the video- it was very well done. I am wondering- isn't it recommended that the flask containing frozen solvent be submerged in a bath of tepid water after removal from the Dewar? This helps avoid uneven thawing of the solvent that could lead to an explosion.
I would add that it is much safer to use dry ice and acetone as your bath when doing freeze-pump-thaw, as using liquid nitrogen adds to the risk of condensing dangerous liquid oxygen. The lowering of the vapor pressure of substance is all that is really needed in a FPT, so even if dry ice acetone bath doesn't freeze your compound, it is typically sufficient to remove oxygen.
It depends on the solvent you are degasing. There is no reason not to use liquid nitrogen. Condensing liquid oxygen is highly unlikely since the vessel is evaporated and filled with inert oxygen free gas.
I am currently finishing my masters degree in chemistry and work a lot with liquid nitrogen and I love it...it is like the coolest thing ever! Well....besides the helium in our NMR
Chidren book. Pg 70. R_m_n s_ld__r's sw_rd 1. Draw a blade on thin cardboard, then cut it out. Draw a rectangle for a handle, then lay the blade next to it, like this, and draw around it. 2. Cut around the second shape. Pressing with a ballpoint pen, draw a line along the middle of each blade. Turns the blade over and pinch along the lines. 3. 4. 5. 6. 7. 8.
I think the pressure inside would increase a bit when it thawed, so if adding nitrogen imediately after vaccum, the lid would be poped out or even worese the whole glassware would explode ...
+Diego Magalhães do Nascimento Specification? I suppose you want to know the type of glass - it's all borosilicate glassware. The schlenk tube being used is probably about 100 mL volume sealed with a greased glass stopcock and glass stopper. Is there anything else you're wanting to know?
This was brill.Please be careful wearing gloves.They can stick to your skin, if any liquid nitrogen gets between them and your skin....ouch! We have to F.P.T at least 5 times in our lab and then sit the bomb into an adequate volume of ambient water.We also have to turn the pump on first,then the manometer, flush the line with gas and then put on the cold trap.Has anybody else got any good tips.Hope to see more from your channel soon. Irish Chemist.
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Always, ALWAYS let the pump run for a few minutes and turning on the vacuum BEFORE you cool the solvent trap. You can get liquid oxygen in it if you do it this way.
Useful video!
I agree with what other commenters have said - it is inadvisable to wear non-cryogenic gloves when handling liquid nitrogen as they can freeze to the skin. It is better to either wear cryogenic gloves or no gloves whatsoever.
As an addition - there is always a risk when doing a freeze pump thaw that a vessel fails, particularly if there is a structural defect such as a crack that you haven't noticed. I saw that you have performed this with the sash particularly high.
I would lower the sash when doing this.
I've always been told it prolongs the life of a vacuum to open it to air before turning it off.
This was brill.Please be careful wearing gloves.They can stick to your skin, if any liquid nitrogen gets between them and your skin....ouch! We have to F.P.T at least 5 times in our lab and then sit the bomb into an adequate volume of ambient water.We also have to turn the pump on first,then the manometer, flush the line with gas and then put on the cold trap.Has anybody else got any good tips.Hope to see more from your channel soon. Irish Chemist.
Hi! I really appreciated the video- it was very well done. I am wondering- isn't it recommended that the flask containing frozen solvent be submerged in a bath of tepid water after removal from the Dewar? This helps avoid uneven thawing of the solvent that could lead to an explosion.
I also use a warm water bath to thaw.
I have also read the same
Never seen an Edwards being used to pull solvents/Degas, normally we use welch pumps for solvents/Degas, Edwards for glovebox antechambers.
I would add that it is much safer to use dry ice and acetone as your bath when doing freeze-pump-thaw, as using liquid nitrogen adds to the risk of condensing dangerous liquid oxygen. The lowering of the vapor pressure of substance is all that is really needed in a FPT, so even if dry ice acetone bath doesn't freeze your compound, it is typically sufficient to remove oxygen.
It depends on the solvent you are degasing. There is no reason not to use liquid nitrogen. Condensing liquid oxygen is highly unlikely since the vessel is evaporated and filled with inert oxygen free gas.
I am currently finishing my masters degree in chemistry and work a lot with liquid nitrogen and I love it...it is like the coolest thing ever! Well....besides the helium in our NMR
Chidren book. Pg 70.
R_m_n s_ld__r's sw_rd
1. Draw a blade on thin cardboard, then cut it out. Draw a rectangle for a handle, then lay the blade next to it, like this, and draw around it.
2. Cut around the second shape. Pressing with a ballpoint pen, draw a line along the middle of each blade. Turns the blade over and pinch along the lines.
3.
4.
5.
6.
7.
8.
Why do you add nitrogen after the solvent has thawed and not right after adding the vacuum?
I think the pressure inside would increase a bit when it thawed, so if adding nitrogen imediately after vaccum, the lid would be poped out or even worese the whole glassware would explode ...
I think the dewar for the cooling trap is too high. It will freeze the joints and the grease there. Except this, everything is perfect.
Hi, I really liked your video!
Please, which specification of tubes?
+Diego Magalhães do Nascimento Specification? I suppose you want to know the type of glass - it's all borosilicate glassware. The schlenk tube being used is probably about 100 mL volume sealed with a greased glass stopcock and glass stopper. Is there anything else you're wanting to know?
My mother has this birthmark on her leg and in the 70s a GP put liquid nitrogen on it claiming it will remove it 🤮
I don't see an outlet for your solution, please expound on that.
Yes, I was surprised by this too
It looks to me that there is no way to balance the pressure inside the solvent flask?
I have no idea what you did or why you did it, but I like a lady with a big dewar.
cryogenic gloves
This was brill.Please be careful wearing gloves.They can stick to your skin, if any liquid nitrogen gets between them and your skin....ouch! We have to F.P.T at least 5 times in our lab and then sit the bomb into an adequate volume of ambient water.We also have to turn the pump on first,then the manometer, flush the line with gas and then put on the cold trap.Has anybody else got any good tips.Hope to see more from your channel soon. Irish Chemist.