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Author: Subject: angle of graham condenser
Thanatops1s
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[*] posted on 31-8-2013 at 13:11
angle of graham condenser


I was distilling nitric acid today and some was collecting in the bottom of the coils slowly making its way down coil by coil(it wasn't totally horizontal, there was some angle). I figured it would work its way down and then come out. It did but then my thermometer adapter popped up a bit to release pressure that had built up. Should i clamp things together and allow the pressure to build so it pushes the liquid through? Or what I'd rather not do unless i must, reconfigure it so the condenser is vertical.
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PeeWee2000
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[*] posted on 31-8-2013 at 13:26


Wrong area to post this imo, but anyways with a graham condenser you would want it pointing straight down as pressure in your apparatus can be dangerous, if you do want to use it at an angle a vacuum would be much more prefferable. Although in my experience even with keck clamps attached the joints will still come undone enough to let gas escape if pressure does build in the system.

Heres an example of what you would want to use to get the condenser horizontal
http://www.ebay.com/itm/NEW-Adapter-Distillation-24-40-tube-...




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Thanatops1s
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[*] posted on 31-8-2013 at 13:29


i was going to use a 105 deg angle adapter to make it vertical.
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PeeWee2000
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[*] posted on 31-8-2013 at 13:33


That works just as well good luck with your nitric acid endeavors, and just from my experience you dont need a graham condenser for making nitric acid a west or liebig works just fine with cold water but the graham does look alot cooler :cool:



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Thanatops1s
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[*] posted on 31-8-2013 at 15:40


Quote: Originally posted by PeeWee2000  
That works just as well good luck with your nitric acid endeavors, and just from my experience you dont need a graham condenser for making nitric acid a west or liebig works just fine with cold water but the graham does look alot cooler :cool:


The Graham happens to be what i own(and yeah, it definitely looks cooler I think a nice Vigreux column is beautiful too). Definitely going to grab a Liebig in the near future as well.
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sonogashira
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[*] posted on 31-8-2013 at 18:21


Quote: Originally posted by Thanatops1s  
Should i clamp things together and allow the pressure to build so it pushes the liquid through?
It is only hot nitric acid. Nothing serious. :o Get a good head of steam and blow it out! :D
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Thanatops1s
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[*] posted on 31-8-2013 at 18:55


Quote: Originally posted by sonogashira  
Quote: Originally posted by Thanatops1s  
Should i clamp things together and allow the pressure to build so it pushes the liquid through?
It is only hot nitric acid. Nothing serious. :o Get a good head of steam and blow it out! :D


Well it was only a few ml's in the bottom of the coil so it's not like there's a large amount of pressure, I figure the pressure to push that through is far less than what the glass can handle. Not to mention I've read conflicting opinions here and there about whether or not the back pressure using a Graham as such is beneficial to the distillation process. The system is not closed either, there is a vacuum adapter vented to a gas trap.
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Lambda-Eyde
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[*] posted on 31-8-2013 at 20:24


A graham condenser should only ever be used vertically and only for distillation, never for reflux. The idiots who sells their sets on eBay with tilted graham condensers have no idea what they're doing and should be shot.



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crazyboy
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[*] posted on 1-9-2013 at 12:04


Quote: Originally posted by Lambda-Eyde  
A graham condenser should only ever be used vertically and only for distillation, never for reflux. The idiots who sells their sets on eBay with tilted graham condensers have no idea what they're doing and should be shot.


I agree that a Graham condenser should only be used vertically but disagree that it should never be used for reflux. Graham condensers are useful for refluxing volatile solvents such as ethers. I have used them in the past for reductions where THF or diethyl ether was being refluxed. In addition at the lab I work at a graham condenser is used on the THF solvent still.




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Marvin
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[*] posted on 1-9-2013 at 13:48


Could you be confusing it with a cool coil condenser crazyboy?
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Thanatops1s
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[*] posted on 1-9-2013 at 15:32


Quote: Originally posted by Lambda-Eyde  
A graham condenser should only ever be used vertically and only for distillation, never for reflux. The idiots who sells their sets on eBay with tilted graham condensers have no idea what they're doing and should be shot.

That I'm definitely aware of. I have Vigreux column for reflux.
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Lambda-Eyde
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[*] posted on 2-9-2013 at 06:15


Quote: Originally posted by crazyboy  

I agree that a Graham condenser should only be used vertically but disagree that it should never be used for reflux. Graham condensers are useful for refluxing volatile solvents such as ethers. I have used them in the past for reductions where THF or diethyl ether was being refluxed. In addition at the lab I work at a graham condenser is used on the THF solvent still.

Are you sure you're talking about graham condensers?





The one on the right, where the vapors flow inside the coil, is a graham condenser (also known as inland revenue condenser, for some reason). The one on the left is called a coil condenser, sometimes mistakenly (I think?) also called graham condensers. The type on the left is useful not only vertically but also for reflux. The problem with using true graham condensers for reflux is that you risk having the pressure inside the flask pushing condensed solvent through the coil.




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crazyboy
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[*] posted on 2-9-2013 at 12:45


Quote: Originally posted by Marvin  
Could you be confusing it with a cool coil condenser crazyboy?



Quote:

Are you sure you're talking about graham condensers?


Yes, I'm sure. Yes I know the difference. Yes some solvent can be pushed through the coils but it is not a serious issue and the liquid drains continuously. I have even refluxed ether with a graham condenser with a stopper at the top of the condenser for 48 hours with no issue.




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