Thanatops1s
Hazard to Self
Posts: 54
Registered: 24-6-2013
Member Is Offline
Mood: No Mood
|
|
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.
|
|
|
PeeWee2000
Hazard to Self
Posts: 58
Registered: 2-7-2013
Location: Michigan
Member Is Offline
Mood: No Mood
|
|
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-...
“Everything is relative in this world, where change alone endures.”
― Leon Trotsky
|
|
|
Thanatops1s
Hazard to Self
Posts: 54
Registered: 24-6-2013
Member Is Offline
Mood: No Mood
|
|
i was going to use a 105 deg angle adapter to make it vertical.
|
|
|
PeeWee2000
Hazard to Self
Posts: 58
Registered: 2-7-2013
Location: Michigan
Member Is Offline
Mood: No Mood
|
|
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 
“Everything is relative in this world, where change alone endures.”
― Leon Trotsky
|
|
|
Thanatops1s
Hazard to Self
Posts: 54
Registered: 24-6-2013
Member Is Offline
Mood: No Mood
|
|
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 |
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.
|
|
|
sonogashira
National Hazard
Posts: 555
Registered: 10-9-2006
Member Is Offline
Mood: No Mood
|
|
It is only
hot nitric acid. Nothing serious.  Get a good head of steam and blow it out!
|
|
|
Thanatops1s
Hazard to Self
Posts: 54
Registered: 24-6-2013
Member Is Offline
Mood: No Mood
|
|
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.
|
|
|
Lambda-Eyde
National Hazard
Posts: 857
Registered: 20-11-2008
Location: Norway
Member Is Offline
Mood: Cleaved
|
|
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.
This just in: 95,5 % of the world population lives outside the USA
You should really listen to ABBAPlease drop by our IRC channel: #sciencemadness @ irc.efnet.org
|
|
|
crazyboy
Hazard to Others
Posts: 436
Registered: 31-1-2008
Member Is Offline
Mood: Marginally insane
|
|
| 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.
|
|
|
Marvin
National Hazard
Posts: 995
Registered: 13-10-2002
Member Is Offline
Mood: No Mood
|
|
Could you be confusing it with a cool coil condenser crazyboy?
|
|
|
Thanatops1s
Hazard to Self
Posts: 54
Registered: 24-6-2013
Member Is Offline
Mood: No Mood
|
|
| 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.
|
|
|
Lambda-Eyde
National Hazard
Posts: 857
Registered: 20-11-2008
Location: Norway
Member Is Offline
Mood: Cleaved
|
|
| 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.
This just in: 95,5 % of the world population lives outside the USA
You should really listen to ABBAPlease drop by our IRC channel: #sciencemadness @ irc.efnet.org
|
|
|
crazyboy
Hazard to Others
Posts: 436
Registered: 31-1-2008
Member Is Offline
Mood: Marginally insane
|
|
| 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.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
