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Topic: drawing appratus  (Read 4513 times)

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Offline rita87

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drawing appratus
« on: April 03, 2009, 07:26:27 PM »
Hi guys,
Does anybody know how the following appratus looks like?could you draw it please?
 
fractionating column of the Vigreux type is fitted with a condenser and receiving flask provided with a vent. The extension of this vent is covered with a test tube carrying another small tube for admitting carbon dioxide; the end of the test tube is then loosely plugged by a piece of cotton wool (Note 11). The apparatus is swept out with carbon dioxide, and the round-bottomed flask containing the once-distilled diethyl zinc is connected to the column. The diethyl zinc is then redistilled at atmospheric pressure.

Thank you

Offline azmanam

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Re: drawing appratus
« Reply #1 on: April 04, 2009, 06:32:20 AM »
Is this an org synth prep?  (Note 11) makes me think that it is.  Do you have the reference?

Vigreux looks like this:
http://chemistry.about.com/od/chemistrylabexperiments/ig/Chemistry-Laboratory-Glassware/Condenser.htm

I'd use a short path as the condenser, thermometer holder, distillation head, and vent:
http://pipeline.corante.com/still%20head.jpg
(the vent is the tubing entry port furthest to the right.  The other two on the left are the entry/exit for the water condenser).

I don't really understand what the test tube with tube for admitting carbon dioxide... but it sounds like you're supposed to do the distillation under an atmosphere of carbon dioxide???  If you use a short path, a 14/20 septum will fit over the vent, and you can just hook some tygon tubing up to a lecture bottle of carbon dioxide.  You can put a venting needle in the septum and flush out the ambient atmosphere and replace it with carbon dioxide, then remove the venting needle.  If I'm reading it wrong, then I don't know what the test tube is about.
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Offline sjb

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Re: drawing appratus
« Reply #2 on: April 04, 2009, 08:00:19 AM »
A quick google on the phrase turns up an Org Synth prep for Et2Zn - http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV2P0184

Offline nj_bartel

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Re: drawing appratus
« Reply #3 on: April 04, 2009, 12:26:56 PM »
Is the OP planning on making himself a rocket?  :P

Offline Squirmy

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Re: drawing appratus
« Reply #4 on: April 04, 2009, 11:45:33 PM »
I hate to explain jokes, but safety is an exception. I believe nj_bartel is alluding to the pyrophoric nature of neat diethylzinc. This makes for a good point of reference.

DAIB is air sensitive in the sense that it will decompose over time if stored improperly. Neat Et2Zn is air sensitive as in it can catch on fire just transferring it to the reaction.

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