![]() | This article is rated Start-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
|
Hi and thanks for the benzophenone images, great!. I have some remarks on the main image though:
Please keep those images coming, they are great!
V8rik 17:34, 5 September 2006 (UTC)[reply]
Hi V8rik
Glad that you enjoy the pictures. I think it's quite fun that the world can see a blow-by-blow account of what I do in my lab. =)
Check out the article page. I've posted a new picture showing how I collect the dry distilled toluene. While refluxing the toluene, the stillhead, condenser, and receiving Schlenk flask are greased, fitted together, and undergo three evacuate and purge with nitrogen cycles. Of course, they are sealed as appropriate.
Once done, a positive pressure of nitrogen on the receiving assembly and the still (through the joint of the two-necked flask connected to the Schlenk line). It's a bit tricky (even with 4 hands), especially with all the water and nitrogen hoses dangling everywehre, but the main thing is to pop off both caps and fit them together quickly, while the nitrogen flow prevents air from entering. To ensure a good flow of nitrogen, the bubbler on the Schlenk line (to protect from overpressure) is turned off for a while. They are opened once the whole darn thing is assembled.
We do have something similar to http://www.sigmaaldrich.com/img/assets/4686/al_Z14785L.gif. The difference is ours is not directly connected to the receiving flask. Rather, it the sep-funnel-like bulb has another joint which is usually sealed. When we need to draw the solvent, we switch it to a septum and transfer using a cannula.
Those rigs are "standing" in that they are not set up and torn down all the time. Rather, they stir the required solvent constantly with the sodium/benzophenone, and when dry solvent is needed the heater is turned on. We don't use dry toluene that often, explaining why I had to do it separately.
Regarding the picture with the stopcock of the nitrogen line closed - nitrogen is fed from the top. There is no constant stream of nitrogen; rather, it just prevents air from leaking in. Overpressure is vented to the bubbler on the Schlenk line.
I accept your criticisms regarding the safety of the rig. There's always more for improvements. As can be seen from the mess on the benchtop, I was in a bit of a hurry when I set this up! I'm not sure what you mean about the jacketed flask, though.
--Rifleman 82 18:27, 5 September 2006 (UTC)[reply]
Ah, I see. --Rifleman 82 03:02, 6 September 2006 (UTC)[reply]
Hey guys, the tag line on this page reads something like "This article is about the basic chemical, for benzophenone-n see this other page" (I should've copied it so I could cut and paste instead of relying on my crummy memory). I'd prefer to see the word "basic" changed to something like "fundamental" or "single-unit" or any word someone else can come up with. "Basic" means something specific to me, as a chemist, and "basic" does not describe benzophenone. Thanks. 76.126.21.91 (talk) 20:24, 10 April 2010 (UTC)[reply]
Hello fellow Wikipedians,
I have just modified one external link on Benzophenone. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to trueorfailed to let others know (documentation at {{Sourcecheck}}
).
This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}}
(last update: 5 June 2024).
Cheers.—InternetArchiveBot (Report bug) 06:15, 31 October 2016 (UTC)[reply]