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Laboratory Tips Safety proceedures, test reagents, drilling rubber stoppers, bending glass tubes, etc. Contributed to by chemists.

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 #1 
Old 2008-12-10, 15:55
somewilliepete somewilliepete is offline
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Default Pyridine synth w/pics

While not entirely OTC, all chemicals are unwatched and easy to come by. This can be scaled up to suit your needs.

(Thanks goes to ordenblitz.)

I decided since I have a lot of the required intermediary copper chromite material I would try this reaction again scaled up and in glass. Damage was possible to the boiling flask but I have a few, so was prepared to sacrifice one for the cause. I was in fact completely wrong about the temperatures required and the possible heat transfer issues of the starting mix.*
In a 50 ml flask was placed 24 grams of nicotinic acid intimately mixed with 12 grams of Cr2CuO4·CuO·BaCrO4 catalyst mix.*

http://i397.photobucket.com/albums/pp53/tawayemail/1.jpg
http://i397.photobucket.com/albums/pp53/tawayemail/2.jpg


One should definitely start by warming this mix slowly because it will limit or avoid all together much of the sublimation of the nicotinic acid.


http://i397.photobucket.com/albums/pp53/tawayemail/3.jpg


A little heat blanket is handy here to speed things along.

http://i397.photobucket.com/albums/pp53/tawayemail/4.jpg

I got in a hurry though and turned the mantle all the way up in the beginning thinking I would not have enough heat. I had to unplug and let the moving air of the hood cool things a little. You can see the white smoke of nicotinic acid filling the flask and condenser.

http://i397.photobucket.com/albums/pp53/tawayemail/5.jpg

After things got settled down and a little cooler, it really only took a setting of about 50% on my controller to keep the reaction running smoothly. This lower temperature allowed some pyridine to reflux into the mix washing back any escaped C6H5NO2. You can see small droplets forming here but really no white fumes indicating sublimed material. I did not measure the temperature of the reactants but I guess the flask to be at less then 250 deg at this point and working well.

http://i397.photobucket.com/albums/pp53/tawayemail/6.jpg

At this point I was collecting about a drop every 6 to 8 seconds. Total time of the reaction was about 40 minutes pushing it slowly. With set up and takedown all told about an hour and a half of lab time.

http://i397.photobucket.com/albums/pp53/tawayemail/7.jpg

The result was 11.8 grams of a fairly clean first run product. I will distill the pyridine after I have made a few more runs to perfect the technique at this size.

http://i397.photobucket.com/albums/pp53/tawayemail/8.jpg

=====

Bulk niacin can be bought cheaply online, making this a viable route to pyridine
I'm not a skilled chemist, and I am sure there is a better way to do this
 #2 
Old 2008-12-10, 16:22
Von Bass Von Bass is offline
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Default Re: Pyridine synth w/pics

Very fucking nice indeed, thats excellent. Props on the nice clean looking yield, setup and decent pictures! :D

Stupid question, but is the catalyst you name, literally just a mixture of Cr2CuO4, CuO and BaCrO4, or in anyway similar to the 'Copper chromite, barium promoted (62-64% Cr2CuO4, |22-24% CuO, 6%BaO, 0-4% Graphite, 1% CrO3, |1% Cr2O3)' catalyst mentioned in various places?
 #3 
Old 2008-12-10, 16:32
somewilliepete somewilliepete is offline
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Default Re: Pyridine synth w/pics

Just a mixture of the three. There is room for experimentation of the ratio, I am sure.
 #4 
Old 2008-12-10, 18:01
Regular
 
Utah: Mountains, Mormons, Meth
Default Re: Pyridine synth w/pics

http://www.sciencemadness.org/talk/viewthread.php?tid=9717&page=2

Coincidence?
 #5 
Old 2008-12-10, 19:47
fcknut fcknut is offline
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Default Re: Pyridine synth w/pics

http://www.sciencemadness.org/talk/viewthread.php?tid=9717&page=2

Coincidence?


nope!

(Thanks goes to ordenblitz.)


Though I think perhaps you are right - more definate acknowledgement might have been appropriate...

;)
 #6 
Old 2008-12-11, 00:13
Regular
 
Utah: Mountains, Mormons, Meth
Default Re: Pyridine synth w/pics

Not to play mod here, but let's keep totse shit to totse. If you wanted ideas on that synth you should have asked the folks at SM. Some chemistry you just can't interact with and that's why posting say, rhodium synths is fine, as long as you put your own input into it and don't just ask "lol haz any1 dun dis?" or "looks kewl".

Sorry SN.
 #7 
Old 2008-12-12, 01:26
somewilliepete somewilliepete is offline
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Default Re: Pyridine synth w/pics

My major reason for posting these things here on totse, is because the community is different, and some insight could be applied to existing techs/synths.

But my secondary reason is because I am not going to sign up for a shitload of forums that I will never use.
 #8 
Old 2008-12-18, 05:11
Regular
 
USA
Default Re: Pyridine synth w/pics

What are some more commonplace oxidizers that can be used? KMnO4? Fe/HCl? I doubt I could get that exact mix, but I can do stoichiometry ;) Would K2Cr2O7 work? and what would not produce side reactions or sublime easily? This is a very good synth. Beautiful and product.

edit: ah, decarboxylation..... what else will prip it off? besides that mix you used? anything more OTC?
 #9 
Old 2008-12-18, 05:25
Regular
 
Utah: Mountains, Mormons, Meth
Default Re: Pyridine synth w/pics

What are some more commonplace oxidizers that can be used? Fe/HCl?

Last time I checked that was a reducing agent.
 #10 
Old 2008-12-18, 15:00
Regular
 
USA
Default Re: Pyridine synth w/pics

I'm pretty sure it still is... I posted that in my bed before passing out. Not in the best state of mind. What I meant was

"What are some more common, accessible reagents that can be used to decarboxylate niacin to pyridine???"

or what is that chromium shit mix used for?
 #11 
Old 2008-12-18, 18:47
FullMetalJacket FullMetalJacket is offline
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Default Re: Pyridine synth w/pics

Ketone catalyst.
 #12 
Old 2008-12-18, 21:12
Regular
 
Utah: Mountains, Mormons, Meth
Default Re: Pyridine synth w/pics

Ketone catalyst.

I know it works for aliphatic carbons but I'm not so sure about benzylics. refs?
 #13 
Old 2009-01-06, 18:47
Regular
 
Default Re: Pyridine synth w/pics

Excellent thread. This should shut all the naysayers up. Pyridine can be had almost OTC. You shoulda heard some of the pessimism people were dumping on me at WD when I was pondering ways to get OTC or near OTC pyridine.
 #14 
Old 2009-01-07, 07:04
Regular
 
Utah: Mountains, Mormons, Meth
Default Re: Pyridine synth w/pics

I know it works for aliphatic carbons but I'm not so sure about benzylics. refs?

*ahem* This is getting more important the more useless carboxyl groups I find on an aromatic. Mad
 #15 
Old 2009-01-08, 08:46
Regular
 
Default Re: Pyridine synth w/pics

*ahem* This is getting more important the more useless carboxyl groups I find on an aromatic. Mad

A niacin tablet can't be *that* expensive. Why not give it a go?

If that penny is too much for you to spend, there's always soda lime (http://www.chemguide.co.uk/organicprops/acids/decarbox.html).
 #16 
Old 2009-01-08, 14:29
Regular
 
Utah: Mountains, Mormons, Meth
Default Re: Pyridine synth w/pics

A niacin tablet can't be *that* expensive. Why not give it a go?

If that penny is too much for you to spend, there's always soda lime (http://www.chemguide.co.uk/organicprops/acids/decarbox.html).

Coincidentally I noticed the pyridine thread right after this one. :) It wouldn't be difficult to do a base decarboxylation except for the fact that the particular compound I'm thinking of has base-sensitive moieties
 #17 
Old 2009-01-08, 23:38
stateofhack stateofhack is offline
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Default Re: Pyridine synth w/pics

Coincidentally I noticed the pyridine thread right after this one. :) It wouldn't be difficult to do a base decarboxylation except for the fact that the particular compound I'm thinking of has base-sensitive moieties

I have a strange feeling i can read in your head..hmm :p
 #18 
Old 2009-01-09, 07:21
Regular
 
Utah: Mountains, Mormons, Meth
Default Re: Pyridine synth w/pics

Wait a second. Confused Wrong thread. Just wondering if ketone catalyst would work for aromatics, but it doesn't matter because using base is easier.
 
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