evil_lurker
National Hazard
Posts: 767
Registered: 12-3-2005
Location: United States of Elbonia
Member Is Offline
Mood: On the wagon again.
|
|
So what can I do with a liter of pyridine?
I found a supplier that actually sold me a liter of pyridine via the internet, no questions asked... 
And to make it an even sweeter deal, it cost under $100, and was shipped ORM-D (no-hazmat fees, woo hoo!).
Supposedly its en-route and I'm looking forward to getting it so I can synthesize some bromobenzene... hopefully my door won't get kicked in before I
can get that done! 
So other than making bromobenzene, any other ideas on stuff I can make with this? (other than a big stink or non-working testicles)
|
|
|
Jome
Hazard to Others
Posts: 154
Registered: 10-6-2004
Location: Soutwest sweden
Member Is Offline
Mood: desiccated
|
|
PCC (pyridinium chloro-chromate) for selective oxidation of alcohols to aldehydes? Requires CrO3 though.
[Edited on 24-6-2006 by Jome]
|
|
|
chromium
Hazard to Others
Posts: 284
Registered: 27-6-2005
Member Is Offline
Mood: reactive
|
|
Pyridine is one of those solvents that can be used for nonaqueos electrolysis.
It can be used as starting point for compounds that contain pyridine ring just like benzene can be used to make complex aromatic compounds.
A. Brenthsen - A Textbook of Organic Chemistry, London 1941, page 680
| Quote: |
Pyridine, C6H5N, resembles benzene in many points:
1. It is even more stable than benzene, and yields substituted derivatives with sulphuric and nitric acids or the halogens, but not so readily as
benzene. Sulphonic acids are obtained at very high temperatures only, and only a few chloro- and bromo-pyridines have been prepared. Pyridine and its
carboxylic acids are not affected by oxidizing agents.
2. Its derivatives resemble those of benzene. Thus its homologues (and also quinoline, &c.) are transformed into pyridine carboxylic acids when
oxidised, and these acids yield pyridine when distilled with lime, just as benzoic acid yields benzene.
3. The isomeric relations are also precisely analogous to those of the benzene derivatives. Thus the number of the isomeric mono-derivatives of
pyridine is the same as that of the isomeric bi-derivatives of benzene, viz. three; and the number of the bi-derivatives of pyridine, containing the
same substituents, the same as that of the benzene derivatives, C6H3X3, viz. six.
4. Just as two benzene nuclei can form naphthalene, so can a benzene and a pyridine form the compound quinoline.
5. The products of reduction are likewise analogous. Pyridine like benzene yields a hexahydro derivative, C5H11N, only somewhat more readily; this is
known as piperidine. Quinoline yields a tetrahydro-derivative, C12H11N, which is analogous to anthracene dihydride. In these latter compounds further
combination with hydrogen my take place, but there is likewise a tendency to the reproduction of the original bases.
|
page 681
| Quote: |
In contradiction to the neutral benzene hydrocarbons, pyridine and its homologues are bases of the same order of strength as aniline and have
characteristic odours. Pyridine is readily soluble in water, but quinoline only slightly so. They distill or sublime without decomposiition, and form
salts; those with hydrochloric and sulphuric acids are for the most part readily soluble, while those with chromic acid or hydroferrocyanic acids,
though often characteristic, are usually only sparingly soluble; they also form double salts with chlorides of platinum, gold and mercury, most of
which are sparingly soluble, e.g. (C5H5N)2H2PtCl6?.
The bases are tetriary, and hence cannot be acetylated; they combine however, with alkyl iodides, yielding quaternary ammonium salts, e.g. pyridine
and methyl iodide yield [formula unreadable] methyl-pyridonium iodide.
|
Edit: Pyridine is quite toxic, so treat it with respect!
[Edited on 24-6-2006 by chromium]
|
|
|
garage chemist
chemical wizard
Posts: 1803
Registered: 16-8-2004
Location: Germany
Member Is Offline
Mood: No Mood
|
|
How are going to make bromobenzene from pyridine? I don't get that.
Pyridine can be used as solvent for room-temperature electrolysis of lithium salts to obtain the metal. I haven't tried that (I have a bit of
pyridine, but no Lithium salts), but it supposedly works. Be aware that the anode products must be kept separate from the lithium, and that chlorine
and bromine (from LiBr or LiCl) will react with the pyridine, forming halogenated derivatives and HCl or HBr. Only iodine doesn't react, and LiI
should therefore be the preferred electrolyte.
Pyridine is a basic solvent (forms crystalline pyridinium salts with acids) and can be used for shifting the equilibrium to the product side in
certain reactions which take place under evolution of a hydrogen halide or other acid.
Be aware that pyridine stinks, so use it outside or in a fume hood. You can't work with it indoors.
If you try the lithium electrolysis, please report it and make pics! I and a lot of other members would be highly interested.
|
|
|
virgil
Harmless
Posts: 5
Registered: 24-6-2006
Member Is Offline
Mood: No Mood
|
|
You could make a bit of original Karl-Fischer reagent for determination of water.
|
|
|
evil_lurker
National Hazard
Posts: 767
Registered: 12-3-2005
Location: United States of Elbonia
Member Is Offline
Mood: On the wagon again.
|
|
You can make bromobenzene according to Vogel's III'rd using pyridine, bromine, and benzene.
The pyridine supposedly acts as a halogen carrier which allows the ring to be brominated.
By products are p-dibromobenzene which after primary distillation are crystalized out of the solution by putting into the freezer and filtering.
Re-distillation yields pure product.
|
|
|
garage chemist
chemical wizard
Posts: 1803
Registered: 16-8-2004
Location: Germany
Member Is Offline
Mood: No Mood
|
|
You don't need pyridine for making bromobenzene. That's a waste of pyridine.
Bromobenzene is made from benzene + bromine in the cold with a catalyst like FeBr3 (just add some iron powder, it reacts with the bromine). The
evolution of HBr is the indication that the reaction has started. The benzene should be present in excess, and the mixture is separated by
distillation afterwards.
|
|
|
evil_lurker
National Hazard
Posts: 767
Registered: 12-3-2005
Location: United States of Elbonia
Member Is Offline
Mood: On the wagon again.
|
|
| Quote: | Originally posted by garage chemist
You don't need pyridine for making bromobenzene. That's a waste of pyridine.
Bromobenzene is made from benzene + bromine in the cold with a catalyst like FeBr3 (just add some iron powder, it reacts with the bromine). The
evolution of HBr is the indication that the reaction has started. The benzene should be present in excess, and the mixture is separated by
distillation afterwards. |
I seen it, but thought it best though to stick to the write up as provided. The reaction from what I have seen needs to be performed dry, and I wasn't
too sure of my abiltity to create an anhydrous catalyst. Plus I didn't know how much catalyst to add to the reaction to keep it under control and
moving at the proper rate.
Still though, 9ml of pyridine is all it takes per liter of benzene used. While it might be a waste of pyridine, at least it won't be very much.
|
|
|
Magpie
lab constructor
Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline
Mood: Chemistry: the subtle science.
|
|
I have seen the use of pyridine for capture of H+ which is useful to promote some reactions, as noted by garage chemist.
I find it very interesting that pyridine can be used as a catalyst for the bromination of benzene. I can speculate that it functions as a carrier of
Br+ at the N's lone pair site. Or perhaps the N carrys Br2 as "+Br:Br-". Anyone care to explain the actual mechanism?
The single most important condition for a successful synthesis is good mixing - Nicodem
|
|
|
Maja
Hazard to Others
Posts: 143
Registered: 27-2-2006
Member Is Offline
Mood: No Mood
|
|
I can sell a few pyridine 1l analytical grade bottles for about 120$ + shipping if anyone is interested please PM me 
[Edited on 28-6-2006 by Maja]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
