Sciencemadness Discussion Board - New Amateur Way to Prepare Pyridine

New Amateur Way to Prepare Pyridine

Hexavalent - 18-5-2012 at 12:23

Here is a new idea I've had for the preparation of pyridine by the amateur, which came partially from Magpie's original idea and this paper.

It simply involves the reaction of pyridine-3-carboxylic acid, or niacin/nicotinic acid, with a soluble copper salt to produce the transition metal complex copper (II) nicotinate, and then the thermal decomposition of this under a distillation setup to collect the pyridine which forms and evaporates at the high temperatures.

Any suggestions or ideas for development with this?

Magpie's original work was undeniably excellent, but this is intended to be an alternative for those who don't have access to the salts specified for the catalyst he uses or the silver salts suggested by another user in his thread.

[Edited on 18-5-2012 by Hexavalent]

jon - 18-5-2012 at 13:46

antocho the russian chemist at the hive got it right using 1/3 naoh CAO
just heated to about 320 until the pyridine distilled off it was used for qauntitative analysis so i'm sure it yeilded well

Hexavalent - 18-5-2012 at 13:56

Can you please word your answer slightly better? Got what right? Do you mean the thermal decomposition?

What do you mean by 1/3 NaOH (and do you also mean CaO)? Writing formulae correctly really helps other people interpret your suggestions and answers. According to what I've read, both in the paper and what I was told by Polverone, no additional solids are needed, just to heat the copper complex in a distillation rig is sufficient. I could perhaps understand why Ca(OH)2 could be added, perhaps to absorb some of the CO2, but that's as far as I can understand with what you've written so far.

[Edited on 18-5-2012 by Hexavalent]

Nicodem - 19-5-2012 at 02:06

Usually it's not worth bothering with jon's dementia, but he is probably trying to derange the discussion to a different type of decarboxylation that has nothing to do with the Cu-catalysed one. The possibility of that type of decarboxylation on nicotinic acid was already suggested in some posts in the Pyridine synthesis/extraction thread. I don't remember ever reading Antoncho's report on this type of decarboxylation and currently don't have the time to search the Hyperlab forum or the old Hive's remains, but you can ask Antoncho directly. He has an member account here, or alternatively ask him at the Hyperlab in case he rarely checks his U2U messages here.

I would suggest you to follow the exact procedure that Magpie did, but substitute copper chromite with anything from 1/2 to an equal amount of basic copper carbonate (CuCO3.Cu(OH)2

. This can easily be prepared from copper(II) sulfate. I'm sure there must be examples of its preparation on the forum, or at least references toward it. It is worth trying, as even if it does not work it is still a scientific contribution.

Hexavalent - 19-5-2012 at 03:01

Thanks for the idea, Nicodem. I'll ppt. some fresh basic copper carbonate and dry it later and have a go, following Magpie's procedure.

Would you recommend a half-to-full MOLAR or MASS amount if substituting basic copper carbonate for the chromite?

[Edited on 19-5-2012 by Hexavalent]

Nicodem - 19-5-2012 at 11:05

Quote: Originally posted by Hexavalent

Would you recommend a half-to-full MOLAR or MASS amount if substituting basic copper carbonate for the chromite?

Well, empirical conversion and selectivity measurements are the only way to find out the optimal catalyst loadings. There is no way to calculate such things. Magpie used about 11 mol% of the catalyst and it worked fine for his reaction conditions. So I would suggest to try out with anything from 5 to 20 mol% of CuCO3.Cu(OH)2.

The concept of "amount" in chemistry means amounts of substances measured in mol units (and not mass which is measured in grams): http://en.wikipedia.org/wiki/Amount_of_substance
This is because only amounts correlate in equivalents, while mass never correlates except in the case of isomers or simply coincidence.

GreenD - 22-5-2012 at 12:25

I'm confused.

This isn't a catalyst, is it, as the carbonate gets used up, or is the carbonate regenerated by the loss of CO2 from the decarboxylation?

Why does copper carbonate work here, while copper nitrate wouldn't?

This may seem quite elementary but I am very young in understanding metallic catalysis.

Dr.Bob - 22-5-2012 at 13:11

If the copper is catalytic, then the proton from the original acid (or another nearby acid molecule) will protonate the cation generated by the loss of CO2 from the carboxylate copper salt, and form the pyridine, at that point the copper is still oxidized and can react with another molecule of acid. So the copper is not being reduced by the pyridine reaction, lose of CO2 leaves pyridine and CO2, which are both uncharged, so there is no net reduction. The pyridine may complex with the pyridine formed, but that will break apart as the pyridine distills off.

And if there were some reduction of Cu(II), copper(0) at 280C would likely oxidize in air.

Nicodem - 27-5-2012 at 06:09

Quote: Originally posted by Dr.Bob

If the copper is catalytic, then the proton from the original acid (or another nearby acid molecule) will protonate the cation generated by the loss of CO2 from the carboxylate copper salt, and form the pyridine, at that point the copper is still oxidized and can react with another molecule of acid.

The formation of an arylic carbocation is the least likely scenario from the thermodinamic perspective. Also, protons obviously do not protonate cations as cations are generally acids.

There has been some moderate investigation into this reaction mechanism. A very good starting article and a must read for those getting involved in this field of synthesis is DOI: 10.1021/ja00713a047. It also gives a good review of the older investigations.

According to the current understanding, the copper carboxylate losses CO2 to give the corresponding organocopper compound (hence the need for efficient ligands). The ligand stabilized aryl-Cu intermediate then gets protodemetalated by another arylcarboxylic acid and the cycle continues again and again (DOI: 10.1039/C1DT10771B). This mechanistic hypothesis explains all the experimental observations, including also the formation of biaryl side products.

Quote:

So the copper is not being reduced by the pyridine reaction, lose of CO2 leaves pyridine and CO2, which are both uncharged, so there is no net reduction.

The Cu oxidation state in the precatalyst is of little importance. It was proved by ESR that the Cu(II) species get reduced to Cu(I) early in the reaction when quinoline is used as the solvent. I would tend to believe such is the case in other media as well. In any case Cu is well known for its ease of disproportionation reactions. Still, the use of inert atmosphere is recommended for these type of decarboxylations.

Quote: Originally posted by GreenD

I'm confused.

This isn't a catalyst, is it, as the carbonate gets used up, or is the carbonate regenerated by the loss of CO2 from the decarboxylation?

Why does copper carbonate work here, while copper nitrate wouldn't?

The correct terminology would be calling it a precatalyst, but since in organic synthesis a large proportion of all catalytic systems are actually started by the use of a precatalyst, the use of this terminology kind of lost its value.
Copper nitrate is unlikely to work eficiently for several reasons. One of them is its acidity which would inhibit the likely required deprotonation of the substrate. The other problem is the nitrate induced redox side reactions that would inhibit the formation of suitable amounts of active Cu(I) species or decompose the reaction intermediates. Optimally, one designs experiments by using conditions that are most likely efficient according to the reaction theory. The whole point of scientific investigations of the reaction mechanisms is the value these studies represent for the synthetic chemists.

smaerd - 27-5-2012 at 09:51

I've been very interested in copper ligands for decarboxylation on other substrates for a little while. Copper(II) Acetate can be made very easily as well. In some cases a ligand will form using Copper Sulfate if one is patient.

Some of these ligands are not soluble in water or most other solvents aside from DMSO(even then sparingly). However I was given advice from a friend that adding sulfuric acid to an insoluble ligand will allow them to be soluble in aq. solutions. Whereas with ammonium ion there was no notable increase in solubility(iirc). On treatment with base the insoluble ligand forms again. I am not seasoned enough with metal-organic/inorganic chemistry to know exactly how the sulfuric acid interacts here or if it actually destroys the complex or not. I'd like to know though.

An idea I have given only preliminary experiments towards was anodic oxidative decarboxylation of the sulfuric acid solutions, using Al electrodes. In a single cell an electro-plating effect was noted on the Anode(brown thin 'rusty' layer formed on the side facing the other electrode maybe Cu(I)O?). After basification an oily layer was observed which was not characteristic of the original solution. Again this was on another substrate, but it could be worth further experimentation?

Thanks for the DOI reference nicodem, looks like a great place to start.

[Edited on 27-5-2012 by smaerd]

ubungy - 1-6-2012 at 15:23

I ran the reaction of niacin with CuCO3.Cu(OH)2 in place of the copper chromite catalyst as per the directions in Magpie's thread, and recommendations in this thread. I hope it is okay to share my results here.

The niacin was obtained from GNC niacin supplement tablets (500mg) and recrystallized. Basic copper carbonate was precipitated from CuSO4 and Na2CO3.

For 8g niacin, I calculated 12.5 mol % CuCO3.Cu(OH)2:
8g/(123.11g/mol)=.065mol(.125)(221.12g/mol)=1.8g CuCO3.Cu(OH)2

Magpie's procedure was followed, substituting an oil bath for mantle. Oil temp was 160C when the rxn was started and immediately some water began to form around the neck. The temperature was allowed to increase steadily, and at approx 235C the smell of pyridine was evident. (I was removing therm. adapter for intermittent whiffs

) The temperature inside the still head reached 103C and decreased to 95C. 3.8ml of azeotropic mixture was collected, for approx 73% yield, assuming theoretical yield of 5.2ml.

Taking a mp of the recrystallized niacin indicated some impurity, probably the 'rice powder' from the supplements in the form of starch, as noticable decomposition occured around 215-220C and some melting around 227C, below the literature value of 237C. I believe a better yield could be had from purer niacin.

Also, if the water formed was from decomp of Cu(OH)2 (at 80C according to wikipedia), is there any reason the CuCO3.Cu(OH)2 just couldn't be dried at 120C or something prior to use?

Anyway, hope it was ok to post this, none of this was my idea I just ran the reaction. Also, it's been a year and a half, need an excuse to get my first post out of the way

.

[Edited on 2-6-2012 by ubungy]

Hexavalent - 2-6-2012 at 03:21

Very nice work ubungy, and an excellent first post. Congratulations!

What solvent did you use for the niacin recrystalliztion?

ubungy - 2-6-2012 at 06:48

I used water for the recrystallization because I was low on ethanol. The tablets are 800mg containing 500mg niacin and I was able to remove a large amount of insoluble material, but this wasn't the best option. There is solubility data on page 4 here.

I just went the other way though and am waiting for some usp grade from ebay.

Hexavalent - 2-6-2012 at 14:07

Thanks a lot for that reference . . .it's difficult to find proper solubility curves and data for some compounds. I've plotted a graph of the data you've given in that reference and drawn it up for a permanent record in my notebook for future reference.

SM2 - 21-6-2012 at 06:08

There's lots of things you could use. Maybe stay away from NaOH as it eats/etches glass. Why not just pure Niacin powder and sodium carbonate?

Hexavalent - 21-6-2012 at 10:52

Would sodium carbonate even work for this type of decarboxylation?

What we've discussed here is a type that uses copper as a catalyst in some way.

SM2 - 10-8-2012 at 11:44

Quote: Originally posted by Hexavalent

Can you please word your answer slightly better? Got what right? Do you mean the thermal decomposition?

What do you mean by 1/3 NaOH (and do you also mean CaO)? Writing formulae correctly really helps other people interpret your suggestions and answers. According to what I've read, both in the paper and what I was told by Polverone, no additional solids are needed, just to heat the copper complex in a distillation rig is sufficient. I could perhaps understand why Ca(OH)2 could be added, perhaps to absorb some of the CO2, but that's as far as I can understand with what you've written so far.

[Edited on 18-5-2012 by Hexavalent]

so sorry to but in, buy I am fairly certain you got the general gist of what Jon was saying. Perhaps his English is poor. In any event, more information is better, and should be encouraged, not belittled.

OK, on further review, he needs some serious help. I'll leave it at that!

[Edited on 10-8-2012 by Fennel Ass Ih Tone]

ScienceHideout - 13-8-2012 at 06:37

Now the only question is... where to get niacin

... Can it be extracted from cigarettes? Even that is sorta difficult now because a pack of cigs in MI are almost $7... wow...

Lambda-Eyde - 13-8-2012 at 06:46

Niacin is also known as vitamin B3 and can be bought as a pure powder in kilogram quantities on eBay. You seriously have to be clinically insane to make pyridine (in visible amounts) from niacin extracted from cigarettes (if it contains any at all). Insane and insanely rich. And a lot of spare time and patience.

Dr.Bob - 13-8-2012 at 11:44

Or you could just buy the bottle of pyridine on Ebay for not much more:

http://www.ebay.com/itm/Karl-fischer-reagent-pyridine-free-5...

runne - 13-8-2012 at 11:59

Quote: Originally posted by Dr.Bob

Or you could just buy the bottle of pyridine on Ebay for not much more:

http://www.ebay.com/itm/Karl-fischer-reagent-pyridine-free-5...

*cough* Pyridine free

Mailinmypocket - 13-8-2012 at 12:12

Quote: Originally posted by Dr.Bob

Or you could just buy the bottle of pyridine on Ebay for not much more:

http://www.ebay.com/itm/Karl-fischer-reagent-pyridine-free-5...

This supplier unfortunately only ships to the USA

He claims international shipping however to ship anywhere else in the world is ridiculous... he charges $900,000.00 to send the pyridine to Canada.

The lowest shipping cost he charges (for Canada anyways) is $86 and that is to send something like 5g of luminol. I guess he just wants his items to appear in all eBay searches, unless there is somebody in the USA who can receive the item and re-ship it...which would work but would be a hassle probably.

Dr.Bob - 14-8-2012 at 06:21

Quote: Originally posted by runne

*cough* Pyridine free

My bad. There used to be people selling it on Ebay as Karl Fisher Reagent. I know several people that have to those annoying titration tests often. Not sure what they have substituted for it now.

Sorry, false alarm.

Bob

FJS - 13-4-2013 at 02:51

Quote: Originally posted by ubungy

I ran the reaction of niacin with CuCO3.Cu(OH)2 in place of the copper chromite catalyst as per the directions in Magpie's thread, and recommendations in this thread. I hope it is okay to share my results here.

Few years ago when I saw that post like anyone when seeing new names like Copper chromite backed off! lol but think the knowledge all comes from searching and searching or better says googling and googling. now believe making Pyriding could be absolutely OTC consider current web resources.

firstly for making copper chromite, as original post by magpie says ... read on below:

A. Preparation of Copper Chromite

Cu(NO3)2 + Ba(NO3)2 + (NH4)2Cr2O7 ---> complex chromates ---(ignition)---> Cr2CuO4•CuO•BaCrO4 + gases (likely NOx + NH3 + H2O)

if you youtube you can easily find out how to make CU derivations, like sulfate (think by user Nerdrage) or even nitrate etc. then you need Ba element, the nitrate one. for this one just use sparkle in water as Youtube instructed. for the rest that's is same as before. just type Ammunium chromate in youtube. now you have all 3 regent for making copper chromite!

Personally I have not done Copper Chromite but gone up to making Copper II sulfate by own and it was easy for someone who not knowing much about chemistry.

For Niacin I plan to use waste water from Shoshah bang that in Akl is very common in cafe. it's a kind of tabaco that use a kind of device called Shisha or Shosha not knowing what's that. but believe the waste contain rich Niacin derivations.

Anyway hope that's help but not sure how accurate be my assumptions as explained not tried but theoretically should work or other expert correct or refine it.

Cheers

paw_20 - 13-4-2013 at 08:30

Do you mean a hookah? The device that is, a water bong sort of contraption with 1 or more hoses to smoke from. Shisha is the tobacco blend used in hookahs, very sticky and full of flavorings and such. One trick is to replace the water in the hookah with milk, makes for a very smooth smoke. It was the one time I tried it anyway.

I wouldn't bet on extracting much nicotine or nicotinic acid from shisha and/or hookah waste, for the same reasons Lambda posted above. Also because a lot of the nicotine will have already been removed from the shisha by smoking.

FJS - 13-4-2013 at 20:34

That's exactly what I mean, but also there's another alternative that you can buy from farm supply and feedstock a 25kg bag Niacin for $21 per KG. if you buy of eBay they sells around $30 for 500g. regards the Hooka I've one that the water not been changed and not it's a very dense and dark looking. I mean after around 6 months used. lol

but believe the main point is not Niacin and most important are other intransigents.

Scr0t - 30-12-2013 at 09:29

To expand upon the work done by member "ubungy". I attempted the Prep. of pyridine using both basic copper(II) carbonate and copper(II) oxide as the precatalysts.
Use of CuCO₃.Cu(OH)₂ causes some water contamination in the obtained pyridine but can be removed with NaOH.
My first runs overdid the heating... just a tad.

Preparation with basic copper(II) carbonate.

Into a 250ml RBF was added an intimate mixture of 30g niacin (244mmol) and 26.9g CuCO₃.Cu(OH)₂ (122mmol) and the mixture was heated on a hotplate on full power (plate surface Temp. 480°C), internal Temp. was unmonitored. Heat transfer to the flask was aided with a stainless steel scouring pad 'nested' between the flask and hotplate.
In total 19ml yellow liquid was collected.
The residue in the RBF appeared to consist of mostly of a black powder (possibly CuO) containing some Cu⁰ that broke apart into a fine dust upon shaking the flask, a partial copper mirror had formed on the very bottom of the flask.

The reaction above was repeated with a smaller proportion of copper carbonate.
50g Niacin (406mmol) and 12g CuCO₃.Cu(OH)₂ (54mmol, 13%mol) was heated as above.
28ml of yellow liquid was collected.
As the reaction progressed a stream of a white vapor was carried along with the CO₂ that was possibly subliming niacin.
This time the residue in the flask left some hard black organic crap stuck to the walls but was removed most easily by soaking with aqueous H₂SO₄ for a few hours (NaOH did not appear to touch it).

Treatment of the distillates above with NaOH formed a voluminous salt in suspension occupying about half the visible volume. Both distillates were combined and the whole was distilled to collect a clear colorless liquid. The distillate was treated with ~2g of NaOH and stirred for ~0.5hrs. The upper pyridine phase was separated from the
lower aqueous phase and re-distilled to give 35ml (68% overall yield) of pyridine.

The last run above with 50g of niacin was repeated but with more cautious heating. Heating was slowly brought up to temperature
until distillation began (plate surface Temp. ~350°C). The 27ml of very pale yellow distillate obtained (~3hrs) was re-distilled to remove niacin by putting it
back into the cooled reaction flask with the black residue and distilling normally (aspirator vacuum to pull the last of it over),
dried over 1g NaOH, separated and re-distilled to give 25ml (78% yield) of pyridine.
While a slightly smaller volume was initially collected than the previous run it contained less niacin.

-------------------

Near identical results were obtained when CuO was used instead, although the distillate contained less H2O.

It appears that both basic copper carbonate and copper(II) oxide are adequate substitutes for the copper chromite catalyst.

When larger amounts of catalyst were used (i.e. equimolar Cu to niacin) residue cleanup was much easier.