Patent DE944251
Example 2A solution of 200 parts 1,5-pentanedial in 800 parts 3% sulfuric acid is added, over the course of 2 h, to a boiling solution of 1100 parts crystallized FeSO
4 and 200 parts (NH
4)
2SO
4 in 1500 parts water. Workup as in example 1 yields 82% pure pyridine.
workup as in example 1: rxn-mixture is made alkaline and the aromatic base is distilled off.
Pyridine from nicotinic acid, found at
http://www.korbis-labor.de/experimente/carbonsaeuren/darstellungpyridin.htm
.
1.5 g nicotinic acid and 2.5 g CaCO
3, when heated to decarboxylation with a bunsen burner give 0.3 mL py. not worth the hassle, nicotinic acid is also quite expensive
There's also another really crappy method, that produces mainly picoline (methyl-pyridine), but it's the most simple way I've seen so far. The guy just gives a brief description of what he did, including the note of his intended future publication of a detailed write-up, when his research would be done; the world is still waiting for it to be published. Well, maybe picoline can substitute for pyridine in some reactions...
It's in
J.prakt.chem., 45,1.1892;22. He let's the world know that you "just have to distill the right amounts of ammonium phosphate and glycerine at such a temperature, that the formed aromatic base can be distilled off, as it is formed." "using 500 g propanetriol the reaction can be done in 6-8 h" "yield of total bases is ~25% of the theoretical amount, based on the glycerine"
Conclusion: Py remains a pain in the ass to synth at home. But at least for the dealkylation of vanillin / ethyl vanillin there's methods that work w/o it :
Post 291912
(Antoncho: "Demethylation of vanillin.", Novel Discourse) Post 351285
(6079_Smith_W_II: "JP10265428", Novel Discourse) --
psyloxy--