paracelsus (Stranger)
05-15-02 17:46
No 309008
      Photocatalysed pyridine synthesis  Bookmark   

Perhaps of theoretical value only - my chem knowledge doesn't reach far enough for me to make sense of the article - but outlines the synthesis of pyridine and derivatives using cobalt complexes under mild conditions.
(Chief Bee)
05-15-02 21:46
No 309175
      HCN + C2H2 -> Pyridine  Bookmark   

It seems like pyridine is formed in 90% yield by reacting aqueous HCN (from NaCN/HCl?) with acetylene (welder's supply, or calcium carbide/water?) at atmospherical pressure in the presence of a Cobalt(I) complex and sunlight.
(Hive Prodigy)
05-16-02 03:42
No 309303
      True  Bookmark   

I read up on that exact reaction yesterday. But please note that if CaC2 were used as the acetylene source, the formed calcium hydroxide would react with the HCN as well.

Vivent Longtemps La Ruche!
(Chief Bee)
05-16-02 03:49
No 309307
      Acetylene generation  Bookmark   

Oh, the acetylene should preferably not be generated in the same vessel, rather in a separate one and then be scrubbed through a suitable solution to remove phosphines and similar impurities (UTFSE for a list of common impurities).
(Hive Bee)
05-23-02 15:12
No 313329
      What are the current industrial manufaturing ...  Bookmark   

What are the current industrial manufaturing process used for making pyridine? I have seen many requests from bees on making their own pyridine, how applicable do you think the proecdure described is?

05-30-02 07:47
      well ill be @#$%^d
(Rated as: insignificant)
(Hive Bee)
05-30-02 07:59
No 315943
      dont know if this helps  Bookmark   

man hydrogen cyanide sound pritty nasty
found this on the net

Sodium cyanide dissolved in water forms a strong alkaline solution and an equilibrium between ionized sodium cyanide and highly volatile hydrogen cyanide (HCN). HCN is toxic with an OSHA workplace exposure limit of 10 ppm (8-hour average) in air. However, HCN formation can be controlled by maintaining the alkalinity, or pH, of the cyanide solution. Golden Queen will maintain an alkaline cyanide solution at 10.5 pH or greater to control HCN formation.

10ppm dont want to be making this stuff I think unless
its all enclosed and will never touch the air you breath

e3500 console login: root
(Hive Bee)
05-31-02 11:53
No 316369
      You can buy HCN detectors, probably a must for ...  Bookmark   

You can buy HCN detectors, probably a must for this sort of thing. They run about $300 but i supose its worth it. An alternative would be to keep some canaries around the lab ;-)

05-31-02 13:39
No 316399
      Old Method  Bookmark   

The old method, taken from Organic Synthesis, is to smoke tobacco, which sensitizes the cyanide chemist to the almond smell enough so that the antidote (sodium thiosulfate) can be consumed in time, commonly known as photographer's hypo smile
05-31-02 14:17
No 316415
      Old method  Bookmark   

That's right, even small amounts of HCN will give the cigarette smoke a metallic taste (personal experience wink, tastes really shitty). But thiosulfate...hmm, shouldn't this  be administered by i.v. injection, along with breathing oxygen or in more serious cases of poisoning also along with inhalation of a small amount of amyl nitrite?

Quidquid agis, prudenter agas et respice finem!
05-31-02 17:43
No 316480
      Therapy  Bookmark   

Yes, the therapy is sodium nitrate (i.v.) or amyl nitrate inhaled followed by 65 mL/kg 25% sodium thiosulfate IV; hyperbaric oxygen if available smile
(Hive Bee)
06-19-02 14:30
No 323143
      methinks that i.m. injection is the method IF my ...  Bookmark   

methinks that i.m. injection is the method IF my memory is correct. but that seems relatively slow in light of the rather serious consequences of antidotal nature.

OTEECEE & meeeee!!!!
(Ubiquitous Precursor Medal Winner)
06-19-02 20:00
No 323238
      OK, say we don't breathe the cyanide.  Bookmark   

Now that we've all figured out not to breathe the cyanide, the easiest way to retain 1 bar of acetylene in the water is to stopper the flask. The cobalt compound won't evaporate, but both reagents are gases. It shouldn't bee that hard to figure out to put a lid on it. A lid made of glass, if you're using external light, but why do that? This 380-500 nm light is very long wave for the general run of photocatalysis, coming way down into visible blues and greens. This reaction would probably work well with the most easily obtainable black lights, like for gemstone examination, or would certainly work well with a grow-light. So to do it, you could just seal the light source inside the reaction chamber. Scale, from paint can size to aquarium/terrarium size. Do it in batch mode, completely sealed, keep well away from it, then open it remotely.

Heat it to drive out dissolved gases, then make sure there's no HCN with a dab of sodium thiosulfate solution, acidulate with HCl, strip off the water at the aspirator and save the pyridine.HCl as the solid salt residue.

a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.
(Hive Prodigy)
09-23-02 06:21
No 359466
      Easier way  Bookmark   

A much easier way appears to be the ring expansion of pyrrole by dichlorocarbene to pyridine. Dichlorocarbene is easily generated in situ by reacting sodium ethoxide with chloroform:

CHCl3 + NaOC2H5 --> :CCl2 + NaCl + C2H5OH

Dichlorocarbene adds to pyrrole and causes ring expansion yielding pyridine, according to pg. 1087-1088 of March's 5th.

This acetylene trimerization business is neat. Simple Zn(CN)2 causes trimerization of acetylenes at atmosphereic pressure. It also says that substituted acetylenes give substituted benzenes, including benzenes that have yet to be prepared by other means, like hexaisopropylbenzene (extremely sterically crowded) and 1,2,3-triisobutyl-4,5,6-trifluorobenzene. Interesting.

What about using 2-(N-methyl)-pent-4-yne in conjunction with 25+ times excess acetylene gas to facilitate a benzene ring, making methamphetamine. tongue

HC#C-CH2CH2(NHCH3)CH3 + 2C2H2 ==Zn(CN)2==> C6H5-CH2CH(NHCH3)CH3 (methamphetamine)


Will perform sexual favors for females in exchange for 1,2-dimethylaziridine. PM for details.