The Vespiary

The Hive => Chemistry Discourse => Topic started by: stratosphere on October 11, 2003, 11:55:00 PM

Title: direct amination
Post by: stratosphere on October 11, 2003, 11:55:00 PM
i was reading some archived posts which seemed to indicate that direct amination of of secondary haloalkanes did not produce satisfactory yields, (specifically AFOAF was wondering about aminating apiol-HBr)

this seems contrary to everything in my organic chemistry texts...
anyhow i was wondering if the combined use of a non-protic solvent and letting the reaction sit at room temp for a few weeks would cause this reaction to yield.

or another possibility is if there are any catalysts which cause nh3 to be more nucleophilic, or solvents/catalysts which cause the halogen to leave so the reaction could proceed via a SN1 mechanism?
Title: If I have understood things correctly the...
Post by: josef_k on October 12, 2003, 05:48:00 PM
If I have understood things correctly the problem is not that the NH3 doesn't want to react with the haloalkane. It is rather that when it has done that, the other haloalkanes react with the amine that is produced, so you get lots of di and tri substituted strange amines. Because of this you have to use a massive amount of ammonium.

A better way would be to form the azide, and then reduce that with SnCl2
Title: multiple alkalation shouldn't be much of a...
Post by: stratosphere on October 12, 2003, 08:29:00 PM
multiple alkalation shouldn't be much of a problem due to steric hendrince, and using a large excess of ammonia is not much of a problem as its pretty cheap.

i forgot where is saw the article discussing how direct amination performs poorly, but the subject had something to do with amination using the chemical that is used to heat portable camping/army meals.

is azide a watched chem?
Title: delepine
Post by: hypo on October 12, 2003, 08:57:00 PM
> i forgot where is saw the article discussing how direct amination performs
> poorly, but the subject had something to do with amination using the chemical
> that is used to heat portable camping/army meals.

you think about the delepine reaction. consensus is that it does not work
on secondary amines.

how do you intend of doing the halogenation? afaik you need a good pump
for the distillation of the halo-derivate.

Title: azide
Post by: Vitus_Verdegast on October 12, 2003, 09:52:00 PM
is azide a watched chem?

Probably, as it is even more toxic than NaCN, and if it comes in contact with acid it forms hydrazoic acid (HN3) which is not only very toxic but explosive too.

But nevertheless NaN3 can be obtained OTC in good quantities from certain types of airbags (esp. the older ones).

Title: Yes, delepine on secondary bromide is said to...
Post by: Chimimanie on October 12, 2003, 10:05:00 PM
Yes, delepine on secondary bromide is said to not work.

Azide swap in DMSO or DMF as a solvent will work good for secondary bromide.

Direct amination has to bee done under pressure in pipe bomb, and elimination is a major side reaction in this synthesis.

You prolly prefer the azide route, reduction is very quick and easy w/ Zn/NH4Cl and yield will be higher. Azide is found in ~100g from a driver airbag, and twice that amount from passenger one. Extraction is easy in water, then crashing out with EtOH. Beware the solutions are very toxic, react with acid to form explosive hydrazoic gaz, and with various metals (as those in the pipes) to form explosive and toxic salts, dispose accordingly.
Title: That's a lot!
Post by: Rhodium on October 13, 2003, 03:12:00 PM
Azide is found in ~100g from a driver airbag, and twice that amount from passenger one.

!!! Reference, or personal experience?
Title: A lot!
Post by: Chromic on October 13, 2003, 06:55:00 PM
200g is 3 mol, which would produce 2/3 a mol of N2... ie 2mol N2, or about 50L of RT gas... are airbags really that big when exploded?
Title: Here you are:
Post by: Vitus_Verdegast on October 13, 2003, 08:13:00 PM


Sodium azide tablets are stacked in five cm diameter metal canisters inside airbags. The driver-side airbag can is about 3.8cm long and holds about 50 grams of sodium azide. The passenger-side airbag can is about 15cm long and holds about 200 grams to inflate a bag big enough to fill the front-seat passenger area.



http://www.abc.net.au/science/news/stories/s114815.htm (http://www.abc.net.au/science/news/stories/s114815.htm)



200 grams!! drool...  :P



Title: !!! Reference, or personal experience?
Post by: Chimimanie on October 13, 2003, 09:45:00 PM
!!! Reference, or personal experience?

Both:

see

Post 435713 (https://www.thevespiary.org/talk/index.php?topic=6128.msg43571300#msg43571300)

(nitroglycerin: "sodium azide", Chemicals & Equipment)
J. Chem. Educ. 1996, 73, 347.

http://bhs.smuhsd.org/science-dept/bhschemistry/bhschempdf/bhschemanspdf/gasans/gasws7key.pdf (http://bhs.smuhsd.org/science-dept/bhschemistry/bhschempdf/bhschemanspdf/gasans/gasws7key.pdf)



+ others sites i didnt refound by googling ten minutes.

Also i personally dismantled a passenger side airbag, it contained 420g of the airbag mixture in 14 x 30g pieces, mainly NaN3, with SiO2, KNO3, some color and a binder.

A passenger on i have too, but i still dont have dismantled it as it is a nice piece of hardware to have around. 

Otherwise, hydrazine and an alkyl nitrite will easily and cheaply make sodium azide, i have some synth around, or simply interested people can look in any inorganic synthesis book, as maybe it is not very wise to share that kind of info as someone could bee dumb enough to add acid on it or mix with silver nitrate, mercury, lead or copper, or simply dump it in metal pipes (a not so uncommon cause of explosion in biochemical lab). It is possible to destroy the azide with an excess nitrite solution, then acidifying, UTFG and beeware!
Title: >>how do you intend of doing the ...
Post by: stratosphere on October 14, 2003, 12:15:00 AM
>>how do you intend of doing the halogenation? afaik you need a good pump
for the distillation of the halo-derivate.

it would most likely be done with HBr/DCM.
seperating the apiol-HBr from any unreacted apiol would not be necassary because only the apiol-HBr would get animated, and could thus be seperated by 2layer solution technique
Title: but how expensive are airbag modules?
Post by: stratosphere on October 14, 2003, 12:20:00 AM
but how expensive are airbag modules?

i believe i saw something that KN3 is used as a pestacide...
Title: Depends
Post by: Chimimanie on October 14, 2003, 12:50:00 AM
New it is expensive.

Old and used it is cheap. Just go to your local graveyard, ask them to have an airbag or if you can dismantle one, i got mine for 20$.
Title: apparently sodium azide could also be used as...
Post by: stratosphere on October 16, 2003, 10:26:00 PM
apparently sodium azide could also be used as a source of sodium metal via decomposition.

http://www.sciam.com/askexpert_question.cfm?articleID=0008ACD8-5AF8-1C72-9EB7809EC588F2D7 (http://www.sciam.com/askexpert_question.cfm?articleID=0008ACD8-5AF8-1C72-9EB7809EC588F2D7)



although finding a way to safely decompose it, and collect the sodium metal might be tricky.

NaN3 is definitly used in the lab and agriculture as a broad spectrum biocide, but ive yet to determine how easily obtained it is for these purposes, or how feasible it would be to extract these biocides.