The Hive > Methods Discourse
Phenyl-2-nitropropene crystallization
APOPLEX:
He will try it soon ala Shulgin, but with n-Butylamine.
1 mole Benzaldehyde and 1.1 mole Nitroethane are mixed with 200 ml GAA. Then about 10 ml n-Butylamine is added while stirring. The whole mix is then brought to a mild reflux for about 2 hours in a water bath until the color changes to a light orange yellow. After slowly cooling to RT a piece of dry ice is dumped into the post reaction mix. * Cool idea, starlight ! ;) *
The hopefully produced crystals will then recrystalized with a suitable solvent to get clean crystals.
Notes:
He will use a glas jar with a vent on the top as rxn vessel, because his dist. setup is broken a whil ago ! :(
He think this should work for a mild reflux, and probably produced pressure could be released with the vent.
He don`t know if the rxn-time of 2 hours is correct for this catalyst (n-butylamine-acetate).
He has made 3,4,5-Trimethoxy-beta-nitropropene in the past with GAA as solvent and Cyclohexylamine as the base and about 4 hours rxn-time without any problems to crystalize the Nitropropene. This was probably because of the higher bp. of the M-nitropropene than of the Phenyl-2-nitropropene.
The n-Butylamine is a little bit stronger base than the Cyclohexylamine. So about 2 hours rxn-time shoul be enough. What do you think ?
Yields and hopefully success will be reported in a few weeks because now he has absolutely no time to do this...
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APOPLEX
bio:
Following the method of Susie and Heider in an old JOC (can't find it now) I always got easy crystals without removing the solvent. Yields are excellent even w/o a Dean Stark tube (but at least use a drying tube). The solvent was benzene, NButylamine 20ml/mole (i've heard 25 is better)and about 5 or 6 hour reflux. Maybe some bee can find this ref for you. You can also use PhCH3 solvent per Org. Syn and reduce insitu w/o separating.
bio:
starlite.....Am using another method now but will try the PNP with ammonium acetate in a little while. How much should be used? I always used the BuNH so don't know. Check out this patent for EtN02 from EtOH (US4431842)Will use the new furnace tube I'm making to try it out. By the way does anyone know a good way to remove O2 from air? I once read a procedure using rusting steel wool but can't find it now. Fe makes several oxides you see. I need a way that will make a small continuous flow relatively O2 free to eliminate the inert gas bottle.
Also I used PhCH3 in a similar tube to make PhCHO in high yield using CeMo catalyst before. It really is quite easy and is found in the Journal of Chemical Education (around 1950"s). I had to ditch my library a couple years ago so lost all my refs which took hundreds od hours to copy on the machine at the library. I just love the internet. Didn't have it then.
hest:
Don't estimate the reaction time. Use TLC !
starlight:
but 10g of ammonium acetate for 60g benzaldeyde works ok.
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