Sorry, no refs, they are all wellknown already.
I do not agree to have this edited without me agreeing before, you can take it down if you like to but not change it. Thats the deal.
Here we go:
Maybe the best P2NP synthesis ever
The best catalysts are mono and diammonium acetates made by adding the amine to the freezer-cold Nitroethane slowly under stirring followed by the fridge-cold Benzaldehyde.* GAA may be a small stöchiometric excess. That makes it much easier. B-dehyde should be fresh or get distilled beforehand.
1 mol B-dehyde, 1 mol Nitroethane, 0,05 to 0,2 mol amine enough GAA to neutralize the amine + an extra spritz of it.
- with Cyclohexylamine:
10ml B-dehyde + 11ml Nitro + 2ml cyclo + 1,6ml GAA
- with Ethylene Diamine:
10ml B-dehyde + 11ml Nitro + 0,5ml EDA + 0,9ml GAA + 5ml ethanol (didnt really dissolve the crystals which formed, didn´t matter either)**
As told all monoamines work and most diamines too. Say, propyl, diisopropyl, methyl, dimethyl, ethyl, ethanol, cyclohexyl, ethylene diamine and on and on. Of the over 100 (di)amines you might be able to get one I believe. If not: Get another hobby.
Not only GAA can be used as acid but other organic acids too.
Known to work well are formic acid (courtesy hest/HIVE) and benzoic acid (some articel and confirmed). Others will work too - give it a shot and report!
Benzoic acid is told to be very soft on the substrates so if one is to condense a substituted sensibel B-dehyde this might be the best choice.
Procedure 1 (recommended): Microwave
- mix and nuke up to 60/70°C
- cool down in cold waterbath
- do this as often until SLIGHT discoloration is visible
- let cool down slowly at RT and then in the fridge.
Crystallisation occurs like magic. For me. If not scratch with glassrod against beaker walls. Seed crystals are best. Safe some and relax.
Filter P2NP on the pump (that means Büchner + vacuum). Rinse with a little ice-cold anhydrous alcohol (ethyl, methyl IPA...). This adds to the liquid from filtration.
This combined liquid:
- nuke again to 60°C
- just once
- cool down to RT, fridge etc.
If you got the timing more or less right there is 70% yield on the first crop, 20% on the second and more comes third maybe fourth (dry weight after recrystallisation from alcohol or petrolether. Use MeOH so you are masochistic or just love to cry a bit from time to time, use IPA if you are not such a painslut)
Of course the broth gets darker every round, doesnt matter after recrystalisation it will be pristine.
The trick is to remove P2NP in time so it stands not in its own way and more can form. The little dilution every time by the rinsing alcohol helps also, it proceeds beautifully.
Drawback: You have to wait for cooling down/crystals and filter more often.
Plus: The reaction is done in 10 minutes, 5 minutes filtering, this 3x makes 45 minutes the rest is watching porn.
Procedure 2: No Microwave
- the same just use a heating plate/preheated waterbath
- needs longer heating and due to this gives more discoloration and less time for watching porn
- in this reaction the microwave is clearly superior to other heating methodsMicrowave additional information:
- use a not-rotating-table model, a "mode stirrer" type so any possible.
- The microwave must be a dedicated one, dedicated to science and progress as you don´t want to use this microwave for food preparation after this.
- For batches up to 300ml a low-power model (500-600Watt) is preferred. Bigger batches are better done using several smaller flasks (like 4x 250ml at the same time) then a single big one as the penetration depth of microwaves is limited.
- Wide neck Erlenmeyers are preferred, some cotton stuffed loosely into the neck reduces obnoxious fumes to almost zero.
- having "nitro" in its name makes nitroethane no explosive per se in special not in solution. Should something happen then not because of the microwaves but because you are an idiot and then the cavity of a microwave is a much better place then a flask on a hotplate near balls or face.
Congratulation! You made it through all these words until the end! Not all hope is lost!