A chemist decided to give that alcohol >> nitro synth a whirl last nite. A couple things become immediately apparent. This rxn is volumetrically unrealistic for any kind of scale up.
at 10X you have ca 4mls of EtOH in 300ml DCM and the proceedure reccomends adding another 1500mls DCM to crash out the NaOAc. FUCK ME, that is a buttload of solvent!
I'm not writing this one off, but there are some problems here.
1. NaNO2 does not come anywhere near going into solution, it isn't even a suspension, it just sits on the bottom of the flask.
2. The HCl does not remain longer than a couple of seconds. Its addition results in an immediate release of a small amount of N2O3 (fine, but you want some ventilation.) I think that this is simply to initiate or kick start the rxn between the NaNO2 and AcOH which are close to equimolar quantities.
so this creates NaOAc and free NO and NO2 in solution, which I assume then attaches to the ethanol (very similar to the pseudonitrosite synth) to form the EtNO2.
3. without stirring, it appears that alot of the NaNO2 is unreacted as it becomes coated with a coating of NaOAc. So the chemist swirled the reactants a couple times.
4. The NaNO2 needs to be very finely ground I think.
Two runs were done, results will be posted pending work-up.
Here are a couple questions
1. Is the addition of DCM really required to crash out the NaOAc? seems like we have it precipitating without the DCM to crash it out.
2. If the addition of more DCM is skipped will the residual NaOAc get picked up in the water washs?
3. When scaling this one does the quantity of DCM need to go up at the same rate as the reagents? (I hope not)
4. The proceedure does not mention mixing the reactants prior to the HCl addition, should they be? It says not to after but how about before? The chemist did, we will see.