I checked that procedure once with p-methoxy-nitrostyrene and ended up with a really lousy yield of 20%. However, I used a Al/HCl generator as a hydrogen source and that didn’t gave my neither a stabile flow nor a pure gas (so the partial pressure of H2 must have been lower than 1atm). Considering that, I would say to check it out, but only if you have a bomb of hydrogen. Don’t forget to purify your nitrostyrene with recrystallization to avoid catalyst poisoning.
I think the reduction goes all the way to the amine once started, as I was able to isolate the starting nitrostyrene out of the reaction mixture (or maybe it was p-methoxy-phenylnitroethane? - I just discarded it without making a TLC). So either it gets reduced to the amine or it does not get reduced at all, but it certainly does not stop at the oxime.
Why this should not scale? I see no reason. It is not extremely exothermic, so that shouldn’t be a problem as long you have the necessary equipment. Well, if you don’t, at least try not to smoke around the reaction vessel as hydrogen gets trough many materials including rubber tubes and it does not have any smell to alarm you neither!
