A minor correction : Adams catalyst (a brown powder)is neither PtO or PtO4, it is known as PtO2.H2O, also called Pt(IV)O2.
In the actual hydrogenation the platinumIVoxide PtO2.H2O is first reduced to an active form of finely-divided platinum, which is the real catalyst.
That's why Pt-black, pure Pt powder, was also used in the past.
The cost of the catalyst was not such a big deal in those days (20 years ago), because the price of the endproduct was at least 10x higher as nowadays, and nobody even knew, or was interested in, your intentions with it.
KrZ is totally right, reading these patents seem to give us both the same ideas, this opens up a whole new field of research for us, you guys seem to switch slowly when it comes to inventive thinking (It seems to take 2 years here before you can stamp innovative ideas in the mudbrains from most of you
. Luckily we also have some brighter ones, or they would still try to aminate peanutbutter. The ones who
read this are excluded ofcourse from this lecture.
)
With these catalysts, an in situ catalytic amination of nitromethane to methylamine seems feasable, then in the same pot a MeNH2/ketone imination, then hydrogenation to amine, all with the same catalyst !
Well, to add something valuable also to this interesting topic, here's my way of working up all those filtrates/solvents with your precious catalyst in it :
. Test a small portion of your filtrates or solvent for platinum rests by acidifying with HCl and adding a few drops of stannous chloride solution : a yellow or brown colour develops according to the quantity of platinum present.
The yellow colour is soluble in ether, thus rendering the test more sensitive.
If Pt is found, treat the filtrate/solvent with excess of formaldehyde and NaOH solution and heat; Pt-black separates on standing and may be filtered and worked up with other Pt residues, f.e. :
[II]. Dissolve the Pt metal or Pt residues in aqua regia, evaporate just to dryness several times with concentrated HCl, dissolve the final residue in a little water and precipitate as ammoniumchloroplatinate with excess of saturated ammoniumchloride solution. Filter and dry the precipitate at 100 C.
Then you can make any favorable Pt complex with it, f.e. make PtO2.H2O again from it with sodium nitrate in 1 hour.
A damm simple way of avoiding all this is to just re-use your Pt "contaminated" solvents in your next hydrogenation, of course. LT/
WISDOMwillWIN