03-08-02 23:01
No 279306
Since the mighty Antoncho pointed our collective attention toward the fact benzene and acetone can bee merged to form P2P, using a characteristic single-electron oxidation of manganese (III) acetate, this virtual place has been all abuzz with the possibilities. In Post 205055 (Antoncho: "P2Ps from benzene, acetone and Mn(AcO)3", Novel Discourse) you may see this develop, and in a couple documents on Rhodium's web site. This is meant to continue that thread, now grown large as befits its importance.
Very recently I learned (Post 278841 (halfapint: "Acetate of Manganese", Novel Discourse)) that manganous acetate is obtainable by reducing a potassium permanganate solution in acetic acid with hydrogen peroxide, which makes it E-Z.
For us, this could bee a big one. The reaction sequence forseeable, is that this manganous acetate in acetic acid can be heated with benzene and acetone, and by periodic introduction of powdered potassium permanganate generate and regenerate manganic acetate, with progressive formation of phenyl-2-propanone.
A factor which accentuates its importance, is that p-dimethoxy benzene should undergo the same reaction, providing the basis for some extremely powerful amphetamine psychedelics, after 4-halogenation of the resultant 2,5-dimethoxy amphetamine. The substrates benzene and hydroquinone can never get sucessfully interdicted, and potassium permanganate isn't rare. Acetic acid, hydrogen peroxide and acetone aren't specialty chemicals either.
A question I have: in the manganic acetate catalyzed fusion of benzene or dimethoxybenzene with acetone in acetic acid, what is the optimal portion of water in the reaction mix? Could near anhydrous conditions prove beneficial, or can aqueous conditions provide satisfactory results?
a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.
(Official Hive Translator)
03-09-02 02:25
No 279401
Unhydrous.
If you wanna know why i think so, PM me.
Antoncho
(Chief Bee)
03-09-02 08:22
No 279513
As it is a free-radical reaction, the formed acetonyl radicals will react with anything nearby, therefore the reactants are used as solvents. If you have water in the mix, the acetonyl radicals might add to the water instead of the benzene, lowering overall yields.
(Ubiquitous Precursor Medal Winner)
03-11-02 06:48
No 280649
So, my choice of sodium perborate reduction of potassium permanganate in acetic acid to form manganous acetate could prove fortuitous. Hydrogen peroxide in any sane concentration would introduce water. Other common peroxy preparations of commerce, Oxone(R) and Oxi-Clean(R), are compounded with additional base. AFAIK, none of these solids, nor peroxide of urea ("peroxycarbamate"), is hydrated. I may experiment with sodium peroxide in acetic acid containing permanganate, to form manganous acetate under anhydrous conditions. (Methyl borate, if you have any, is an ideal drying agent, for it splits water up to form methanol and boric acid.)
So if your manganous acetate is produced in anhydrous conditions (in practical terms), this can conceivably bee a clean one-pot reaction, rare as that may bee. If, on the other hand, you introduce water during the manganous acetate production, you are stuck with the step of drying your acetic acid solution, or if you can't achieve that in an acceptable time frame, of distilling off all the solvent, then re-introducing the dried solid residue into fresh glacial acetic acid. One pot sounds much better.
a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.
(Ubiquitous Precursor Medal Winner)
03-15-02 03:37
No 282958
All of a sudden, my buddy SWIM lost some of that obnoxious confidence. She was adding sodium peroxide prills to a flask with acetic acid with potassium permanganate dissolved in it. The sodium peroxide danced along the surface of the liquid when it wasn't stirring. Such a very energetic reaction should have told her to use a cooling bath, but her impatience pressed her on, in spite of the solution heating up. Some of the peroxide stuck to the flask neck; she was pushing it down with a glass tube, when poof there was a flash of light.
A tiny explosion had occurred in the flask neck. No glass broken, no liquids spewed, no caustic materials on the operator. Not even a loud noise, just a puff of hot gas. Nevertheless, SWIM took that as a Sign. (She's the superstitious sort; it was her first ever lab "explosion.") Could there have been an error in the reaction design, she asked me?
I explained to her again that she's a slow learner, so she should leave the fancy high-powered chemistry to folks who know which way is up. She wailed that just a little bit of something had given her that extreme warning, and she already had a flask full of stuff just like that something, so she didn't want to even think of what might happen if the whole thing blew up.
So I told her she might really have a problem, that is even after the flask was cooled down, adding enough solid peroxide to make the purple permanganate clear. She should first mix the peroxide a little at a time into some other glacial acetic acid, to see how that worked. Then after that, the two cold liquids should get added very slowly, with stirring. She might try doing that at the end of a long pole, behind a big wall...
a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.
(Ubiquitous Precursor Medal Winner)
03-15-02 22:06
No 283318
I checked back with SWIM on this. She sez that dissolving sodium peroxide in acetic acid bothers her now. She sez this one went into an acetone-rinsed jug, and literally on the shelf, while her nerves get better. She sez sodium peroxide is no fun to work with. Sez it wants to be 100% hydrogen peroxide, and lye, if it can find some water somewhere. Sez it's happy to show you exactly how much water's in the air, and how fast it can pull it out. Sez it's almost in the "nasty stuff" category.
a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.
(Stranger)
04-11-02 19:19
No 295777
SWIM just told me that mixing H2O2 with Potassium Permangenate of any concentration isn't pretty. In fact, SWIM's old interesting party trick was to take about 100mL of 30% H2O2 and throw in a pinch of Permangenate just to watch it heat up to above 100°C in less than a second. Not a pretty mixture if you ask SWIM.
(Stranger)
05-03-02 23:09
No 304805
Advanced Organic Chemistry, Jerry March, 3rd Edition 5-44 p. 742:
The Conversion of Olefins to gamma-Lactones (Addition of Oxygen, Carbon)
CH2=CH2 + Mn(OAc)3 --HOAc--> (GBL)
Olefins react with manganese(III) acetate to give gamma-lactones617. The mechanism is probably free-radical, involving addition of .CH2COOH to the double bond.
617Bush and Finkbeiner, J. Am. Chem. Soc. 90, 5903 (1968); Heiba, Dessau, and Koehl, J. Am. Chem. Soc. 90, 5905 (1968); Heiba, Dessau and Rodewald, J. Am. Chem. Soc. 96, 7977 (1974).
Mellow out.