05-18-02 22:59
No 310463
How come bicarb is used to basify the oxone solution? Would NaOH or KOH work as well to maintain a slightly acidic solution?
<Cheeseboy-a whiteboy with soul, like a black guy without soul
May De Sorce Bee Wit Chu-Always
(Chief Bee)
05-18-02 23:22
No 310472
It is too easy to overshoot the pH with such strong bases, and besides the carbonate ion acts as a buffer. What's wrong with bicarbonate - it's cheap and OTC everywhere!
(I'm not Cheesie)
05-18-02 23:50
No 310483
Thanks Big R. I knew there was some sort of other reason that bicarb's used. it was just that lazy bone kicking in. Lot's of OTC NaOH around here as well. Just happened to be out of baking soda and sporting a bottle of lye.Like cheese said, lazy....(and a cheap BASTARD! LOL)
<Cheeseboy-a whiteboy with soul, like a black guy without soul
May De Sorce Bee Wit Chu-Always
(I'm not Cheesie)
05-20-02 01:52
No 310983
After one half botched attempt at the oxone route, cheese finally had complete success (with poor 30% yields) but the reason why things worked this time was becuase cheese buffered the oxone to get the Epoxide, instead of unbuffered to Glycol. Plus cheese learned that washing the Epoxide/Ketone with basic washes only works if the oil is suspended in toluene or another solvent of choice. Now the bisulphite test worked like a charm, 4 drops of light brown ketone solidified into a mass of buttery crystals int the test vial. The ketone appears to be relatively clean even without vacuum distilling it. Yields suffered due to impatience on cheese's half, not waiting long enough for washes to completely settle before tapping off with sep funnel, but cheese was happy to se them crystals form after 3 minutes of harsh aggravation. Thanks pickler, goiterjoe, Big R, locrian, VL_, and cheesegirl for putting up with cheese.
<Cheeseboy-a whiteboy with soul, like a black guy without soul
May De Sorce Bee Wit Chu-Always
Hey BigR. Quick question, You know in Strike's book where you are making MDA from MD-Phenyl-2-Nitropropene, well after your last bit of boro is added you filtered through celite to remove the boride , then a quick wash with MeOH, then stripped of solvents with a vacuum and the residue is taken up with a dilute H2SO4 solution. OK here's the question and cheese thinks he knows the answer but wants things to be clear. Can a dilute H2SO4 solution be used to digest the aminated product from a cyano/ammonium acetate rxn as well? How come it's usually HCl that is called for with this step, will bothe types of acids work?
(Chief Bee)
05-20-02 07:01
No 311144
In this case (MDA) it makes no difference which acid you use, but with 2C-B for example, only H2SO4 can be used, because 2C-B*HCl is insoluble in water and would precipitate from the solution.
And By the way, the NiCl2/NaBH4 reduction was a mistake, it gives only 15% yield if it's done as written - the ultrasound treatment found in the original reference I wrote that article from is necessary for the advertised high yields.
(I'm not Cheesie)
05-20-02 22:04
No 311413
Thanks BigR. Cheese will use up his excess of 15% H2SO$ on the aminated MDA solution/cake.Cheersebro
<Cheeseboy-a whiteboy with soul, like a black guy without soul
May De Sorce Bee Wit Chu-Always
Amination of crude ketone was unsuccessful, zip, nada. The metabisulphite test was proof that the shit was in fact ketone but it wasn't vacuum distilled, just heavily washed with basic water washes. The route of amination was sodium cyanoborohydride/ammonium acetate-->MDA. Had success with other ketone in past with same reagents so they aren't the culprit. Starting to get sick of wasteingammonijm acetate/cyano on faile aminations though. Is it because the ketone wasn't pure that it did NOT aminate?