Questions about methcat procedures / Hello

Hello all.

I found this web board while researching this, and while i've only just registered today, i've been lurking and reading for a few weeks. I Hang out at the hive and rhodium a lot, but they have been down for a day or two now.
Not to mention Lycaeum and erowid.

I am an aspiring home chemist. I haven't done any chemistry since the 80's, and during that time it really wasn't quality stuff. Ahhh high school.

I've been doing some reading for the last few months about basic organic chemistry and have really started to devote some time into learning about this. I'm keen to try out the simple methcat synthesis, acheived thru oxidisation. I've done a few simple procedures before this (it'll make you laugh). One memorable was a polar/non polar solvent involving LSA. (successful)

Anyway, my question is about the KMnO4 passages. Would it be correct to assume the following summary about the procedure -


1) Weigh up 7.43 grams of KMnO4 and dissolve until settled in 100mls of purified water. Do this at 25C (room temp)

2) Measure out 15.45 (reccommends a little more) mls of the solution

3) Dilute the 15 mls into 250mls dH20, put in fridge. (>0c)

Have i got the idea? The KMnO4, this will be in crystal form...? For some reason I'm thinking they resemble condies crystals. Not sure if i picked that up somewhere or i'm being delusional. Oh dear.


Thanks anyone that takes the time to answer my q. Or just says hello.

Below is the passage i am writing about.

Cheers,

Tim



MEASURING OUT & PREPARING THE KMnO4 FOR REACTION:
KMnO4 is saturated at 25c in water - 100ml of solution holds 7.43g This time I will be using just under 3g of pseudephedrine (if extract was perfect would be exactly 3g pseudephedrine). Keep in mind that when preparing the saturated solution you need room temperature and time - you need to let the crystals settle!!! Excess (undisolved) KMnO4 will stay "swirled in" the solution. Let it settle for a while at room temp, _then_ measure the 15mL or so... Failure to do this will result in a failed synthesis. If you are too impatient to do this, then you should purchase a miligram-quantity scale.

In acid conditions, 1 mole of KMnO4 will oxidize 5 hydrogens. In basic conditions, 1 mole of KMnO4 will oxidize 3 hydrogens. We won't be specifically using either, because KMnO4 also works nicely under neutral conditions.

It can be reasonably anticipated that the Pseudephedrine HCl will posess somewhat of an acidic character, so we will 'assume' acidic conditions, which also will allow us to avoid using TOO MUCH KMnO4... small amounts of pseudephedrine will go unnoticed in the final product, but gooey messes will ot, for obvious reasons.

The Pseudephedrine/KMnO4 ratio should be 2.5Mole to 1Mole, according to previous calculations. 3g pseudephedrine is 18.15mMole, therefore 7.26mMole of KMnO4, or 1.148g will be needed for the reaction. This means that 15.45mL of concentrated solution at room temperature will be needed. Obviously us kitchen chemists can't be that precise, so aim a little high, as previous margins were set about 10% low... use AT LEAST 15.45mL prepared at AT LEAST 25c.

This 15.5 or so mL of solution is then diluted with 250mL H2O, and is started chilling in a refridgerator, with just over 0c the goal.

 

Not sure what a "condies crystal" is, but KMnO4 is a blackish-purple metallic-looking crystalline powder.

 

that kmno4 synth will result in benzaldehyde

 

tselliot, that's called a cold cat extraction. There are warm ones, too, which may work better, but I don't know. I haven't tried it. I looks like it might work, but if mycoguy is right then I'd heed his advice.

 

KMnO4 is a strong oxidizer, and can/will oxidize the ephedrine all the way to benzaldehyde if you allow it to. This is one reason that you need to follow the directions CAREFULLY, especially the parts about CAREFULLY MEASURING the KMnO4, making the permanganate solution at the proper temperature, and keeping the reaction mix COLD while the oxidation is going.

If you use too much KMnO4, or the reaction gets too warm, the reaction goes too fast/too far, and your product goes to shit....