
Wacker KRV - Ketone's Guide to Wacker-powered Production of MD-P2P
==================================================================

v1.00 - Oct 16th 1998

***LEGAL NOTICE***
This is provided for informational and educational purposes only. Please do not 
attempt anything written here. By proceeding to read, you automatically 
indemnify me from the consequences.

Overview
========

The Wacker process has been widely documented since the 1960s and is a 
relatively simple and easy process to perform. With respect to our desires, 
we are looking to take our olefin (safrole) and hydrogenize it (add an oxygen 
group). To do this we will be using a catalyst in the form of palladium (II) 
chloride (PdCl2). To help the palladium chloride do its job, we also require 
a co-catalyst. In this case, we'll be using cupric chloride (CuCl2). Copper 
chloride (CuCl) cannot be used in the procedure outlined here as it does not 
dissolve in methanol (MeOH) or ethanol (EtOH) and thus does not form the 
required complex. If you wish to use CuCl you would have to perform the 
following reaction in dimethylformamide (DMF) which tends to be more 
expensive and not quite as easily obtainable as MeOH or EtOH.

I've chosen to outline the method at a relatively small scale - a scale that 
would be suitable for personal research in a country that sanctioned this. 
You can probably use the same procedure to process 100mL or maybe even 150mL 
of olefin. Do be aware that processing more olefin requires even more air 
refills and more shaking.


Building the KRV (Ketone Reaction Vessel)
=========================================

The original inspiration goes to spiceboy and a big nod to him. You'll require:

- A 2L soda bottle*
- Tubeless tire valve (1.25" variety seems to work nicely)
- Something to melt the bottle cap plastic with (candle, lighter, etc).
- Car tire pump (hand, foot, battery, electric operated -- you pick)

*Barq's root beer or cream soda bottles are the authors favorites. They have 
smooth sides unlike the contoured sides of a Coke bottle and thus are less 
prone to rupture due fatigue. Plus they're clear allowing you to easily see 
what's going on inside.

Take your soda bottle and wash it THOROUGHLY in warm water and soap. Do not 
use water that is too hot. The label should gracefully fall off during the 
washing process. Do not place the cap back on the bottle after washing -- the 
warm air inside will contract as it cools causing the bottle to deform. Why is 
ketone harping-on about deforming so much? Well, it's like this kids. If the 
bottle deforms you're causing fissures to form in the plastic. You may not even 
be able to see them. Pump this baby up to pressure and BOOM!!! You may just 
create a pressure bomb that distributes a nice corrosive solution around your 
lovely home or over your body.

The next bit can be a bit tricky. You need to take that tubeless tire valve and 
insert it into the neck of the bottle. You may need to squeeze the rubber 
surround a bit to soften it up. It should fit very snuggly in the neck of the 
bottle. If it doesn't, go find a valve that will. Where I live, I was able to 
buy two packs of suitable valves for less than $4. Get several if you can.

Taking the bottle cap, remove the plastic liner that's inside the cap and throw 
it away. Apply heat from a candle to the top of the cap so that you can poke a 
hole in the soft plastic that the valve can poke through. BE CAREFUL! 
Hot plastic is napalm!!!.

Once you have a suitable hole in the cap, screw it down on the bottle so that 
the valve is secured but the valve threading protrudes through the cap allowing 
you to attach the tire pump. Pressurize the KRV to 40psi.

Fill a bucket or bath with water and place the KRV into the water. Squeeze 
gently. See a stream of bubbles? Nope? Good. If you do see bubbles you obviously 
have a leak that needs to be fixed.

You now have a KRV. Congratulations. He will serve your faitfully for several 
reactions.


The Chemical Part
=================

The beauty of this reaction is it can be done with easily obtainable chemicals. 
PdCl2 is used in specialist photography (see my PdCl2 FAQ), cupric chloride can 
be made at a pinch but is not at all suspicious to buy, methanol and ethanol are 
often available at hardware or automotive stores (look for methanol, methyl 
alcohol, methyl hydrate, Everclear).

You will need:

- 1g palladium chloride (PdCl2)
- 5g cupric chloride (CuCl2)
- 250mL methanol (MeOH) or ethanol (EtOH)
- 50mL safrole

A couple of points about these chemicals. Some photography suppliers will sell 
you sodium palladium chloride as a direct replacement for palladium chloride. 
Insist on straight palladium chloride. The most common form of CuCl2 is the 
dihydrate which has two water molecules attached to it. If you are using the 
anhydrous form, there is really no need to adjust the amount used as a 3-8 molar 
excess of CuCl2 is what's required.

If you are using anhydrous solvent you should add 1% (2.5mL) dH2O to the 
reaction. This reaction needs a bit of water to perform. If you're using 
anhydrous CuCl2 and not CuCl2.2H2O, add another 2.5mL of dH2O.

With respect to our favorite olefin, remember that garbage in equals garbage 
out. You should at least single distill to obtain relatively pure olefin. The 
other products in the oil have the capability to interfere with this reaction.

Take a glass, beaker, or flask and pour 100mL of solvent into it. Then add the 
1g of PdCl2. If you have a magenetic stirrer, toss in a stir bar and let it 
stir for a bit (a bit is 15-30 minutes is normally good enough). The solution 
should turn a dirty brown color. DO NOT WORRY IF IT DOESN'T COMPLETELY DISSOLVE. 
Pour this liquid into the soda bottle.

Take the 5g of cupric chloride and throw it into the same beaker. You don't 
even need to wash it. Add 50mL of solvent and the cupric chloride should easily 
dissolve giving a bright green fluid. This gets poured into the soda bottle too.

Take that very same beaker and pour your safrole into it along with the remaining 
100mL of solvent. Stir. Pour into the soda bottle. Add parsley. Serves two.


Shake, Rattle'n'Roll
====================

Now that you have all the goodies in the soda bottle, it's time to put the 
tubeless tire valve in the bottle neck and secure it with the modifed bottle cap. 
Be careful not to push the tire valve all the way through!

You're now ready to charge the bottle with air. Take your trusty pump and attach 
it to the valve. Pump until you have around 40psi in the bottle. You don't *need* 
that much pressure, what you really need is an large oxygen reserve and anything 
over atmospheric pressure. However, compressing the air gives you a large reserve 
of oxygen close to hand and also provides the pressure required.

Shake the bottle like crazy. How crazy? Well, you should see foam appear as you 
shake. Ideally, shake for at least 5 minutes. Preferably 10 minutes.The shaking 
is VERY important in this reaction, the more you do the better.

After shaking let the bottle stand for 20 minutes. De-pressurize the KRV and 
squeeze the bottle to expell all the gas inside. Some nasty gasses form during 
this reaction, and you want to get them out of the KRV. With a little bit of 
skill you can hold the valve open while you squeeze-release-squeeze the bottle 
a few times to pump the gasses out. Alternatively, you can remove the valve and 
the cap and remove the gasses that way, but it gets a little tiresome.

Replace the valve and cap if necessary and re-pressurize to ~40psi. Shake again 
for at least 5 minutes. You will need to repeat this no less than 10 times at 
this scale. This reaction is time dependant too meaning that if you think you 
can get away with re-pressurizing once per day for 10-days and get the same 
results, you won't. What will happen is that you either won't get enough O2 
into the olefin, or you will run out of O2 resulting in side products being 
formed instead of the ketone.Do the whole thing in a day including work-up of 
the final ketone and you'll be a happy camper.

Infact, if you can handle more shaking and more re-pressurizations at shorter 
time intervals you'll probably increase your yield and have a higher assurrance 
of getting final product.


Work It On Up
=============

When you're arms are falling off and you've re-pressurized at 10 times or so, 
add 500mL of distilled water (dH2O) to the solution in the bottle. This should 
be enough to precipitate the catalyst out of solution because the contents of 
the flask should already be acidic.

If you have a buchner funnel and vacuum source, filter this solution a couple 
of times to remove the catalyst. If you don't have a buchner and vacuum source, 
you can improvise with coffee filter and gravity.

The solution should now be relatively free of PdCl2 and CuCl2. You can extract 
the goodies from this solution using your favorite organic solvent. I quite like 
DCM (dichloromenthane) but you could also use ether or petroleum ether. Add 50mL 
of DCM (or ether or petroleum ether) to the solution, extract and repeat two or 
three times to get all the good stuff. Combine the extracts and then remove the 
solvent either under vacuum or at atmospheric pressure.

Once you've removed the solvent you'll be left with crude ketone which might 
well have some tar, isosafrole and other junk in it. If you have vacuum 
distillation equipment, then this is the optimum way to purify the crude ketone. 
If not, I'm afraid the bisulfite procedure is probably your only hope. 
It's pretty messy and you will lose some product doing it, but clean ketone is 
a good starting point for any amination or reduction.

And that's it. A simple, fairly inexpensive, easy to do reaction for making 
MD-P2P. Enjoy.

