04-13-03 23:05
No 426408
okay well swim is new and suffering. having many different problems cleaning o2 methnaol wacker. Regardless on how much swim washes it with 5% NaOH soln., NaCl soln., and water.... wacker has been running at 60 psi in 2l pop bottle and warmed total run time 8 hours, when the reaction stopped there was little to no PdCl falling out.... Does that mean the wacker is under developed not allowing the PdCl to affectively fall out?
(Hive Bee)
04-14-03 16:08
No 426621
There is a color change that takes place in the O2 wacker reaction.It starts out brown , and goes red as time progresses....
Was the vessel heated to 40°C ?
How about the olefin ? Frozen or distilled ?
Ratio of Pd/CuCl/Olefin ?
Was a pressure drop seen ?
More info is needed ....
A water wash can be used to remove most of the metallic salts...
my guru once told me to "just be" , now I realize he meant "just bee" :)
(Hive Bee)
04-15-03 00:53
No 426714
Man, salt, sodium bicarbonate, whatother wimpy means are a waste of your time. You need a %15-20% NaOH mx to clean it up. 5% will do nothing. Do it cold if possible. or use edta. Nothing precipitates out until ph10 is hit.
(Greenhorn)
04-15-03 01:09
No 426716
Scram, I have to disagree with you. On an o2 wacker the only washes needed are nacl,bicarb and dh2o. There is no need for a naoh wash at all. A benzo wacker does need a few naoh washes, but were talkin about the o2 wacker.
I went into the business for the money, and the art grew out of it.-Charlie Chaplin
(Hive Bee)
04-15-03 03:43
No 426776
First test your KRV by pressurizing it then placing it underwater. Does it leak? If not read on....
There is no need to use NaOH washes with the O2 wacker.
Place your wacker solution in the freezer for about an hour until it is cold, you should notice a very fine red particulate settled on the bottom of your container.
Filter the PdCl sediment from your wacker before doing any NaCl or dh2o washes.
You may notice the PdCl getting a little more grainy as the reaction progress's but this is not always the case. The real way to tell the reaction is progressing is by pressure drop in the vessel.
By that we mean you pressurize the vessel to say 45 psi using pure O2. Then after the shaking just before purging the vessel meassure it again. If the pressure is less than what we started with, we can assume O2 is being transfered.
"Sometimes I sits and thinks, and sometimes I just sits." Satchel Paige
(Stranger)
04-15-03 20:52
No 427017
frozen olefin ,40 degress, 50 psi and significant color change 1 gr pdcl2 5 gr cucl2
(Stranger)
04-15-03 20:55
No 427018
see you make it sound easier then it is when using a 20% naoh wash it causes the oil to reheat and form more waste and polymerisation
(Stranger)
04-15-03 21:02
No 427021
Thanks, much need but, i always check for leaks first but,i forgot to check the pressure before purging and refilling with o2 i will take the advice and use it wisely
(Hive Bee)
04-16-03 01:12
No 427074
Just want to check Sodium Bicarbonate is Baking Soda right.
How much of the Baking Soda should bee used in a wash.
(Greenhorn)
04-16-03 03:54
No 427120
you make a solution of baking soda. Just keep adding it to some water until no more will disolve. Swim makes up gallons in advance because you always need salt and bicarb washes.
I went into the business for the money, and the art grew out of it.-Charlie Chaplin
(Hive Bee)
04-24-03 00:11
No 429032
"Place your wacker solution in the freezer for about an hour until it is cold, you should notice a very fine red particulate settled on the bottom of your container."
I tried this and it pretty much sucked. Very minimal palladium precipate even as low as -7c in for 8 hours.
"see you make it sound easier then it is when using a 20% naoh wash it causes the oil to reheat and form more waste and polymerisation"
What?! It doesn't heat up. Never noticed any temp climb here. Besides thats why you pre-chill your naoh mix before adding to the oil/toluene.
Man, I'm telling you, there is no comparison between the precipitate that you'll get between a naoh wash and and punk-ass bicarbonate wash. I need to do naoh washes, I don't distill at all. If i relied solely on salt and bicarbonate washes then I would get absolutely nothing in yeild. The 2 best chems I have found are in the order NaOH, KOH, EDTA. I imagine any strong base would work.
(Hive Bee)
04-25-03 13:13
No 429312
how many times do you use a 25% NaOH wash, swim has been using everyone elses ideas on cleanup now maybe yours will bee the one.
(Hive Bee)
04-28-03 05:01
No 429877
With toluene on the post 02 wacker. With 7x volume toluene to oil, use an equal volume of 15% NaOH solution. Don't use above 15%, I found out that it works just as good. Your best off not shaking this solution in a sep funnel because the bubbles could create an emulsion. Stir for 10 minutes instead. I can't promise it won't be a bitch of an emulsion with DCM or gun scrubbing chlorinated solvents. the 2 or 3 times I tried them it was very very difficult to separate when the hydroxide hit it. I think it has to do with the close density of the DCM/OIL and the NaOH/water phases.
You wash it once of twice until the polar phase is clear. It will be tar black the first wash. Don't let it sit longer than needed in that base solution and try to keep in the freezer. Check your stopcock, it will loosen when it gets cold possibly dumping ketone and solvent all over your freezer.