posted 03-03-2000 05:06 PM         

'Cause you come off as a stupid motherfucker to be so damn educated, y'know that smart guy? Im not talkin about your science, either.

posted 03-03-2000 05:44 PM         

Hey KrZ, ever considered running three or more small ghetto reactors in parallel? You don't have to build a dangerous big one when you can do the same amount with several small safe ones, in the same time.
>>Just because seams and flat parts are weak points doesn't mean that they can't be compensated for!! Look at a god damn Parr hydrogenator for fucks sake, 1/2" thick borosilicate and it's rated for safe operation at 60 psi and at various temperatures, and the damn thing isn't round either.

Yes, it is designed for that purpose. I don't think that your fermentation tank is. Maybe it can stand that abuse. But I don't think it will, not unless someone has thoroughly tested and blown up a few.

>>You know exactly NOTHING.

posted 03-03-2000 07:55 PM         

quote:

---

Originally posted by Osmium:
Maybe you can explain to me why the 4L erlenmeyer will crack in most cases while the small one will not, even when they have the same glass thickness and therefore the same strengh to external force? Someone with the proper terminology explain that to him, it has something to do with leverage.

---

I have to agree with Os on this one, I am not gonna go rip the physics books out, and quote some shit! But I will stake my left testicle that it is correct!

Multiple rxn vessels all set up running off 1 O2 supply seems like the way around it but it would bee a pain in the ass to set up and run and a pain for filling/removing contents etc.

There must bee something easy just waiting for us! I pride myself in nigga rigging things, as I have experience in many trades, welding, building, auto, etc, I'll keep eyes open!
What about my previous suggestion (probably thought of before) of making ones own vessel from scratch, using a higher grade, thicker S/S then the crappy thin, soda keg??

And guys, on the pimp-as-fuck scale...

Osmium<----->KrZ

Both equally pimp-as-fuck, and nada to prove here guys!

posted 03-03-2000 08:58 PM         

780
680
610

"according to your theory, it doesn't matter if I pull a full vacuum on a 100ml or 250ml erlenmeyer or a 4L erlenmeyer, because the pressure differential is always 14.7 psi (or 1 atm for the Europe bees)." No the SAInternal/OAExternal is what matters. I said it matters very little, not that it was prefect. And did you pay attention to what I said about the SA at all?

Look say you has 3 flasks with radiuses (internal) 10, 20, and 30. They all have thickness=5. And they are all at 100psi, what is the effective force on each per unti area?

SAI1=1256.63
SAI2=5026.54
SAI3=11309.73

SAO1=2827.43
SAO2=7853.98
SAO3=15393.8

IA/OA1=0.44444
IA/OA2=0.63999
IA/OA3=0.73469

See how the ratios rapidly level out when using the same wall thickness? If these were all at 100psi, the effective pounds of force on every square inch of them would be 44.4, 63.9, and 73.46. The size difference matters less and less with increasing size. If the diameter distance was in cm then the sizes would be, 523ml, 4188ml, and 14137. ~500, 5000, and 15000ml. Regardless you can see than the effective boost is only 10psi when going from a 5L to a 15L.

When you're pushing in as when applying vacuum, the curvature is very important. Its just like the keystone in a bridge! The more curvature the more the weight will be distributed about the bridge. Even across the flat region, the larger the area of this region the weaker it will be. I assume that when erlenmeyers explode they do it at the flat base correct?

posted 03-04-2000 03:26 AM         

Plastic is great, it starts to deform and show structural defects before it blows, it gives you some warning. On the down side, it will fatigue. Glass won't. It'll just eventually snap when the pressure gets high enough, giving no warning.

posted 03-04-2000 06:24 AM         

2. Some alternatives to think about:

A. The 20 liter thick walled glass filtration flasks, they are prepared with the above method and can withhold pressures in your range. They have a thick glass collar to fit a clamp on.( Put 2 half-moon shaped white thick Teflon pieces under the collar, and one thick Teflon ring on top, and now you can use a 3 screwed clamp to fit a rig of your choise on top of the flask). And they have this side vacuum adapter thingy, to fix a blowout valve on. That will be the weakest spot, because it is shaped to fit a vacuum tube on. But it could be done with a big strap around the whole flask which holds the valve tight to that side thingy. And use extra 2-component glue to fix it. Or fix a big ball of silicone glue for aquariums around the valve and the side thingy, as a second extra safety. Use a thick white Teflon ring between the valve and the thingy as a third safety.

B. A used, empty HCl cylinder, which is allready conveniently coated with Teflon at the inside. Problem here could be the stirring. I would try to use 3 to 4 home-made magnetic stirrer motors ( a fan-cooled induction-electromotor with a keramic extra-strong-magnetic bar with a hole exactly in the middle of the bar, screwed on the motor axis, so it is perfectly balanced), together with 3 to 4 big egg-shaped magnetic stirrer bars, and use the HCl tank LAYING DOWN! This will solve all stirring problems in the stand-up position, when you place them at equal distances under the laying cylinder. You have to unscrew the main valve, place your stirrer eggs above the motors, fill your reactants, screw the main valve on again, which you attached a Monel stainless steel T-piece on, and on the end of the short leg of the T screw the blowout valve. The long leg can be used to connect to the oxygen cylinder with a regulator+pressure meter on it(or the hydrogen cylinder in case of using it as a hydrogenator).
It will be the ideal pressure chamber, rated for much higher pressures then ever needed. That's quite a safe feeling.
The T-piece must have a valve in the right end of the short leg, to use the blowout valve as a connection point for a vacuum tube, when used as a hydrogenator. Just unscrew the blowout valve when you need vacuum in the system.
These T-pieces you can buy at Medical/Chemical gas suppliers.
An empty NH3 cylinder would be even better, they are coated also, but are much wider in diameter.
The cylinder would lay in a big wooden bed, with two end-blocks, with a half-moon space in them, with the 3 to 4 motors screwed tight on the bottom of the wooden bed, so they can not move and loose feeling with the stirrer bar.
I would use 4 motors, and the 2e and the 4e I would let rotate in the opposite direction as the 2 others, to create a continious flow inside the cylinder from one end to the other, to let the catalyst move around as much as possible.

3. Can it be that you used too much catalyst in your reaction mix? You seem to be a strong believer in the fact that an overdose of it can not hurt, but in this reaction it will, and in most hydrogenation reactions also. And specially when you start to use pure catalysts, which take shorter reaction times generally, but are more prone to get out of hand, if the exact quantities of a ref are not followed up.
But I nearly can not believe it, because you gave the impression at the beginning of the thread that you followed the same rules all the time, you only changed to another container.
Only this is confusing me:
""This explains the strange data we were getting, increasing pressure and time giving a decreasing yield!""
Did you alter the circumstances, and got decreasing yields, or do you mean that you waited and saw then these effects?

4. You did till now not answer this question:
""KrZ, is there any sign of Pd or Cu plating on the SS after a reaction? Or does the solution contain metal particles when discharged from the reactor?"" This is asked with a specific reason, so could you answer it? In the interest of all who want to try this also. It can proof that your theory with the steel is right, and something equal happening to the zinc pieces on the hull of seagoing ships has occured. Perhaps introducing a small piece of zinc, a way of offering a less precious metal then steel or iron to prevent any form of electrolysis of the steel in the container. What those zinc ions will do in the reaction, I don't know.

5. When the original write-up states that you must cool the reaction flask in water, it means simply that the reaction is exothermic, and it should be cooled to slow down any unwanted side reactions. See this from b1055: ""thanks for the insight KrZ, nothing like that has happened, but the water bath was always monitored. does some H2O need to be present using 99% IPA??
God,that burned ketone smells like shit and likes to makes those neat little poof explosions like fireworks. nasty shite.""

6. I believe Semtex Enigma tried IPA, and got a black tar. You got both 90% yield with methanol. So it looks as when you find the answer to why this happened and find a solution, all will be happy again. If you don't find a satisfying answer, you still have the 90% yield. LT/

posted 03-04-2000 10:46 AM         

The biphasic relationship of the two states clearly lends itself to greater extraction of the isolated substrate media genomic prep. While it is possible to run in circle, it seems that isolation and enrichment of the enolate condensation boration product interstitially could yield optimal results. I don't see WHY everyone here tries to argue of falsified reaction specifo-dynamics whihc have clearly been engineered with maximum safety in mind. Even though the filanderers often seem to try to dissuade us from the truw path we all know that bending spoons with your mind from across the room is sure proof.

Let me reiteriate the topico-antispetics which have already isolated and pure media. The chirality of the application point has already been deteremined and now we see that adherence to the main line will yield success. While the product produced is damaging both mentally and physically, it's proponents still seem to act as if it were some sort of crusade. However, we know that this is in fact true for if the cause were not truly just then thousands of deviant criminal minds would not leap to the task. But the question remains, where have the vectors been hidden? Is it in the alpha-helices due to truncated bending due to uncalculated over-intensity of the hydrophobic effect. Or perhaps the problem lies in the beta-sheets with their cooking cutter london dispersion forces not actually occuring in a logarithmic regression form as previously supposed but instead flowing from the words of the prophet like channel zero.

All of this over-complification and distractionary ponitification may serve to bolster the newbees intellectual somato-reactivity. While increasing the likelihood of the subject fragmentation from the main primate group being studied. If the primary group perhaps attempts to return from the lush mountain jungle area where they have chosen to feed since breaking from the main force of the population, only then, at the time of return to the valley floor, will monkeys and worms walk together in harmony once again. What can we do to help you say? Why we can fight the good cause and serve out country well, to block the mountain apes from returning to the worm population. However, we need strong and willing troops to fight against the incoming pe population, or perhaps we should more properly call them inverted parabolic monkeys, rather than apes. These troops will help to push the advancement of reading things that have already been discovered and pushing the limits of how amateur info can be used to convert a beleagered group of other-beings to yield a force of powerfull ghettoness and great intensity.

Sure Where do I sign up? The answer to this question is a complex solution. In order to answer it we MUST find non-parallel solution using both the real and imaginary part sof our 4n differential equation. How can we do this if we don't have a piece of paper? Well the answer is really quite ingenius, in fact no one has thought of not thinkingn of it before, we must create posters, lots and lots of posters, proclaiming the cause! Fight the good fight my troopers and learn what it's all about. While many don't know what it is all about they have still determined that being what it is all about without knowing it is an effective method for extrapolating data points close to and around the true value. While this value may be a limit at infinity it's not going to stop this brave little girl who has been riding towards here goal of negative infinity ever since she was old enough to write her dissertation. You may be asking yourself, what is wrong with me? Why can't I be like that little girl with her great motiation to ride a disertation on wheels all the way around the world, over the edge, and down the turtles backs for a good infinity trip or so.

Although I hate to be harsh the answer is going to be painful. The truth is your tricycle riding skills are not all that great, and as a matter of fact I think that the developmental stage where such skills could have been fostered has passed. WELL, what to do about a situation such as this? You could kick yourself in the ass while chanting to the gods. But what if they aren't listening? You may have to keep calling back again and again. This sort of repeated dialing may wear on the thumn of the imbecile, becuase imbeciles use their thumbs to dial. Well, you may laugh at all of that but I don't see you picking up the phone now? Perhaps your opposability of thumb is not as great as yoru neighbors? Taking spectrophotometer readings of your two lawns and performing protein assays we have determined that your neighbors lawn may indeedbe up to an order of magnitude better than yours. But do you still give a fuck? We're 12 minutes into it here and you're still going. Please remember to check your times against other members of your species. If your time is lower you've got to serve your species well. Sure we may have developed some sort of all-species-member empathy but it's buried deep underneath a smoldering need to kill all the other males and fucking the bitches. I am right homies? Now while this might not be a viable solution we can at least hypnotically induce the homosexual suggestion in an extended portion of the male population thereby freeing up possible mating units for outself.

The procedure is simple, and its execution is ingenius. By installing the picture of richard simons (remember if the image is not a mirrot image at this point you might as well wave goodby to your chromosomes), onto the wheels of your car, the other, unsuspecting ghetto hodrats will be mesmerized by your presumably hookedup wheels. However, as you travel at signficant speeds they will never realize the hypnotic suggestion that the become extreme halophiles capable of exsisting in the deep sea or other extremely corny locations.

How do you make a living this way? The answer is quite simple, first you have an extremely versatile metabolic pathway. It can be reveresed, donors and acceptors can be switched, all in a very short number of generations. As long as an environmental nutrient gradient is sufficently not-steep but rather good and soldified much as the candy bars of yore, we can sustain this sort of evolutionary velocity, but we can only hope. Regardless of all the it appears that as the timer approaches fifteen minutes perhaps the typing velocity has accelerated somewhat. No for parting words let us reiterate everything which we have discussed sofar and we can summarize all that will be discussed in teh future 1) everything is completely the opposite of what it seems, 2) diversion of competition is the primary motivation of the hereby resident primate population. Deceivability of intake flow material is relatively high but at the same time there is no way to know who has been absorbed into the primary population of deceivers. I can tell you one thing for sure, your trusty sidekick, FMAN, will never lie to you, nor any of his counterpats. And I will do my continued part to make sure that the artform of deception never is lost to the wind like all those professional witch drowners who were simply thrown out on their ears when it was decided that their services were simply not needed anymore. Some traditions of ancient society should last forever.

15:33

posted 03-07-2000 04:43 AM         

In another recent article, Eur. J. Org. Chem. 1998, 1901-1906: Oxidation of terminal olefins by dioxygen in the presence of PdCl2/CuCl2 systems and coreducer (Ethanol), the authors suggest that the reaction mechanism in the presence of EtOH is very different from that of classical non-alcohol Wacker process and that the reaction yields also acetaldehyde, ethyl acetate and diethyl acetate as cooxidation byproducts by following scheme:
EtOH is oxidised to acetaldehyde and water, acetaldehyde either reacts with 2 moles of EtOH to form diethyl acetal and water or is further oxidised to acetic acid that reversibly reacts with another mole of EtOH to form ethyl acetate and water. Another primary or secondary alcohol will yield corresponding compounds.

posted 03-07-2000 07:10 PM         

I've run the O2 wacker a number of times now using a PdCl2 lefin ratio ranging from 1:200g to 1:250 added dual stage, all with success. IPA the solvent, ~100psi, and strong egg stirring. Every distillation had only a few drops of prerun then its just greeny goodness. The last run wass of particular interest as I believe it went exo on me. The bath normally holds at 50 to 55 yet it shot up to past 70. Workup yeilded lots of tar and a low yeild, suspect much is aldehyde. Anyone else noted an exo reaction?

posted 03-07-2000 08:49 PM         

Tell US ALL!!!!

Vessel construction,
Cucl2 ratio's
Shaking method, purging or not
Desired temp
Time length of reaction
Yield

Also how are you going on the reduction side of things,

Your'ol pal

posted 03-07-2000 09:28 PM         

quote:

---

Originally posted by dr.strangelove:
P
L
A
S
T
I
C

---

posted 03-08-2000 05:00 AM         

DAMN IT!!! Boys and girls, put your fucking slingshots away until after recess...

I cannot for the life of me figure out how this went from a group of people with MUTUAL RESPECT for each other talking about some inherent problems with probably the most popular method to ketone to this day, to a bunch of fucking bickering(sorry for the run on sentance).

With the obvious advancements of the wacker, due to the work by bees such as Osmium and Spiceboy and KRZ(YES YOU STUPID FUCKERS I STILL CLASS YOU ALL IN THE SAME GROUP, then again I'm not trying to deal with EGO's i'm just trying to tell it the way i see it) I think that all of this counter productive bitching has no place here. But then again what the fuck do I know, pretty much just the stuff that YOU FUCKERS ARE WILLING TO TEACH ME!!!

Now with all that aside(flame away if you'd really like to show how inmature you all can be, BTW i'll let you know in advance that if you decide to flame, I really couldn't care less) lets get on with the discussion.

Now, Osmium has suggested a possible solution with the soda keg reacting with the catalysts, i.e. glass coating the interior of the keg. While doing this would prove to be effective(in theory at least, although I cannot see a problem with it) it may indeed become too costly for most bees looking to go OTC. Add to that the fact that one would have to remove and replace all the rubber hardware on the soda keg(gotta get to that 400C) and it starts looking more and more complicated which is exactly what we are trying to avoid here(remember the term OTC?). Now I threw out an idea about silicon grease coating the interior of the keg, I really haven't looked up the properties of silicon so I don't know if this a viable alternative or not. Someone also suggested possibly teflon coating the inside of the keg, or the use of Teflon based paint(i.e. Uncle Fester's Vestbusters). Does anyone have information on the chemically resistant two part epoxy paints that are commercially available? Or do the catalysts react with Nickle or Copper which could be easily plated onto the interior of the keg(I don't know if this is a problem on SS, but from what i've read electro plating doesn't seem that hard. Hell if you think about it, what about plating the interior with Pd(It's expensive, but a very thin coating might suffice)? Or would the Copper compound(s) change it from Pd to PdCl2? There is something which will solve this problem, all we have to do is find it.

What considerations are needed to be taken when looking for a coating material? All I can think of right off the bat is the solvent or any of the reagents or catalysts reacting or solvating(sp?) the coating. So looking back at the failed soda keg wackers, what's happening? Is the PdCl2 reacting with the SS, or does it have more to do with the Copper compound? The answer might be as simple as finding out that it's only the PdCl2 that is reacting, and then get something that will selectivly stop the SS and the PdCl2 from reacting, or what have you.

Well enough of wasting your time, i'll see if I can come up with anything. BTW your all welcome back to this conversation, you know the ONE YOU'VE ALL BEEN YELLING RIGHT OVER... :rolleyes

posted 03-08-2000 09:01 AM         

There is almost twice the pressure in most of these setups that I've read of, and they are dependent upon stirring for the agitation.

Batch sizes in the 100 g range were ALL I ever desired to run while researching these reactions.

Had I been full of meth and ego, I FOR SURE
could have designed the unit to handle any pressures and conditions deemed relevant.

The pressures he is working at seem to preclude the uses of most plastics such as
polyethylene(HDPE) and PETE, or polyethyleneterephthalate, due to a lack in wall thickness. Also, the stirbar will serve to create a stress point that will be the weak link in any (plastic)container ran at these pressures. It should generate a stress on the unit that may be signifigant,
relevant to these conditions.

If anyone is wondering how this thread had devolved into flames, I merely ask them to redirect their attention to the tone of the replies the originator of this topic gives to everyone.

Sorry, but disrespect engenders the same.

posted 03-08-2000 04:54 PM         

Reaction vessel: le keg!!!! Are you guys really so sure that SS is reacting? Aren't Parr bombs made of SS. Wouldn't there be evidence of pitting of scarring of the vessel after repeated usage?
CuCl2.2H20 : olefin = 5:100
The Pd is predissolved at least 24 hours earlier w/ stirring and a pinch of cupric added.
Successful reduction? yes yes yes
Stirring: fast as possible via 2" egg, no vortex = no O2uptake.
PdCl2:Olefin = up to 1:250 which I beleive is the lowest anyone has had success with to date.. and that was on the exo reaction possibly indicating that less catalyst leads to a more vigourous reaction. The olefin is added 1/2 at the beginning and 1/2 (more cupric and solvent too) at around the 8hr mark. Turn the bath off then stirred overnight.
Volume: done 1/2 kg, expect ~.8kg is max with this 2" bar, a 3" would do a lot.
Open to see a black mixture, smells flowery / IPA.. very pleasant and aromatic. O2 is seen bubbling from solution, indicating that it was in there in the first place.
O2 consumed: ~~100psi to 80psi (delta 20) over 8h per ~200g S.
Purging?: no need.
Distillation: only a few drops prerun then the entire setup is glowing flouresenty green, stop if flow starts to turn orangey.
Workup: Add dilute NaOH for the worst emulsion ever seen.

Perhaps we could nail down a good basic workup: How about
Vac filter
Flood with 3N HCl
Remove bottom oily layer
Extract a couple of times w/ Toluene
Wash oil / extracts w/ water and acidic water many times
Distil her

posted 03-08-2000 10:50 PM         

Nice work,.
Your cucl2 addition style is unique, Could you please explain your method,.
I'm assuming you mean 10% in the predissolving bit, then 50% of what's left into the 50% safrole addition first stage, then the rest in after that with the remainder of the safrole????..

Any way, good to see the ketone down pat,.

'A good naoh wash' brigtens up anyday for the vac. distillition impaired'

So Equarius you find that at 16-20 hours of reacting time at 100psi with your method doesn't produce too many side products??.

Interesting!!!
Maybee it's kinda like your essentially doing 2 reactions at different stages of about 8 hours intervals each,.

If it's giving you unparalled success Equarius, I believe I can feel a long winded professional write-up coming our way, showing us that we have licked the O2 wacker, Equarius style!!!.

Hellman
'O2 wacker progress in action'
We know the ratios!
We just need the optimum psi vs time @50C

posted 03-09-2000 01:28 AM         

Some shit though still doesn't make sense, first off, when SWIM tried the IPA run(500g saf scale), he left it run for a while(8 hours if i'm not mistaken) for the first hour or two the pressure dropped a little and it was going exo as one could feel the heat on the side of the keg. It was then topped up with pressure and left for the remainder of time due to circumstances beyond SWIM's control. When SWIM got back, there was ZERO pressure(possibly a slight vac) and NASTY black tar shit all throughout the whole keg, or up to the solution level anyways. Oh and the stirbar was stopped dead in that mass of tarry shit too. What would have caused that tarry shit? Lack of O2 or something? SWIM used 1L of 99%IPA and 500g saf, 5g PdCl2, and the hydrate of the CuCl2(25g), was/is that enough solvent for that sized rxn(perhaps this was the problem)? Out of two runs of this, one with MeOH and one with 99% IPA, SWIM got LOADS of bright yellow SAF back, and about 30ml of suspected ketone(out of 1kg of saf only 2.2g of honey.hcl was not-got). So Equarius, your ABSOLUTLY sure that what you got back was ketone and not saf? I agree with KRZ on this one, Your currently the PiMP Master!!! I am jealous as hell, but maybe with all of us back on topic now, we can figure this out. Oh another thing, SWIM didn't use a water bath, could that maybe be the reason for the goop shit? Stumped...

Thanks for getting back on track people, this IS why we are here after all...

KRZ, I forgot to ask you, you said your keg blew, the over pressure release valve or did it puncture the keg? What exactly happened?

posted 03-09-2000 09:34 AM         

Object of the improvement is to recover substantially all of the palladium catalyst for re-use. Generally, the reaction mixture comprise of olefin, catalytic system, a polar solvent and a higher boiling solvent. After the reaction, the product (=ketone) is separated from the catalyst system and other components by distillation.
The high boiling solvent can be any organic compound or mixture of organic compounds that is liquid under the conditions of the reaction, which has a boiling point higher than the boiling point of ketone, and which is a solvent for the catalyst system used in the reaction. Solvents must be selected that do not enter into the reaction and do not interfere with the reaction product.
In US patent 3932521 has been found that the use of a polar solvent in combination with the high boiling solvent provides a reaction medium with increased reactivity. This enables the reaction to proceed at a faster rate. Suitable polar solvents are methanol, ethanol, propanol, isopropanol, n-butanol, sec.-butanol.
The polar solvent is present at a level of from about 20 to about 60 percent by weight based on the weight of the high boiling solvent used.
The process is limited to conversion of olefins of at least five carbon atoms, but having 20 carbon atoms or less. Those olefins having more than 20 carbon atoms have boiling points which are excessively high and distillation to separate ketones from the high boiling solvent must be carried out at temperatures such that charring and deterioration of the catalyst system and product are incurred.
Water must also be present in the reaction system but need be present only in trace amounts. The function of the water is to provide the necessary oxygen to form the desired carbonyl compound from the decomposition of the platinum group metal compound-olefin complex.
For batch and semi-batch reactions, it is preferred that the olefin is added at levels of from about 40 percent to about 600 percent by weight of the high boiling solvent.
The high boiling solvent also prevents ketone from charring during distillation. After the distillation step, the catalyst system remains within the distillation chamber, and may be re-used. The high boiling solvent, which also remains substantially within the distillation chamber, may also be re-used so long as the temperature at which the distillation is effected is not sufficient to damage the high boiling solvent and the catalyst. The liquid reaction product obtained by distillation containing the ketone may be further treated by fractional distillation to achieve higher purity. The catalyst system is usually present in the ketone in amounts of less than about 25 ppm.

Suggestion for experimental set-up:

A catalyst solution containing approx. 100 g of high boiling solvent , approx. 100-150 g methanol, 0,5 - 1 g palladium chloride and 3 - 5 g copper chloride and trace amount of water is charged to a reaction vessel (preferably from titanium, ha ha ha ...), preheated to reaction temperature (40-50°C or other at your convenience), purged with oxygen and the catalyst is allowed to dissolve completely (with stirring, sonification etc.). 100 g of alkene is added and the vessel is then pressurised with oxygen to a pressure of 100 psig (or other at your convenience). It is advantageous to introduce olefin to the autoclave over a period of time (best done automatically by a piston pump). Throughout the reaction, the solution is stirred (at at least 1000 rpm. or shaken) and the temperature is maintained. The oxygen pressure is also maintained at 100 psig. throughout the reaction by re-pressurisation with oxygen. Thereafter, the reaction mixture is transferred to a distillation flask. The mixture is then vacuum distilled and the distillation residue containing catalyst (if not burned and charred) may be reused for other run.

Suitable high boiling solvent for this reaction might be glycerol (b.p. 290 °C /760 mm Hg, 182°C/20 mm Hg).

posted 03-09-2000 09:37 AM         

Please be aware that the following set-up is NOT very OTC. (Now you are warned, so please do not comment that it will be expensive. It will ....)

The principle idea is to use pressure tubular vertical reactor, without the necessity of mixing or shaking. The proper contacting of gas and liquid phase and mass transfer in the reaction mixture is achieve either by introduction of oxygen under pressure to the bottom of tubular reactor with stationary layer of liquid or by pumping the reaction mixture to a packed-bed column with counter-current flow of oxygen.

Apparatus description:

Technical details can be elaborated by someone skilled in this art. I will focus only on the mail idea.
The body of the reactor can be made from thick-wall chemical glass tubes (glass tubes with different diameter from 5 cm up to 25 cm, up to 2 m long are commonly used as ion-exchange columns or big chromatographic columns, chemists will know what I am talking about. They can withstand high oil-vacuum so should work with elevated pressure up to necessary 100 psig too). These tubes are already supplied with heads, adapters etc. Advantage - you can see progress of the reaction by eyes.
Another possibility is SS coated by PTFE. Those better skilled can weld a duplicator on the tubular reactor (and create something like „Liebig condenser“), connect it to termostate/cryostate (or tap water) and use it for temperature control. Titanium will work even better ........

The tubular reactor is situated in vertical position. In the upper end is inlet for reaction mixture. The mixture is sprayed through a distributor (shower head for instance) on the packing of the column. A typical column consist of a cylindrical shell containing a support plate for the packing material and a liquid-distributing device designed to provide effective irrigation of the packing. Devices may be added to the packed bed to provide redistribution of liquid that might channel down the wall. The packing assure excellent liquid-gas contacting. Typical packing are Rashig rings, Berl and Intalox saddles, glass bolls or pieces of broken porcelain for kitchen chemists. In the lower end of the column there is inlet for the gas, usually a sintered glass is used to create small bubbles of gas. Also a tap to drain the column is located here.

With packed bed reactor, you connect ends of the reactor to the oxygen cylinder (by a regulation valve etc.) to maintain constant high pressure in the reactor. From the upper end, you pump your reaction mixture (containing all ingredients, eg. PdCl2, CuCl2, solvents and olefin). The liquid flows down and on the surface of packing goes into contact with oxygen. This system is usually more effective than batch mixed reactors in bigger scales. The liquid is collected in the bottom of the reactor and by means of high pressure chemical pump (with ptfe coating) - the expensive staff is returned to the top of the reactor until the uptake of oxygen cease.
Carefful adjustment of the liquid flow rate is necessary not no flooded the column and to achieve maximum efficiency. Glass reactor is thus preferred here.
Of course another possibility with this reactor is to use heterogeneous catalysis with immobilised palladium.

Another possibility is just to fill at the beginning the reactor with reaction mixture and start introducing oxygen under pressure from the gas diffuser at the bottom The tiny bubbles rise through the liquid, mixing the liquid. At the upper end of the reactor must be left some free space and an demister made from wire-mesh to eliminate any liquid drops. The oxygen coming out from the upper outlet goes into the oxygen compressor (extremely expensive staff too ) and at desired frow-rate is introduced back to the bottom of the reactor. Gas cylinder is connected throuhg regulation walve and flow meter to the compressor too, to maintain constant pressure and supplement oxygen consumed during the reaction. Not sure, wether chaper common air compresors (for filling the diving botles) will not create an expolsion with pure oxigen and solvent wapors.

Both approaches can be further combined to create counter-current system.

No need for stirring, shaking, easy scale-up. Just imagine series of reactors with 20 cm diameter, 2 m high .

Application of this kind of reactor is not limited only to oxidations, it can be used as well for pressure hydrogenations or fermentations.

posted 03-09-2000 01:36 PM         

one company was producing hexanone with this procedure. But they use dodecanol, glycols or benzonitrile as high boiling solvent. Unfortunately they have lover bp. that ketone of our interest. Glycerol was claimed in the mentioned patent among suiteble solvents and I choose it for its bp. and low price.
I believe it can be reused again and again with maybe minor loss in activity due to some losses of catalyst. Of course, one must avoid burning the mixture during vacuum distillation. 150°C seems to be maximum for it, so a good oil pump has to be used. May be a small addition of a fresh catalyst in each run might be advantagous. Anyway, you can easily recover the Palladium from glycerol by formaldehyde reduction at any stage if you thing the mixture looses its reactivity. But only experiment will tell....
I believe that no other workup is necessahy here, just double distillation to obtain substantiallly pure product.
Also my opinion is that separate oxidation of catalyst is not necessary during each run, as far as you have sufficient supply of oxygen, there is always an equilibrium of Cu+/Cu++ so all you probably have to do in a new run is to apply oxigen to the new reaction mixture some time befor the addition of olefine.