Willgerodt rxn: Styrene monomer -> phenylacetamide

There is a method using ethanol during the reaction. It was quoted in a Chinese article if my memory serves me correctly and was tested by a member at the Hive.

The efficacy of it might have been specific to the styrene -> phenylacetamide reaction.

Thanks for your digging and searching you guys!

Screen shot of majik paragraph

OK

Sorry for my bad attitude. It was not meant to be as such, but more as a stimulation (or kick) to find some simpler solutions by yourself without me doing the search for you. Just consider it as a cultural difference. For some reason I’m unable of being pathologically polite. Bear with my personality like I do or simply ignore my replies.

Anyway, I would certainly not use the vessel you described for this reaction and certainly not only because of the unnecessary fuss of building it. See Not_important’s reply above for initial information. But to give an additional hint, I can tell you that uncoated steal (interior of a gas tank) in the presence of polysulfides at 100°C is a “don’t-trust-that-pressure-bomb” kind of thing. In short, corrosion of steal with polysulfides results in a non-adherent film of iron sulfides. To get a better picture, imagine your gas tank consistently corroding from the inside until the 2-3 bars of pressure blows it apart (makes for nice stinky bomb, now that I think of it).
Uncoated steal is one of the worst choices for such a corrosive mixtures like ammonium polysulfides.
Hopefully, you will understand why the alternative I offered you is better when you find the relevant threads.

I have not read the translation in the link you provided before and I took it that you meant what you wrote: “the phenylacetamide is extracted with H2O”. While in the translation it says that hot water is used which when cooled yielded the product as a precipitate. In chemical terminology this is generally called a recrystallization and not extraction, though the first part (dissolution) is indeed equivalent to an extraction. Nevertheless, if you consider using 1,5 litters of water for the recrystallization of 27g of product as practical then just do it. I have no problem with that since I’m not the one who is going to do that. Also, don’t trust that translation 100%. I don’t know if you have noticed it, but there already is an obvious mistake there: “100 g of the above phenylacetonitrile”. There might be similar ones that can not be identified easily. Note also, that the yield given (97%) is suspect and can only be explained by the simple fact that what is said to be phenylacetamide is either not well dried or actually a mixture of phenylacetamide and phenylthioacetamide (and the m.p. the usual bluff).
So I warn you (kindly, this time) again to be careful not to kill yourself with H2S.

I would also suggest you to substitute ethanol with isopropanol as the cosolvent in that procedure. This way you get better solubility of styrene, lower internal pressure and get faster sulfur consumption. (i-PrOH performed well as a cosolvent in certain other Willgerodt examples).

Regards,
your chemistry boy

Edit: Gave additional info in order to improve my bad attitude.

[Edited on 31-8-2006 by Nicodem]

Sincerely I'm not sure anymore if you understand where the pressure comes from. If is not from the gases evolved because of the reaction. It comes from the:

• ammonia in the reaction mixture solution which at 95°C is already well above the saturation point and consequently equilibrates by increasing its partial pressure above the liquid phase;
  
• the partial pressure of the ethanol (or isopropanol) cosolvent that at atmospheric pressure boils at a temperature lower than 95°C even when diluted by water and ammonia;
  
• partial pressures of water, styrene and other volatiles;
  
• partial pressure of the air that was left inside when closing the vessel.

Now, as you see you certainly don’t want a valve to moderate or vent the pressure out as this means you would loose the precious ammonia and ethanol, both of which concentration also determines the speed of reaction.
All these listed factors increase the pressure to about 3 bars (my estimation based on experience from similar examples) which is quite low and could be contained even by a simple PET bottle if it wasn’t for the temperature softening the polymer. What I’m saying is that even though you are such a tenacious DIY guy, you don’t really need to go as far as mounting a valve and all that funcy stuff on the bottle. Just use a champagne bottle (which are said to stand the min of 20 bars, IIRC), a champagne bottle stopper and wire the stopper very well so it won’t pop out before its time to celebrate. Immerse the bottle for up to 3/4 height in water bath and heat the bath slowly (glass does not like sudden changes of temperature).
I have heated this way saturated solutions of NH3 in isopropanol at 100°C for days in normal 100ml Fluka bottles without troubles as long as the stopper was well fixed.
I’m truly sorry if I disappointed you, but this reaction is nothing special and does not require anything really special. The only reason people prefer to talk a lot about it, but try it not, is not because it would be difficult or complex like Chinese writting, but simply because they are lazy, mentally and physically (actually mentally mostly).
But look at its bright side. You can even have fun emptying the champagne bottle.

Edit: According to this site: "Today, the dark green Champagne bottle is designed to resist a pressure of 12 atmospheres..."

[Edited on 1-9-2006 by Nicodem]

You'd best pay attention to what's been said and forget about modifying a champagne bottle in too complex of a manner It should serve the purpose using the original stopper as long as it's heated and cooled slowly Complications are fine when they work, but the old time tested rule about keeping things simple is still just as true as it was long ago even if it's not taught in many schools anymore

It would be best not to fill it up all the way as doing that would increase your chances of failure

willgerodt

BTW:
Some time ago I made (few times) reaction aceotpenone/S/morpholine (without any acid calalyst). After hydrolize of reaction products and purification, about 50% theoretical amount of PAA was obtained Some says it should be not less than 90%.
But acetophenone is exepensive, so in future experiments I try to use styrene from depolimerization of polystyrene. Yeld of monomer is ~90%, they say (an article from SD says ). Without pressure vessel only morpholine works good, giving high yelds of thiomorpholides.

[Edited on 16-9-2006 by kmno4]

kmno4:

Literature gives divided reports on efficancy of reaction... But hey... 50% isn't so bad... I wouldn't say acetophenone to be very expensive at ~20$ per litre... Maybe MW would help the rxn...

If you have access to morpholine you could also try using styrene (paint thinner at ~3$/litre). The only drawback i see are harsher rxn conditions and smelly styrene (The closed can smells even if closed in plastic bag...) Also styrene doesn't keep well (likes to polimerize)...


In my search for cheap "high" pressure reaction container i have found that slightly modified old N2O containers work ok for nano scale rxns... The only drawback here is the oxidation of the inside of the container (it seems to be some kind of steel)... Also for this type of rxn sealed glass test tubes work (tried EtOH+S+NH4OH+Acetone ~100 deg C). But if using glass you should always keep them in some kind of blow container, in case the tube explodes... I use short piece of plumbing, loosely capped (you can get precut pieces and caps in plumbing shop)...

Will post some reports shortly

I never said that steel or other metal tanks can't withstand a single run. What I said is that it would be highly irresponsible to use if you value your health. If you would ask an engineer if you can use a steel tank for a reaction where polysulfides form he would have told you that you must be out of your mind. This however does not mean that the containers walls would disintegrate before you finish the reaction, they may or may not, though the additional consumption of sulfur and the contamination of the reaction mixture with iron sulfides would be terrible to deal with.

PS: Nice to see you still prefer to complicate instead of just doing the simple things. Some things never change.

Nicodem, your smart and a fool at the same time.

Your going to have to boil or heat all those stinking fluids away during work-up, polysulfides reek too. Smell a bottle of "Lime-Sulfur".

I'm just saying something like a gas-tank has some characteristics which are conducive to a SAFER rxn and follow-up as opposed to a wine bottle.

But if you can't even guarantee it could survive a single run it isn't ideal at all.







[Edited on 26-4-2007 by visitation123]

Quote:

Originally posted by visitation123 Your going to have to boil or heat all those stinking fluids away during work-up, polysulfides reek too. Smell a bottle of "Lime-Sulfur".

If you trully knew what you were talking about you'd know ammonium polysulfides are used in stink bombs I would have thought.

You have a lot of chemistry knowledge and useful knowledge in general, but you seem very proficient at handing out condescending remarks simultaneously with the other hand - I guess it's cultural.

Do I know hat a rotovap is? Yes
Do I have one? No
Do I know how to evaporate the reaction fluids in the steel vessel described? Yes....With an aspirator to hasten the evaporation of the fluids? Yes

Do I know how to evaporate the reaction fluids from a champagne bottle relatively quickly? Don't know never tried but with a barbed SS fitting it shouldn't be too difficult.

So are you going to tell me how you'd isolate the phenylacetamide without evaporating the reaction fluids as the patent calls for?

Having said that, the patents' leading the game 2-0 at the moment from memory...


P.S. try to forgive my ignorant attitude as you perceive it - it's cultural.

Because, as it sounds you are unaware the reaction has been undertaken before and it was evauated to be phenylacetamide by people with more knowledge than me, and you.

Nice to see you listing the solvents for the washing and extractions, uh oh that's right you just came to invade a conversation, take one side and spill nonsense.

Yeah and it also seems that the reaction couldn't even be undertaken with the said compounds until I dug up the patent translation or that it can be EXTRACTED (not recrystalised Nicodem, that follows) with hot water.

Basically all I've learnt is that I was right all along as far as the reaction and work-up goes. Although I thank Nicodem for warning me about ammonium polysulfides and ferrous metals.

So I've learnt with vague, lazy descriptions that a champagne bottle might be implemented instead, that isn't too technically advanced, and certainly doesn't give either of you the intellectual high-ground.

Hmm, I think we shall stick with water extractions since it's clear neither of you are willing to detail further and rationalise use of filtering and washing, including solvents used and why. etc etc

Sorry, no time to chat about worthless theories etc.

Come to think of it, your both wrong again.

Extracting and recrystallising with hot H2O then filtering is quicker, easier and cleaner for the environment than your methods using solvent washes.

So how do you imagine you'll ever isolate the substance?

I don't have my merck 13 installed, but i have it...well guess i am lazy

So you don't think the red layer contains the phenylacetamide or your unsure?

Well, bad news folks, it looks like the Chinese patent was all a big joke/nasty prank.

Don't shoot the messenger.

The other person who tried it on a large scale () got the same red substance as tr41414. It sounds as though it's worthless crap.

Physical State: Solid
Appearance: white glistening crystals.
Odor: Not available.
pH: Not available.
Vapor Pressure: 1 mm Hg @237 deg F
Vapor Density: 4.65
Evaporation Rate:Negligible.
Viscosity: Not available.
Boiling Point: 304 deg C @ 760.00mm Hg
Freezing/Melting Point:113.00 - 115.00 deg C
Autoignition Temperature: 545 deg C ( 1,013.00 deg F)
Flash Point: 173 deg C ( 343.40 deg F)
Decomposition Temperature:Not available.
NFPA Rating: (estimated) Health: 1; Flammability: 0; Reactivity: 0
Explosion Limits, Lower:Not available.
Upper: Not available.
Solubility: Slightly soluble.
Specific Gravity/Density:Not available.
Molecular Formula:C8H9NO
Molecular Weight:135.17

See we needed this discussion




Read this it's funny: http://www.synthetikal.org/hiveboard/arch/forum/topic/topic_...

Polverone tried this and seemed to think he had some success:

So now I'm completely confused as to whether this reaction is actually legit or not. My suspicion is not now.








[Edited on 28-4-2007 by visitation123]

Fine Nicodem, be that way, your info is dodgy anyway. I have no idea what your talking about when you describe me as greedy either...*bewildered by these statements*. I was just enjoying the conversation and trying to find out more.

I note that you give no information to tr41414 either



Not knowing what I'm doing is all the more reason to discuss it and all the more reason not to experiment.

OK, the red solution is simply ammonium polysulfide solution, whether it contains phenylacetamide or not I do not know.


http://cameochemicals.noaa.gov/chemical/107#section4

General Description
A red liquid with an odor like rotten eggs or ammonia. Corrosive. Irritating to tissue. Long-term exposure to low concentrations or short-term exposure to high concentrations may have ill effects. Used as an analytical reagent and an insecticide spray. (REACTIVITY, 2003)


Thanks fo the info on Parr bottles Sauron, they sound great.

[Edited on 29-4-2007 by visitation123]

A few days ago I made pyrolysis of polystyrene (at last...).
Reaction was conducted in air atmoshpere and normal pressure. I used only colourless (or almost) pieces of PS.
From ~75 g of PS I got ~60 cm3 of clear, water-like distillate, of toluene-benzene mixture smell. Remaider in a flask was dark brown, gummy substance, not completely solid at r.t. , soluble in toluene, dioxane but best soluble in TRI (it was at hand).
I tried to re-distill colourless product (+hydrochinone) but I get the same liquid + colourless reminder in a flask - probably styrene polymerised again . I think than distillations under reduced pressure would be the best solution.
Colourless reminder was pyrolised again, all liquids were gathered and used for Willgerodt reaction (standard conditions, 3 hours at reflux).
According to mechanism of reaction, styrene is oxidised to phenylacetylene at first and evolution of H2S takes place.
All these substances: ethylbenzene, styrene, phenylacetylene can be converted in thiomorpholides, with the highest yield for PhCCH.
Reaction mixture after cooling was introduced to water (~20 fold mass excess)and let stay for ~24 hours. There were two layers: deeply brown coloured water layer (I discarded it) and oily layer, also deeply coloured on the bottom.
It all did not look good, because I expected to get some solid thiomorpholide and I got only some oil....
But I took to the reaction product of pyrolysis, containing possibly larger amounts of toluene and benzene (as reported in papers about PS pyrolysis), not pure styrene.
I took this oil and let it evaporate in an open vessel at ~50 C. Indeed, strong toluene/benzene smell was easy detecable. It became semi-solid and finally turn to thick mixture of needle-like crystals and some brown oil***.
I thought that these crystals - it is just sulphur, heh.
But I took small sample of this glop and put it to small amount of ethanol (probe test only). It dissolved qiuckly - so it could not be sulphur ! During slow self-evaporation of ethanol from a tube I got needle-like yellow crystals on the wall of test tube and coloured ethanol layer with visible droplets of some deep-brown oil.
I will report results of purification of this "glob" when I find appropriate solvent for crystalisation.
I hate palying with such tarry things so I would like to find better solvent (possibly dissolving brown oil and not dissolving crystals of (probably) thiomorpholide.

*** I could take a photo but.... everyone knows how shit looks like, it looks very similar
But my mixture has sulpury-styrene smell (not H2S), not even very strong.

I forgot to report results here
The best solvent for crystallisation seems to be mixture 50/50 water-ethanol. Yield of thiomorpholide is about 25g - about 10% counting on polystyrene.
It is probably effect of low content of styrene in my product of pyrolysis (more benzene/toluene odour than styrene) of PS.
It is very stinky way for making phenylacetic acid, but on a small scale, just for fun, synthesis PS -> PAA is not so bad

here comes the sun

The attached article could help to lessen the confusion, oh had it been available already 2007!

It is a good final and worth to awake this old thread.

It is the high yielding acetophenone to phenylacetamide with alcohol as solvent and no amines needed.
There can be little doubt it will not work with styrene.

The problem is - as it is pretty obvious from reading the threads information now, the temperature and the pressure coming with it.
It is 165°C and 18atm and this is not done in a champagne bottle anymore. No way.
Even if standing the pressure it would be hard to provide the needed agitation with all the solid sulfur and the rest thats pretty thick and one thing I can assure everybody: Here the success depends on the mixing, and reaction time too.
The aticle sounds rather down to earth and realistic IMHO not questionable like so many from this corner.

But look for yourselfs.

And sorry Nicodem, I dont do this by purpose, but I had to laugh when I reread the thread and your first heated posts - what you will understand I hope.
And if you have any of the references to IPA instead of EtOH being beneficial then that would be great as I could find a lot (like the one below) but not anything with IPA.
I thought some waterbed conditioner would be ok though.

regards
/ORG

Attachment: willgerodt-PhenylaceticAcid.pdf (320kB)
This file has been downloaded 1945 times



[Edited on 17-4-2014 by Organikum]

Quote: Originally posted by Organikum

And if you have any of the references to IPA instead of EtOH being beneficial then that would be great as I could find a lot (like the one below) but not anything with IPA.