Sciencemadness Discussion Board

Willgerodt rxn: Styrene monomer -> phenylacetamide

visitation123 - 25-8-2006 at 03:35

Information on this reaction is quite difficult to track outside the Hive, did anyone keep notes on it?

It involved styrene monomer, NH3 solution, ethanol, and H2O from memory.

solo - 25-8-2006 at 05:03

Go here and get organic reactions vol III check out page 97............solo

visitation123 - 25-8-2006 at 06:19

Thanks a lot solo, it looks like they just used pyridine rather than ethanol...

with ethanol the yield is much higher, in to the excellent range. And from memory the temperature was more like 100C.

not_important - 25-8-2006 at 06:28

That's the classic reference solo gave,
With aqueuos NH3, and sulfur or sulfer + ammonium sulfide, it must be run under pressure, usually in a sealed tube. It can be run with a high boiling amine and dry sulfur at atmospheric pressure; under these conditions it forms a thioamide which is hydrolised during workup to the free acid.

No ethanol, except as a solvent for workup; the reaction conditions would convert it to acetic acid and/or boil it off.

improved yields - you'll want the full article, this is just 1st page

Works OK on simple alphatic ketones too

Why don't we do it in the microwave?

solo - 25-8-2006 at 07:57

Reference Information

The Willgerodt Reaction
Ellis V. BROWN*
Synthesis pg.358, 1975

The Willgerodt reaction is discussed from a synthetic standpoint including types of compounds for starting material and conditions of operation. The Kindler modification and its usefulness is also indicated. The behavior of heterocyclic compounds in the reaction is mentioned followed by a number of interesting special compounds prepared. The results obtained by applying the reaction conditions to cyclic ketones are covered and, finally, work on the reaction mechanism to date is discussed.
1. Introduction
2. Kindler Modification
3. Reaction of Heterocyclic Compounds
4. Special Syntheses
5. Results with Cyclic Ketones
6. The Overall Mechanism
7. The Detailed Mechanism

[Edited on 25-8-2006 by solo]

Attachment: The Willgerodt Reaction.pdf (803kB)
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solo - 25-8-2006 at 08:18

Reference Information

The Willgerodt Reaction. 11. A Study of Reaction Conditions with Acetophenone
and Other Ketones

Journal of the American Chemical Society pg 2025, 1946

Attachment: The Willgerodt Reaction.11. A Study of Reaction Conditions with Acetophenone and Other Ketones.pdf (635kB)
This file has been downloaded 1968 times

solo - 25-8-2006 at 11:51

Reference Information

Studies in the Mechanism of the Willgerodt Reaction. 111. Nature of the Labile

JACS vol. 53, pg. 30, 1952

The nature of the labile intermediate participating in the Willgerodt reaction with phenyl n-butyl ketone has been investigated using deuterium as a tracer. 6-Phenylvaleramide, the reaction product from this ketone, was found to have retained only 5% of the deuterium which had originally replaced hydrogen on the beta carbon of the alkyl side chain. This evidence is interpreted as indicating that an unsaturated intermediate has been formed during the course of the Willgerodt reaction.

Attachment: Studies in the Mechanism of the Willgerodt Reaction.pdf (579kB)
This file has been downloaded 1238 times

visitation123 - 26-8-2006 at 02:04

No ethanol, except as a solvent for workup; the reaction conditions would convert it to acetic acid and/or boil it off.

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!;)

not_important - 26-8-2006 at 03:00

It's mentioned here
and is being used as a solvent. Being a patent, it could be someone attempting to get around another patent. Many solvents have been tried in the past, we tried ethylene glycol but it was oxidised by the reaction conditions. You really need to seal it, to keep the NH3 from escaping, or use a higher boiling amine.

This might prove interesting,21,21;journal,135,136;link ingpublicationresults,1:107868,1#search=%22Willgerodt%20%20reaction%20ethanol%22

visitation123 - 27-8-2006 at 05:07

My understanding was that ethanol replaced pyridine in the reaction, and the temperature was approximately 94 or 96 degrees centigrade.

Having said that, there's much more info outside the Hive suggesting that your right.

ORganikum would remember the two discussions im refering to at the Hive.

Anyhow, about the reaction, does anybody know how smelly it is, whether the gases are toxic, and what would be the best method of measuring temperature of the sealed vessel?

I was thinking an infra-red pyrometer.

not_important - 27-8-2006 at 08:12

Just use a heating bath, the tube won't get hotter than the open bath which is easy to monitor the temperature of.

visitation123 - 27-8-2006 at 08:12

not_important do you have the full text for the microwave-assisted variation?

leu - 27-8-2006 at 18:23

not_important do you have the full text for the microwave-assisted variation?

The article:

Microwave assisted Willgerodt-Kindler reaction of styrenes
Moghaddam F.M.; Ghaffarzadeh M.; Dakamin M. G.
Journal of Chemical Research, 1 May (2000), pp. 228-229(2)

Styrenes are efficiently transformed to thioamides via the Willgerodt-Kindler reaction under microwave irradiation.

[Edited on 28-8-2006 by leu]

Attachment: (32kB)
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not_important - 27-8-2006 at 22:32

Well, now I have the full text. Thank you, leu!

visitation123 - 29-8-2006 at 22:44

See, this guy is working off the same information, Ill try get the patent he mentions translated.

But the numbers he produces aren't what I remember at all, they were more like:

Sulfur 12.5g
ethanol 10ml
styrene 7.4g
NH4OH 10ml

The guy who translated them at the Hive was Chinese I believe, so...

EDIT: actually from looking at the patent I think roger2003 has it right, and 21.7g does ring a bell.

Ill post an image of the description section and hopefully someone who knows Chinese can match the amounts with the compounds.

[Edited on 30-8-2006 by visitation123]

Screen shot of majik paragraph

visitation123 - 29-8-2006 at 23:28

ScreenShot001.jpg - 99kB


visitation123 - 30-8-2006 at 06:13

I think I've worked it out by translating the english words for the compounds to simplified chinese then matching the characters with what appears on the patent...

21.7g styrene monomer
37.5g sulfur
50ml NH4OH
30ml ethanol

I think the reaction calls for a reflux but it can be done in a sealed vessel submerged in boiling water for four hours...I know (believe) this because someone at the Hive claimed to have done so and yielded a red product (phenylacetamide).

The yields are said to be in the 80+% range.

Polverone - 30-8-2006 at 08:56

I think this is supposed to happen in a sealed vessel, not at reflux. I recall someone else's translation revealing that the reaction is supposed to be conducted at 100 C, but that mixture will certainly start boiling at lower temperatures. I've tried it with improvised reflux. I don't think I got much, but I will say that a uniquely clinging, unpleasant stench is one of the products. I don't know if that is a byproduct or the main show. Who can describe the odor of phenylacetamide?

[Edited on 8-30-2006 by Polverone]

visitation123 - 30-8-2006 at 19:51

As far as the smell Polverone I'm uncertain, but I think that phenylacetic acid can be a by-product of the reaction so it might have been that?

Phenylacetic is said to be a very strong sweet smell AFAIK.

About whether it's reflux or sealed, well sealed would be consistent with most literature on the reaction.

A pressure vessel could be constructed with a gas tank, a short length of copper tubing leading to a ball valve and so that the fluid contents can be distilled away when the ball valve is in the open position. Hopefully that'd run smoothly. Only one way to find out!

For the work-up, I recall that the reaction fluids are distilled away and that the phenylacetamide is extracted with H2O. But I can't remember if the H2O was supposed to be heated or rt.

not_important - 30-8-2006 at 20:32

The free acid is a byproduct, from hydrolysis of the amide. Phenylacetic acid has a strong smell, some consider it unpleasant. Its esters are more enjoyable, many are used in perfumery. (phenethyl alcohol is nice, flowery) The thioamide and/or similar compounds stink, even traces are noticable.

The amide is not very soluble in cool water, even hot water isn't a great solvent; the free acid dissolves well enough in hot water that recrystallisation from water has been used for purification.

I wouldn't use copper around reactions that use ammonia or the lighter amines, they can greatly speed up corrosion of copper. Even worse when there is going to be free sulfur and H2S around.

Worse that the solvent boiling is the loss of NH3 if the reaction isn't sealed away. That's why the Kindler modification switched from ammonia to morpholine; other high boiling amines will work.

Nicodem - 30-8-2006 at 23:05

Originally posted by visitation123
A pressure vessel could be constructed with a gas tank, a short length of copper tubing leading to a ball valve and so that the fluid contents can be distilled away when the ball valve is in the open position. Hopefully that'd run smoothly. Only one way to find out!

Don't you think you are exaggerating big time. You don't need a hardcore metal autoclave. The pressure stays below 5 bar so you can use simple and ready made solutions. Search the forum for "pressure vessel"! (Or should I say UTFSE?)
For the work-up, I recall that the reaction fluids are distilled away and that the phenylacetamide is extracted with H2O. But I can't remember if the H2O was supposed to be heated or rt.

Nonsense. As you were already told, phenylacetamide is not water soluble and I'm pretty sure the other main product, phenylthioacetamide, is even less watter soluble. Most of the sulfur is going to be dissolved as the polysulfide and most styrene either reacted or polymerized. So there should mostly be organic solids left which should be ready for hydrolysis by a simple filtration and washing. Sulfur and other contamination will not affect the hydrolysis. If instead a paste is obtained (quite likely), then you would need to extract and purify by recrystallization.
In my experience phenylacetamide barely has any smell which is just a subtle indefinable one. It is a white crystalline powder. I don’t know about the thioamide. I never had the “pleasure” to work with it. Phenylacetic acid smells bad and the description of “mouse shit smell” that I read somewhere pretty much applies. I don’t mind the smell, however some people are much more sensitive to it and will find it truly disgusting and will smell its impregnated smell for months.
While opening the vessel and later on hydrolyzing the thioamide, you should know that H2S is only two times less deadly than HCN. That should be a consolation, but mind that it is one HELL of a SMELL.

visitation123 - 31-8-2006 at 01:29

Don't you think you are exaggerating big time. You don't need a hardcore metal autoclave. The pressure stays below 5 bar so you can use simple and ready made solutions. Search the forum for "pressure vessel"! (Or should I say UTFSE?)

Wow, you really have an attitude problem. There's no great task in drilling a hole through the valve of a gas tank, using a camping fitting to connect it to copper tubing and then attaching a ball valve to the end of the copper tubing for most - sorry this is beyond your means. Ill read the threads your speaking of, but not because YOU told me to.

visitation123 - 31-8-2006 at 01:32

'Under stirring and heated at 93-95 C for 3-4 hours. Fluids were evaporated from the mixture, it was allowed to cool, and extracted 3 times with 500 ml hot water. The decolorized solution after standing yielded 26.7 g (97%) white sheets having MP of 157-158 C and BP of 280-290. (Phenylacetamide C8H9NO)'

Whaddya know? How you like them apples chemistry boy?

[Edited on 31-8-2006 by visitation123]

Nicodem - 31-8-2006 at 01:59

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). :D
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).

your chemistry boy :)

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

[Edited on 31-8-2006 by Nicodem]

visitation123 - 31-8-2006 at 07:09

Your forgiven chemistry boy, you've helped me before whether your aware of it or not.

Isopropanol it may be.

As for the pressure vessel, how would this suffice: a wine bottle fitted with a PVC T fitting, a balloon and a plastic ball valve connected to some PVC tubing/bubbler submerged in a basin of water, so that when/if the balloon fills pressure can be released with the ball valve and the excess gases including H2S can be bubbled through the water.

Needless to say, evaporating the fluids is going to stink, so a filtration might be a better option as you and some lit suggests...

Nicodem - 31-8-2006 at 11:20

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: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]

not_important - 31-8-2006 at 23:58

I'm seconding Nicodem, and adding that with styrene having a vapour pressure of very roughly 200 mm at 100 C, you'd best be real careful in the selection of any plastics exposed to those vapours; styrene is a pretty good solvent for organics. Use a real cork stopper.

Rather than evaporating everything off, you might be able add some water, warm to near boiling (of alcohol), filter to remove styrene and polystyrene, distill the alcohol off from the filter, add NaHCO3 until all of the free acid is in salt form, cool and filter to collect the amide.

visitation123 - 2-9-2006 at 03:06

Thanks all I appreciate, I think we've well and trully sorted out how to conduct this experiment - the only thing left is to conduct it.

At the moment I'm washing some dusting sulfur with H2O then we can tread farther.

leu - 2-9-2006 at 04:39

You'd best pay attention to what's been said and forget about modifying a champagne bottle in too complex of a manner :P It should serve the purpose using the original stopper as long as it's heated and cooled slowly :cool: 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 :D

visitation123 - 2-9-2006 at 06:02

True, well yesterday I inserted a wine cork (a champagne cork is nigh imposible to re-insert in to a bottle) about 2/3's into a wine bottle and the things pretty tight.

When it comes to the crunch Ill use a wooden mallet to jam the cork in.

Is the pressure in the apparatus sensitive to how high I fill the bottle i.e the amount of reactants?

leu - 2-9-2006 at 12:42

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


beebo - 15-9-2006 at 18:15

Originally posted by visitation123
Information on this reaction is quite difficult to track outside the Hive, did anyone keep notes on it?

It involved styrene monomer, NH3 solution, ethanol, and H2O from memory.

contact beebo at wetdreams ...
we have extensive personal notes including:
vogels excerpts, the hive archive, and safety addressed

kmno4 - 16-9-2006 at 02:29

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]

tr41414 - 12-11-2006 at 10:21


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 :)

kemm10 - 12-11-2006 at 16:11

try using styrene (paint thinner at ~3$/litre).

Don't you mean resin thinner? I've never seen styrene sold as a paint thinner.

tr41414 - 21-11-2006 at 22:01

I think it's thinner for some kind of polystyrene based car color or sth. like that...
Don't know exact content of styrene, but it is the only thing on the label so there should be a good amount of it...

The N2O containers are suitable only for nano rxns... but this time i tried the rxn in sealed glass tubes, to avoid any problems because of metal reactor (there shouldn't be any even with metal)...

There were 2 tubes one with EtOH as solvent and the other with IPA, ratios according to chinese patent... I have also done some quasi-willgerodt rxns with acetone and MEK.

I first tried the MW method but soon stopped, because there was too much pointed heat and heating also seemed to be wery quick. I think my self-sealed tubes wouldn't take much heat-stress. At this point (30s MW in a glass of water) the IPA tube was already slightly yellow, which might prove IPA to be a better solvent, if it was not involved in some kind of rxn. I think that it doesn't react, as there are references of its use in willgerodt-kindler...

Then the tubes were heated at the bp of water for 3h... Now the content of tubes is a reddish liquid and on the bottom is something yellow, covered with a thin layer of oily liquid... My question is which is the product and what is the yellow powder at the bottom? I guess the oily liquid at the bottom is salted-out alcohol or/and unreacted styrene. The yellow powder is more puzzling, as it resembles the inital sulfur in the reaction, but if you look closely it is a bit shiny, which would suggest some kind of crystal structure... Should all the sulfur react to form polysulfides?

pics and analysis comming soon...

visitation123 - 26-4-2007 at 10:43

The red substance is phenylacetamide.

Just going back to this discussion... a ball-valve or similar is highly desirable, as it allows for the safe piping of gases, especially and specifically H2S following the rxn to a bucket of H2O2 solution for example to convert or recycle the sulfur by forming elemental sulfur; but primarilly to avoid most of the toxic and pungent stench of the H2S.

A wine bottle just doesn't give you that option that I can think of, even if teflon fittings and tubing were used, there's a question mark as to whether they would withstand the ~5 bar pressures of the reaction - probably not.

tr41414, so do you know for sure whether a metal vessel (gas tank as I already suggested) can withstand a single run? I'd be surprised if it can't as Nicodem says.

Nicodem - 26-4-2007 at 11:24

Originally posted by visitation123
Just going back to this discussion... a ball-valve or similar is highly desirable, as it allows for the safe piping of gases, especially and specifically H2S following the rxn to a bucket of H2O2 solution for example to convert or recycle the sulfur by forming elemental sulfur; but primarilly to avoid most of the toxic and pungent stench of the H2S.

The amount of H2S that gets released when you open the bottle is minimal if you do things correctly. Most consumed sulfur ends up as ammonium polysulfide and only a little portion disproportionates to ammonium sulfide of which some hydrolyzes to H2S of which a negligible part escapes the solution. Still enough to smell it, but not more than that unless you do anything stupid.
A wine bottle just doesn't give you that option that I can think of, even if teflon fittings and tubing were used, there's a question mark as to whether they would withstand the ~5 bar pressures of the reaction - probably not.

You were already told that it does withstand that pressure. Just don't forget to wire the stopper. Besides, the reaction never reaches 5 bars anyway.
tr41414, so do you know for sure whether a metal vessel (gas tank as I already suggested) can withstand a single run? I'd be surprised if it can't as Nicodem says.

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. :P

visitation123 - 26-4-2007 at 13:34

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". :P :D

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]

Nicodem - 26-4-2007 at 21:00

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". :P :D

No need to continuously show your ignorance in the process you are so determined to use. You only need to evaporate the fluids if you don't know what you are doing. Do you even know how is that done? Do you even have a rotavapor? I guess not. Do you know how to use an aspirator to do that? I guess no or else you would not live in the illusion that you will have to smell H2S while evaporating these liquids. Besides there are simple alternatives to evaporation, but you would have to think about it to get to it.

visitation123 - 27-4-2007 at 08:28

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

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.

S.C. Wack - 27-4-2007 at 12:26

That you think Chinese patents are more reliable than the literature methods already known and procedures that could be guessed by those with a clue is telling. It looks suspiciously like another example of the drug cooks thinking they've got it all figured out and organic chemists are clueless morons. One can distill off the ammonium polysulfide if desired but this seems without benefit over filtering and solvents if desired.

The red substance is phenylacetamide? What makes you so sure?

visitation123 - 27-4-2007 at 13:41

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. :D :P

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.

visitation123 - 27-4-2007 at 14:04

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. :P

S.C. Wack - 27-4-2007 at 14:41

I never suggested the need for extraction with solvent, or even mentioned washing anything with solvent. It might be wise to recover a small percentage of phenylacetamide and all of the ammonium phenylacetate that may have been formed, but the majority of product can be obtained without solvent or distillation of the polysulfide.

It might be worth your while to look up the properties of phenylacetamide.

My bad for lack of detail on the worthless theories published by retard authors in JOC and JACS, and for not uploading such garbage to this wonderful thread. It has been uploaded elsewhere and that is enough for me.

If you want good advice, here it is: do it.

visitation123 - 27-4-2007 at 15:25

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 :D

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

visitation123 - 27-4-2007 at 16:34

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

Don't shoot the messenger.

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

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:

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]

Polverone - 27-4-2007 at 18:18

I posted that I was able to produce a uniquely foul-smelling something but I did not claim to have definitively produced phenylacetamide. I haven't done it again because the smell took forever to go away last time.

visitation123 - 27-4-2007 at 22:12

Don't worry Polverone, you weren't the only one fooled (if that's what has occured). A whole host of Bees were, and a few made attempts.

Nicodem - 27-4-2007 at 23:17

I wander why the hell did you even start this thread when already from the beginning it was clear you have neither a clue of what you are doing, neither the intentions to do any experiment at all. Is yours some kinky way of trolling or are you only trying to feed your greed by continuous requests for spoon feeding. Get this into your head: greed is great for wishful thinking and masturbation but is not good enough for success in real world!
I refuse to give you any more information that can be found in libraries or by using common sense coupled with what you learn in elementary school. I have no objections if someone else does that, it is just that I simply gave up. Sorry, I just can't cope with that much stupidity.

Sauron - 28-4-2007 at 02:54

If I wanted to run a reaction at 5 bar (80 psi) i'd do it in a Parr bottle with a neoprene stopper either in a Parr shaker or in an improvised fixture as described in Journal of Chemiucal Education. (much cheaper)

Parr bottles available from Parr or Ace up to 2200 L and useable volume up to 2/3 that so 1500 ml. The 250, 500 and 1000 ml machine made bottles are a lot more economical than the hand blown 2200 ml ones.

Ace also makes borosilicate pressure reactors with Ace-thread joints but I think they advise Pmax 50 psig. Parr says 60 psig but in both cases their lawyers are meddling. The Parr bottles are all tested to 150 psi so at 60 psi they have built in a 2.5X safety factor. 75-80 psi @100 C ought to be a walk in the park. To be prudent use a shield.

[Edited on 28-4-2007 by Sauron]

visitation123 - 29-4-2007 at 06:44

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.

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]

Nicodem - 29-4-2007 at 12:26

Originally posted by visitation123
Fine Nicodem, be that way, your info is dodgy anyway.

You got me. I can't lie about it anymore. I was giving you misinformation all the time. It was never my intention to help you in any way, on the contrary. Everything I posted is completely false information and useless advices.

not_important - 29-4-2007 at 13:01

Boys, save the squabbling for when you run for elective office, OK?

Sauron's right, a shield is wise when running reactions under much pressure, it can save your girlish good looks if there's a flaw in the pressure vessel.

You can DYI yourself for less than the commericial gear, but pressure test it with compressed air first, go for 2X the expected pressure.

The reaction works with styrene giving satisfactory yields if done correctly. It does really stink, chilling the reaction vessel before opening helps a bit. Then add a little ice water, filter off the acid+amide; the filtrate can be regenerated with addition of NH3, H2S, and S, and used in another run. The reaction products should be hydrolized in a flask, capturing the H2S in a dry ice trap, leading it through NH3 aq to make more ammonium sulfide, or wasted by oxidising it.

You'll generally get some polystyrene and various complex product formation as well, taking the reaction product up in NaOH and filtering off the insoluble PS and other gorp cleans that up.

visitation123 - 29-4-2007 at 14:09

not_important, was the reaction tested with ethanol or pyridine?

I'm beginning to think pyridine is the way to go as you mentioned before because there's more solid literature on it....or morpholine, sulfur and styrene.

So the phenylacetamide and phenylacetic acid is relatively insoluble in the ammonium polysulfide solution and hence the ammonium polysulfide solution can be cooled to reduce solubility further and discarded as a filtrate if desired?

Thanks for all your info.

[Edited on 29-4-2007 by visitation123]

manimal - 11-2-2009 at 04:00

Evaporating the reaction slurry and extracting with hotwater will yield an additional measure of amide. JACS 12, 76 works up the reaction in the following manner.

When the mixture had cooled to room temperature, the supernatant liquid was decanted from the crystals of nearly pure amide, which were then washed with ammonium sulfide solution and recrystallized from water to give 1.36 g. of colorless phenylacetamide, m.p. 159-160C. The mother liquor from the reaction mixture was evaporated to dryness and the remaining amide was extracted from the residue with hot water, giving an additional 1.40 g. of phenylacetamide, m.p. 158-159C; total yield, 76.7%.

manimal - 4-3-2009 at 17:59

One thing I don't understand about this procedure is how the addition of ethanol can improve the reaction so much. There is a US patent that gives the following example:

A mixture of 27.2 parts of styrene, 138 parts of ammonium sulfide-sulfur solution (containing the equivalent of 12.0 M. ammonium hydroxide, 0.60 M. hydrogen sulfide, and 19.2 parts of sulfur), and 155 parts of dioxane was heated for seven hours at 160° C. From the residue obtained after evaporation of the reaction mixture to dryness 19.1 parts (54%) of phenylacetamide was isolated by extraction with hot water.

What makes ethanol so superior to dioxane in that it can increase yields and decrease the reaction time and temperature?

manimal - 14-3-2009 at 13:50

I just realized that the experimental part of the Chinese patent came straight out of Organic Reactions vol. 3. Pg. 97 states:

Phenylacetamide from Acetophenone (Use of Sulfur, Aqueous Ammonia, and Pyridine).
A mixture of 25 g. of acetophenone, 50 cc. of concentrated (15 M) aqueous ammonia, 37.5 g. of sulfur, and 30 cc. of pyridine is heated in a sealed glass tube at 150° for one hour and at 163° for three and one-half hours (heating at 165° for four hours is equally effective). The tube is cooled and opened, the contents removed, and the mixture evaporated to dryness on a water bath. The residue is extracted with approximately 500 cc. of boiling water in several portions. From the filtrate, upon cooling, 20.0 g. of phenylacetamide, m.p. 156- 58° (cor.), separates. Concentration of the filtrate affords 2.7 g. of additional amide. The oily residue from evaporation of the filtrate is washed with ether, whereupon 0.32 g. of amide separates, and from the ether layer 1.2 g. of phenylacetic acid is isolated. The acid melts at 76.3-77.3° (cor.) after recrystallization. The total yield of amide is 23.0 g. (82%), and the combined yield of amide and acid is 86%.

Phenylacetamide from Styrene (Use of Sulfur, Aqueous Ammonia, and Pyridine).
In a sealed glass tube 21.7 g. of styrene (99.5% material) is heated for four hours at 165° with the same amounts of reagents as described in the previous experiment for acetophenone; two crops of phenylacetamide are obtained, amounting to 16.1 g. (57%) of colorless plates; m.p. 158.6-160.1° (cor.). From the filtrate a second crop of 2.0 g. of crystalline phenylacetamide is obtained. This fraction contains some phenylacetic acid. The total yield of acid and amide is 64%.

So, for anyone who was wondering what concentration of ammonia was used in this reaction, there it is (15 M).

rajip - 7-3-2010 at 05:46

I read the thread and I was wondering if you could elucidate some things for me.

1. do you think ETOH should be used or Isopropyl alc? ( if EtOH would methylated spirits do the trick?) (if isopropyl - how much should be used)?_

2. Can the rxn be scaled up? e.g. can u just double or triple etc. the reagents and solvents used?

3. if an alcohol is used instead of pyridine, do u think a boiling water bath would be sufficient to heat the rxn vessel (champagne bottle)?

3. how would you hyudrolyze the phenylacetamide to phenylacetic acid?

Any help would be good.

kmno4 - 11-6-2010 at 05:02

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 :D
But my mixture has sulpury-styrene smell (not H2S), not even very strong.

kmno4 - 12-10-2010 at 01:34

I forgot to report results here :P
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

Organikum - 16-4-2014 at 19:11

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. ;)


Attachment: willgerodt-PhenylaceticAcid.pdf (320kB)
This file has been downloaded 1718 times

[Edited on 17-4-2014 by Organikum]

Nicodem - 17-4-2014 at 08:15

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.

If you need references for a Willgerodt reaction where 2-propanol is used as a solvent, here are a few for one same reaction:

JACS, 68, 2633-2634; US5041657; and Journal of Chemical and Pharmaceutical Research, 4, 375-382 (aq. NH3, S, p-hydroxyacetophenone to p-hydroxyphenylacetamide, 12h, 160 °C, 65% yield)

PEG has also been used: Green Chemistry Letters and Reviews, 3, 315-318.

DMF is one of the most commonly used solvent for this reaction, so NMP should be suitable as well (NMP is the most OTC-ish aprotic polar solvent in most European countries). I found only one example in the literature: 10th Electronic Conference on Synthetic Organic Chemistry, Nov. 1-30, 2006, e003/1-e003/7. Note that the high bp of NMP and the PEGs give a lower pressure at the required temperatures.

Organikum - 17-4-2014 at 14:29

Thanks a lot Nicodem,as it is always the same, short after posting and bemourning my lack of success finding IPA-Willgerodts I stumbled upon this here:


Patent Number: 225792
Indian Patent Application Number: 533/DEL/2003
Published: 2009

It has a good references part for those interested:


Reference may be made to U.S. Patent 2,459,706,1949 wherein the production of amides is realized by reacting aliphatic mercaptans, ammonia or amine with ammonium polysulphide or sulphur in secondary or tetairy alcohol via Willgerodt reaction. Reference may be made to U.S. Patent No. 2,572,809,1951 wherein the Willgerodt reaction between acetal and ammonium polysulphide or ammonium hydroxide and sulphur in aq. System, secondary or primary amine and sulphur in anhydrous system to produce amides. Reference may be made to U.S.Patent 2,610,980, 1952 discloses the formation of amide by reacting aromatic hydrocarbon with ammonium polysulphide or sulphur and ammonia in the presence of water as well as under anhydrous conditions. Reference may be made to U.S. Patent No.2,689,246,1954 indicates the Willgerodt reaction of unsaturated nitro compounds with ammonium polysulphide or ammonia or an amine and sulphur in aq. system for a carboxylic acid amine or an anhydrous system to form the corresponding thioamide. Reference may be made to German Patent No. 405,675 ,1924 reports the preparation of thioamide by reacting aldehyde or ketone with ammonia, primary or seconday amine with sulphur. However the only specific example utilizing ammonia gas , benzaldehyde is reacted to form thiobenzamide, Reference may be made to "The Willgerodt Reaction " synthesis 1975, p. 358 wherein reports the Willgerodt reaction of various aryl methyl ketones and other compounds with ammonium polysulphide or suphur and ammonium hydroxide in an aq. system to produce aryl acetamide or sulphur and amine such as morpholine in Willgerodt-Kindler reaction to produce thioamide. Reference may be made to "The willgerodt reaction " Vol.111 ,1946, 83 reports the Willgerodt reaction of several aryl ketones with ammonium polysulphide or sulphur and aq. ammonia to produce aromatic acetamide and also shows example of the Kindler modification involve the reaction any of various methyl aryl ketones with sulphur and amine in an anhydrous system to produce acetothioamide. Reference may be made to J. Amer. Chem. Soc. 68, 1946, 2633 describe the preparation of p-hydroxy phenyl acetamide by Willgerodt reaction of p-hydroxy acetophenone and ammonium sulphide in an aq. System.

Otherwise the patent covers whats here discussed, Willgerodt on a (substituted)acetophenone in IPA with sulfur and ammonium hydroxide.
From whats known I would dare to claim that this is will work on styrene too including some substituted species. Whats not bad to know.