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Author: Subject: Willgerodt rxn: Styrene monomer -> phenylacetamide
Sauron
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[*] posted on 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]
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[*] posted on 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.


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]
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Nicodem
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[*] posted on 29-4-2007 at 12:26


Quote:
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.
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[*] posted on 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.
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visitation123
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[*] posted on 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]
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[*] posted on 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.

Quote:
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%.




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[*] posted on 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:

Quote:
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?




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[*] posted on 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:

Quote:
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).
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[*] posted on 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.
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[*] posted on 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.
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[*] posted on 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 ;)
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biggrin.gif posted on 16-4-2014 at 19:11
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 1387 times



[Edited on 17-4-2014 by Organikum]




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[*] posted on 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.




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[*] posted on 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:

AN IMPROVED PROCESS FOR THE PREPARATION OF p-METHOXY PHENYLACETIC ACID FROM p-METHOXY ACETOPHENONE

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

It has a good references part for those interested:

Quote:

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.


/ORG




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