(Hive Addict)
05-05-02 02:43
No 305031
      More Paths To Phenylacetic acid !
(Rated as: excellent)


Extract from page :

3. Other Methods of Preparation

The standard method of preparation of phenylacetic acid is by the hydrolysis of benzyl cyanide with either alkali[1a] or acid.[2a] The acid hydrolysis runs by far the more smoothly and so was the only one studied. There are numerous other ways in which phenylacetic acid has been formed, but none of them is of practical importance for its preparation. These methods include the following: the action of water on phenyl ketene;[3a] the hydrolysis and subsequent oxidation of the product between benzaldehyde and hippuric acid;[1] the reduction of mandelic acid;[2] the reduction of benzoylformic acid with hydriodic acid and phosphorus;[3] the hydrolysis of benzyl glyoxalidone;[4] the fusion of atropic acid with potassium hydroxide;[5] the action of alcoholic potash upon chlorophenylacetylene;[6] the action of benzoyl peroxide upon phenylacetylene;[7] the alkaline hydrolysis of triphenylphloroglucinol;[8] the action of ammonium sulfide upon acetophenone;[9] the heating of phenylmalonic acid;[10] the hydrolysis of phenylacetoacetic ester;[11] the action of hydriodic acid upon mandelonitrile.[12]

[1a] Ann. 96, 247 (1855); Ber. 14, 1645 (1881); Compt. rend. 151, 236 (1910).
[2a] Ber. 19, 1950 (1886).
[3a] Ber. 44, 537 (1911).
[1] Ann. 370, 371 (1909)a
[2] Chem. (2) 1, 443 (1865); Ber. 14, 239 (1881).
[3] Ber. 10, 847 (1877)
[4] J. prakt. Chem. (2) 82, 52, 58 (1910).
[5] Ann. 148, 242 (1868).
[6] Ann. 308, 318 (1899).
[7] J. Russ. Phys. Chem. Soc. 42, 1387 (1910); Chem. Zentr. 1911 (I) 1279.
[8] Ann. 378, 263 (1911).
[9 Ber. 21, 534 (1888); J. prakt. Chem. (2) 81, 384 (1910).
[10] Ber. 27, (1894).
[11] Ber. 31, 3163 (1898)
[12] Inaugural Dissertation of A. Kohler (1909), Univ. of Bern.

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(Hive Addict)
05-05-02 03:42
No 305043
      This patent mentions the conversion of ...  Bookmark   

This patent mentions the conversion of acetophenone to phenylacetic acid

Patent US4196299

Nobodys home
05-05-02 04:46
No 305057
      No it don't  Bookmark   

That patent is on the preparation of thienyl-2-acetic acid from thiophene. Wild goose chasing red herring.

That [7] alkaline hydrolysis of triphenylphloroglucinol is interesting in terms of theory. The phloroglucinol ring has to bee busted up.
And [8] ammonium sulfide acting on acetophenone sounds like the closest approach to a feasible route, though I may have overlooked something.

Like [9] heating phenylmalonic acid, or ...
(Chief Bee)
05-05-02 05:01
No 305064
      Organic Synthesis Online  Bookmark   

Elementary: If you go to http://www.orgsyn.org/ you'll find all volumes of Organic Synthesis in a much more readable format, with advanced search features and reaction diagrams.
(Master Searcher)
05-05-02 14:30
No 305125
      fast way  Bookmark   


The hardest thing to explain is the obvious
(Hive Addict)
05-05-02 14:33
No 305126
      side_arm you silly person  Bookmark   

That patent is on the preparation of thienyl-2-acetic acid from thiophene. Wild goose chasing red herring.

Did you even try reading past the title of the patent ?
No you didn't  ! tonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetonguetongue

Thanks for you help Rhodium and Polythenesam but orgsyn.org did not give this information in its other preparations of phenylacetic acid.

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(Chief Bee)
05-05-02 17:23
No 305146
      Basic hydrolysis of the willgerodt intermediate  Bookmark   

The Patent mentioned by Elementary in Post 305043 (Elementary: "This patent mentions the conversion of ...", Novel Discourse) is actually very interesting, not because of the reference to the reaction with acetophenone, but because of the general reaction scheme where the thioacetamide produced by the willgerodt reaction is hydrolyzed by KOH instead of the more common acid hydrolysis - which means that the sulfur is converted to K2S instead of being liberated as H2S gas, making the reaction a lot less smelly/toxic.
(Hive Addict)
05-05-02 18:48
No 305157
      Microwave willgerodt
(Rated as: excellent)



Patent US5932075

Abstract :

Examples of the Willgerodt Reaction.


Preparation of Phenylacetamide from Acetophenone

To a suspension of sulfur (15 g, 58.4 mmol) in pyridine (15 mL, 14.67 g, 185.5 mmol) and aqueous ammonia (28%; 20 mL) was added acetophenone (10 g, 83.3 mmol). The stirred mixture was heated rapidly to 185.degree. C., held at this temperature for 10 min, then rapidly cooled using the cold-finger. Concentration (reduced pressure) afforded a solid (32 g) which was suspended in ether (80 mL) then filtered, and the solid collected, washed with ether (2.times.10 mL), then suspended in boiling water (ca. 1 L) and filtered. The filtrate obtained was continuously extracted with dichloromethane (500 mL) and the organic phase evaporated. The residue was recrystallised from dichloromethane (decolourising charcoal) and dried (vacuum/P.sub.2 O.sub.5) to afford the acetamide as colourless flakes, m.p. 157-158.degree. C. (8.1 g, 72%).


Preparation of Phenylacetamide from Styrene

A mixture of sulfur (15 g, 58.4 mmol), pyridine (15 mL, 14.67 g, 185.5 mmol), aqueous ammonia (28%; 20 mL), styrene (8.66 g, 83.3 mmol) and 4-t-butylcatechol (0.23 g, 1.69 mmol) was heated to 170.degree. C. for 10 minutes then rapidly cooled using the cold-finger. Phenylacetamide was obtained upon workup (5.7 g, 51%). No impurities were detected in the .sup.1 H n.m.r. or .sup.13 C n.m.r. spectra.


The phenylacetamide can then be hydrolyzed to give phenylacetic acid.


Please also check out this excellent thread started by foxy2 Post 258134 (foxy2: "New preparation of phenylacetic acid", Chemistry Discourse)

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