Sciencemadness Discussion Board

Synthesis of phenol

jarynth - 2-10-2008 at 21:15

Does anyone have experience with the Dakin reaction to gain phenol from benzaldehyde, acetophenone, etc (R=H; R'=H, CH3, ...)?


http://www.organic-chemistry.org/namedreactions/Dakin.1.gif

In particular, could we start with salicylamide (R=ortho-OH; R'=NH2) to get catechol?

Nicodem - 2-10-2008 at 23:01

The Dakin reaction works on benzaldehydes and only exceptionally on ketones. It does not work on benzamides. Besides, even on benzaldehydes it is only works particularly well on o- and p-hydroxybenzaldehydes, while on other benzaldehydes it either work less efficiently or requires modifications. For the more troublesome benzaldehydes and acetophenones the Baeyer-Villiger oxidation is more efficient and the phenyl esters that form are easily hydrolysed to phenols (sometimes already at the reaction conditions). But not even the Baeyer-Villiger oxidation works on benzamides.

Klute - 2-10-2008 at 23:12

You could form benzonitriles from the amides, and thenr educe with copper-treated Raney nickel to obtain the aldehdye. I think certain CTH with HCOOH can do this also, there was a discussion on this not too long ago. But that would be a veerrry loong way to phenol. At that point you could even start considering starting from cumene!

Nicodem - 2-10-2008 at 23:25

That would be one hell of a synthesis of something as cheap and easily available as catechol. The cost of all the reagents and solvents used would amount to many times the price of the product. :o
Anyhow, Klute could you please post the reference to that "copper-treated Raney nickel to obtain the aldehdye". Sounds like an interesting alternative to SnCl2/HCl of which I never heard.

Klute - 3-10-2008 at 03:06

See US4500721 for the copper-treated Raney nickel reduction with atm H2, and US4383949 for an example of a CTH with formivc acid and Raney nickel (they also detail the formation of the amide, the nitrile, and acetals of the aldehyde.

jarynth - 3-10-2008 at 05:41

Quote:
Originally posted by Nicodem
The Dakin reaction works on benzaldehydes and only exceptionally on ketones. It does not work on benzamides. Besides, even on benzaldehydes it is only works particularly well on o- and p-hydroxybenzaldehydes, while on other benzaldehydes it either work less efficiently or requires modifications. For the more troublesome benzaldehydes and acetophenones the Baeyer-Villiger oxidation is more efficient and the phenyl esters that form are easily hydrolysed to phenols (sometimes already at the reaction conditions). But not even the Baeyer-Villiger oxidation works on benzamides.


Sadly enlightening. The way the general reaction was written, it looked like there was some choice for R'.

Anyway, I also looked at the following alternative routes to phenol, but am not sure about the practicalities. What do you think?

1) Decarboxylation of salicylic acid by refluxing in conc. NaOH (or solid-phase MW method).


2) (WRONG: Diazotization of nitrophenol and reduction.) RIGHT: Reduction of nitrophenol followed by diazotation :D


Both salicylic acid and ?-nitrophenol can be gained from acetylsalicylic acid, or extracted from flants. By the diazotization route we can also make benzenediols (even easier).

Toxic fine chemicals like phenol are getting increasingly harder to obtain in Europe. Every OTC recipe must be cherished.

[Edited on 3-10-2008 by jarynth]

Sauron - 3-10-2008 at 11:07

How does one diazotize nitrophenol? I think you mean reduction of o-nitrophenol, followed by diazotization in which case maybe you can get some 1,2-benzenediol.

Magpie - 3-10-2008 at 11:39

Did I miss something here, I thought you just wanted phenol?

benzoic acid --> benzene -->nitrobenzene --> aniline ---> phenol

So, any of those intermediates will get you to phenol. Yields may be low if you have to start with benzoic acid or benzene, but you will get some phenol.

jarynth - 3-10-2008 at 16:31

Quote:
Originally posted by Sauron
How does one diazotize nitrophenol? I think you mean reduction of o-nitrophenol, followed by diazotization in which case maybe you can get some 1,2-benzenediol.


:o You're obviously right, the nitrocompound is the result of the introduction of a nitro group (eg via chlorophenol and nitrite), nothing to do with diazotization (which also uses nitrite...that's what got me confused).
Quote:
Originally posted by Magpie
Did I miss something here, I thought you just wanted phenol?


I'm talking about different things at once, namely phenol and benzenediols. Sorry about the misunderstanding!

Here's a third route via an isomer of salicylic acid:
3) Anethole -(oxidation)-> 4-methoxybenzoic acid -(decarboxylation)-> anisole -(hydrolysis)-> phenol

[Edited on 3-10-2008 by jarynth]

chloric1 - 3-10-2008 at 17:03

Acetylsalicylic acid is easily hydrolysized with dilute H2SO4. Salicylic acid can simple be decarboxylated by strong heating. Some sublimation occurs but most is converted to phenol. I am interested to learn more about the NaOH route. I imagine you get sodium phenate and sodium carbonate which can be separated by 95% alcohol.

Sauron - 3-10-2008 at 19:46

He wants catechol, not phenol. Probably, substituted catechols. Of course the thread author keeps bouncing all over the map and is not being very coherent or comprehensible so thinking he wants simply phenol is not such an error.

Ephoton - 4-10-2008 at 06:52

true sauron but the title is for phenol which is still very usefull.

I do like the aspirin route though I have yet to see any documentation of it working.

why waist an aldehyde if aspirin works.

[Edited on 4-10-2008 by Ephoton]

Sauron - 4-10-2008 at 07:02

Catechols are phenols, just as resorcinols and so on are phenols, phenol itself is not the target, so useful or not, preparation of phenol itself is off topic, as it is not what the thread author is asking about.

Making phenol is trivial. There are threads on making benzene from sodium benzoate, threads on making chlorobenzene, and once you have chlorobenzene and sodium hydroxide, you are home free. See Vogel.

All you guys exploiting aspirin must own shares in Bayer.

What does it matter than the guy mistitled the thread? Should have said catechols not phenol. All you have to do is read the first post to see clearly that catechol or substituted catechols are what he is after. So don't derail the thread.

[Edited on 4-10-2008 by Sauron]

ScienceSquirrel - 4-10-2008 at 09:04

In Europe catechol is available from specialised photography supply houses for use in developer solutions.
If you appear to be a responsible individual with a legitimate reason to own the material then there is no difficulty in buying a hundred grams or so.

Sauron - 4-10-2008 at 10:00

Since in my distant and misspent youth I operated a B&W darkroom for a year or two, this does not amaze me. I have also seen mail order specialty photographic chemical suppliers advertising in USA. I did not look for catechol on their list, but it ought to be there. Kodak (after all owned by Eastman Chemical) probably sells it at theirregional offices or can at least order it in.

jarynth - 4-10-2008 at 14:12

Quote:
Originally posted by Sauron
Catechols are phenols, just as resorcinols and so on are phenols, phenol itself is not the target, so useful or not, preparation of phenol itself is off topic, as it is not what the thread author is asking about.

Making phenol is trivial. There are threads on making benzene from sodium benzoate, threads on making chlorobenzene, and once you have chlorobenzene and sodium hydroxide, you are home free. See Vogel.

All you guys exploiting aspirin must own shares in Bayer.

What does it matter than the guy mistitled the thread? Should have said catechols not phenol. All you have to do is read the first post to see clearly that catechol or substituted catechols are what he is after. So don't derail the thread.

[Edited on 4-10-2008 by Sauron]


I appreciate your contribution, but I'm interested in both. It might look like I mistitled the thread, but I started it with phenol in mind. The discussion then involuntarily broadened to include benzediols because of the sneaky -R in the Dakin rxn picture I found.

Of course the (mono-, di-, ...) chlorobenzene route to phenols is straightforward, but I wanted to explore friendlier processes that did not necessarily go through benzene and chlorine. Aspirin and anethol seem somewhat more benign to the public eye.

Ephoton - 4-10-2008 at 16:07

aspirin is cheap ;)

Sauron - 5-10-2008 at 08:06

I'm a little fuzzy about what you want and even more so about what you regard as "good" reagents and "bad" reagents.

Also what does public perception have to do with the price of beans?

Benzene might vell be regarded as nasty in EU but benzoic acid, sodium benzoate, and benzyl alcohol, not so. So you can get to benzene and chlorobenzene from there (the latter via TCCA which the public regards as wimming pool chlorinator). I fail to see how you plan to get to phenols other than through benzene, chlorobenzene, or aniline?

You can get to various catechols via essential oils like eugenol, for example. The public regards that as a toothache remedy (oil of cloves). Some of our members can tell you all about how to manipulate that molecule.

I wish you would state your problem more precisely.

jarynth - 5-10-2008 at 20:02

I'm not really stuck with a problem, since I barely used the phenol I bought long ago, and I could probably get some overpriced benzenediols legitimately as well. Rather, I started some brainstorming for ways to make these simple but interesting compounds. It's exciting to end up with an unusual compound just by carefree stirring and baking a mixture of red devil and aspirin, or some essential oil. Chlorine, after all, is a reagent used in many a dull brute force procedure. As to benzene, it's not like that only in the EU, and not even everywhere in the EU In face, I just recently came across a French site offering that, and even CCl4, as entomology killers...

Sauron - 5-10-2008 at 21:20

No one is particularly suggesting "dull brute force" chlorination of benzene. Axt has a thread on chlorobenzene via TCCA. Does that sound like dull brute force to you? Once you have chlorobenzene then your choice of lye for alkili fusion will get you phenol. See Vogel.

Do you really think catechol is overpriced? Or resorcinol? Or quinol/hydroquinone? I bet these are cheaper than the essential oils in question. Or the herbs they come from. I used to buy bulk herbs from Ricard & Frappa in Marseilles so why not ask them for a quote for cloves?

Really unless you narrow your question to a specific target, no one can help you. And having a vaguely defined horror of many reagents is simply shooting yourself in the foot before starting.

This thread is a joke!

Aliquot - 25-7-2009 at 00:42

Hi

Some on know FENTON'S REAGENT ?. This reagent turn phenol to catechol. Take a look to: http://www.h2o2.com/applications/industrialwastewater/fenton...
:D
Where on WEB can I find the Vogel?

Aliquot


JohnWW - 25-7-2009 at 01:55

Quote: Originally posted by Aliquot  

Where on WEB can I find the Vogel?

I have uploaded all of Vogel's works to rapidshare.com, and posted links for downloading them in the References section. Because Vogel himself has now been dead for 50 years, and his works must have been originally authored by him more than 50 years ago, they are now out of copyright in my country and many others. In spite of this, a few days ago I had to reupload one of his books, on Quantitative Organic Analysis, published in 1958, which had been deleted as the result of some cretin squealing to rapidshare alleging breach of copyright. (The deletion was quickly detected because I keep a tally of the total number and size of my premium-account uploads).