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[*] posted on 23-9-2002 at 14:09
Phenol


My first post! Why, just to busy I guess!

Does anyone know of a way to convert Acetylsalicylic acid (common Aspirin) to Phenol. I have seen little tid bits but knowing more. Any idea's! Thanks!
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[*] posted on 23-9-2002 at 14:35


I haven't gotten around to doing a titration to see if this really did work, but here's my idea. Hydrate acetylsalicylic acid to acetic acid and salicylic acid. Heat the salicylic acid strongly, below its boiling point, until it ceases bubbling (salicylic acid supposedly decarboxylates when heated).



I weep at the sight of flaming acetic anhydride.
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[*] posted on 26-9-2002 at 13:49


Heat it with NaOH, it'll help to decarboxylate it, then fractionally crystalise the Ph-Na and treat it with HCl to get phenol.
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[*] posted on 26-9-2002 at 14:11


Hello all,

Thanks Nick F.. Do you have the file, name of book, or web page you got this info from? What I am relly looking for are some steps with quantities,temp.,formula's, and etc.. If I/we can get this to work good, Phenol has many uses. Phenol can even be used to make Benzene and I need this to make Aniline!
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[*] posted on 26-9-2002 at 17:45
Phenol, the hard way


I doubt that you will find any detailed guides on the process of converting acetylsalicylic acid to salicylic acid and then to phenol. After all, it's these reactions going the other way (phenol -> sodium phenolate -> sodium salicylate -> salicylic acid -> acetylsalicylic acid) that are important from a historical and commercial perspective.

However, since the Kolbe synthesis of sodium salicylate is conducted under high pressure carbon dioxide at somewhat elevated temperatures, we can infer that tilting the equilibrium the other way (by heating sodium salicylate under atmospheric pressure in ordinary air) will cause the salt to revert to sodium phenolate. The phenolate can then be treated with acid to obtain free phenol.

Do you ever buy chemicals online? Because I can tell you where you can just order aniline, benzene, and phenol.
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[*] posted on 27-9-2002 at 02:59


Sorry, but no, I don't know the name of the book I read it in. It was just a general organic chemistry book. It said that most benzoic acids could be decarboxylated into the corresponding substituted benzenes by heating with a strong acid or a strong alkali.
It also said that heating phenol with Zn produced benzene.

It would be simpler just to order it, if you can...
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[*] posted on 27-9-2002 at 04:17


Benzene can also be prepared from toluene and anhydrous aluminum trichloride.



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[*] posted on 27-9-2002 at 04:34
Easier way for benzene


You can also use AlI3 instead of AlCl3 as the Friedel-Crafts catalyst for that reaction.

The products are very easily seperable via distillation, as the products are benzene and mesitylene.

If anyone can get ahold of an acetylene tank, all it takes for benzene is catalytic CuCN to cause trimerization of acetylene to benzene.

Oh, and Ca(OH)2 is the best hydroxide for decarboxylation as far as I know.

PrimoPyro
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[*] posted on 27-9-2002 at 06:25


Hello all,

thanks to everyone! This is all good info. I like the Benzene from Tolulene, has anyone tried it? Also where have you seen this published. I have looked in a lot of Organic Chemistry books and the web also, but have never seen this reaction! Again thanks a million.
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[*] posted on 27-9-2002 at 09:09
Friedel-Crafts


Its a simple Friedel-Crafts reaction in which the methyl group on toluene gets scrambled onto other toluene molecules in the meta positions, forming two moles of benzene and one mole of mesitylene.

I have no ref for it, but Osmium brought it to our attention at the Hive, and personally, to me, his word is gold. If he says it works, then it works. My faith is in short supply these days, and I am able to take whatever he says for truth as is. That's how smart he is. Heh.

PrimoPyro
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[*] posted on 19-10-2002 at 20:51


Benzene from asprin sounds tortuous, salicylic acid can be decarboxylated to phenol is reasonable yeild, and so far as I know CaO or Ca(OH)2 with a little NaOH is indeed the best method. Turning phenol into benzene by the zinc route sounds tortuous though. The yeilds are probably very crappy.

In the US you should be able to buy benzoic acid, or sodium/potassium benzoate, decarboxylation produces benzene directly, no fractionating needed.

It might be better to nitrate first, then decarboxylate to nitrobenzene, and then do the reduction to aniline. Just some thoughts.

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[*] posted on 20-10-2002 at 15:47
Phenol


Marvin,

I have come to the conclusion you are right! I do live in Calif., but can not find Benzoic Acid antwhere. If you know where I can find it please let me know. Thanks...

P.S., Phenol from Aspirin is still a good one though as Phenol has many uses also.

P.P.S., Can Aspirin be decarboxylated directly or does it have to be converted to Salicylic Acid first? Has anyone tried this! If NOT I will try it as soon as I get some FREE time.

[Edited on 25-8-2005 by Ramiel]
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[*] posted on 20-10-2002 at 17:08


I suppose benzene might be prepared by pyrolyzing benzoic acid?

If you're looking for aniline, here's an idea for preparing it that I am about to try myself. First, prepare benzoic acid. React the benzoic acid with urea to form benzamide (or react the benzoic acid with an alcohol in the presence of sulfuric acid to yield an ester, then react with ammonia to form benzamide). Benzamide isn't much more water-soluble than benzoic acid. Then react the benzamide with calcium hypochlorite - that should yield aniline.




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[*] posted on 27-10-2002 at 12:55


bensoic acid molten together with soda-lime releases benzene.

Phenole can be synthesised from toluene which first is oxidized to benzoic acid.

The latter is converted to phenole by a copper-catalyzed oxidation with air in the molten phase at 220-250 C.
(from Ullmann)

/rickard
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[*] posted on 3-11-2002 at 18:15


I translated this procedure from my Practical Organic Chemistry (by an Iranian):

[102-95-2] C6H5OH -- work No 88

Kekule,Wurtz,Busart,Zeitschrift.f.Chem.N.F

1867.3.219 Degener,J.Pract.Chem.1878 (2) 17.344


sodium benzenesulfonate 20 g
caustic soda(NaOH) 35 g
First the NaOH is dessolved in 5 cm3 water in a nickel crucible and is heated and then the finely powdered solfonate salt is added the mixture's temperature shouldn't raise more than 250°C while stirring and performing. after it reached to 250°C, tempreture should be lowered. at first the molten mixture is in a paste form later it will become fluid and its color will change from yellow to brown. at the end (after 1 hour) it is turned into the first state. after cooling, the molten substance is dissolved in a small volume of water and the red alkaline solution which contains sodium phenate and a lot of NaOH is acidified with concentrated hydrochloric acid at low temperatures. Phenol is removed in a yellow oil form and is extracted 3 times with ether. the solution is dryed with anhydrous sodium sulfate. The ether is removed by a hot water bath. It is then distilled (boils at 185-175°C) it is observed as a colorless liquid while heating and as a solid while cooling. Yield= 6-7 g.

heat
C6H5SO3Na + NaOH ====> C6H5ONa + NaHSO3

C6H5ONa + HCl ====> C6H5OH + NaCl

sorry for my bad translation but some parts of the text are really confusing.
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[*] posted on 2-12-2002 at 13:00


hmmmm
In my contry 1000ml of Phenol (in polish langueg Fenol) cost 3 $ :-), and we don't have any problem of buy thish chemical : D

(hmm ciekawe czy na tym forum kuma cos polski jezyk khe :-) )
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[*] posted on 20-1-2003 at 18:49


today i took 5g ASA and added it to some water, i boiled it down, it crystalized, then i put the heat down and melted the stuff(SA) it bubbled, gave off nasty chokeing fumes, and then i let it cool, i got 1.5g of product, sticky, melts at around 40C



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sad.gif posted on 21-1-2003 at 04:45


Im confused. Someone sugggested turning, toluene to benzene with AlCl3, via the Friedel-Crafts reaction. However i thought that the friedel-Crafts reaction was the adding of an alkyl group to a benzene ring, using benzene, an alkyl halide and AlCl3 (as a catylist) not to take an alkyl group away!? :
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[*] posted on 21-1-2003 at 20:34
perhaps misnamed?


The reaction stated does occur, but I'm not sure the name Friedel-Crafts should be applied to it. Apparently this general reaction (conversion of Ar-R to Ar-H via Lewis acid) goes tertiary to secondary to primary alkyl groups in order of difficulty - so primary alkyl groups (like the methyl in toluene) are the hardest to remove. I found this by browsing March's Advanced Organic Chemistry, but it did not give specifics of the reaction conditions. They may be unmanageably extreme for home experimentation.
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[*] posted on 22-1-2003 at 11:39


hey, yesterday i did hte same experiment as before useing 10g of ASA and got 4 grams of shinny, translucent, brown(i cooked it a little too long) product, melts very easy, i used my hands and a lighter to make it into one mass

it is hard at room temp, the other product is stickyish at room temp and its a tarnished off white. the other product is less consistant in apearance




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[*] posted on 30-1-2003 at 18:57
if u wanna know whether what u have synthesised is phenol...


    prepare an aqueous solution of phenol divide it into three parts.


    1. add ferric chloride to the first part, it should turn purple.
    2. add one drop bromine into second solution, white crystals of tribromophenol will precipitate.(it's better not to dial with bromine)
    3. to the last solution add equal amount of NH3 solution, then add a few drops of bleach and warm. it should make a light blue color.
    4. add some NaNO2 in 5 Cm3 conc H2SO4, warm until it's completely dissolved. if u add 0.5 g phenol, the solution will turn brown but immediately changes its color into blue, now if u pour it into water it will become puce
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[*] posted on 1-2-2003 at 08:31
Phenol from dimethylketone


I have investigated the aldol reactions of carbanions leading to phorone. Hence a I met the mesithylene, via acid aldolisation of dimethylketone. I think, it's wonderful. From common aliphatic chain we can obtain stuff with aromatic centre (is it right in English?)...reaction of dimethylketone with sulphuric acid really works, I have tried it. Thus why not to try convert mesithylene (1,2,3-trimethylbenzene) to phenol. In my opinion it should be managed by powerful oxidation (acidulated CrO3), than dekarboxylation under heat and... I don't know how it could be completed.
Has anybody a solution?




The cyanides are good to digesting!
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[*] posted on 25-9-2006 at 19:12


Any results on the phenol here? I found this thread looking for other stuff, and I left some ASA on the stove to long, got lots of acetic acid fumes and thick brown goo... So I thought I'd ask if this mystery has been sovled. If not I will try a few of the above tests on my product, because if it worked I'm not going to bother extracting more ASA if phenol will work too...
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[*] posted on 26-9-2006 at 07:59


The synthesis of benzene from toluene catalyzed by AlCl3 is called transalkylation and was used in the petrochemical industry to produce benzene, but nowdays it's been abandoned because toluene is more valuable than benzene. This reaction works (yielding benzene and mesytilene) because the alkylated benzenes are more reactive in SE reactions than benzene itself (it's kind of reversed Friedel-Crafts).
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[*] posted on 26-9-2006 at 16:23


This sort of reaction is also partially driven by fractionating off the benzene from the reaction mixture during the reaction.
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