| Pages:
1
2 |
Alchemist
Hazard to Self
Posts: 93
Registered: 22-6-2002
Location: Hostton Texas
Member Is Offline
Mood: No Mood
|
|
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!
|
|
|
madscientist
National Hazard
Posts: 962
Registered: 19-5-2002
Location: American Midwest
Member Is Offline
Mood: pyrophoric
|
|
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.
|
|
|
Nick F
Hazard to Others
Posts: 439
Registered: 7-9-2002
Member Is Offline
Mood: No Mood
|
|
Heat it with NaOH, it'll help to decarboxylate it, then fractionally crystalise the Ph-Na and treat it with HCl to get phenol.
|
|
|
Alchemist
Hazard to Self
Posts: 93
Registered: 22-6-2002
Location: Hostton Texas
Member Is Offline
Mood: No Mood
|
|
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!
|
|
|
Polverone
Now celebrating 21 years of madness
Posts: 3186
Registered: 19-5-2002
Location: The Sunny Pacific Northwest
Member Is Offline
Mood: Waiting for spring
|
|
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.
|
|
|
Nick F
Hazard to Others
Posts: 439
Registered: 7-9-2002
Member Is Offline
Mood: No Mood
|
|
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...
|
|
|
madscientist
National Hazard
Posts: 962
Registered: 19-5-2002
Location: American Midwest
Member Is Offline
Mood: pyrophoric
|
|
Benzene can also be prepared from toluene and anhydrous aluminum trichloride.
I weep at the sight of flaming acetic anhydride.
|
|
|
PrimoPyro
on fire
Posts: 122
Registered: 7-8-2002
Member Is Offline
Mood: No Mood
|
|
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
|
|
|
Alchemist
Hazard to Self
Posts: 93
Registered: 22-6-2002
Location: Hostton Texas
Member Is Offline
Mood: No Mood
|
|
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.
|
|
|
PrimoPyro
on fire
Posts: 122
Registered: 7-8-2002
Member Is Offline
Mood: No Mood
|
|
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
|
|
|
Marvin
National Hazard
Posts: 995
Registered: 13-10-2002
Member Is Offline
Mood: No Mood
|
|
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.
|
|
|
Alchemist
Hazard to Self
Posts: 93
Registered: 22-6-2002
Location: Hostton Texas
Member Is Offline
Mood: No Mood
|
|
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]
|
|
|
madscientist
National Hazard
Posts: 962
Registered: 19-5-2002
Location: American Midwest
Member Is Offline
Mood: pyrophoric
|
|
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.
I weep at the sight of flaming acetic anhydride.
|
|
|
rikkitikkitavi
Hazard to Others
Posts: 192
Registered: 17-6-2002
Member Is Offline
Mood: No Mood
|
|
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
|
|
|
KABOOOM(pyrojustforfun)
Hazard to Others
Posts: 254
Registered: 12-10-2002
Location: Iran (pseudoislamic dictatorship of)
Member Is Offline
Mood: exuviating!
|
|
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.
|
|
|
snop
Harmless
Posts: 3
Registered: 2-12-2002
Member Is Offline
Mood: No Mood
|
|
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 :-) )
|
|
|
Madog
Hazard to Others
Posts: 221
Registered: 20-5-2002
Location: USA
Member Is Offline
Mood: lysergic
|
|
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
Most people outgrow their pyro tendencies, we are the ones who\'s tendencies outgrew us.
|
|
|
fluffy bunny
Harmless
Posts: 25
Registered: 17-10-2002
Location: Australia
Member Is Offline
Mood: No Mood
|
|
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!? :
|
|
|
Polverone
Now celebrating 21 years of madness
Posts: 3186
Registered: 19-5-2002
Location: The Sunny Pacific Northwest
Member Is Offline
Mood: Waiting for spring
|
|
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.
|
|
|
Madog
Hazard to Others
Posts: 221
Registered: 20-5-2002
Location: USA
Member Is Offline
Mood: lysergic
|
|
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
Most people outgrow their pyro tendencies, we are the ones who\'s tendencies outgrew us.
|
|
|
KABOOOM(pyrojustforfun)
Hazard to Others
Posts: 254
Registered: 12-10-2002
Location: Iran (pseudoislamic dictatorship of)
Member Is Offline
Mood: exuviating!
|
|
if u wanna know whether what u have synthesised is phenol...
prepare an aqueous solution of phenol divide it into three parts.
add ferric chloride to the first part, it should turn purple.
add one drop bromine into second solution, white crystals of tribromophenol will precipitate.(it's better not to dial with bromine)
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.
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
|
|
|
Praetorian
Harmless
Posts: 7
Registered: 7-11-2002
Location: Czech republic
Member Is Offline
Mood: No Mood
|
|
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!
|
|
|
Chris The Great
Hazard to Others
Posts: 463
Registered: 29-10-2004
Location: Canada
Member Is Offline
Mood: No Mood
|
|
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...
|
|
|
matei
Hazard to Others
Posts: 205
Registered: 16-9-2006
Member Is Offline
Mood: No Mood
|
|
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).
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
This sort of reaction is also partially driven by fractionating off the benzene from the reaction mixture during the reaction.
|
|
|
| Pages:
1
2 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
