Sciencemadness Discussion Board

How do I make Phenol from dichlorobenzene

Jmap science - 9-1-2014 at 17:28

I have a solution of sodium hydroxide in water and insoluble dichlorobenzene stirring together, I was thinking they did would forum 1,4 phenol.

There was a change in color, to yellow.

Is it working and if not how do I make phenol from paradichlorobenzene?

DraconicAcid - 9-1-2014 at 17:34

Most alkyl halides will react with hydroxide to give alcohols through nucleophilic substitution reactions. Aryl halides (such as chlorobenzene) will not do this unless there are strongly electron-withdrawing groups on the aromatic ring (trinitrochlorobenzene will react with hydroxide to give sodium pictrate, for example). If it's turning yellow, it's probably doing something, but I wouldn't hazard a guess as to what.

ETA: To get chlorobenzene to react with aqueous sodium hydroxide, you have to heat it under pressure to 300 oC, according to Brown and Foote's Organic Chemistry 3rd Ed.

[Edited on 10-1-2014 by DraconicAcid]

plante1999 - 9-1-2014 at 17:35

Maybe potassium tert-butoxide in an fatty alcohol at high heat could remove the chlorine atoms.

UnintentionalChaos - 9-1-2014 at 17:54

Quote: Originally posted by Jmap science  
I was thinking they did would forum 1,4 phenol.


ಠ_ಠ

1) It's called hydroquinone
2) It's not reacting because see DraconicAcid's post.
3) You can't make phenol from it (by any sane approach).

Metacelsus - 9-1-2014 at 18:02

Hypothesis: You could react with ammonia to form 1,4-diaminobenzene, react with hydrogen peroxide to form quinone, and then reduce the quinone.

Alternatively (and an easier, though more hazardous process), you could melt it with KOH.
http://ir.uiowa.edu/cgi/viewcontent.cgi?article=4111&con...

leu - 9-1-2014 at 18:31

At least one of the chlorine atoms would have to be removed via reductive dehalogenation which according to Houben-Weyl is rather difficult ;) As this chemical process is needed for hazardous waste disposal there have been many articles published on the subject :P Six such documents are in the attached zip file :) Phenol used to be made by hydrolysis of chlorobenzene using the Raschig-Hooker process:

http://en.wikipedia.org/wiki/Raschig%E2%80%93Hooker_process

as has been stated already it's not a cost effective or practical route :cool:

Attachment: Dechlorination.zip (866kB)
This file has been downloaded 356 times

Jmap science - 9-1-2014 at 19:01

Is there any way to make benzene from it or any useful compounds from it?

BromicAcid - 9-1-2014 at 20:30

Dechlorinating Dichlorobenzene
https://www.sciencemadness.org/whisper/viewthread.php?tid=17...

BTW UnintentionalChaos, I prefer benzene-1,4-diol over hydroquinone... there are only so many trivial names I can remember :P

leu - 10-1-2014 at 02:10

Quote:
Is there any way to make benzene from it or any useful compounds from it?


You would learn a lot more effectively by researching and reading published literature than you ever will by posting questions ;) The ACS overview mentioned in the linked thread by bbartlog is attached :cool:

Attachment: ie50218a006.pdf (329kB)
This file has been downloaded 703 times