Does someone know how to synthetise pure 3-chlorophenol, or the potential precursor (for example 3-chloroaniline) of them? Orgsyn, Vogel don't have
information.
Thank'spanziandi - 11-11-2008 at 15:17
I would imagine you would start with (benzene and nitrate it to nitrobenzene) nitrobenzene, chlorinate it yielding 3-chloronitrobenzene, then reduce
this to yield 3-chloroaniline, diazotise and hydrolyse to yield 3-chlorophenol. Alternatively start with 1,3-diaminobenzene and diazotise 1 amino
group and then treat with copper (I) chloride then diazotise and hydrolyse the second amino group. You could start with nitrobenzene, nitrate to yield
1,3-dinitrobenzene then reduce one nitro group selectively with sodium sulphide, then diazotise and chlorinate, then reduce, diazotise and hydrolyse
the second nitro group.Aqua-regia1 - 12-11-2008 at 02:15
Quote:
You could start with nitrobenzene, nitrate to yield 1,3-dinitrobenzene then reduce one nitro group selectively with sodium sulphide, then diazotise
and chlorinate, then reduce, diazotise and hydrolyse the second nitro group.
Yes, this way is workabkle, at least, when I do the OH-group -building with hydrolyse the procedure resulted a tarry mass. I need a good paper about
this methode.
By all means thank you!panziandi - 12-11-2008 at 16:06
How did you perform the hyrolysis of the diazonium? I would be worried that if you heat the bulk of the solution too quickly or not quick enough or
too hot(?), you may get the phenol reacting with excess diazonium to form azo compounds (azo dyes), these may be the tarry material seen. I would
either be carefull what temperature you perform the hydrolysis (e.g. Vogel below) or add the diazonium in small portions at a time to a boiling acid
thus hydrolysing all of the diazonium before it has a chance to react (OrgSyn below). This later method may not be best for your compound as the
3-chlorophenol is probably quite volatile in steam, and as such if this later method were to be used you may notice losses, perhaps using a condenser
it would work. What scale are you working on? Perhaps scale down would allow better heating/mixing and thus cleaner hydrolysis?
Vogel (3rd Ed) has on page 613 a preparation of Phenol from Aniline:
"Place the flask in a water bath, and heat the latter until the
temperature of the diazotised solution reaches 50°. Continue the heating
for 15 minutes or until the evolution of nitrogen ceases, taking care that
the temperature of the solution does not exceed 55°."
"To a 2-l. three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a dropping funnel is added a mixture of 600 ml. of water and
150 ml. of concentrated sulfuric acid (d 1.84). The acid solution is vigorously stirred and heated to boiling, and the cold diazonium salt solution is
added at such a rate that the boiling is not interrupted (Note 6). The time required for this addition should not exceed 30 minutes. After the
addition is completed, boiling is continued for 10 minutes and then the mixture is allowed to cool to room temperature with stirring."UnintentionalChaos - 12-11-2008 at 19:31
I don't think you're going to get a clean *looking* hydrolysis of the diazonium salt. You may find that your product only looks like a pile of tar. I
recall from a thread on preparing iodobenzene by addition of KI to the diazonium salt, that the result was a thick black oil that was then distilled
to clean product in good yield. Im seeing 214C as the b.p. You may want to consider vacuum distillation.
The above is of course irrelevant if you have attempted to distill your product, but you have not given us details.
[Edited on 11-12-08 by UnintentionalChaos]panziandi - 13-11-2008 at 09:19
I expect you would be able to use steam distillation to get the product.
