Why do we add HCl to purify an amine?

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Bert770 - 27 Jan 2004 15:02 GMT

I have to produce 4-Bromoacetanilide with 4-Bromoaniline and acetic
ahydrid.

The first manipulation of the experience is to take 2,5 g of
4-Bromoaniline, to put this in a erlenmeyer and to add 50 ml of water
with 1,3 ml of HCl.

Why do we add the HCl to purify the amine (4-Bromoaniline)?

Thanks to anybody wo will help me.

Signature

Paul J. Franklin(moderator - sci.chem.organic.synthesis)
http://organicworldwide.net/sci.chem.organic.synthesis
Georgia State University <chepjf@panther.gsu.edu>
Atlanta, GA

Reply to this Message

Uncle Al - 27 Jan 2004 19:41 GMT

> I have to produce 4-Bromoacetanilide with 4-Bromoaniline and acetic
> ahydrid.
[quoted text clipped - 4 lines]
>
> Why do we add the HCl to purify the amine (4-Bromoaniline)?

The pure chemical is colorless. What color is your starting
material? Make the hydrochloride for water solubility and to protect
against air oxidation (why does this work?). Add some activated
charcoal, swirl and maybe heat, then cool, filter with suction through
a pre-formed moist Celite pad, wash with more water. Purge with
argon, neutralize to basic, collect the precipitated clean white
bromoaniline under more inert gas and suck reasoanbly dry. Now
derivatize then isolate.

Why is adding some SOP zinc dust to the aniline purification scheme a
really bad idea?

Signature

Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
--
Paul J. Franklin(moderator - sci.chem.organic.synthesis)
http://organicworldwide.net/sci.chem.organic.synthesis
Georgia State University <chepjf@panther.gsu.edu>
Atlanta, GA

Reply to this Message

Bert770 - 28 Jan 2004 20:38 GMT

Uncle Al <UncleAl0@hate.spam.net> wrote in message news:<bv6esj$k03@panther.Gsu.EDU>...

> Bert770 wrote:

> > I have to produce 4-Bromoacetanilide with 4-Bromoaniline and acetic
> > ahydrid.

> > The first manipulation of the experience is to take 2,5 g of
> > 4-Bromoaniline, to put this in a erlenmeyer and to add 50 ml of water
> > with 1,3 ml of HCl.

> > Why do we add the HCl to purify the amine (4-Bromoaniline)?

> The pure chemical is colorless. What color is your starting
> material? Make the hydrochloride for water solubility and to protect
[quoted text clipped - 4 lines]
> bromoaniline under more inert gas and suck reasoanbly dry. Now
> derivatize then isolate.

> Why is adding some SOP zinc dust to the aniline purification scheme a
> really bad idea?

So, we add HCl "for water solubility and to protect against air
oxidation" ?
Is that ok.

Somebody told me that we add HCl to form a salt and that impurities
that are not solubles will be filtrated. Is that ok?

Signature

Paul J. Franklin(moderator - sci.chem.organic.synthesis)
http://organicworldwide.net/sci.chem.organic.synthesis
Georgia State University <chepjf@panther.gsu.edu>
Atlanta, GA

Reply to this Message

Uncle Al - 06 Feb 2004 21:33 GMT

> Uncle Al <UncleAl0@hate.spam.net> wrote in message news:<bv6esj$k03@panther.Gsu.EDU>...
> > Bert770 wrote:

> > > I have to produce 4-Bromoacetanilide with 4-Bromoaniline and acetic
> > > ahydrid.

> > > The first manipulation of the experience is to take 2,5 g of
> > > 4-Bromoaniline, to put this in a erlenmeyer and to add 50 ml of water
> > > with 1,3 ml of HCl.

> > > Why do we add the HCl to purify the amine (4-Bromoaniline)?
>
[quoted text clipped - 6 lines]
> > bromoaniline under more inert gas and suck reasoanbly dry. Now
> > derivatize then isolate.

> > Why is adding some SOP zinc dust to the aniline purification scheme a
> > really bad idea?

> So, we add HCl "for water solubility and to protect against air
> oxidation" ?
> Is that ok.
>
> Somebody told me that we add HCl to form a salt and that impurities
> that are not solubles will be filtrated. Is that ok?

Do the world and yourself a favor. Fail the course, change your
major, and let somebody who is qualified take your place as a chemist
in the great scheme of things.

Signature

Reply to this Message

LOUIS - 06 Feb 2004 21:47 GMT

Yep about solubility and purification...prevention against oxygen is another story.

Ph Z

> So, we add HCl "for water solubility and to protect against air
> oxidation" ?
> Is that ok.

> Somebody told me that we add HCl to form a salt and that impurities
> that are not solubles will be filtrated. Is that ok?

Signature

Paul J. Franklin(moderator - sci.chem.organic.synthesis)
http://organicworldwide.net/sci.chem.organic.synthesis
Georgia State University <chepjf@panther.gsu.edu>
Atlanta, GA

Reply to this Message

Natural Science Forum / Chemistry / Organic Synthesis / February 2004

Why do we add HCl to purify an amine?