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HCl in dioxane

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Josh Hoyne

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Jun 5, 2002, 1:45:38 PM6/5/02
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I'm about to perform a reaction that calls for the use of "dry" HCl, and
is listed as using 4M HCl in dioxane. As there is none of this currently
available in my lab, I was considering using either a combination of
acetyl chloride + methanol or benzoyl chloride + methanol to generate
the HCl in the dioxane solution. (The presence of the ester product
shouldn't be a problem.)

Does anyone have experience or a good method for this prep, or am I just
better off ordering it from Aldrich? (A Google search gives me a lot of
uses of HCl/dioxane, but nothing that I've seen on its preparation; most
every source has purchased it.)

Thanks...

--
Josh


Lab Rat

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Jun 5, 2002, 8:02:19 PM6/5/02
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"Josh Hoyne" <hoyne@F_U_SPAMuiuc.edu> wrote in message news:<K4sL8.12084$U7.1...@vixen.cso.uiuc.edu>...

If you want to guarantee that the solution is really dry, may I
suggest adding a bit of 2,2-dimethoxypropane to scavenge any water
present? The HCl wil catalyse the reaction with water. You will get
traces of methanol and acetone from the reaction with water.

Bill Walker

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Jun 6, 2002, 12:42:07 PM6/6/02
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Drip conc. H2SO4 onto solid NaCl that's been wet with a wee bit of conc.
HCl.
Bubble the HCl gas generated through conc. H2SO4 to dry it.
Periodically measure the increase in weight of the stoppered flask of
dioxane until you've absorbed the calculated amount.

I would tend to keep the dioxane in an ice bath to make the absorption of
the gas more efficient and keep it from cleaving the dioxane. Vigorous
stirring while introducing the HCl wouldn't be a bad idea either.

Bill

Artem Evdokimov

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Jun 6, 2002, 7:22:02 PM6/6/02
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Among others, a decent method is to use SOCl2 which will react with trace
water producing the relatively unreactive SO2 and dry HCl.

A.G.E.


"Josh Hoyne" <hoyne@F_U_SPAMuiuc.edu> wrote in message
news:K4sL8.12084$U7.1...@vixen.cso.uiuc.edu...

Thomas R. Burkholder

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Jun 9, 2002, 2:50:59 PM6/9/02
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Lecture bottle containing 225 g of Tech Grade (99%) HCl, or 99.995% HCl
appropriate valve/regulator from a specialty gas supplier such as BOC
or Matheson. I recommend stainless steel or Monel for the valve.
You may still have to bubble the HCl through a drying agent, but you get
less stuff than trying to make it from benzoyl chloride or SOCl2.

Tom

mohana...@gmail.com

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Mar 23, 2016, 4:01:49 AM3/23/16
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Hi everyone
If I make the reaction in order to prepare NHC. So to make this reaction I will add HCl in dioxane, and paraformaldehyde. The question is what is the importance of add HCl in dioxane and paraformaldehyde?
many thanks
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