Author Topic: Acyl Chlorides  (Read 111 times)

Vesp

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Acyl Chlorides
« on: August 15, 2009, 05:51:45 AM »
Acyl Chlorides are useful, and it would be nice to have an easy OTC method to them.
This is an idea I have had for a while, and I would like some feed back on it. I know most Acyl chlorides are made by adding thionyl chloride, phosphorous chlorides, etc, but Those are all annoying to deal with and hard to get..

Consider these reactions:

RCOOH + SOCl2 = RCOOCl + SO2 + HCl

SO2 + Br2 + SCl2 = SOBr2 + SOCl2


Idea: Add a liquid RCOOH to Br2, SCl2, and a small amount of SO2 to initiate the correct reaction. The SO2 added will produce SOCl2 from the Br2, and SCl2, which will be consumed by the RCOOH producing RCOOCl, SO2, and HCl. The HCl will leave, and the SO2 will react with the Br2,  and SCl2 producing more SOCl2. 

The SO2, and SCl2 work essentially as catalyst to get the halides to react properly with the RCOOH's. The only chemicals consumed in this theoretical reaction are the carboxylic acids, and the halides Chlorine and Bromine. The only products of this reaction are Organic Acid chlorides, and the Hydrogen halides Hydrogen bromide, and Hydrogen Chloride.

This would obviously lead to a run away reaction if they were all added together, but does this seem practical, and do-able?

Obviously the SO2 and HCl will not react with anything, but would the S2Cl2 and Br2 react and cause serious problems with the Acyl chloride or Acyl acid?
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Vesp

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Re: Acyl Chlorides
« Reply #1 on: August 16, 2009, 12:02:00 AM »
http://www.freepatentsonline.com/3894923.html

This patent makes me wonder two things.
One is would this produce naphthoyl chloride if you do the same thing on napthaldehyde, or would the napthalene rings get halogenated? I know it is more reactive then benzene, but I do not know if it will make much of a difference in this situation. I know naphthalene itself is easy chlorinated/brominated, while benzene is not, so this method may not be a practical way to naphthoyl chloride.

The second is if bromine could be replaced by the chlorine so one doesn't have to use such an insane amount of halides, since you could reflux the bromine continually.

I am interested in making naphthoyl bromide.  ::)

Note: I think the chlorination of the naphthyl group is inevitable and so this method will not work.
« Last Edit: August 20, 2009, 05:42:07 AM by Vesp »
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hypnos

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Re: Acyl Chlorides
« Reply #2 on: September 09, 2009, 05:16:33 AM »
vesp you have hit the nail on the head with your ideas re; see the posts

on Science Madness.org for this synthesis using OTC precursors+a good basic setup

 by "benzylchloride1" and "magpie" who have both performed the synthesis you propose with good results

its in the organic synthesis section re:acetic anhydride-near the end of the thread-some very interestig ideas there

all the best with your endeavors
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Vesp

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Re: Acyl Chlorides
« Reply #3 on: September 10, 2009, 12:04:33 AM »
This is the thread you are talking about, correct?
http://www.sciencemadness.org/talk/viewthread.php?tid=9&page=16
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hypnos

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Re: Acyl Chlorides
« Reply #4 on: October 26, 2009, 10:31:13 PM »
yep--its a long thread but its at the end--specifically look for' benzyl chloride'+'magpie's posts as they have done the rxn successfully 8) 8)
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