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Author: Subject: propionyl chloride
Sauron
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[*] posted on 14-4-2008 at 19:09


That is the H.C.Brown article, I believe. Chemrox is well aware of it. It's a good procedure as long as the target acyl chloride is volatile enough and propionyl chloride certainly is.

I was going to use this method to prepare chloroacetyl chloride, and still might. I have the chloroacetic acid and benzoyl chloride. But I think I will try the GAA + TCCA method to make chloroacetic acid and then use TCT to get to the chloride. Save the benzoyl chloride for something more interesting.




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[*] posted on 8-7-2015 at 01:06


I tried the Comptes Rendus, 121 1155-6 (1895) method using HCl gas bubbling through chilled acetonitrile and glacial acetic acid.

The gas dissolved in the liquid very readily to the point that I ran out of salt and so didn't even get to see where saturation point was, even using 25% more than the theoretical amount (i.e. 2 x molar equivalents + 25%).

Left overnight the resulting liquid generated pretty snowflake crystals and on distillation the fuming liquid that was decanted off yielded a small amount (8% based on acetic acid) of acetyl chloride.

So this works but needs some playing around to get a better yield (my first attempt at the reaction so I assume the bad yield is my inexperience rather than the reaction itself at this stage). Definitely has potential I think as a non-CWC route to acyl chlorides...

The usual video shows the process I followed: https://www.youtube.com/watch?v=Q2ArDw0vf2Q




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[*] posted on 8-7-2015 at 08:33


Your video is, as usual, very well presented. Have you seen my similar method?:

http://www.sciencemadness.org/talk/viewthread.php?tid=32991#...

Who owns the sexy female voice of the narrator in your videos? She has such a steady, almost metered, delivery. All her words have a nice lilting inflection, being almost musical. ;)




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[*] posted on 9-7-2015 at 21:16


Yes I saw that - very nice!

It seems relatively easy to convert anhydride to chloride and chloride to anhdride (heat with sodium acetate and then fractionally distill the product - we tried this and it works ok), but not so easy to get the chloride / anhydride in the first place from other sources without using the usual highly restricted reagents.

We're also having a play with the sodium pyrosulfate route to the anhydride although actually making even vaguely pure pyrosulfate is extremely difficult even with accurate temperature control. If this has any success then we'll create a video on this too, but at the moment our instinct is that it won't be viable.

Why that is Tess, our corporate spokeswoman :)




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[*] posted on 10-7-2015 at 09:24


acetic anhydride is a tricky one. It is currently available from the secondary market in the US. However, I understand many countries have it banned or restricted.

Making it using sulfur halides is feasible for the home chemist. See my procedure in Prepublication. The key to making this a facile procedure is to use some of the anhydride as a solvent, I believe. So once you have some on hand making it becomes much easier.

Hi Tess!




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[*] posted on 10-7-2015 at 10:25


Why can't you just use anhydrous acetic acid as initial solvent? Contamination of anhydride with acetic acid is completely acceptable.
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[*] posted on 12-7-2015 at 00:15


Magpie, your method intrigues me and makes me wonder if it's possible to produce some aromatic acid chlorides in the same way.

I wonder if phthalic anhydride would react with HCl gas (perhaps molten, or in a solvent system) to produce an acid chloride, or perhaps even a 'half chloride' (I guess this might convert into the full chloride and phthalic acid).

I will do some experiments with this and see...




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