RareEarth
Hazard to Self
Posts: 69
Registered: 1-4-2015
Member Is Offline
Mood: No Mood
|
|
Can Acyl Chlorides be prepared with Alkalai Hypochlorites (bleach)?
I haven't been able to find anything about this online. I found that Tert-Butyl Hypochlorite can be used to produce acyl chlorides, along with TCCA
(pool chlorinator).
Does anyone have experience using bleach for this purpose? The only reason I can imagine Tert-Butyl Hypochlorite reacting and bleach not, would maybe
be because of a biphasic issue, but I don't imagine this being a problem with with the carboxylic acid in the solid form.
|
|
|
Pumukli
National Hazard
Posts: 705
Registered: 2-3-2014
Location: EU
Member Is Offline
Mood: No Mood
|
|
Aren't acyl chlorides sensitive to water?
Then bleach is not a likely candidate for this.
Even biphasic reactions are unlikely (hypochlorite likes water, acyl chloride hates it...)
How is that reaction involving TCCA?
|
|
|
RareEarth
Hazard to Self
Posts: 69
Registered: 1-4-2015
Member Is Offline
Mood: No Mood
|
|
TCCA was a separate reagent, also used to produce acyl chlorides on its own, with the respective carboxylic acid.
|
|
|
softbeard
Hazard to Self
Posts: 69
Registered: 23-7-2013
Member Is Offline
Mood: moody
|
|
If you're asking 'can I use my 5% sodium hypochlorite Clorox bleach to directly make some acetyl or oxalyl chloride?' The answer is no.
Realize that most simple acyl chlorides like acetyl chloride are readily and violently hydrolyzed by water into the corresponding carboxylic acid and
hydrogen chloride. To produce acyl chlorides you need anhydrous conditions. An alkaline 5% sodium hypochlorite-water solution won't cut it.
Reagents like Tert-Butyl Hypochlorite and TCCA can undergo reactions under anhydrous conditions, but they generally act as oxidant chlorinators, not
hydrochlorinators, which is what you want. Acyl chlorides are normally produced by hydrochlorination; substituting the OH in R-C=O-OH by Cl to produce
your R-C=O-Cl. That is something that Tert-Butyl Hypochlorite or TCCA won't do.
You need reagents such as PCl5, POCl3, SOCl2, or S2Cl2, or cyanuric chloride to produce your
acyl chlorides.
Come to think of it, I think this is all related to the TCCA vs. cyanuric chloride confusion that so many people seem to have a problem with.
|
|
|
RareEarth
Hazard to Self
Posts: 69
Registered: 1-4-2015
Member Is Offline
Mood: No Mood
|
|
Hmmm, yes, I wasn't thinking about the water. Silly me.
TCCA will definitely work in this scenario, it's just a pain in the ass because it is soluble in organic, and tedious to remove. There are write ups
(on this forum I believe), for using it to chlorinate acetic acid.
One approach I am planning to try, is to use the Appel reaction to form the acyl chloride. Instead of using stochiometric quantities of
triphenylphosphine, I am going to try to use cobalt cation on a solid-support resin. Cobalt chloride works for regeneration of the catalytic cycle.
The support resin would allow its use without water. There's a few similar approaches I have in mind, but this seems to be the least tedious.
|
|
|
Pumukli
National Hazard
Posts: 705
Registered: 2-3-2014
Location: EU
Member Is Offline
Mood: No Mood
|
|
I'm still not sure about "TCCA will definitely work".
Yes, there is a thread here on chlorinating acetic acid and in that thread there is TCCA used (to make chlorine), but they are shooting for
2-chloro-acetic acid (alpha-chlorination of alkyl chain) and not for acetyl chloride (OH substitution). This is why I asked about the reference.
|
|
|
CuReUS
National Hazard
Posts: 928
Registered: 9-9-2014
Member Is Offline
Mood: No Mood
|
|
I must say,I am quite impressed with your idea.I came across the appel reaction a long time ago,but I never thought it would be used for home
chemistry because of the aryl phosphine reagent.Are you going to make that or buy it?
I found a procedure for making acyl chlorides from acids using appel reaction
| Quote: | To a suspension of 3.66 g (30 mmol) benzoic acid and 18.89 g (72 mmol) triphenylphosphine in 100 ml abs.
acetonitrile, 46.146 g (300 mmol) CCl4 were added at +2“C and the reaction mixture stirred for 2 h at +2”C.
whereupon a clear solution formed which smelled of benzoylchloride. |
from http://www.sciencedirect.com/science/article/pii/00404020938...
| Quote: | | I'm still not sure about "TCCA will definitely work". |
pumukli,I think he meant the TCT/DMF method to make acyl halides.There was, is and always will be an eternal confusion between TCCA and TCT 
[Edited on 1-8-2015 by CuReUS]
|
|
|
RareEarth
Hazard to Self
Posts: 69
Registered: 1-4-2015
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by CuReUS  |
I must say,I am quite impressed with your idea.I came across the appel reaction a long time ago,but I never thought it would be used for home
chemistry because of the aryl phosphine reagent.Are you going to make that or buy it?
|
Triphenylphosphine is an extremely easy to and safe to handle solid, and so is the oxide. It is also fairly commercially available.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
