[harmonic_op]

Hello everyone,


Can anyone help me with synthesis of 2-nitrobenzoyl chloride?


Thanks

[rolnor]

Can you use o-nitrotoluene as starting material maybe? Why do you want to make it and not buy it?

[clarkstill]

You can obviously make it from 2-nitrobenzoic acid, but a word of caution: i made about 200 mL of this during my PhD and purified it by vacuum distillation. Once I'd finished, I foolishly let air into the distillation kit before it was fully cooled to room temperature - it exploded pretty violently, but luckily while I (and everyone else) was elsewhere in the lab. The glass thermometer was projected into the ceiling of the fumehood and pretty much turned into sand by the impact.

So, be careful and use appropriate PPE (e.g. blast shield) if you're inclined to make this on a large scale.

[wildfyr]

What caused the explosion? This compound doesn't seem shock sensitive.

[rolnor]

The first lab i worked in have had similar accident with distillation of o-nitrotoluene, when air was let in the apparatus a flame shot out from it and left a deep mark in the thick plastic blast-shield they used.

[harmonic_op]

You can obviously make it from 2-nitrobenzoic acid, but a word of caution: i made about 200 mL of this during my PhD and purified it by vacuum distillation. Once I'd finished, I foolishly let air into the distillation kit before it was fully cooled to room temperature - it exploded pretty violently, but luckily while I (and everyone else) was elsewhere in the lab. The glass thermometer was projected into the ceiling of the fumehood and pretty much turned into sand by the impact.

So, be careful and use appropriate PPE (e.g. blast shield) if you're inclined to make this on a large scale.

Thank you for the heads up i didnt knew that it is an unstable product.

[clarkstill]

What caused the explosion? This compound doesn't seem shock sensitive.

Hard to know, all that was left was black char! Like I say, it was the stuff left in the still pot that went up, and only when exposed to air, but that's all I know. It totally caught me by surprise because, like you say, I hadn't expected it to be a major hazard.

[clarkstill]

Although looking just now, the EROS entry mentions explosion during distillation.

https://onlinelibrary.wiley.com/doi/abs/10.1002/047084289X.rn030

Just goes to show it’s worth doing your due diligence, especially when scaling up...

[wildfyr]

Trace iron or aluminum, presence of HCl from acid chloride forms some Al/FeCl3, makes the ketone via friedel-krafts acylation upon heating, that is the explosive when some moisture hits or it cools and crystallizes?

[rolnor]

I think the nitro-group de-activates the ring and inhibits Friedel Craft? Also the carbonyl is de-activating.

[wildfyr]

Certainly true, but you are heating this up quite a bit! BP=148°C at 9mmHg

[clarkstill]

Text from Brethrick:

"The hot material remaining after vacuum stripping of solvent up to 130°C decom-posed with evolution of gas and then exploded violently 50 min after heating hadceased. Further attempts to distil the acid chloride even in small amounts at below1.3 mbar  caused  exothermic  decomposition  at  110°C.  It  was,  however,  possibleto flash-distil the chloride in special equipment [1]. Two later similar publicationsrecommend  use  in  solution  of  the  unisolated  material  [2].  Smaller  scale  distilla-tion of the chloride at 94 – 95°C/0.03 mbar had been uneventful, but a 1.2 mol scalepreparation exploded during distillation at 128°C/1.2 mbar [3], even in presence ofphosphorus pentachloride, previously recommended to reduce the danger of explo-sion during distillation [4]. Many previous explosions had been reported, and theneed for adequate purity of intermediates was stressed. It is shock sensitive [5]"

[wildfyr]

What caused the explosion? This compound doesn't seem shock sensitive.

Guess I was wrong! Careful handling this bad boy!

Probably the way to do this is take 2-nitrobenzoic acid and dissolve it in thionyl chloride overnight, then just distill the thionyl chloride off at room temp under reduced pressure, then use the crude. You won't get it much purer than that anyhow.

[rolnor]

You can just buy it, its not so expensive
https://www.sigmaaldrich.com/catalog/search?term=2-Nitrobenzoyl+chloride&interface=Product%20Name&N=0+&mode=mode%20matchpartialmax&lang=en&region=SE&focus=productN=0%20220003048%20219853286%20219853235
If you follow the link there is a also abstract on the explosive nature of this material.

[hollytara]

Any compound with a nitro group is worth treating with caution.  There are certain functional groups that need to be respected - azides, nitro compounds, azo and diazo compounds, peroxides... 

I remember reading (in the original german) how 18 mg of dimethylamino azide blew off a technician's hand.