[curiouscat]

I was planning an acylation reaction of toluene using excess acetic anhydride. What's a good way to determine the leftover acetic anhydride at end of reaction?

Normally we wash the organics & do a GC to quantitate the toluene & products. Would a GC work for anhydride too?

[discodermolide]

GC should work for the anhydride. I assume your wash is basic?
Just get your analytics people to run it through the GC.

[curiouscat]

GC should work for the anhydride. I assume your wash is basic?

Should it be? Right now they simply do a distilled water wash and it looks like we see only the Toluene and products on the GC.

If the basic wash is better I can have them try that.

Just get your analytics people to run it through the GC.

Ok I will! Thanks. Meaning, run an end sample through the GC without any wash? Correct? Just clarifying.

PS. I was afraid if the acetic acid might damage the column?

[discodermolide]

I assumed a basic wash to remove and acetic acid and anhydride, pot. carb should be good enough, 10%?
Yeah, rune the end sample through the GC.
What are the specs for acetic anhydride?

[curiouscat]

I assumed a basic wash to remove and acetic acid and anhydride, pot. carb should be good enough, 10%?

Yes, that makes sense.

Yeah, rune the end sample through the GC.
What are the specs for acetic anhydride?

Hmm...we start out with a molar excess. 20% to 40% of the anhydride. Not sure of the other specs. I assume it is close to pure Anhydride, say >98%. But I can check.

[discodermolide]

Sorry, I meant the specs for acetic anhydride in the product.

[curiouscat]

Sorry, I meant the specs for acetic anhydride in the product.

Oh, ok. I should've clarified. No specs yet. This is still in the lab stage.

Just figuring out quantitation for running a set of probing exploratory experiments.