Schotten-Baumann Benzoylation of Diamines

Do you only get 50%? I would use DCM/NaHCO3(aq) and 1:2ratio amine/acid chloride, then wash with dil. HCl(aq) after reaction is complete, it should be very fast.

S-B conditions are lit. I was able to get better results using their conditions compared to anhydrous conditions:

THF: ~20%

THF/NaOH/NaCl, 0 C, biphasic: ~50%

Water has an amazing heat capacity, and carbonyl chlorides are stable enough when cold :-)

Its really 6 of one, half a dozen of the other.

It's an acid scavenger. It's there so suck up any protons that would prevent reaction or cause something to be reversible.

So anything that can't react in protonated form, or if protonated could reverse react.

I dont see the neccesity of using excess benzoylchloride?

So in this case is it just neutralizing the HCl, or is it soaking up the acidic hydrogen of the amine?

Usually some of it does get hydrolyzed to carboxylic acid, doesn't hurt to use an excess.

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Do you only get 50%? I would use DCM/NaHCO3(aq) and 1:2ratio amine/acid chloride, then wash with dil. HCl(aq) after reaction is complete, it should be very fast.

Seconded. I used same conditions few times and worked well. Even using NaOH as a base without any problems. Colleague of mine did lots of those and she just mix all in DCM in sep funnel, then add aq. NaOH shake few times and its done