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The following mechanism for acyl chloride hydrolysis was given by my professor :
However I do not understand why in the second step, oxygen has a partially negative charge, should it not gain a positive charge as it is bonded to three atoms, furthermore shouldn't the $\text{O}-\text{H}$ bond breaking homolytically form a $\text{H}^-$ ion and not a proton?
Should the arrow be reversed in the second step?
This reaction is mostly ignored in basic organic texts and the mechanism you give is straight out of Wikipedia with some modification. I am sure some serious study exists some where but not on the web. Please bear with me because I can't[or just don't know how to] do drawings. The first step is probably as written and is most likely slow because it involves charge separations. You are right there is a + charge on the O of water. [btw there is no homolysis involved, that generates radicals, and there is no reasonable path to generate hydride ions] The second step seems to require the participation of a base this may be loosely described as an E2 reaction where a proton is removed from the protonated O atom by another water molecule and the developing negative charge on the other oxygen expels the chloride ion. This mechanism[if plausible] requires enough water for active solvation. This mechanism possibly explains the success of the Schotten-Bauman method where base is added to the reaction as a "catalyst" [tho it is consumed]. If water is limited the base may be the attached chlorine and references do state that dry reactions evolve HCl gas. These are my thoughts on the reaction; library research is in order.
