[gingi85]

In my Organic Physical Chemistry course, the professor mentioned a mechanism hydrolysis of benzoic esther in acid (to benzoic acid and alcohol) that goes through an acylium ion. Apparently, this is the "preferred" mechanism when there is an electron donating substituent on the aromatic ring. Is anybody familiar with what exactly this mechanism is and why it happens?

[spirochete]

Once you think about it for a second I'm sure you could reason through the mechanism and figure out why electron donating groups on benzoic ester (probably only para/ortho) would favor this mechanism.  It starts with protonation of the non carbonyl oxygen.

My text (modern physical organic chemistry) says acylium ions are favored under highly acidic conditions, even without the benefit of EDG.  The benzoic version with an EDG favors the acylium ion formation under more mild conditions.