[JRebelo]

Ok, so I'm completely lost on how this happens. From what i could find, when o-benzoylbenzoic acid is heated with sulphuric acid, some sort of cyclization occurs and you get anthraquinone. This is apparently a well known reaction but i can't for the life of me find a mechanism of how this occurs. Any help would be greatly appreciated. Thanks.

[ooosh]

It's F-C acylation,an electrophilic substitution reaction.You can find some literatures about it in google or wiki.