Solvent for recrystallization of benzoic acid?
It can be difficult to guess at what a given compound will crystallise out from, and often there is a lot of trial and error involved.

Generally, the most 'common' type of recrystallisation involves finding a solvent in which the compound of interest is sparingly soluble at room temperature, but highly soluble at elevated temperature such that slow cooling of a saturated solution affords recrystallised material. 

If you look up the entry for benzoic acid in Purification of Laboratory Chemicals, Armagero and Perrin, several solvents are suggested: 


  Benzoic acid has been crystallised from boiling water (charcoal), aqueous acetic acid, glacial acetic acid, benzene, aqueous EtOH, petroleum ether (b 60-80C), and from EtOH solution by adding water.