The production of phenyl salicylate (salol) from phenol over solid acid catalysts

Objective: The production of salol over acid activated fly ash catalyst (AAFA) and their application in pharmaceuticals.Methods: An efficient solid acid catalyst (AAFA) has been synthesized by mechanical and thermal activation of F-type fly ash (SiO2 and Al2O3>70%) followed by chemical activation using concentrated acid at 110ºC. The activation of fly ash resulted in increased silica content (79%) and surface area (5.42 m2/g) having sufficient silanol activity for esterification of salicylic acid and phenol to give phenyl salicylate (salol), which is used in suntan lotions as an antiseptic and pain-relieving agent. The Catalyst was characterized by XRD, FT-IR, and SEM techniques.Results: The product is a mild analgesic, antiseptic and an important fine chemical intermediate, widely used in pharmaceutical. The catalyst was completely recyclable without significant loss in activity up to five reaction cycles, which confers its stability during reaction.Conclusions: The work reports an innovative use of solid waste fly ash as an effective solid acid catalyst in the production of salol.