High activity magnetic core-mesoporous shell sulfonic acid silica nanoparticles for carboxylic acid esterification

Magnetically-separable solid acid nanoparticle catalysts, comprising 80 nm Fe3 O4 cores, a thin, dense silica inner shell and a mesoporous sulfonic acid silica outer shell, have been synthesized through a surfactant-templating and hydrothermal saline-promoted grafting protocol. These porous nanocomposites offer excellent activity towards propanoic acid esterification, in combination with facile recovery and re-use.