12-Tungstophosphoric acid immobilized on modified macroporous phenol-furfural sulfonic acid resin for tert-butylation of p-cresol.

12-Tungstophosphoric acid (HPW) had been immobilized on phenol-furfural sulfonic acid resin (PFuSR) using γ-aminopropyltriethoxy silane (KH). FT-IR spectra indicate that the immobilized HPW on KH modified PFuSR (PFuSR-KH) keeps its Keggin structure and IR subtraction spectra confirm the immobilization of HPW on PFuSRKH through the interaction between amino groups of KH and bridge oxygen atom of W₃O₁₃. XRD patterns of the HPW illustrate that its second-order structure is changed greatly after being immobilized. The immobilized HPW on KH-modified PFuSR not only maintains its selectivity but also possesses high acidic activity in catalyzing t-butylation of p-cresol with t-butanol, though the by-product water hindered the reaction. The PFuSR-KH-immobilized HPW loses only half of its activity after being reused five times, while the PFuSR-supported one has no catalytic activity in the second run.