Friedel-Crafts green alkylation of xylenes with tert-butanol over mesoporous superacid UDCaT-5

► Friedel-Crafts green alkylation of xylenes with tert-butanol. ► Mesoporous superacidic catalysts named as UDCaT-4, UDCaT-5 and UDCaT-6. ► UDCaT-5 (most active) > UDCaT-6 > UDCaT-4 > sulfated zirconia. ► Very high sulfur content and preservation of tetragonal phase in UDCaT-5. ► 96% conversion with 82% selectivity towards 5-tert-butyl-m-xylene.