The liquid phase alkylation of catechol with tert-butyl alcohol to produce4-tert-butyl catechol (4-TBC) was carried out over MCM-41, HZSM-5, H-exchanged montmorillonite andnovel acidic porous montmorillonite heterostructures (PMHs). Upon all catalysts tested, 4-TBC is themain product and 3-tert-butyl catechol (3-TBC) and 3,5-di-tert-butyl catechol are the sideproducts. The synthetic PMHs showed higher conversion of catechol and better selectivity to 4-TBCcompared to other solid acid catalysts tested. Over the PMHs derived from H-exchangedmontmorillonite through template extraction processes, the suitable reaction temperature is ca 410K, the ratio of catechol to tert-butyl alcohol is 1:2. Increasing the amount of catalyst (lowerweight hourly space velocity) can improve the conversion of catechol and influence the selectivityslightly. The reasonable reaction time is ca 8 h. The type and strength of acidity ofH-montmorillonite and PMH were determined by pyridine adsorption FT-IR and ammoniatemperature-programmed desorption techniques. The medium and strong acid sites are conducive toproducing 4-TBC and the weak acid sites to facilitating the 3-TBC formation. The differences betweenthe PMHs from calcination and those from extraction are attributed to proton migration and aciditychange in the gallery surface.
Mesoporous silicoaluminum pillared clays have been synthesized by one-potgallery-templated synthesis using organomontmorillonite, tetraethyl orthosilicate and aluminaisopropoxide as precursor. According to the characterization by powder X-ray diffraction(PXRD), thermogravimetric analysis (TGA), N2 adsorption isotherms and pyridine adsorptioninfrared (IR) techniques, the synthetic silicoaluminum pillared clays possess regular porosity withhigh thermal stability up to 750 ℃ and Br?nsted /Lewis acidity.
