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Generation of Brönsted acidity in AlMCM-41 by sulphation for enhanced liquid phase tert-butylation of phenol
Applied Catalysis A: General (2007)
  • Eng-Poh Ng, University Technology Malaysia
  • Hadi Nur, University Technology Malaysia
  • Ka-Lun Wong, University Technology Malaysia
  • Mohd Nazlan Mohd Muhid, University Technology Malaysia
  • Halimaton Hamdan, University Technology Malaysia
Abstract

AlMCM-41 mesoporous molecular sieve modified by impregnation with sulphuric acid in toluene possesses only Brönsted acid sites. The catalyst exhibits a high catalytic activity for tert-butylation of phenol with high selectivity to 2,4-di-tert-butylphenol in liquid phase. 27Al MAS NMR study indicates that the modification of AlMCM-41 with sulphuric acid in toluene leaves only octahedrally coordinated Al species. The tetrahedrally coordinated Al species which exist before modification with sulphuric acid in toluene being dealuminated to form extraframework octahedrally coordinated Al species. The mesoporous structure of AlMCM-41 is retained after modification, but pore size decreases by ca. 3 Å by the modification. The active sites are postulated on the basis of XRD, FTIR, 27Al MAS NMR, TGA, BET analysis and FTIR-pyridine adsorption studies that –OSO3H bonded to octahedrally coordinated Al species.

Keywords
  • Sulphation; AlMCM-41; Brönsted acid; tert-Butylation; Phenol
Disciplines
Publication Date
June, 2007
Citation Information
Eng-Poh Ng, Hadi Nur, Ka-Lun Wong, Mohd Nazlan Mohd Muhid, et al.. "Generation of Brönsted acidity in AlMCM-41 by sulphation for enhanced liquid phase tert-butylation of phenol" Applied Catalysis A: General Vol. 323 (2007)
Available at: http://works.bepress.com/hadi_nur/22/