Physics Journal of the Indonesian Physical Society
SURFACE STRUCTURE OF ALKYLSILYLATED HZSM-5 AS PHASE-BOUNDARY CATALYST
Hadi Nur, Ng Yun Hau, Mohd Nazlan Mohd Muhid and Halimaton Hamdan
Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
The need for cleaner environment concerns motivates the development of more efficient catalytic system. Based on this consideration, recently a novel catalyst named "Phase-boundary catalyst", a bimodal amphiphilic solid catalyst, was proposed. It was demonstrated that the catalytic system containing phase-boundary catalyst required neither stirring to make an emulsion nor addition of a co-solvent to make a homogeneous solution to drive the reaction. The driving force that has prompted this paper is to investigate the surface structure of alkylsilylated HZSM-5 as phase-boundary catalyst. Temperature Programmed Desorption (TPD) of ammonia and, 13C and 29Si MAS NMR spectroscopy were used to elucidate the surface structure of alkylsilylated HZSM-5. It is suggested the addition of small amount of water to the solid particles before alkylsilylation, as a recipe to make a bimodal amphiphilic particles, is desired to enhance the acidity of HZSM-5. The enhancement of acidity might be induced by polymeric octadecylsiloxane as elucidated by 13C and 29Si MAS NMR spectroscopy.