Issue
Korean Journal of Chemical Engineering,
Vol.17, No.4, 461-467, 2000
p-Selectivity of the Al-MFI Substitutional Series in Alkylation of Toluene
Al-MFI and various kinds of metallosilicates were synthesized hydrothermally under various conditions. When fumed silica was as the Si source, we could observe a regular variation in the crystal morphology from cubic to planar shape of elongated prism as the Si/Al ratio of the Al-MFI increased. For metallosilicates the reversed variation in morphology was detected with respect to the amount of metal per unit cell. In regard to the crystal symmetry, the transition from orthorhombic to monoclinic phase took place as the Si/Al ratio changed from 63 to 99, whereas all the metallosilicates had orthorhombic phase because of the metal ions present in the non-framework. A careful XRD analysis indicated that the intensity ratio of the 8.8o 2θ peak to the 7.8o 2θpeak was strongly influenced by the moprphology. It turned out that, as the peak ratio increased, the morphology tended to change from cubic to planar shape. This leads to the speculation that the p-selectivity might be related to the said peak ratio and this was confirmed by experimental data obtained from toluene alkylation.
[References]
  1. Argauer RJ, Landolt GR, U.S. Patent 3,762,888, 1972
  2. Cejka J, Zilkova N, Wichterlova B, Edermirth G, Lercher JA, Zeolites, 17, 265, 1996
  3. Fang LY, Liu SB, Wang I, J. Catal., 185(1), 33, 1999
  4. Gabelica Z, Blom N, Derouane EG, Appl. Catal., 5, 227, 1983
  5. Jansen JC, Engelen CWR, van Bekkum H, "Crystal Growth Regulation and Morphology of Zeolite Single Crystals of the MFI Type," Zeolite Synthesis, Occelli, M.L. and Robson, H.E., eds., ACS Symp. Ser., Am. Chem. Soc., Washington DC, 398, 257, 1989
  6. Jeong JH, "A Study on the Alkylation of Aromatic Compounds over ZSM-5 Type Catalysts," Ph.D. Thesis, Seoul Nat. Univ., Seoul, 1992
  7. Kim JK, "The Morphological Effect of MFI-Zeolite Catalysts on the para-Selectivity in Toluene Alkylation," M.S. Thesis, Seoul Nat. Univ., Seoul, 1994
  8. Masuda T, Fujikata Y, Nishida T, Hashimo K, Microporous Mater., 23, 157, 1998
  9. Mirth G, Lercher JA, J. Catal., 147(1), 199, 1994
  10. Nakamoto H, Takahashi H, Chem. Lett., 1013, 1981
  11. Paparatto G, Moretti E, Leofanti G, Gatti F, J. Catal., 105, 227, 1987
  12. Szostak R, "Molecular Sieves: Principles of Synthesis and Identification," Van Nostrand Reinhold, New York, 1989
  13. Triantafillidis CS, Evmiridis NP, Nalbandian L, Vasalos IA, Ind. Eng. Chem. Res., 38(3), 916, 1999
  14. Wu EL, Lawton SL, Olson DH, Rohrman AC, Phys. Chem., 83, 2777, 1979