Effect of Metal/Acid Balance in Pt-Loaded Large Pore Zeolites on the Hydroisomerization of n-Hexane and n-Heptane

Lee JK; Rhee HK

Korean Journal of Chemical Engineering, Vol.14, No.6, 451-458, November, 1997

Large-pore zeolites H-Beta, H-Mordenite and H-Omega were loaded with platinum and applied for the hydroisomerization of n-hexane and n-heptane. The catalytic activity of Pt-loaded zeolite showed good correlation with the effective acidity probed by pyridine rather than with the total acidity probed by ammonia when equal amounts of metal sites are present. The selectivity to multibranched isomers over three different catalysts was found dependent upon the conversion of n-paraffin. At low conversion, the selectivity to multibranched isomers was higher over Pt-loaded zeolites with high acid strength. At high conversion level, however, the selectivity was mainly governed by the metal/acid balance. On H-Mordenite and H-Omega, large amount of strong acid sites are located in the small pore or cage. In Pt/H-MOR, the metal/acid balance was poor because there was detrimental loss of metal sites caused by isolation of Pt in the side pockets of 8-MR and/or pore blockage of the linear 12-MR channel. Even though the acidity of H-Beta was very low compared to H-MOR and H-Omega, Pt/H-Beta yielded the best performance for the hydroisomerization of n-paraffin because of better metal/acid balance in Pt/H-Beta.

Keywords:Pt/Zeolite;Hydroisomerization;n-Hexane;n-Heptane;Metal/Acid Balance

[References]

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Buckermann WA, Huong CB, Fajula F, Gueguen C, Zeolites, 13, 448 (1993)
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Giannetto GE, Perot GR, Guisnet MR, Ind. Eng. Chem. Prod. Res. Dev., 25, 481 (1986)
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Homeyer ST, Sachtler WMH, J. Catal., 118, 266 (1989)
Klinowski J, Anderson MW, J. Chem. Soc.-Faraday Trans., 82, 569 (1986)
Lee JK, Lee HT, Rhee HK, React. Kinet. Catal. Lett., 57(2), 323 (1996)
Lee JK, Rhee HK, Catal. Today, 38(2), 235 (1997)
Leu LJ, Hou LY, Kang BC, Li C, Wu ST, Wu JC, Appl. Catal., 69, 49 (1991)
Massiani P, Chauvin B, Fajula F, Figueras F, Appl. Catal., 42, 105 (1988)
Maxwell IE, Stork WHJ, Stud. Surf. Sci. Catal., 58, 571 (1990)
Mortier WJ, J. Phys. Chem. US, 81, 1334 (1977)
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Wadlinger RL, Kerr GT, Rosinski EJ, U.S. Patent, 3,308,069 (1967)
Zholobenko VL, Lei GD, Carvill BT, Lerner BA, Sachtler WMH, J. Chem. Soc.-Faraday Trans., 90(1), 233 (1994)

[Referenced By]

[1] Alvarez F, Giannetto G, Guisnet M, Perot G, Appl. Catal. A: Gen., 34, 353 (1987)

[2] Buckermann WA, Huong CB, Fajula F, Gueguen C, Zeolites, 13, 448 (1993)

[3] Chmelka BF, Rosin RR, Went GT, Bell AT, Radke CJ, Petersen EE, Stud. Surf. Sci. Catal., 49, 995 (1989)

[4] Folefoc GN, Dwyer J, J. Catal., 136, 43 (1992)

[5] Giannetto GE, Perot GR, Guisnet MR, Ind. Eng. Chem. Prod. Res. Dev., 25, 481 (1986)

[6] Guisnet MR, Perot GR, "Zeolite: Science and Technology," (Ribeiro, F.R., Rodrigues, A.E., Rollmann, L.D., Naccache, C., Eds.), Martinus Nijihoff, Hague, 397 (1984)

[7] Higgins JB, LaPierre RB, Schlenker JL, Rohrman AC, Wood JD, Kerr GT, Rohrbaugh WJ, Zeolites, 8, 446 (1988)

[8] Homeyer ST, Sachtler WMH, J. Catal., 118, 266 (1989)

[9] Klinowski J, Anderson MW, J. Chem. Soc.-Faraday Trans., 82, 569 (1986)

[10] Lee JK, Lee HT, Rhee HK, React. Kinet. Catal. Lett., 57(2), 323 (1996)

[11] Lee JK, Rhee HK, Catal. Today, 38(2), 235 (1997)

[12] Leu LJ, Hou LY, Kang BC, Li C, Wu ST, Wu JC, Appl. Catal., 69, 49 (1991)

[13] Massiani P, Chauvin B, Fajula F, Figueras F, Appl. Catal., 42, 105 (1988)

[14] Maxwell IE, Stork WHJ, Stud. Surf. Sci. Catal., 58, 571 (1990)

[15] Mortier WJ, J. Phys. Chem. US, 81, 1334 (1977)

[16] Nicolas S, Massiani P, Vera Pacheco M, Fajula F, Figueras F, Stud. Surf. Sci. Catal., 37, 115 (1988)

[17] Otten MM, Clayton MJ, Lamb HH, J. Catal., 149(1), 211 (1994)

[18] Shpiro ES, Joyner RW, Minachev KM, Pudney PDA, J. Catal., 127, 366 (1991)

[19] Stakheev AY, Shpiro ES, Tkachenko OP, Jaeger NI, Schulzekloff G, J. Catal., 169(1), 382 (1997)

[20] Wadlinger RL, Kerr GT, Rosinski EJ, U.S. Patent, 3,308,069 (1967)

[21] Zholobenko VL, Lei GD, Carvill BT, Lerner BA, Sachtler WMH, J. Chem. Soc.-Faraday Trans., 90(1), 233 (1994)