Infoscience

Journal article

Differences between MFI- and MEL-Type Zeolites in Paraffin Hydrocracking

A crit. evaluation of published paraffin hydroconversion data shows that MEL-type zeolites preferentially hydrocrack paraffins where two Me groups are sepd. by a methylene group, whereas MFI-type zeolites prefer paraffins with geminal Me groups (preferably at the central carbon atom). Due to this difference in hydrocracking pathway, MEL-type zeolites will hydroisomerize a higher percentage of the feed than MFI-type zeolites at low temp., while the reverse is true at high temp. The free energies of adsorption calcd. by means of configurational bias Monte Carlo (CBMC) mol. simulations are used to explain these differences in selectivity. They show that the MEL- and MFI-type zeolites favor the formation and hydrocracking of the di-Me paraffins that have a shape commensurate with that of their pores. They indicate that the higher paraffin hydroisomerization selectivity of the MEL-type zeolites can also be explained by their higher selectivity for adsorbing linear rather than branched paraffins at high paraffin loading. At low paraffin loading this difference in adsorption selectivity disappears. Both temp. and loading effects could resolve a disparity in the literature between n-decane and n-heptane hydroisomerization selectivity data. (c) 2001 Academic Press.

    Keywords: alkane hydrocracking catalyst MFI MEL zeolite hydroisomerization shape selectivity

    Note:

    Copyright 2002 ACS

    CAPLUS

    AN 2001:819149

    CAN 136:104788

    51-6

    Fossil Fuels, Derivatives, and Related Products

    Zeolyst International,PQ R&D; Center Conshohocken,PA,USA.

    Journal

    JCTLA5

    written in English.

    Alkanes Role: FMU (Formation, unclassified), FORM (Formation, nonpreparative) (Me, dimethyl-; differences between MFI- and MEL-type zeolites in paraffin hydrocracking); Simulation and Modeling (Monte Carlo, configurational bias, free energies of adsorption calcd. by means of; differences between MFI- and MEL-type zeolites in paraffin hydrocracking); Free energy of adsorption; Hydrocracking; Hydrocracking catalysts; Reaction mechanism (differences between MFI- and MEL-type zeolites in paraffin hydrocracking); Zeolite ZSM-11; Zeolite ZSM-5 Role: CAT (Catalyst use), USES (Uses) (differences between MFI- and MEL-type zeolites in paraffin hydrocracking); Alkanes Role: CPS (Chemical process), PEP (Physical, engineering or chemical process), PROC (Process) (differences between MFI- and MEL-type zeolites in paraffin hydrocracking); Isomerization (hydroisomerization; differences between MFI- and MEL-type zeolites in paraffin hydrocracking); Pore (shape selectivity of; differences between MFI- and MEL-type zeolites in paraffin hydrocracking)

    1) Blauwhoff, P; Catalysis and Zeolites 1999, 437|2) Chen, N; Shape Selective Catalysis in Industrial Applications 1996, 38|3) Free, H; Fuel Process Technol 1993, 35, 111|4) Miller, S; Microporous Mater 1994, 2, 439|5) Jacobs, P; Faraday Discuss Chem Soc 1982, 72, 353|6) Chen, N; US 4877581 1989|7) Chester, A; EP 0155822 1985|8) Giannetto, G; Stud Surf Sci Catal 1985, 24, 631|9) Derouane, E; Farad Discuss Chem Soc 1981, 72, 331|10) Martens, J; Zeolites 1986, 6, 334|11a) Meier, W; Atlas of Zeolite Structure Types, 4th ed 1996|11b) Baerlocher, C; http://www.izastructure.org/databases/|12) Schenk, M; Angew Chemie Int Ed Engl 2001, 40, 736|13) Webb, E; Catal Lett 1998, 86, 95|14) Raybaud, P; J Catal 2001, 197, 98|15) Siepmann, J; Mol Phys 1992, 75, 59|16) Frenkel, D; J Phys: Condens Matter 1992, 4, 3053|17) De Pablo, J; J Chem Phys 1992, 967, 6157|18) Guisnet, M; Catal Today 1987, 1, 415|19) Weitkamp, J; Appl Catal 1983, 8, 123|20) Jacobs, P; Proceedings of the Fifth International Conference on Zeolites 1980, 607|21) Martens, J; Acta Chim Hung 1985, 119, 203|22) Martens, J; Appl Catal 1991, 76, 95|23) Jacobs, P; J Chem Soc Chem Commun 1981, 12, 591|24) Vlugt, T; J Phys Chem B 1999, 103, 1102|25) Bezus, A; J Chem Soc Faraday Trans II 1978, 74, 367|26) June, R; J Phys Chem 1992, 96, 1051|27) Smit, B; J Phys Chem 1994, 98, 8442|28) Maesen, T; J Catal 1999, 188, 403|29) June, R; J Phys Chem 1990, 94, 1508|30) Giannetto, G; Stud Surf Sci Catal 1984, 20, 265|31) Smit, B; Faraday Discuss 1997, 106, 93|32) Webb, E; J Phys Chem B 1999, 103, 4949|33) Haag, W; Faraday Discuss Chem Soc 1982, 72, 317|34) Post, M; Proceedings, 6th International Zeolite Conference 1983, 517|35) Voogd, P; Stud Surf Sci Catal 1990, 65, 467|36) Namba, S; Stud Surf Sci Catal 1986, 28, 661|37) Giannetto, G; Ind Eng Chem Prod Res Dev 1986, 25, 481|38) Lugstein, A; Appl Catal 1998, 166, 29|39) Martens, J; Theoretical Aspects of heterogeneous Catalysis 1990, 52|40) Hochtl, M; J Catal 2000, 190, 419|41) Weisz, P; Adv Catal 1962, 13, 137|42) Coonradt, H; Ind Eng Chem, Prod Res Dev 1964, 3, 38|43) Degnan, T; AIChE J 1993, 39, 607|44) Martens, J; Appl Catal 1986, 20, 283|45) Martens, J; Catal Today 1987, 1, 435|46) Alvarez, F; J Catal 1996, 162, 179|47a) Svoboda, G; Ind Eng Chem Res 1995, 34, 3793|47b) Martens, G; Stud Surf Sci Catal 1999, 122, 333|48) Martens, G; J Catal 2000, 195, 253|49) Kondo, J; J Phys Chem B 1999, 103, 8538|50) Froment, G; Catal Today 1987, 1, 455|51) Weitkamp, J; ACS Symposium Series 1975, 20, 1|52) DeNayer, J; Ind Eng Chem Res 1998, 37, 3691|53) Krishna, R; J Phys Chem A 1998, 102, 7727|54) Stull, D; The Chemical Thermodynamics of Organic Compounds 1987, 249

    Reference

    Record created on 2014-08-14, modified on 2016-08-09

Related material