N-Heptane hydroconversion over nickel-loaded aluminum- and/or boron-containing BEA zeolites prepared by recrystallization of magadiite varieties

R. M. Mihályi, F. Lónyi, H. K. Beyer, A. Szegedi, M. Kollár, Borbély G. Páł, J. Valyon

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13 Citations (Scopus)

Abstract

Phase-pure [Al]BEA and [Al,B]BEA zeolites, prepared by solid-state recrystallization of synthetic aluminum-containing magadiites and conventionally synthesized [B]BEA, were tested, after ion exchange with nickel, as bifunctional catalysts for hydroconversion of n-heptane. The reducibility of nickel ions incorporated into BEA zeolites by ion exchange was investigated by temperature-programmed reduction (TPR). The acidity of the samples was characterized with strong (pyridine (Py) and ammonia (NH3)) and weak (nitrogen) bases. The adsorbed bases were studied by transmission FT-IR (Py), diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy (N 2), and temperature-programmed ammonia evolution (TPAE, NH 3). Over Ni/H-[B]BEA the reactants were completely converted via fast hydrogenolysis, whereas this reaction pathway plays only a negligible role in the hydroconversion over Ni/H-[Al]BEA and Ni/H-[Al,B]BEA zeolites. Boron-containing BEA zeolites were less active catalysts than the boron-free catalyst in the principal unimolecular hydroconversion reactions. However, incorporation of boron into the framework of BEA zeolite results in a considerable selectivity shift toward isomerization. Results suggest that the acid strength of bridged hydroxyls, probed with weak (N2) and strong basis (pyridine), was found to be similar in the boron-free and boron-containing BEA samples. The decrease in the isomerization rate and the increase of the apparent activation energy upon incorporation of boron may be attributed to the decrease in the heat of n-heptane adsorption.

Original languageEnglish
Pages (from-to)77-88
Number of pages12
JournalJournal of Molecular Catalysis A: Chemical
Volume367
DOIs
Publication statusPublished - Feb 2013

Fingerprint

Zeolites
Heptanes
Boron
Heptane
heptanes
Nickel
Aluminum
zeolites
boron
nickel
aluminum
Pyridine
pyridines
Isomerization
Ammonia
catalysts
isomerization
Catalysts
ammonia
Ion exchange

Keywords

  • [Al,B]BEA-type zeolites
  • Acidity
  • Adsorption heat
  • Bifunctional Ni/H-BEA
  • n-Heptane hydroconversion

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry
  • Process Chemistry and Technology

Cite this

@article{86a92307e8e747a4bb9e2dfc41097b81,
title = "N-Heptane hydroconversion over nickel-loaded aluminum- and/or boron-containing BEA zeolites prepared by recrystallization of magadiite varieties",
abstract = "Phase-pure [Al]BEA and [Al,B]BEA zeolites, prepared by solid-state recrystallization of synthetic aluminum-containing magadiites and conventionally synthesized [B]BEA, were tested, after ion exchange with nickel, as bifunctional catalysts for hydroconversion of n-heptane. The reducibility of nickel ions incorporated into BEA zeolites by ion exchange was investigated by temperature-programmed reduction (TPR). The acidity of the samples was characterized with strong (pyridine (Py) and ammonia (NH3)) and weak (nitrogen) bases. The adsorbed bases were studied by transmission FT-IR (Py), diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy (N 2), and temperature-programmed ammonia evolution (TPAE, NH 3). Over Ni/H-[B]BEA the reactants were completely converted via fast hydrogenolysis, whereas this reaction pathway plays only a negligible role in the hydroconversion over Ni/H-[Al]BEA and Ni/H-[Al,B]BEA zeolites. Boron-containing BEA zeolites were less active catalysts than the boron-free catalyst in the principal unimolecular hydroconversion reactions. However, incorporation of boron into the framework of BEA zeolite results in a considerable selectivity shift toward isomerization. Results suggest that the acid strength of bridged hydroxyls, probed with weak (N2) and strong basis (pyridine), was found to be similar in the boron-free and boron-containing BEA samples. The decrease in the isomerization rate and the increase of the apparent activation energy upon incorporation of boron may be attributed to the decrease in the heat of n-heptane adsorption.",
keywords = "[Al,B]BEA-type zeolites, Acidity, Adsorption heat, Bifunctional Ni/H-BEA, n-Heptane hydroconversion",
author = "Mih{\'a}lyi, {R. M.} and F. L{\'o}nyi and Beyer, {H. K.} and A. Szegedi and M. Koll{\'a}r and P{\'a}ł, {Borb{\'e}ly G.} and J. Valyon",
year = "2013",
month = "2",
doi = "10.1016/j.molcata.2012.09.030",
language = "English",
volume = "367",
pages = "77--88",
journal = "Journal of Molecular Catalysis A: Chemical",
issn = "1381-1169",
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TY - JOUR

T1 - N-Heptane hydroconversion over nickel-loaded aluminum- and/or boron-containing BEA zeolites prepared by recrystallization of magadiite varieties

AU - Mihályi, R. M.

AU - Lónyi, F.

AU - Beyer, H. K.

AU - Szegedi, A.

AU - Kollár, M.

AU - Páł, Borbély G.

AU - Valyon, J.

PY - 2013/2

Y1 - 2013/2

N2 - Phase-pure [Al]BEA and [Al,B]BEA zeolites, prepared by solid-state recrystallization of synthetic aluminum-containing magadiites and conventionally synthesized [B]BEA, were tested, after ion exchange with nickel, as bifunctional catalysts for hydroconversion of n-heptane. The reducibility of nickel ions incorporated into BEA zeolites by ion exchange was investigated by temperature-programmed reduction (TPR). The acidity of the samples was characterized with strong (pyridine (Py) and ammonia (NH3)) and weak (nitrogen) bases. The adsorbed bases were studied by transmission FT-IR (Py), diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy (N 2), and temperature-programmed ammonia evolution (TPAE, NH 3). Over Ni/H-[B]BEA the reactants were completely converted via fast hydrogenolysis, whereas this reaction pathway plays only a negligible role in the hydroconversion over Ni/H-[Al]BEA and Ni/H-[Al,B]BEA zeolites. Boron-containing BEA zeolites were less active catalysts than the boron-free catalyst in the principal unimolecular hydroconversion reactions. However, incorporation of boron into the framework of BEA zeolite results in a considerable selectivity shift toward isomerization. Results suggest that the acid strength of bridged hydroxyls, probed with weak (N2) and strong basis (pyridine), was found to be similar in the boron-free and boron-containing BEA samples. The decrease in the isomerization rate and the increase of the apparent activation energy upon incorporation of boron may be attributed to the decrease in the heat of n-heptane adsorption.

AB - Phase-pure [Al]BEA and [Al,B]BEA zeolites, prepared by solid-state recrystallization of synthetic aluminum-containing magadiites and conventionally synthesized [B]BEA, were tested, after ion exchange with nickel, as bifunctional catalysts for hydroconversion of n-heptane. The reducibility of nickel ions incorporated into BEA zeolites by ion exchange was investigated by temperature-programmed reduction (TPR). The acidity of the samples was characterized with strong (pyridine (Py) and ammonia (NH3)) and weak (nitrogen) bases. The adsorbed bases were studied by transmission FT-IR (Py), diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy (N 2), and temperature-programmed ammonia evolution (TPAE, NH 3). Over Ni/H-[B]BEA the reactants were completely converted via fast hydrogenolysis, whereas this reaction pathway plays only a negligible role in the hydroconversion over Ni/H-[Al]BEA and Ni/H-[Al,B]BEA zeolites. Boron-containing BEA zeolites were less active catalysts than the boron-free catalyst in the principal unimolecular hydroconversion reactions. However, incorporation of boron into the framework of BEA zeolite results in a considerable selectivity shift toward isomerization. Results suggest that the acid strength of bridged hydroxyls, probed with weak (N2) and strong basis (pyridine), was found to be similar in the boron-free and boron-containing BEA samples. The decrease in the isomerization rate and the increase of the apparent activation energy upon incorporation of boron may be attributed to the decrease in the heat of n-heptane adsorption.

KW - [Al,B]BEA-type zeolites

KW - Acidity

KW - Adsorption heat

KW - Bifunctional Ni/H-BEA

KW - n-Heptane hydroconversion

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U2 - 10.1016/j.molcata.2012.09.030

DO - 10.1016/j.molcata.2012.09.030

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AN - SCOPUS:84871715171

VL - 367

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EP - 88

JO - Journal of Molecular Catalysis A: Chemical

JF - Journal of Molecular Catalysis A: Chemical

SN - 1381-1169

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