TY - JOUR
T1 - Active copper species in 1-butene skeletal isomerization
T2 - Comparison between copper-modified MCM-41 and beta catalysts
AU - Nieminen, V.
AU - Kumar, N.
AU - Datka, J.
AU - Päivärinta, J.
AU - Hotokka, M.
AU - Laine, E.
AU - Salmi, T.
AU - Murzin, D. Yu.
N1 - Funding Information:
This work is part of the activities at the Åbo Akademi Process Chemistry Group within the Finnish Centre of Excellence Programme (2000–2005) by the Academy of Finland. Financial support from Fortum Foundation and Tutkimuksen edistämissäätiö is gratefully acknowledged.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2003/6/19
Y1 - 2003/6/19
N2 - The role of copper was studied in the skeletal isomerization of 1-butene over copper-modified mesoporous MCM-41 molecular sieve and Beta zeolite. The Cu-H-MCM-41 and Cu-H-Beta catalysts were synthesized in our laboratory and characterized by XRD, nitrogen adsorption, X-ray fluorescence, FTIR of adsorbed pyridine and direct current plasma atomic emission spectrometry. The oxidation state of copper after oxidation and reduction in Cu-H-MCM-41 was evaluated by FTIR with probe molecules. Copper ion-exchanged and the proton forms of MCM-41 and Beta catalysts were tested towards 1-butene skeletal isomerization by varying the weight hourly space velocity and temperature. Quantum chemical calculations at the B3LYP/6-31 + G** level were performed in order to understand the role of copper at the molecular level. Copper in Cu-H-MCM-41 pretreated in synthetic air was mostly in the form of Cu2+ but reduced during the catalytic experiment to the metallic form Cu0 via Cu+. Even if the copper exchange decreased the amount of Brønsted acid sites, Cu-H-MCM-41 pretreated in synthetic air was more active than H-MCM-41 towards 1-butene skeletal isomerization. The enhanced catalytic activity is due to copper Cu+, which was formed during the reaction. Introduction of copper into H-Beta, however, did not have any effect at all on the performance of the catalyst. The probable reason for this is the high initial activity of copper-modified H-Beta causing a very fast reduction of copper to the inactive metallic form Cu0.
AB - The role of copper was studied in the skeletal isomerization of 1-butene over copper-modified mesoporous MCM-41 molecular sieve and Beta zeolite. The Cu-H-MCM-41 and Cu-H-Beta catalysts were synthesized in our laboratory and characterized by XRD, nitrogen adsorption, X-ray fluorescence, FTIR of adsorbed pyridine and direct current plasma atomic emission spectrometry. The oxidation state of copper after oxidation and reduction in Cu-H-MCM-41 was evaluated by FTIR with probe molecules. Copper ion-exchanged and the proton forms of MCM-41 and Beta catalysts were tested towards 1-butene skeletal isomerization by varying the weight hourly space velocity and temperature. Quantum chemical calculations at the B3LYP/6-31 + G** level were performed in order to understand the role of copper at the molecular level. Copper in Cu-H-MCM-41 pretreated in synthetic air was mostly in the form of Cu2+ but reduced during the catalytic experiment to the metallic form Cu0 via Cu+. Even if the copper exchange decreased the amount of Brønsted acid sites, Cu-H-MCM-41 pretreated in synthetic air was more active than H-MCM-41 towards 1-butene skeletal isomerization. The enhanced catalytic activity is due to copper Cu+, which was formed during the reaction. Introduction of copper into H-Beta, however, did not have any effect at all on the performance of the catalyst. The probable reason for this is the high initial activity of copper-modified H-Beta causing a very fast reduction of copper to the inactive metallic form Cu0.
KW - Beta zeolite
KW - Butene skeletal isomerization
KW - Copper ion exchange
KW - FTIR
KW - Mesoporous MCM-41
UR - http://www.scopus.com/inward/record.url?scp=0038506201&partnerID=8YFLogxK
U2 - 10.1016/S1387-1811(03)00337-8
DO - 10.1016/S1387-1811(03)00337-8
M3 - Article
AN - SCOPUS:0038506201
SN - 1387-1811
VL - 60
SP - 159
EP - 171
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
IS - 1-3
ER -