Dehydration of lactic acid to acrylic acid over lanthanum phosphate catalysts: the role of Lewis acid sites

Aromatization of n-hexane over zinc-modified ZSM-5 zeolites was investigated. It was shown that incorporation of zinc by ion exchange into cationic positions of NH4-ZSM-5 zeolite causes acid-site strength redistribution and generation of new relatively strong Lewis acid sites in zeolite increasing the selectivity of n-hexane aromatization in comparison with the parent NH4-ZSM-5 zeolite. Simultaneous presence of Lewis and Broensted acid sites in ZSM-5 zeolite does not affect the strength of Broensted acid sites in zeolite. For the activity/selectivity of aromatization of n-hexane on Zn-modified ZSM-5 zeolites, the amount of Zn and its localization in the cationic positions are decisive. The reaction of n-hexane can be also initiated by the Zn species alone in the cationic positions. ZnO species alone as an extraframework phase was found inactive in the catalyst for aromatization of n-hexane. The influence of ZnO addition on the performance of pure ammonium forms of ZSM-5 zeolites in n-hexane conversion is a result of partial migration of zinc into cationic positions of zeolite by solid-state ion exchange.

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The role of weak Lewis acid sites for methanol thiolation

Catalysis Science & Technology ◽

10.1039/c8cy02250j ◽

2019 ◽

Vol 9 (2) ◽

pp. 509-516 ◽

Cited By ~ 4

Author(s):

Manuel Weber-Stockbauer ◽

Oliver Y. Gutiérrez ◽

Ricardo Bermejo-Deval ◽

Johannes A. Lercher

Keyword(s):

Lewis Acid ◽

Active Sites ◽

Acid Sites ◽

Lewis Acid Sites ◽

Strong Base

Weak Lewis acid sites combined with strong base sites of Cs+ supported on WS2 and γ-Al2O3 are the active sites in the thiolation of methanol.

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Combined IR and catalytic studies of the role of lewis acid sites in creating acid sites of enhanced catalytic activity in steamed HZSM-5

Studies in Surface Science and Catalysis - Impact of Zeolites and other Porous Materials on the new Technologies at the Beginning of the New Millennium, Proceedings of the 2nd International FEZA (Federation of the European Zeolite Associations) Conference ◽

10.1016/s0167-2991(02)80059-3 ◽

2002 ◽

pp. 439-444

Author(s):

J. Datka ◽

B. Gil ◽

P. Baran ◽

B. Staudte

Keyword(s):

Catalytic Activity ◽

Lewis Acid ◽

Acid Sites ◽

Lewis Acid Sites

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Solid Acids for the Reaction of Bioderived Alcohols into Ethers for Fuel Applications

Catalysts ◽

10.3390/catal9020172 ◽

2019 ◽

Vol 9 (2) ◽

pp. 172 ◽

Cited By ~ 1

Author(s):

Federica Zaccheria ◽

Nicola Scotti ◽

Nicoletta Ravasio

Keyword(s):

Physical Properties ◽

Lignocellulosic Biomass ◽

Lewis Acid ◽

Product Distribution ◽

Acid Sites ◽

Solid Acids ◽

Lewis Acid Sites ◽

Hydroxymethyl Furfural ◽

Brønsted And Lewis Acid

The use of solids acids in the synthesis of ethers suitable to be used as fuels or fuel additives were reviewed in a critical way. In particular, the role of Brønsted and Lewis acid sites was highlighted to focus on the pivotal role of the acidity nature on the product distribution. Particular emphasis is given to the recently proposed ethers prepared starting from furfural and 5-hydroxymethyl furfural. Thus, they are very promising products that can be derived from lignocellulosic biomass and bioalcohols and possess very interesting chemical and physical properties for their use in the diesel sector.

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