Acid-Base and Catalytic Properties of Alkali Metal Exchanged ZSM5

Abstract The stability and acid-base properties of MON2O mixed oxides (where M = Be, Mg, Ca; N = Li, Na, K) are studied by using ab initio methods. It is demonstrated that (i) the basicity of such designed systems evaluated by estimation of electronic proton affinity and gas-phase basicity (defined as the electronic and Gibbs free energies of deprotonation processes for [MON2O]H+) were found significant (in the ranges of 272–333 kcal/mol and 260–322 kcal/mol, respectively); (ii) in each series of MOLi2O/MONa2O/MOK2O the basicity increases with an increase of the atomic number of alkali metal involved; (ii) the Lewis-acidity of the corresponding [MON2O]H+ determined with respect to hydride anion (assessed as the electronic and Gibbs free energies of H− detachment processes for [MON2O]H2) decreases as the basicity of the corresponding oxide increases. The thermodynamic stability of all [MON2O]H2 systems is confirmed by estimating the Gibbs free energies for the fragmentation processes yielding either H2 or H2O.

Download Full-text

Influence of Acid–Base Surface Characteristics of GAxSIBEA Zeolites on their Catalytic Properties in the Process of Oxidative Dehydrogenation of Propane to Propylene with Participation of CO2

Theoretical and Experimental Chemistry ◽

10.1007/s11237-021-09667-5 ◽

2021 ◽

Author(s):

S. M. Orlyk ◽

M. R. Kantserova ◽

V. I. Chedryk ◽

P. I. Kyriienko ◽

D. Yu. Balakin ◽

...

Keyword(s):

Oxidative Dehydrogenation ◽

Catalytic Properties ◽

Surface Characteristics ◽

Oxidative Dehydrogenation Of Propane ◽

Acid Base ◽

Base Surface

Download Full-text

ChemInform Abstract: Alkali Metal Fluorides Supported on Fluorinated γ-Alumina, Lewis Base, and Catalytic Properties.

ChemInform ◽

10.1002/chin.199205023 ◽

2010 ◽

Vol 23 (5) ◽

pp. no-no

Author(s):

T. BAIRD ◽

A. BENDADA ◽

G. WEBB ◽

J. M. WINFIELD

Keyword(s):

Alkali Metal ◽

Catalytic Properties ◽

Lewis Base ◽

Metal Fluorides

Download Full-text

Electron Donating, Acid-Base and Catalytic Properties of Perovskite-Type Mixed Oxides of Rare Earths

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19950977 ◽

1995 ◽

Vol 60 (6) ◽

pp. 977-982

Author(s):

S. Sugunan ◽

V. Meera

Keyword(s):

Catalytic Activity ◽

Electron Donor ◽

Rare Earths ◽

Electron Affinity ◽

Mixed Oxides ◽

Catalytic Properties ◽

Surface Acidity ◽

Electron Acceptors ◽

Acid Base ◽

Perovskite Type

The electron donor properties of perovskite-type mixed oxides (LaFeO3, PrFeO3, SmFeO3, LaCoO3, PrCoO3, SmCoO3, LaNiO3, PrNiO3 and SmNiO3) were studied based on the adsorption of electron acceptors exhibiting different electron affinity viz. 7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrachloro-1,4-benzoquinone, p-dinitrobenzene, and m-dinitrobenzene. The surface acidity/basicity of the oxides was determined using a set of Hammett indicators. The data were correlated with the catalytic activity of the oxides for the reduction of cyclohexanone with 2-propanol.

Download Full-text

Structural and Catalytic Properties of the Alkali Metal Ion-Exchanged Y-Zeolites by 29Si and 27Al Solid-State NMR and FT-IR Spectroscopy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.277-279.708 ◽

2005 ◽

Vol 277-279 ◽

pp. 708-719

Author(s):

Chang Seop Lee ◽

Hee Jung Lee ◽

Sung Woo Choi ◽

Jahun Kwak ◽

Charles H.F. Peden

Keyword(s):

Solid State ◽

Alkali Metal ◽

Photoelectron Spectroscopy ◽

Metal Ion ◽

Nmr Spectra ◽

Catalytic Properties ◽

Nox Reduction ◽

29Si Nmr ◽

Y Zeolites ◽

X Ray

A series of cation exchanged Y-zeolites were prepared by exchanging cations with various alkali (M+, M= Li, Na, K, Cs) metals. The structural and catalytic properties of the alkali metal exchanged Y-zeolites have been investigated by a number of analytical techniques. Comparative elemental analyses were determined by an Energy Dispersive Spectroscopy X-ray (EDS), X-ray Photoelectron Spectroscopy (XPS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and X-ray Fluorescence (XRF) before and after cation substitution. The framework and non-framework Al coordination and the Si/Al ratios of the Y-zeolites were investigated by MAS Solid-State Nuclear Magnetic Resonance (NMR) spectroscopy. The Al NMR spectra were characterized by two 27Al resonance signals at 12 and 59 ppm, indicating the presence of the non-framework and framework Al respectively. The intensities of these resonances were used to monitor the amount of the framework and non-framework Al species in the series of exchanged zeolites. The 29Si NMR spectra were characterized by four resonance signals at -79, -84, -90, and -95 ppm. Changing the alkali metal cations in the exchanged Y-zeolites significantly altered the extent of the octahedral/tetrahedral coordination and the Si/Al ratio. The Fourier Transform Infrared spectra of the CO2 adsorbed on to the exchanged Y-zeolites showed a low frequency shift, as the atomic number of the exchanged alkali metal increased. In addition, the catalytic activity of these samples for NOx reduction were tested in combination with a non-thermal plasma technique and interpreted based on the above structural and spectroscopic information.

Download Full-text

Effect of the structure of Ti-Sb-O catalysts on their acid-base properties, surface oxygen binding energy, and catalytic properties in propylene ammoxidation

Kinetics and Catalysis ◽

10.1134/s0023158408010163 ◽

2008 ◽

Vol 49 (1) ◽

pp. 127-132

Author(s):

G. A. Zenkovets ◽

G. N. Kryukova

Keyword(s):

Binding Energy ◽

Catalytic Properties ◽

Oxygen Binding ◽

Surface Oxygen ◽

Acid Base ◽

Propylene Ammoxidation ◽

Base Properties

Download Full-text

Effects of various alkali metal cations on the synthesis, crystallization and catalytic properties of NKX-2 aluminophosphites

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2018.09.082 ◽

2019 ◽

Vol 222 ◽

pp. 81-86 ◽

Cited By ~ 3

Author(s):

Haruna Abdullahi ◽

Ka-Lun Wong ◽

Gin Keat Lim ◽

Hussein Awala ◽

Aurélie Vicente ◽

...

Keyword(s):

Alkali Metal ◽

Catalytic Properties ◽

Metal Cations ◽

Alkali Metal Cations

Download Full-text

Study of PET Depolymerization Catalyzed by Metal Oxide with Different Acidity/Basicity under Microwave Irradiation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.233-235.1076 ◽

2011 ◽

Vol 233-235 ◽

pp. 1076-1079 ◽

Cited By ~ 2

Author(s):

Yu Zhen Ge ◽

Chun Hua Han ◽

Dong Zhang

Keyword(s):

Alkali Metal ◽

Microwave Irradiation ◽

Metal Oxide ◽

Metal Oxides ◽

Catalytic Effect ◽

Acid Base ◽

Alkali Metal Oxide ◽

Scale Method

In this paper, the PET depolymerization catalyzed by metal oxides (MgO, CdO, Cu2O,Sb2O3, MnO2, V2O5, SiO2,MoO3) under microwave irradiation were investigated, and the effects of acid-base on PET depolymerization was studied by acid-base scale method. The results indicated that the stronger the acidity or basicity of metal oxide was, the better the effects of catalytic depolymerization of PET appeared. Compared with alkali metal oxide, the catalytic effect of acid metal oxide to PET depolymerization was better.

Download Full-text