Characterization of the acidic properties of zeolites by means of temperature-programmed desorption (TPD) of ammonia

1995 ◽  
Vol 44 (2) ◽  
pp. 293-303 ◽  
Author(s):  
B. Hunger ◽  
M. v. Szombathely ◽  
J. Hoffmann ◽  
P. Bräuer
Keyword(s):  
Temperature Programmed Desorption ◽  
Acidic Properties ◽  
Temperature Programmed

A Green Approach

2013 ◽  
Vol 1 ◽  
pp. 194308921350702
Author(s):  
Madhavi Madeti ◽  
Sharad V. Lande ◽  
Kalpana G ◽  
R. K. Mewada ◽  
R. V. Jasra
Keyword(s):  
Catalytic Cracking ◽  
Petroleum Refining ◽  
Temperature Programmed Desorption ◽  
Fluid Catalytic Cracking ◽  
Acidic Properties ◽  
X Ray ◽  
Green Approach ◽  
Fcc Catalyst ◽  
The Matrix ◽  
Temperature Programmed

We have attempted a green alternative to reuse the spent fluid catalytic cracking (FCC) catalyst that is used in petroleum refining industry for the upgradation and purification of various petroleum streams and residues. The spent FCC zeolite–based catalyst modified by enhancing the acidic properties by incorporating Zn and In metals in the matrix. The various prepared catalysts were systematically characterized by X-ray powder diffraction and Brunauer–Emmett–Teller (BET; adsorption isotherm) surface area. The acidity of the materials was studied by temperature-programmed desorption of ammonia (NH3-TPD). The well-characterized catalysts were applied for liquid phase benzylation of o-xylene using benzyl chloride.

scholarly journals In-Exchanged CHA Zeolites for Selective Dehydrogenation of Ethane: Characterization and Effect of Zeolite Framework Type

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 807
Author(s):  
Zen Maeno ◽  
Xiaopeng Wu ◽  
Shunsaku Yasumura ◽  
Takashi Toyao ◽  
Yasuharu Kanda ◽  
...  
Keyword(s):  
Active Sites ◽  
Temperature Programmed Desorption ◽  
X Ray Diffraction ◽  
Zeolite Framework ◽  
X Ray ◽  
Catalytic Activities ◽  
Ethane Dehydrogenation ◽  
Temperature Programmed

In this study, the characterization of In-exchanged CHA zeolite (In-CHA (SiO2/Al2O3 = 22.3)) was conducted by in-situ X-ray diffraction (XRD) and ammonia temperature-programmed desorption (NH3-TPD). We also prepared other In-exchanged zeolites with different zeolite structures (In-MFI (SiO2/Al2O3 = 22.3), In-MOR (SiO2/Al2O3 = 20), and In-BEA (SiO2/Al2O3 = 25)) and different SiO2/Al2O3 ratios (In-CHA(Al-rich) (SiO2/Al2O3 = 13.7)). Their catalytic activities in nonoxidative ethane dehydrogenation were compared. Among the tested catalysts, In-CHA(Al-rich) provided the highest conversion. From kinetic experiments and in-situ Fourier transform infrared (FTIR) spectroscopy, [InH2]+ ions are formed regardless of SiO2/Al2O3 ratio, serving as the active sites.

Characterization of acidity in AlPO4Al2O3 (5–15 wt% Al2O3) catalysts using pyridine temperature programmed desorption

1995 ◽  
Vol 265 ◽  
pp. 103-110 ◽  
Author(s):  
J.M. Campelo ◽  
A. Garcia ◽  
D. Luna ◽  
J.M. Marinas ◽  
A.A. Romero
Keyword(s):  
Temperature Programmed Desorption ◽  
Temperature Programmed

The Characterization of Hydrocarbon Intermediates in H-ZSM-5

1987 ◽  
Vol 111 ◽  
Author(s):  
T. J. Gricus Kofke ◽  
R. J. Gorte ◽  
W. E. Farneth
Keyword(s):  
Infrared Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Acid Site ◽  
Adsorbed Molecule ◽  
Temperature Programmed Desorption ◽  
Acid Sites ◽  
Adsorption State ◽  
Brönsted Acid ◽  
Temperature Programmed

AbstractWe have examined the adsorption of simple alcohols and 2-propanamine on H-ZSM-5 zeolites with Si/Al2 ratios between 38 and 520. Thermogravimetric analysis (TGA) demonstrated that most of the molecules display a clearly defined adsorption state corresponding to a coverage of one molecule per Al site. Temperature programmed desorption (TPD) and transmission infrared spectroscopy results for each of the molecules in this 1:1 adsorption state are consistent with adsorption being due to the transfer of a proton from the zeolite to the adsorbed molecule. These results provide additional evidence that carefully prepared H-ZSM-5 is a Bronsted acid, with one acid site per framework Al atom, in which all of the acid sites are identical in strength.

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