Determination of the Orientation of Adsorbed Pyridine and γ-MPS on Alumina Surface by Photoacoustic FT-IR Spectroscopy

1986 ◽  
Vol 40 (6) ◽  
pp. 851-856 ◽  
Author(s):  
Marek W. Urban ◽  
Jack L. Koenig
Keyword(s):  
Surface Coverage ◽  
Hydroxyl Groups ◽  
Alumina Surface ◽  
Surface Hydroxyl ◽  
Adsorbed Pyridine ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy ◽  
Pyridinium Ion ◽  
Ft Ir Spectroscopy

Fourier transform infrared photoacoustic spectroscopy has been applied to determine the structure and orientation of pyridine and γ-Metacryl-oxypropyltriethoxysilane (γ-MPS) on γ-Al2O3 surface. Adsorption of pyridine on activated γ-Al2O3 leads to formation of a pyridinium ion (pyN+-H) and pyridine N-oxide. The orientation of pyridinium ion on the alumina surface is random, whereas the pyridine N-oxide is parallel with respect to the surface. The adsorption of oligomers of γ-MPS gives parallel layers on the alumina surface. At low γ-MPS surface coverage, the carbonyl groups interact with the surface hydroxyl groups. Increasing surface coverage leads to an excess of the free C=O species.

ChemInform Abstract: A Convenient Determination of Surface Hydroxyl Group on Silica Gel by FT-IR Spectroscopy.

ChemInform ◽  
2010 ◽  
Vol 23 (1) ◽  
pp. no-no
Author(s):  
K. YOSHINAGA ◽  
M. RIKITAKE ◽  
T. KITO ◽  
Y. YAMAMOTO ◽  
H. EGUCHI ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Silica Gel ◽  
Hydroxyl Group ◽  
Surface Hydroxyl ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

A Convenient Determination of Surface Hydroxyl Group on Silica Gel by FT-IR Spectroscopy

1991 ◽  
Vol 20 (7) ◽  
pp. 1129-1132 ◽  
Author(s):  
Kohji Yoshinaga ◽  
Masaru Rikitake ◽  
Taketoshi Kito ◽  
Yukiko Yamamoto ◽  
Hiroshi Eguchi ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Silica Gel ◽  
Hydroxyl Group ◽  
Surface Hydroxyl ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Photoacoustic FT-IR Spectroscopy of Natural Copper Patina

1995 ◽  
Vol 49 (10) ◽  
pp. 1516-1524 ◽  
Author(s):  
Alex O. Salnick ◽  
Werner Faubel
Keyword(s):  
Depth Distribution ◽  
Depth Profiling ◽  
Beam Deflection ◽  
City Hall ◽  
Spectral Bands ◽  
Special Sample Preparation ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy ◽  
Ft Ir Spectroscopy

Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) has proved to be a useful tool for nondestructive testing of copper corrosion layer (patina) formed in the atmosphere. The samples cut from a piece of the roof of the Stockholm City Hall were examined without any additional pretreatment. The components of the patina—brochantite Cu4(OH)6SO4, antlerite Cu3(OH)4SO4, and basic cupric carbonate Cu2CO3(OH)6 · H2O—as well as some other minerals were identified. The photothermal beam deflection (PBD) method was used for independent photoacoustic characterization of the samples. The depth profiling capability of FT-IR/PAS was used to determine the degree of photoacoustic saturation of the spectral bands and to evaluate the depth distribution of the main patina components. The technique thus compares favorably with more common approaches of patina examination which are more expensive and require special sample preparation.

Determination of the Orientation of Silanes on Silica Surfaces by Fourier Transform Infrared Photoacoustic Spectroscopy

1986 ◽  
Vol 40 (4) ◽  
pp. 513-519 ◽  
Author(s):  
Marek W. Urban ◽  
Jack L. Koenig
Keyword(s):  
Fourier Transform ◽  
Photoacoustic Spectroscopy ◽  
Surface Coverage ◽  
Silica Surface ◽  
Fourier Transform Infrared ◽  
Coupling Agents ◽  
Surface Hydroxyl ◽  
Silica Surfaces ◽  
Quantitative Surface Analysis ◽  
Infrared Photoacoustic Spectroscopy

Fourier transform infrared photoacoustic spectroscopy has been used for quantitative surface analysis of silica treated with trifunctional coupling agents such as γ-Methacryloxypropyltriethoxysilane (γ-MPS), γ-Glycidoxypropyltrimethoxysilane (γ-GPS), and γ-Aminopropyltri-ethoxysilane (γ-APS). The calibration curves are obtained for several characteristic bands of the coupling agents. Using a highly polarizable gas in the photoacoustic cell and comparing the spectra with a nonpolarizable coupling gas, it is possible to evaluate orientation of the coupling agents on the silica surface. The type of orientation is a function of the extent of surface coverage. At low surface coverage, coupling agents tend to take a perpendicular orientation with respect to the surface, and increasing surface coverage leads to parallel orientation. Increasing the coupling agent concentration also causes orientational changes of the species which form chemical bonds with the silica surface (hydroxyl, water, and carbonyl groups).

Applications of Diffuse Reflectance FT-IR to Pigment Photodecomposition in Paint

1982 ◽  
Vol 36 (2) ◽  
pp. 155-157 ◽  
Author(s):  
D. B. Chase ◽  
R. L. Amey ◽  
W. G. Holtje
Keyword(s):  
Ir Spectroscopy ◽  
Infrared Spectra ◽  
Diffuse Reflectance ◽  
Spectral Subtraction ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Diffuse reflectance FT-IR spectroscopy is used to obtain infrared spectra of paints directly on paper panels. The binder contribution to the spectrum can be effectively eliminated by spectral subtraction and the spectra of photodecomposition products are obtained. Comparison with reference spectra allows the determination of the photodecomposition mechanism.

Reagentless determination of glucose and other constituents in blood by ATR-FT-IR-spectroscopy.

1989 ◽  
Vol 35 (9) ◽  
pp. 1854-1856 ◽  
Author(s):  
J D Kruse-Jarres ◽  
G Janatsch ◽  
U Gless
Keyword(s):  
Ir Spectroscopy ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

scholarly journals Scale-up of a NiMoP/γAl2O3 catalyst for the hydrotreating and mild hydrocracking of heavy gasoil

2019 ◽  
Vol 74 ◽  
pp. 22 ◽  
Author(s):  
Ricardo Prada Silvy
Keyword(s):  
Scale Up ◽  
Catalyst Support ◽  
Chemical Properties ◽  
Pilot Scale ◽  
Solid Particles ◽  
Metallic Surface ◽  
Hydroxyl Groups ◽  
Alumina Surface ◽  
Distribution Profile ◽  
Surface Hydroxyl

This contribution shows the acquired experience during the scale-up of a NiMoP/γAl2O3 catalyst employed for the hydrotreating and mild hydrocracking of heavy gasoil. Three different strategies were adopted for preparing catalyst batches at pilot scale. They consisted on co-impregnation of γ-alumina extrudates with aqueous solutions containing Ni and Mo salts and phosphoric acid in one or two successive steps. The textural, chemical composition, mechanical strength, metallic surface dispersion and elemental radial distribution profile properties were influenced by the impregnation procedure employed. The co-impregnation with diluted Ni, Mo and P solutions in two successive steps is the best way to prepare the catalyst. This procedure provides a catalyst that exhibits better physico-chemical properties and catalytic activity profile than the other impregnation methods investigated. Heat and mass transfer limitations became very important when preparing catalysts in large quantities. The diffusion intra-particle and extra-particle was observed influenced by the density and viscosity properties of the metallic solution, the liquid-solid contact angle, the reactivity of phosphate, polymolybdate and phosphomolybdate species with the alumina surface hydroxyl groups, the raise of temperature produced in the solid particles during the initial impregnation step and the porosity properties of the catalyst support. It was concluded that the fine control of the metal distribution on the alumina surface during the impregnation is crucial for producing highly active uniform catalysts.

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