Effect of activation temperature on acidity of alumina, silica-alumina and cobalt-molybdenum-alumina catalysts

1985 ◽  
Vol 50 (6) ◽  
pp. 1268-1273 ◽  
Author(s):  
Zdeněk Vít
Keyword(s):  
Acid Sites ◽  
Hydroxyl Groups ◽  
Activation Temperature ◽  
Cumene Cracking ◽  
Surface Hydroxyl ◽  
Catalytic Activities ◽  
Surface Hydroxyl Groups ◽  
Silica Alumina ◽  
Effect Of Surface ◽  
Alumina Catalysts

The effect of surface dehydration on the acidity of silica-alumina and cobalt-molybdenum-alumina catalysts has been studied and compared with alumina. The catalysts were characterized by surface hydroxyl groups concentrations, acid sites concentrations and by catalytic activities in paraldehyde depolymerisation and cumene cracking. It was found that the acidity of alumina and cobalt-molybdenum-alumina catalysts increases significantly with surface dehydration and attains maximum after activation at 500-550 °C. Silica-alumina is strongly acidic even in the hydrated state, the acidity being formed already at relatively low temperature around 100 °C.

Phase transition of capillary condensed liquids in porous silica: effect of surface hydroxyl groups

1995 ◽  
Vol 267 ◽  
pp. 159-167 ◽  
Author(s):  
T. Takei ◽  
T. Konishi ◽  
M. Fuji ◽  
T. Watanabe ◽  
M. Chikazawa
Keyword(s):  
Phase Transition ◽  
Porous Silica ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Effect Of Surface

Effect of surface hydroxyl groups on heat capacity of mesoporous silica

2018 ◽  
Vol 112 (20) ◽  
pp. 201903 ◽  
Author(s):  
Michal Marszewski ◽  
Danielle Butts ◽  
Esther Lan ◽  
Yan Yan ◽  
Sophia C. King ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Mesoporous Silica ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Effect Of Surface

Role of acid sites and surface hydroxyl groups in isophthalonitrile hydrogenation catalyzed by supported Ni–Co catalysts

RSC Advances ◽  
2015 ◽  
Vol 5 (34) ◽  
pp. 26465-26474 ◽  
Author(s):  
Chang Liu ◽  
Ruijun Hou ◽  
Tiefeng Wang
Keyword(s):  
Acid Sites ◽  
Side Reactions ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Co Catalysts ◽  
Surface Hydroxyl Groups ◽  
Hydrogenation Reactions ◽  
Supported Ni

For hydrogenation of isophthalonitrile, the metal sites catalyzed the hydrogenation reactions, while the acid sites (including the original and new ones) and the surface hydroxyl groups catalyzed the condensation side reactions.

scholarly journals The behavior of ozone on different iron oxides surface sites in water

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Liqiang Yan ◽  
Jishuai Bing ◽  
Hecheng Wu
Keyword(s):  
Iron Oxides ◽  
Lewis Acid ◽  
Acid Sites ◽  
Oh Radicals ◽  
Hydroxyl Groups ◽  
Ozone Decomposition ◽  
Lewis Acid Sites ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Surface Metal

Abstract A transformation process of ozone on different iron oxides suspensions, including α-Fe2O3, α-FeOOH, Fe3O4, was carried out using FTIR of adsorbed pyridine, ATR-FTIR and electron paramagnetic resonance (EPR) spectra with isotope 18O3. It was verified that on the surface isolated hydroxyl groups and the surface hydroxyl groups without acid sites of these iron oxides, ozone was electrostatically adsorbed and did not interact with the surface of these oxides, stably existed as ozone molecule. In contrast, ozone could replace the surface hydroxyl groups on Lewis acid sites of oxides, and directly interacted with the surface metal ions, decomposing into reactive oxygen species (ROS) and initiating the surface metal redox. The results indicate that Lewis acid sites were active center while the electronic cycle of the Fe2+/Fe3+ is advantageous to promote ozone decomposition into O2•− and •OH radicals. The mechanism of catalytic ozonation in different surface acid sites of iron oxides aqueous suspension was proposed on the basis of all experimental information.

The Effect of Surface Hydroxyl Groups on the Properties of SR/Al2O3 Composites

2009 ◽  
Vol 66 ◽  
pp. 277-279 ◽  
Author(s):  
Yuan Lu Xiong ◽  
Qiang Shen ◽  
Fei Chen ◽  
Jin Zheng ◽  
Lian Meng Zhang
Keyword(s):  
Heat Treatment ◽  
Flexural Strength ◽  
Relative Density ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Sandy Alumina ◽  
Effect Of Surface

SR/Al2O3 composites were fabricated from different heat treatment temperatures of alumina. The results show that the relative density is over 94% and flexural strength is 66.5MPa when silicone content is 33wt.%. The flexural strength of the obtained SR/Al2O3 composites is decreased when increasing the heat treatment temperature of sandy alumina, indicating that the surface hydroxyl groups directly influence the flexural strength of SR/Al2O3 composites.

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