Silica–alumina catalysts prepared in sol–gel process of TEOS with organic additives

2002 ◽  
Vol 4 (19) ◽  
pp. 4830-4837 ◽  
Author(s):  
Miyuki Yabuki ◽  
Ryoji Takahashi ◽  
Satoshi Sato ◽  
Toshiaki Sodesawa ◽  
Katsuyuki Ogura
Keyword(s):  
Sol Gel ◽  
Organic Additives ◽  
Sol Gel Process ◽  
Silica Alumina ◽  
Alumina Catalysts

A General Nonhydrolytic Sol‐Gel Route to Oxides

1994 ◽  
Vol 346 ◽  
Author(s):  
Sylvie Acosta ◽  
Pascal Arnal ◽  
Robert J.P. Corriu ◽  
Dominique Leclercq ◽  
P. Hubert Mutin ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
High Surface ◽  
Sol Gel ◽  
Metal Center ◽  
Binary Oxides ◽  
Surface Areas ◽  
Sol Gel Process ◽  
Silica Alumina ◽  
The One ◽  
Oxygen Donors

ABSTRACTA nonhydrolytic sol‐gel route based on the condensation between chlorides and oxygen donors such as ethers and alkoxides is presented. Four examples, silica, alumina, titania and binary oxides in the Al/Si system show that this is a general route. The mechanism of this condensation is completely different from the one of classical sol‐gel process, since it implies nucleophilic substitution at the carbon center instead of the metal center. As a consequence, the differences in reactivity between different metals are reduced. In addition, the structure of the precursors may be retained in the gel. Thus, the nonhydrolytic sol‐gel process is very efficient for the preparation of homogeneous bicomponent oxides. Futhermore, nonhydrated gels are formed, which allowed us to prepare amorphous aluminas with high surface areas.

On-Line Spectroscopic Studies of Group iv Alkoxides and their Interactions with Polymerizable Organic Additives During the Sol-Gel Process

1998 ◽  
Vol 519 ◽  
Author(s):  
R. Cinier ◽  
J. Guilment ◽  
O. Poncelet ◽  
S. Truchet ◽  
D. Wettling
Keyword(s):  
Sol Gel ◽  
Nir Spectroscopy ◽  
Relevant Information ◽  
Spectroscopic Studies ◽  
Organic Additives ◽  
Hydrolysis Process ◽  
Sol Gel Process ◽  
On Line ◽  
Versatile Technique ◽  
Ir And Raman

AbstractThe monitoring of different reactions such as the stabilization of the alkoxides with polymerizable organic additives, the building of the inorganic network during the hydrolysis process, and in a same manner, the polymerization of the organic additives, can be of great importance for the development of hybrid materials with improved processability.NIR spectroscopy is a very versatile technique but lacks of specificity. IR and Raman give more interpretative results but are not always easy to run on a process. We used both techniques along with chemometric tools to extract relevant information from our processes. Then 2D correlation allowed to benefit from the specificity of IR and Raman to develop robust NIR methods able to be used on line to control the different steps of the sol-gel process.The hydrolysis of mixed species of titanium containing chloro, isopropoxo and methacrylato ligands will be discussed in terms of mechanism occuring during the sol-gel process.

Genesis and Growth of Nanoparticles during Sol-Gel Synthesis

2003 ◽  
Vol 788 ◽  
Author(s):  
Nan Yao ◽  
King Lun Yeung ◽  
Guoxing Xiong ◽  
Shishan Sheng
Keyword(s):  
Sol Gel ◽  
Nanometer Scale ◽  
In Situ Observation ◽  
Sol Gel Process ◽  
Silica Alumina ◽  
The Rich ◽  
Morphological Transformations ◽  
Sol Gel Synthesis ◽  
Gel Network

ABSTRACTIn situ observation of the genesis and growth of silica-alumina structures during the sol-gel process has been carried out. Although the gross structure of the gel network is kinetically stabilized, in situ AFM study reveals that at nanometer scale, the internal structure of the gel is dynamic as shown by the rich and complex morphological transformations.

Raman and Infrared Study of Metal Alkoxides During Sol-Gel Process

1992 ◽  
Vol 271 ◽  
Author(s):  
O. Poncelet ◽  
J -C. Robert ◽  
J. Guilment
Keyword(s):  
Sol Gel ◽  
Analytical Techniques ◽  
Metal Alkoxides ◽  
Organic Additives ◽  
Chemical Additives ◽  
Reactive Metal ◽  
Infrared Study ◽  
Sol Gel Process ◽  
Hydrolysis Of Metal Alkoxides ◽  
Hydrolysis Of

ABSTRACTOrganic additives are commonly used in sol-gel chemistry [1]. They can operate as stabilizers of reactive metal alkoxides [2] towards hydrolysis or as drying control chemical additives (such as dimethylformamide). These organic compounds and the by-products of sol-gel reactions can drastically modify the physical properties of final oxide materials, so that it is necessary to optimize the use of these additives. The first steps of hydrolysis of metal alkoxides stabilized by organic additives have been studied by many sophisticated analytical techniques which are difficult to use at technical level and often strongly alter the sol-gel reactions [3]. We chose to use FT-Raman and Infrared spectrocopies, which allow to remain as close as possible of the sol-gel process without altering it. The first steps of hydrolysis of group (IVb) metal alkoxides, more particularly titanium, modified by chlorides, carboxylic acids and alkanolamines have been investigated.

Modified colloidal sol–gel process for fabrication of titania nanofiltration membranes with organic additives

2015 ◽  
Vol 476 ◽  
pp. 432-441 ◽  
Author(s):  
Yuanyuan Cai ◽  
Yi Wang ◽  
Xianfu Chen ◽  
Minghui Qiu ◽  
Yiqun Fan
Keyword(s):  
Sol Gel ◽  
Organic Additives ◽  
Nanofiltration Membranes ◽  
Sol Gel Process

Silica–Alumina Catalyst with Bimodal Pore Structure Prepared by Phase Separation in Sol–Gel Process

2001 ◽  
Vol 200 (1) ◽  
pp. 197-202 ◽  
Author(s):  
Ryoji Takahashi ◽  
Satoshi Sato ◽  
Toshiaki Sodesawa ◽  
Miyuki Yabuki
Keyword(s):  
Phase Separation ◽  
Pore Structure ◽  
Sol Gel ◽  
Alumina Catalyst ◽  
Sol Gel Process ◽  
Silica Alumina ◽  
Bimodal Pore Structure

scholarly journals Adsorption of Calcium(II), Cadmium(II) and Copper(II) Ions from Water by Prepared Silicon-Aluminum-Zirconium Oxide Using Sol-Gel Process

2021 ◽  
Author(s):  
Cristiano da Silva ◽  
Maiyara Prete ◽  
César Tarley ◽  
Júlio Afonso ◽  
Emerson Ribeiro
Keyword(s):  
Metal Ions ◽  
Sol Gel ◽  
Aqueous Media ◽  
Freundlich Isotherm ◽  
High Energy ◽  
Isotherm Models ◽  
Ternary Oxide ◽  
Promising Alternative ◽  
Sol Gel Process ◽  
Silica Alumina

Ternary oxide silica-alumina-zirconia (SiO2/Al2O3/ZrO2) obtained by the sol-gel process was applied as novel adsorbent of ions in aqueous solution. Batch isotherms were performed using standard CuII, CdII and CaII solutions at variable pH and different concentrations. Adsorption capacity was best at weakly acidic pH. The maximum adsorption capacities were 2.28 mg g−1 for CaII, 9.89 mg g−1 for CdII, and 14.88 mg g−1 for CuII. The adsorption data fitted well to the single and dual-site Langmuir-Freundlich isotherm models. However, since the adsorption is very low in the sites with high energy, the single-site Langmuir-Freundlich provided a good fit as well. Whereas, the site responsible for the most ion adsorption was assigned to the Zr−OH group. A real sample of produced water was also tested. The new adsorbent showed a wide ability to retain many metal ions (alkali-earth, transition, and p-block metals) and even some anions were also caught by the adsorbent. The ternary oxide silica-alumina-zirconia was found to be a promising alternative adsorbent for metal ions in aqueous media.

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