Production of Spherical Powders of Inorganic Compounds by Water Extraction Variant of Sol-Gel Process

1992 ◽  
Vol 271 ◽  
Author(s):  
A. DeptuLa ◽  
J. Rebandel ◽  
W. Drozda ◽  
W. Lada ◽  
T. Olczak
Keyword(s):  
Acetic Acid ◽  
Pilot Plant ◽  
Inorganic Compounds ◽  
Sol Gel ◽  
Water Extraction ◽  
Salt Solutions ◽  
Sol Gel Process ◽  
Span 80 ◽  
Starting Solutions

ABSTRACTA method of preparation of spherical powders (with particle diameters <100µm) of metal oxidcs, their homegeneous mixtures or compounds, composites and metals has been elaborated. Depending on the nature of cations, the starting solutions were prepared by extraction of anions with Primene JMT from salt solutions, by addition of dopants to the sols or by complexing with acetic acid or/and ammonia. The sols or broths were then emulsified in 2-ethyl-l-hexanol containing SPAN 80. Drops of the emulsion were solidified by extraction of water with the solvent. The process was carried out continuously in a laboratory and/or in a pilot plant.

Preparation of Superconducting YBa2Cu3O7−x Compounds By Water Extraction Variant Of Sol-Gel Process

1990 ◽  
Vol 180 ◽  
Author(s):  
A. Deptula ◽  
W. Lada ◽  
T. Olczak ◽  
T. zoltowski ◽  
A. Di Bartolomeo
Keyword(s):  
Thermal Treatment ◽  
Sol Gel ◽  
Ammonium Hydroxide ◽  
Water Extraction ◽  
Spherical Particles ◽  
Acidic Solutions ◽  
Sol Gel Process

ABSTRACTThe starting sols were prepared by addition of ammonium hydroxide to acidic solutions of Y-Ba-Cu acetates or by dissolving solid Ba9CO9 or CuCO9.CuCOH)2H2O in acetates of the remaining components. The sols were then gelled to spherical particles with diameter below 50μm by extracting water with 2-ethyl-l-hexanol or to shard by evaporation of water. After thermal treatment of both powders amorphous and then crystalline YBa2Cu,9O7−x were obtained. Formation of these compounds is strongly improved by aging the gel at 200°C. Green and sintered pellets exhibit excellent superconductivity properties.

Preparation of BSCCO Precursors by Water Extraction Variant of Sol-Gel Process

1992 ◽  
Vol 271 ◽  
Author(s):  
A. Deptula ◽  
W. Lada ◽  
T. Olczak ◽  
A. Di Bartolomeo
Keyword(s):  
Thermal Treatment ◽  
Sol Gel ◽  
Water Extraction ◽  
Sol Gel Process ◽  
Emulsion Drops ◽  
Preparation Step

ABSTRACTThe starling acetate sols of molar compositions of Bi:Pb:Sr:Ca:Cu=I-2:O:2:l: 2, 11–2:0:2:2:3 and 111–1.6:0.4:2:2:3 were prepared by NH4OH addition at various rates, followed by evaporation. Sols were gelled by further evaporation to shard or to microspheres (diameter below 100 μm) by water extraction from the sol emulsion drops formed in 2-ethyl-l-hexanol. The gels were converted to BSCCO phases by thermal treatment. The processes were characterized by XRD and IR examinations. The influence of the sol preparation step connected with formation of polynuclear cations on the following stages of the process was examined.

Sol-Gel Process from Heterobimetallic Alkoxides to Incorporate Lanthanides in an Alumina Matrix

1992 ◽  
Vol 271 ◽  
Author(s):  
Chaitanya K. Narula
Keyword(s):  
Acetic Acid ◽  
Structural Changes ◽  
Sol Gel ◽  
Alumina Matrix ◽  
Slow Evaporation ◽  
Thermally Induced ◽  
Excess Water ◽  
Sol Gel Process ◽  
Amorphous Powders ◽  
Hydrolysis Of

ABSTRACTGels form on addition of seven or more moles of water diluted withi-PrOH to one mole of M[Al(O-i-Pr)4]3, M = La, Ce dissolved in i-PrOH. Thermal treatment of xerogels derived from La[AI(O-i-Pr)4]3gives amorphous powders below 900°C. LaAIO3crystallizes out at 900°C and residual alumina remains amorphous. CeO2starts to separate out above 600°C from the xerogels prepared from Ce[M(O-i-Pr)4]3. Thermally induced structural changes in xerogels prepared from the mixtures of La[AI(O-i-Pr)4]3and Ce[AI(0-i-Pr)4]3in 1:1 or 1:3 ratio are different from those prepared from individual precursors. These xerogels remain amorphous below 700°C. Crystalline CeO2forms on heating at 900°C but alumina remains amorphous. Sols are formed on hydrolysis of M[AI(0-/-Pr)4]3in excess water and acidifying the reaction mixture with acetic acid. Sols can be converted to gels by slow evaporation of volatiles. This method is useful in preparing coatings.

scholarly journals An Alcohol-Free SiO2Sol-Gel Matrix Functionalized with Acetic Acid as Drug Reservoir for the Controlled Release of Pentoxifylline

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mayra Angélica Alvarez Lemus ◽  
Oscar Javier Ortiz Castañeda ◽  
Alma Delia Hernández Pérez ◽  
Rosendo López González
Keyword(s):  
Acetic Acid ◽  
Controlled Release ◽  
Sol Gel ◽  
Spectroscopic Characterization ◽  
Xanthine Derivative ◽  
Bet Specific Surface Area ◽  
Sol Gel Process ◽  
Drug Reservoir ◽  
Uv Visible ◽  
High Doses

Pentoxifylline (PTX) is a xanthine derivative, with hemorrheologic properties, that has been useful in the treatment of several diseases. However, a conventional route of administration implies high doses, what is unnecessary to the organism, seriously increasing the risk of toxicity because of side effects. Because of the facility to modify their surface, sol-gel materials have proved to be suitable reservoirs for a variety of molecules for biological applications. In this work we prepared alcohol-free SiO2material by the sol-gel process using acetic acid as surface modifier and hydrolysis catalyst, the alkoxide/water ratio (Rw) used was 1/16, and tetraethylorthosilicate was used as SiO2precursor. Spectroscopic characterization was carried out by means of FTIR-ATR and UV-Visible spectroscopies; the results confirmed the presence of the drug and interactions between sol-gel matrix and PTX. BET specific surface area values of the sol-gel materials were 365 and 462 m2/g for SiO2and PTX-SiO2, respectively. Synthesized SiO2nanoparticles showed efficient entrapment of PTX since a controlled release of 83% of drug content was reached.

Sintering of ZrO2 ‐ CeO2 Spherical Powders Prepared by a Water Extraction Variant of the Sol‐Gel Process

1993 ◽  
Vol 140 (8) ◽  
pp. 2294-2297 ◽  
Author(s):  
A. Deptula ◽  
M. Carewska ◽  
T. Olczak ◽  
W. Lada ◽  
F. Croce
Keyword(s):  
Sol Gel ◽  
Water Extraction ◽  
Sol Gel Process

Hollow Mullite Ceramic Microspheres by Water Extraction of Emulsified Aqueous Droplets

1994 ◽  
Vol 346 ◽  
Author(s):  
Guoxu Liu ◽  
David L. Wilcox
Keyword(s):  
Sol Gel ◽  
Model Material ◽  
Water Extraction ◽  
Microelectronic Packaging ◽  
Droplet Dispersion ◽  
Mullite Ceramic ◽  
Sol Gel Process ◽  
Potential Applications ◽  
Important Processing ◽  
Aqueous Droplet

ABSTRACTThis paper describes a novel colloidal route for the preparation of hollow mullite ceramic microspheres with sizes in the range of 10 μm. An emulsion technique was combined with a water extraction sol-gel process, to form an aqueous droplet dispersion and gel the resulting droplets by extracting water with a dehydrating liquid. The liquid-filled gelled microcapsules were then dried and fired to form hollow ceramic microspheres. Important processing variables controlling the microspherc morphology were determined and a formation mechanism was proposed. Due to its potential applications in microelectronic packaging, mullite was selected as the model material for the present work, but the synthesis technique may be used for making other single or multiphase ceramic compositions

Acetic Acid in Sol-Gel Process of Hydrolytic Polycondensation of Tetramethoxysilane

2004 ◽  
Vol 77 (2) ◽  
pp. 290-294 ◽  
Author(s):  
N. N. Khimich ◽  
B. I. Venzel' ◽  
L. A. Koptelova ◽  
I. A. Drozdova
Keyword(s):  
Acetic Acid ◽  
Sol Gel ◽  
Hydrolytic Polycondensation ◽  
Sol Gel Process

Preparation of Calcium Phosphate Powders by Water Extraction Variant of Sol-Gel Process

2017 ◽  
pp. 263-268
Author(s):  
A. Deptuła ◽  
T. Olczak ◽  
W. Łada ◽  
A. Borello ◽  
C. Alvani ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Sol Gel ◽  
Water Extraction ◽  
Sol Gel Process
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