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Activated alumina

About: Activated alumina is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 31090 citations.


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Journal ArticleDOI
TL;DR: In this paper, an oxidation of furfural was carried out using alum-impregnated activated alumina, which led to the formation of 2-furancarboxylic acid (furoic acid).
Abstract: In the present investigation, oxidation of furfural was carried out using alum-impregnated activated alumina, which led to the formation of 2-furancarboxylic acid (furoic acid). Operational parameters such as catalytic ratio were varied from 1 to 9%, temperature from 40 to 70°C, initial concentration from 0.1 to 0.5 m and time from 0.5–7.5 h, and were optimized using Box–Behnken design. The Fisher F-value of 55.10 confirmed that the second-order regression model used for prediction of results was satisfactory. By using the reaction scheme proposed, rate constants at various reaction temperatures were determined. Activation energy and frequency factor corresponding to the reaction were also calculated.

4 citations

Patent
23 Feb 1981
TL;DR: In this article, a deformation-free, high mechanical strength active alumina is used as a catalyst to effect the reaction between an alkylene carbonate and water to produce the titled compound used as starting material for polyester in high selectivity and faciliated the separation and recovery of the catalyst.
Abstract: PURPOSE:A deformation-free, high mechanical strength active alumina is used as a catalyst to effect the reaction between an alkylene carbonate and water to produce the titled compound used as a starting material for polyester in high selectivity and faciliated the separation and recovery of the catalyst. CONSTITUTION:The reaction of an alkylene carbonate of formula I(R1-R4 are H, 1-3C alkyl, 6C aryl, 2-3C alkenyl, 3-6C cycloalkyl) with water is conducted in liquid phase in the presence of an activated alumina catalyst at 100-200 deg.C under a pressure of 10-50kg/cm G to produce a monoalkylene glycol of formula II in high selectivity. As the activated alumina, can be used commercially available half-calcined alumina, which is preferably 50-500m /g in the specific surface area and consists of more than 80wt% of alumina and less than 20wt% of silica. EFFECT:The catalyst life is prolonged and the catalyst is of economically high-efficiency. USE:Starting material for polyether, anti freeze and surfactants.

4 citations

Patent
11 Oct 1996
TL;DR: In this paper, a method for producing phosgene comprises reacting chlorine with carbon monoxide having a hydrogen gas content of ≤ 6.0mol.% in an amount excessive by 1-30mol.
Abstract: PROBLEM TO BE SOLVED: To obtain colorless phosgene in a high yield by reacting chlorine with carbon monoxide reduced in the content of hydrogen in the presence of an activated carbon catalyst. SOLUTION: This method for producing phosgene comprises reacting chlorine with carbon monoxide having a hydrogen gas content of ≤6mol.% in an amount excessive by 1-30mol.% based on a stoichiometric amount in the presence of an activated carbon catalyst in an amount of 800-1300kg based on 1000m 2 /hr of the carbon monoxide. The carbon monoxide reduced in the hydrogen gas content is produced by bringing carbon monoxide having a hydrogen gas content of ≥6.0mol.% into contact with an adsorbent such as silica gel, calcium chloride or activated alumina or by heating the carbon monoxide in the presence of a catalyst such as copper-activated carbon catalyst or copper-manganese- activated carbon catalyst at 40-100°C to convert the hydrogen into water, and subsequently bringing the water-containing carbon monoxide into contact with an adsorbent. COPYRIGHT: (C)1998,JPO

4 citations

Patent
09 Nov 1966
TL;DR: In this article, an organic polyisocyanate with a polyhydroxy compound in the presence of a water fixation agent which is an activated and finelyground alumina having a surface area greater than 300 square meters/gram, the diameter of the particles being 1 to 200 microns and the soda content being not more than 2000 p.p.m. by weight.
Abstract: Non-cellular polyurethanes are prepared by reacting an organic polyisocyanate with a polyhydroxy compound in the presence of a water fixation agent which is an activated and finelyground alumina having a surface area greater than 300 square metres/gram, the diameter of the particles being 1 to 200 microns and the soda content being not more than 2000 p.p.m. by weight. Aromatic polyisocyanates and branched and linear polyethers are exemplified whilst the activated alumina may be gels of calcined and ground pseudo-boehmite or activated hydragillites. The activated alumina may be added to the polyhydroxy compound with, if desired, e.g. fillers, pigments and solvents before the addition of the polyisocyanate. Reference has been directed by the Comptroller to Specification 1,086,449.

4 citations

Journal ArticleDOI
TL;DR: In this article, a green process that uses the spray pyrolysis method to prepare activated alumina is proposed and the effects of spray temperature, carrier gas pressure, and AlCl3 solution concentration are experimentally investigated using pure reagents.
Abstract: Abstract A green process that uses the spray pyrolysis method to prepare activated alumina is proposed in this research. The effects of spray temperature, carrier gas pressure, and AlCl3 solution concentration are experimentally investigated using pure reagents. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and specific surface area (BET) analyses. The results indicate that the spray temperature is the most important factor on the conversion ratio of alumina during the spray pyrolysis process. The conversion ratio of alumina achieved over 99% at the following optimal conditions: temperature of 1000°C, pressure of 0.3 MPa, and AlCl3 solution concentration of 10 wt%. The activated alumina with 8–20 nm particle size (γ-Al2O3+α-Al2O3) was prepared using the same process, which well met the requirement of the catalyst carrier. The green utilization of high-alumina fly ash and acid recycling can be achieved by using this process.

4 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202218
202118
202031
201941
201839