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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.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the aldol condensation of acetone adsorbed on alumina was monitored with C-13 NMR and the detectability of the major reaction products, diacetone alcohol, mesityl oxide, phorone, isophorone and mesitylene, was compared to that previously observed using infrared and gas Chromatographic methods.

19 citations

Patent
31 Mar 1978
TL;DR: In this article, a mixture is prepared by mixing alumina sol and activated alumina which contains not less than 60 Wt % of delta-alumina and then the mixture is thereafter coated on a relatively small specific surface area monolithic catalyst carrier.
Abstract: A mixture is prepared by mixing alumina sol and activated alumina which contains not less than 60 Wt % of delta-alumina. The mixture is thereafter coated on a relatively small specific surface area monolithic catalyst carrier. After being dried, the coated carrier is fired to give a high specific surface area catalyst carrier.

19 citations

Patent
19 Aug 1952
TL;DR: In this paper, a process for the purification of phenol derived from cumene and containing colour forming impurities including aliphatic a-hydroxy carbonyl compounds is described.
Abstract: A process for the purification of phenol derived from cumene and containing colour forming impurities including aliphatic a -hydroxy carbonyl compounds comprises subjecting the impure phenol at an elevated temperature to conditions which will cause the substantially complete condensation of the aliphatic a -hydroxy carbonyl compounds with phenol to form benzofurans and separating the phenol substantially completely from the benzofurans. The condensation of the a -hydroxy carbonyl condensation of the a -hydroxy carbonyl compounds with phenol may be carried out by heating the phenol in liquid or vapour phase at atmospheric, reduced or elevated pressures and optionally in the presence condensation catalysts such as activated alumina, aluminium silicate e.g. acid-or alkali-treated pumice or porcelain, acidic or basic ion exchange resins, mineral acids e.g. sulphuric and phosphoric acid, especially in the presence of iron, strong organic acids, e.g. p-toluene sulphonic acid and surface active earths e.g. montmorillonites such as fuller's earth, bentonite and attapulgite which may be acid-activated or alkali or heattreated. In the liquid phase treatment activated charcoal or metal halides of the Friedel-Crafts type and sulphates of the same metals e.g. aluminium ferric, nickel and zinc chlorides, aluminium, ferric and nickel sulphates or boron trifluoride maye be employed as catalyst. The vapour phase treatment may be carried out by passing the vaporised phenol through a tube which may be packed with catalyst. The liquid phase treatment may be carried out batchwise or continuously. The separation of the phenol from the benzofurans and other impurities is carried out by neutralisation of the phenol with an alkali followed by extraction of the benzofurans with a solvent or by steam distillation or by extractive distillation in the presence of a suitable solvent and preferably by extractive distillation in the presence of water, benzofurans being removed overhead. The aqueous phenol may be subjected to dehydration and fractional distillation. The tendency for the phenol to form coloured products on sulphonation and chlorination is shown to be substantially reduced after purification. Examples are furnished in which crude phenol obtained from cumene by oxidatation and an acid-cleavage of the hydroperoxides formed, is purified.

19 citations

Journal ArticleDOI
TL;DR: A suitable stabilization and disposal method for the treatment residuals inside a well aerated coarse sand filter bed has been developed and standard leaching tests carried out indicated that the leaching of arsenic from the stabilized treatment residual was minimum, and was within the regulatory limit.

19 citations

Journal ArticleDOI
TL;DR: In this article, the equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water.
Abstract: The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated mic rosand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of Ceq = 10 µg/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95%.

19 citations


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