Showing papers on "Activated alumina published in 1981"
Patent•
11 May 1981
TL;DR: In this article, microspheres of activated alumina are thermally and chemically stabilized by soaking the spheres in silicone liquid and decomposing the silicone liquid in an inert atmosphere to leave a silica residue infused in the alumina crystal structure.
Abstract: Microspheres of activated alumina are thermally and chemically stabilized by soaking the spheres in silicone liquid and decomposing the silicone liquid in an inert atmosphere to leave a silica residue infused in the alumina crystal structure resulting in a silica-alumina phase over the internal and external structure of the alumina. The treated microspheres are then heated in the presence of oxygen to burn off residual carbon resulting from the decomposition of the silicone liquid.
73 citations
TL;DR: In this paper, the surface flow of hydrocarbons, such as ethylene, propylene and isobutane, through activated alumina at 10°C and 30°C was measured over a mean pressure level range of a few kPa to about 100kPa using a permeation apparatus.
Abstract: Surface flow of hydrocarbons, such as ethylene, propylene and isobutane, through activated alumina at 10°C and 30°C is measured over a mean pressure level range of a few kPa to about 100kPa using a permeation apparatus. The surface flow coefficient is also determined as a function of amount adsorbed and temperature. The dependence of the surface flow coefficient on the above quantities can be well correlated using the random hopping model previously proposed by the authors. In addition, data from the literature for three other systems are correlated by this model.
27 citations
Patent•
09 Dec 1981TL;DR: In this article, a process for preparing alumina pellets, comprising the following steps, is described: activated alumina is treated in an aqueous medium consisting of a mixture of at least one acide making it possible to dissolve at least a part of the alumina of the pellets and at least an anion capable of combining with aluminium ions in solution, and the pellets are simultaneously or subsequently subjected to a treatment at a temperature of between 80 degrees C and 250 degrees C for a period of between a few minutes and 36 hours.
Abstract: 1. Process for preparing alumina pellets, comprising the following steps : a) activated alumina pellets are treated in an aqueous medium consisting of a mixture of at least one acide making it possible to dissolve at least a part of the alumina of the pellets and at least one compound providing an anion capable of combining with aluminium ions in solution ; b) the pellets treated in this way are simultaneously or subsequently subjected to a treatment at a temperature of between 80 degrees C and 250 degrees C for a period of between a few minutes and 36 hours ; c) the pellets are, if appropriate, dried and subjected to thermal activation at a temperature of between approximately 500 degrees C and approximately 1,100 degrees C ; and at most 15% by weight of alumina of the pellets, the acid being chosen from among the strong acids or the weak acids, its concentration in the aqueous treatment medium being below 20% by weight and preferably between 1% and 15% and the compound providing an anion A**-n forms with the aluminium ions Al**3+ in solutions products in which the atomic ratio n(A/Al) =< 3, and the concentration of this compound in the aqueous treatment medium is below 50% by weight and preferably between 3% and 30%.
26 citations
Patent•
21 Apr 1981
TL;DR: An improved process for the production of a low density formed product of activated alumina having a large macro-pore volume and an excellent abrasion resistance, which comprises mixing the starting solid material selected from an alumina powder being able to be re-hydrated and a mixture of the alumina and other solid material with water, is described in this article.
Abstract: An improved process for the production of a low density formed product of an activated alumina having a large macro-pore volume and an excellent abrasion resistance, which comprises mixing the starting solid material selected from an alumina powder being able to be re-hydrated and a mixture of the alumina and other solid material with water, said starting solid material having an average particle size of 1 micron to 35 micron and a quarter deviation of particle distribution of not more than about 1.5, forming the mixture of a solid material and water into various shapes, re-hydrating the formed product by keeping it under wetted atmosphere or in water, and calcining the resulting re-hydrated product.
26 citations
TL;DR: In this paper, the sorption capacity of an activated alumina columnar packed bed was found to be 30 mg PO 4 −3 per gram alumina, up to the breakthrough of 1000 bed volumes.
13 citations
Patent•
29 Jan 1981
TL;DR: In this paper, the authors proposed to improve catalytic activity and thermal characteristic by wash-coating a carrier by adding a liquid composition of colloidal rare earth element and/or activated alumina.
Abstract: PURPOSE:To improve catalytic activity and thermal characteristic by wash- coating a carrier by adding a liquid composition of colloidal rare earth element and/or activated alumina to a liquid composition of colloidal noble metal- alumina CONSTITUTION:Soluble noble metallic salt is reduced by being adsorbed to an alumina hydrate, and then mixed with an acidic material such as acetic acid This mixture is dried and then deflocculated to obtain a colloidal noble metal- alumina liquid composition To this formation, a colloidal rare earth element liquid composition and/or activated alumina is added and a carrier is wash- coated The catalyst produced as mentioned above has superior catalytic activity and thermal chracteristics
10 citations
Patent•
19 Jan 1981
TL;DR: In this article, a powder of activated alumina and carbon black and other ingredients are formed, dried and calcined in a gas stream containing oxygen to produce particles of activated aluminium suitably used as a catalyst, because of its porocity.
Abstract: PURPOSE: A powder of activated alumina and carbon black and other ingredients are formed, dried and calcined in a gas stream containing oxygen to produce particles of activated alumina suitably used as a catalyst, because of its porocity. CONSTITUTION: A starting mateial containing an activated alumina powder such as γ-alumina or a powdery precursor of activated alumina such as boehmite and carbon black is formed and dried. The carbon black is made 150W3,000Å in particle sizes and 60W300ml/100g in DBP adsorption. The amount of the carbon black is 5W120wt% based on the alumina. When necessary, water and an auxiliary forming agent is added thereto. Then, the formed alumina is calcined in a gas stream containing oxygen at a temperature exceeding 500°C usually for 1hr to 1 day. Thus, a formed activated alumina with high mechanical strength, wearing resistance, large surface area and large void volume is produced. COPYRIGHT: (C)1982,JPO&Japio
8 citations
TL;DR: In this paper, the authors compared the performance of three desiccants (silica gel, activated alumina, and a molecular sieve) with 0 percent and 5 percent dust contamination, and found that the mixture of inorganic dust particles of 10 to 20 micrometers did not affect the equilibrium moisture content of either silica gel or ac-tivated alumina.
Abstract: THE moisture sorption characteristics of silica gel, activated alumina and a molecular sieve each having 0 percent and 5 percent dust were compared. Inorganic dust particles of 10 to 20 micrometers did not affect the equilibrium moisture content of either silica gel, ac-tivated alumina or molecular sieve. Dynamic moisture sorption rates of all three desiccants were reduced by dust contamination. The molecular sieve adsorbs moisture rapidly until saturation, unlike that described by the common falling rate sorption model. While silica gel and activated alumina may be useful in drying air for agricultural applications, the molecular sieve is least likely to be useful due to its low hygroscopic capacity.
6 citations
Patent•
28 Sep 1981
TL;DR: In this article, a working solution for producing hydrogen peroxide (made up of an anthraquinone working compound dissolved in one or more solvents) is regenerated with an alkaline, activated alumina, containing about 3.7 wt. % Na 2 O at temperatures of about 145° C, wherein both the oxidized and hydrogenated work solution are mixed and treated with the said alumina simultaneously on a continuous basis.
Abstract: A working solution for producing hydrogen peroxide (made up of an anthraquinone working compound dissolved in one or more solvents) is regenerated with an alkaline, activated alumina, containing about 3.7 wt. % Na 2 O at temperatures of about 145° C., wherein both the oxidized and hydrogenated work solution are mixed and treated with the said alumina simultaneously on a continuous basis, so that regeneration proceeds continually and degradation products are maintained within controllable limits.
6 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•
28 Jan 1981
TL;DR: In this article, the catalytic reaction between succinic anhydride or ester and formaldehyde is effected in the presence of a catalyst of activated alumina or molybdenum oxide on activated aluminium at 300-500 deg.C to produce citraconic acid or its derivative.
Abstract: PURPOSE:The catalytic reaction of succinic anhydride with formaldehyde, both of which are readily and inexpensively available, is conducted in the presence of a catalyst of activated alumina, which also is readily available, under heating to produce titled compound, a starting material of synthetic resin, in high yield. CONSTITUTION:The catalytic reaction between succinic anhydride or ester and formaldehyde is effected in the presence of a catalyst of activated alumina or molybdenum oxide on activated alumina (the content of the molybudenum oxide is 0.5-30wt% calculated as MoO3 and the catalyst is more active than alumina alone) at 300-500, preferably 300-400 deg.C to produce citraconic acid or its derivative. As the starting material for formaldehyde, its aqueous solution, a solution of paraformaldehyde in methanol or trioxane can be used. The ratio of the succinic derivative to formaldehyde is preferably 1:1-1:10. USE:A starting material of itaconic acid.
Patent•
23 May 1981
TL;DR: In this article, the titled compound was obtained by treating dinitronaphthalene with hydrazine in the presence of a ferric salt catalyst, a carrier therefor and an aromatic hydrocarbon solvent.
Abstract: PURPOSE:To obtain the titled compound which is an important synthetic intermediate for a dye, etc in high yield in a short time, by treating dinitronaphthalene with hydrazine in the presence of a ferric salt catalyst, a carrier therefor and an aromatic hydrocarbon solvent CONSTITUTION:Dinitronaphthalene is treated with hydrazine hydrate in an aromatic hydrocarbon solvent, eg benzene or toluene, in the presence of a ferric salt, eg ferric fluoride or bromide, and a carrier therefor, eg active carbon or activated alumina, as a catalyst at room temperature to 150 degC to give the titled compound The reducing agent hydrazine changes into gaseous nitrogen only and causes no pollution problem of disposal treatment The method is industrial and advantageous without requiring the purification of the raw material
Patent•
03 Jun 1981
TL;DR: In this paper, a fixed-bed reaction with activated alumina particles containing ferric chloride was proposed to remove the titled two ingredients simultaneously from a mixed gas comprising a gas containing ethylene and vinyl chloride and chloride gas.
Abstract: PURPOSE:To remove the titled two ingredients simultaneously from a mixed gas comprising a gas containing ethylene and vinyl chloride and chloride gas, by making the mixed gas flow through a fixed bed reactor packed with activated alumina particles containing ferric chloride, having a specific outer surface area. CONSTITUTION:In removing ethylene and vinyl chloride simultaneously from a mixed gas comprising the gases and chloride gas, the mixed gas is made to flow through a fixed bed reactor packed with activated alumina particles containing not less than 4wt% calculated as iron ferric oxide, having a corresponding diameter not more than 4.5mm.phi or an outer surface area of the catalyst per unit amount of the catalyst packed not less than 7.8cm /ml so that ethylene and vinyl chloride are converted to 1,2-dichloroethane and 1, 1, 2-tricholoroethane respectively to reduce ethylene content in the mixed gas to not more than 10ppm, and vinyl chloride content to not more than 20ppm. The reaction is carried out at average temperature 80-200 deg.C, at space velocity 100-5,000hr , and at a pressure 1-20atm.
Patent•
03 Sep 1981
TL;DR: In this article, the authors describe a process for purifying industrial effluents, which arise in the manufacture of crude aluminium metal by electrolysis, with respect to fluorine.
Abstract: The process serves for purifying industrial effluents, which arise in the manufacture of crude aluminium metal by electrolysis, with respect to fluorine. The waters formed by wet purification of the fluorine-containing waste gases are a) brought by recirculation to contents of from 500 to 6,000 mg of fluorine/litre, b) a first part stream (40) thereof is passed through a number of fixed-bed reactors filled with activated alumina, and c) a second part stream (60) of the first part stream (40) is passed through a further fixed-bed reactor filled with alumina. The residual water of the first part stream (40) is recycled to the scrubbing-water circulation, and the activated alumina loaded with fluorine is, after processing, recycled to the electrolysis.
TL;DR: The rearrangement of 1,3-bromochloropropane (BCP) on activated alumina was carried out at 160 − 280°C as mentioned in this paper.
Abstract: The rearrangement of 1,3-bromochloropropane (BCP) on activated alumina was carried out at 160 – 280°C. This reaction proceeded as follows. Br(CH2)3Cl \leftrightarrows Br(CH2)3Br + Cl(CH2)3Cl It was suggested that the acidic sites of alumina played an important role in the rearrangement of halogen atom.
Patent•
30 Jan 1981
TL;DR: In this article, the activated alumina formed in the above-mentioned process is then introduced into cooling tower 11 with screw 9, 10 and rapidly cooled with cooling pipes stretched in tower 11.
Abstract: PURPOSE:To obtain activated alumina of high strength by rapidly dehydrating and drying alumina hydrate, indirectly cooling the resulting activated alumina with a cooling medium at once, and forming the cooled alumina into granules. CONSTITUTION:Al(OH)3 fed from hopper 3 is dried with hot gas of >=300 deg.C generated from burner 1 in drying pipe 2, and the resulting activated alumina is sent to cyclone 4. Activated coarse alumina particles in cyclone 4 are introduced into screw 10, and activated alumina fine particles not captured by cyclone 4 are carried 6 to bag filter 7 and introduced into screw 9. The activated alumina formed in the above-mentioned process is then introduced into cooling tower 11 with screw 9, 10 and rapidly cooled with cooling pipes stretched in tower 11. The rapidly cooled activated alumina is discharged 14 out of tower 11, pulverized in the next process, and formed into an alumina carrier.
Patent•
10 Dec 1981
Abstract: PURPOSE:To recover a noble metal from a used catalyst having the metal supported on a porous inorg. substance in a high recovering yield while preventing the carrier from being leached out by subjecting the catalyst to oxidation and reduction at a regulated temp. followed by extraction with an inorg. acid. CONSTITUTION:When a noble metal such as a Pt group element is recovered from a used catalyst having the metal supported on a porous inorg. substance such as activated alumina, the catalyst is calcined at >=1,000 deg.C in an oxygen atmosphere to remove stuck org. matter by oxidation. In order to reduce the noble metal oxidized by the operation, the catalyst is reduced at >=200 deg.C in a hydrogen atmosphere, and then extraction is carried out with an inorg. acid such as aqua regia to efficiently recover the noble metal. By raising the calcining temp. to >=1,000 deg.C, the carrier such as alumina is prevented from being leached out during the extraction, and the recovering process is simplified, resulting in an enhanced recovering yield.
Patent•
02 Sep 1981
TL;DR: In this paper, a mixture of activated alumina powder and 3-40% manganese oxide was used to obtain a high purification performance and mechanical strength by molding this then curing and calcining the molding.
Abstract: PURPOSE:To obtain a catalyst carrier having high purification performance and mechanical strength by adding and mixing powder of manganese oxide to and with activated alumina powder, molding this then curing and calcining the molding. CONSTITUTION:Rehydratable activated alumina powder is added and mixed with powder of 3-40wt% manganese oxide as beta-MnO2. Thence, this mixed powder is granulated to a spherical shape with a granulating machine and the granules are cured in saturated steam, and are dried then calcined, whereby the catalyst carrier is obtained. Thereby, the catalyst carrier by which the catalyst for purification of exhaust gas having sufficient purification performance and mechanical strength despite the small carrying amount of noble metals such as Pt, Ph, Pd is obtained.
Patent•
22 Dec 1981
TL;DR: In this article, an activated alumina is immersed in a water-soluble salt such as sulfate or nitrate of a metal selected from Mn, Cu and Co. The resulting activated ion supporting the metal salt is baked in the air or reductive atmosphere to reduce a part of said metal salt to a metal, and the activated ion separated from the solution is re-baked to be used repeatedly.
Abstract: PURPOSE:To efficiently remove the iron cyanide ion in a solution by supporting a specifiec metal or a salt thereof on an activated alumina adsorbing and collecting a cyanide complex ion in the solution. CONSTITUTION:Activated alumina is immersed in a water soluble salt such as sulfate or nitrate of a metal selected from Mn, Cu and Co. The resulting activated alumina supporting said metal salt is baked in the air or a reductive atmosphere to reduce a part of said metal salt to a metal. The activated alumina prepared as described above is brought into contact with a solution containing iron cyanide ion, and the cyanide complex ion in the solution is adsorbed and collected to said activated alumina and separated from the solution. The activated alumina separated from the solution is re-baked to be used repeatedly.
Patent•
30 Jan 1981
TL;DR: In this paper, a binder such as crystal cellulose is added to the powder and mixed, and the mixture is formed into spheres, etc. of a desired diameter, aged in satd. steam, and activated by calcination to obtain activated alumina granules having superior warming effect, high strength and superior attrition resistance.
Abstract: PURPOSE:To obtain alumina granules having high strength and superior attrition resistance by adding a binder to activated alumina powder >=70wt% of which has been specified in particle size and average particle size, and granulating the mixture. CONSTITUTION:Alumina hydrate obtd. by the Bayer process or other process is partially dehydrated to prepare activated alumina powder having preferably 5- 20% residual water content. At this time, the powder is adjusted so that >=70wt% of the powder has <=5mu particle size and <=3mu average particle size. A binder such as crystal cellulose is added to the powder and mixed. After adding water the mixture is formed into spheres, etc. of a desired diameter, aged in satd. steam, and activated by calcination to obtain activated alumina granules having superior warming effect, high strength and superior attrition resistance.
Patent•
18 Jul 1981
TL;DR: In this paper, a honeycomb structure comprising ceramic such as cordierite and having plural macrobores on the surface thereof was fabricated and a coating film comprising methyl cellulose was formed on the surfaces of this structure and the resulting coated structure was immersed in a slurry for an activated alumina coating and baked after drying.
Abstract: PURPOSE:To provide catalyst carrier having a honeycomb structure excellent in heat impact resistance obtained by forming the coating layer of activated alumina on the surface of the honeycomb structure while microcrack voids of the ceramic honeycomb structure are maintained. CONSTITUTION:A honeycomb structure 1 comprising ceramic such as cordierite and having plural macrobores 2 on the surface thereof an microcracks 3 generated from bottom parts of macrobores 2 is fabricated. In the next stage, a coating film comprising, for example, methyl cellulose is formed on the surface of this structure 1 and the resulting coated structure 1 is immersed in a slurry for an activated alumina coating and baked after drying. As the result, the aforementioned coating film is baked off to form an activated alumina coating layer 4 on the surface of the structure containing macrobores and voids of cracks 3 are remained.
TL;DR: The copyrolysis of 1,2,3 trichloropropane and methanol gave 1, 2,dichloro-3methoxypropane and their derivatives as mentioned in this paper.
Abstract: The copyrolysis of 1,2,3-trichloropropane and methanol gave 1,2-dichloro-3-methoxypropane as well as dichloropropenes and their derivatives. The formation of 1,2-dichloro-3-methoxypropane is also described.
Patent•
16 Nov 1981
TL;DR: In this paper, a pre-treatment of foamed ceramics of 87% porosity with activated alumina is used in front of the catalytic layer to remove gaseous poison from exhaust gas in order to maintain the activity of a serving catalyst.
Abstract: PURPOSE:To remove gaseous poison from exhaust gas in order to maintain the activity of a serving catalyst over a long period of time, by passing the exhaust gas through an integrally formed porous material coated with activated alumina, prior to the catalytic treatment. CONSTITUTION:The pretreating material is prepared by coating the foamed ceramics of about 87% porosity with activated alumina; this pretreating material is placed in front of the catalyst layer. A sample gas, containing about 500ppm butylene added with gaseous dimethylsilicone (concentration about 25mg/Nm ) as the poison, is passed through this catalyst with the wind velocity 0.9Nm/s; therefrom, the conversion efficiency of butylene is 45.0% after 140min.
Patent•
17 Jul 1981
TL;DR: In this article, the rotary regenerative dehumidifying body of a rotary hyneycomb like rotary drum is presented, which is able to provide regenerability, durability, and dimensional preciseness.
Abstract: PURPOSE: To provide the rotary regenerative dehumidifying body excellent in moisture absorbing capacity regenerability, durability and dimensional preciseness as well as being prepared easily comprising activated alumina molded into a hyneycomb like rotary drum. CONSTITUTION: Alumina trihydrate is contacted with a hot gas with a temp. of about 400W1,000°C for about 1W10sec to be partially calcined to obtaine a transition alumina powder of which ignition loss is about 2W10% and the particle size is about 1W20μm and a preparation obtained by adding about 20W 60pts.wt. of water to 100pts.wt. of said alumina powder is molded by extrusion to form a honeycomb like rotary drum. In the next stage, this molded body is held in steam with a temp. of about 50W150°C for about 30min or more to cure alumina by rehydration. The resulted alumina is heated to about 300W900°C to activate it to obtain a rotary regenerative dehumidifying body comprising the molded body excellent in moisture absorbing capacity and mechanical strength. COPYRIGHT: (C)1983,JPO&Japio
Patent•
28 Mar 1981
TL;DR: In this paper, a crosslinkable modifier for fluorine rubber with reduced formation of the hydrobromide adduct of the titled compound is presented. But the reaction temperature is not specified.
Abstract: PURPOSE:The reaction between hexafluoropropene and hydrogen bromide is conducted in the presence of a catalyst of fluorinated alumina to produce in high selectivity the titled compound used as a crosslinkable modifier for fluorine rubber with reduced formation of the hydrobromide adduct of the titled compound. CONSTITUTION:1-Bromo-pentafluoro-1-propene is produced by reaction of hexafluoro-propene with hydrogen bromide in the presence of a catalyst of fluorinated alumina (fluorine content is 0.1-30wt%). The reaction temperature is 150-300 deg.C. The amount of hydrogen bromide employed is 0.5-2mol par mole or hexafluoropropene. The fluorinated alumina is prepared by treating an activated alumina with a fluorinating agent such as chlorofluorocarbon at 150-450 deg.C.
Patent•
25 Dec 1981
TL;DR: In this article, the authors proposed a method to obtain a catalyst for cleaning exhaust gas containing rhodium high in activity and durability with a small quantity on the carrier by using a heat-treated crystal of Rhodium nitrate and a compound of platinum group elements supported by the carrier.
Abstract: PURPOSE:To obtain a catalyst for cleaning exhaust gas containing rhodium high in activity and durability with a small quantity on the carrier by using heat-treated crystal of rhodium nitrate and a compound of platinum group elements supported by the carrier. CONSTITUTION:As a catalyst for cleaning exhaust gas of automobiles and general industries, a crystal of rhodium nitrate is heat-treated to produce a complex compound of rhodium nitrate and rhodium oxide expressed by Rh(NO3)xOy. Then, this complex compound and compound of platinum group metal are dissolved in aqueous solution and infiltrated into an inorganic porous substance such as activated alumina carrier, etc. to burn the resulting product. This catalyst can be easily manufactured industrially, and high in activity and durability with a small carried quantity.
TL;DR: For the co-pyrolysis of 2-chloroethyl compounds with methanol on activated alumina, the ρ* value was +0.49, indicating a nucleophilic reaction mechanism.
Abstract: For the co-pyrolysis of 2-chloroethyl compounds with methanol on activated alumina, the ρ* value was +0.49, indicating a nucleophilic reaction mechanism.