Abstract: A process for production of silica having variable thickening wherein a) a product stream I containing at least a vaporous, hydrolysable and/or oxidizable silicon compound, b) a product stream II containing oxygen and c) a product stream III containing at least a combustible gas are made to react, where d) a feed port in a pipepiece A, the pipepiece A containing one or more static mixing elements, is used to import product stream I into product stream II, or vice versa and thereby create product stream IV, then e) a feed port in a pipepiece B, the pipepiece B containing one or more static mixing elements, is used to import product stream III in product stream IV and thereby create product stream V, f) product stream V leaving pipepiece B is imported into a reaction chamber, ignited therein and reacted in a flame, and g) the resultant solid material is separated off.

Abstract: A process for production of silica having variable thickening wherein a) a product stream I containing at least a vaporous, hydrolysable and/or oxidizable silicon compound, b) a product stream II containing oxygen and c) a product stream III containing at least a combustible gas are made to react, where d) a feed port in a pipepiece A, the pipepiece A containing one or more static mixing elements, is used to import product stream I into product stream II, or vice versa and thereby create product stream IV, then e) a feed port in a pipepiece B, the pipepiece B containing one or more static mixing elements, is used to import product stream III in product stream IV and thereby create product stream V, f) product stream V leaving pipepiece B is imported into a reaction chamber, ignited therein and reacted in a flame, and g) the resultant solid material is separated off.

Abstract: Process for production of silica having variable thickening wherein a) a product stream I comprising at least a vaporous, hydrolysable and/or oxidizable silicon compound, b) a product stream II comprising oxygen and c) a product stream III comprising at least a combustible gas are made to react, characterized in that d) a feed port in a pipepiece A, said pipepiece A comprising one or more static mixing elements, is used to import product stream I into product stream II, or vice versa and thereby create product stream IV, then e) a feed port in a pipepiece B, said pipepiece B comprising one or more static mixing elements, is used to import product stream III in product stream IV and thereby create product stream V, f) product stream V leaving pipepiece B is imported into a reaction chamber, ignited therein and reacted in a flame, and g) the resultant solid material is separated off.

Abstract: Method for producing a metal oxide powder in which a) a material stream I containing at least one vaporous hydrolysable metal compound, b) a material stream II containing oxygen and c) a material stream III containing at least one fuel gas are brought to reaction, wherein d) via a feed-in point provided in a pipe piece A, wherein the pipe piece A comprises one or more static mixer elements, the material stream I is introduced into the material stream II, or vice versa, and thereby generates the material stream IV, then e) via a feed-in point provided in a pipe piece B, wherein the pipe piece B comprises one or more static mixer elements, the material stream III is introduced into the material stream IV, and thereby generates the material stream V, f) the material stream V leaving the pipe piece B is introduced into a reaction chamber, ignited there and converted into a flame and g) the resultant solids are separated off.

Abstract: The present invention relates to mixed oxide compositions, to the use thereof as a catalyst for cleavage of alkyl tert-alkyl ethers or tertiary alcohols, and to a process for cleaving alkyl tert-alkyl ethers or tertiary alcohols to isoolefins and alcohol or water.

Abstract: Method for producing a metal oxide powder in which a) a material stream I containing at least one vaporous hydrolysable metal compound, b) a material stream II containing oxygen and c) a material stream III containing at least one fuel gas are brought to reaction, wherein d) via a feed-in point provided in a pipe piece A, wherein the pipe piece A comprises one or more static mixer elements, the material stream I is introduced into the material stream II, or vice versa, and thereby generates the material stream IV, then e) via a feed-in point provided in a pipe piece B, wherein the pipe piece B comprises one or more static mixer elements, the material stream III is introduced into the material stream IV, and thereby generates the material stream V, f) the material stream V leaving the pipe piece B is introduced into a reaction chamber, ignited there and converted into a flame and g) the resultant solids are separated off.

Abstract: Process for production of silica having variable thickening wherein a) a product stream I comprising at least a vaporous, hydrolysable and/or oxidizable silicon compound, b) a product stream II comprising oxygen and c) a product stream III comprising at least a combustible gas are made to react, characterized in that d) a feed port in a pipepiece A, said pipepiece A comprising one or more static mixing elements, is used to import product stream I into product stream II, or vice versa and thereby create product stream IV, then e) a feed port in a pipepiece B, said pipepiece B comprising one or more static mixing elements, is used to import product stream III in product stream IV and thereby create product stream V, f) product stream V leaving pipepiece B is imported into a reaction chamber, ignited therein and reacted in a flame, and g) the resultant solid material is separated off.

Abstract: Silicon-aluminum mixed oxide powder having a weight ratio of (Al2O3/SiO2)ttl in the total primary particle of from 0.003 to 0.05, a weight ratio (Al2O3/SiO2)surface of the primary particles in a surface layer having a thickness of about 5 nm which is less than in the total primary particle and a BET surface area of from 50 to 250 m2/g. It is prepared by igniting one or more silicon compounds selected from the group consisting of CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and (n-C3H7)SiCl3, a hydrolysable and oxidizable aluminum compound, at least one fuel gas and air and burning the flame into a reaction chamber, subsequently separating the solid from gaseous materials and subsequently treating the solid with water vapor. The silicon-aluminum mixed oxide powder can be used as catalyst.

Abstract: Process for preparing an aluminum oxide powder which is present in the form of aggregated primary particles and comprises at least 85% by weight of alpha-aluminum oxide, in which an aluminum oxide powder which a) is present in the form of aggregated primary particles, b) is selected from the group consisting of gamma-aluminum oxide, theta-aluminum oxide, delta-aluminum oxide and/or X-ray amorphous aluminum oxide, and c) has a tamped density of at least 250 g/l, is subject to a heat treatment at 13000 C or more and subsequently milled. Aluminum oxide powder which can be obtained by this process. Aluminum oxide powder in the form of aggregated primary particles having a BET surface area of from 3 to 30 m2/g, in which the proportion of alpha-aluminum oxide is at least 85% by weight and the ratio dgo/dio of the weight distribution of the primary particles is at least 2.8. Use as constituent of fluorescent tubes.

Abstract: The present invention relates to mixed oxide compositions, to the use thereof as a catalyst for cleavage of alkyl tert-alkyl ethers or tertiary alcohols, and to a process for cleaving alkyl tert-alkyl ethers or tertiary alcohols to isoolefins and alcohol or water.

Abstract: Silicon-aluminum mixed oxide powder having a weight ratio of (Al2O3/SiO2)ttl in the total primary particle of from 0.003 to 0.05, a weight ratio (Al2O3/SiO2)surface of the primary particles in a surface layer having a thickness of about 5 nm which is less than in the total primary particle and a BET surface area of from 50 to 250 m2/g. It is prepared by igniting one or more silicon compounds selected from the group consisting of CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and (n-C3H7)SiCl3, a hydrolysable and oxidizable aluminum compound, at least one fuel gas and air and burning the flame into a reaction chamber, subsequently separating the solid from gaseous materials and subsequently treating the solid with water vapor. The silicon-aluminum mixed oxide powder can be used as catalyst.

Abstract: A granulated material comprising a mixed silicon-titanium oxide powder, wherein a proportion of TiO2 is from 70 to 98 wt %, a proportion of SiO2 is from 2 to 30 wt %, and a sum of TiO2 and SiO2 is at least 98% by weight, and wherein: at room temperature, the TiO2 proportion comprises rutile and more than 50% of anatase, the BET surface area is from 10 to 200 m2/g, and the volume of 2 to 50 nm pores is from 0.4 to 2.5 ml/g; and after heating at 900° C. for a period of 4 hours, the anatase proportion is more than 50% of the room temperature proportion, the BET surface area is at least 60% of the room temperature BET surface area, and the volume of 2 to 50 nm pores is at least 50% of the room temperature volume.

Abstract: Silica glass granule having the following features: Area: 100 to 5000 ?m2, ECD: 5 to 100 ?m, Circumference: 20 to 400 ?m, Maximum diameter: 10 to 140 ?m, Minimum diameter: 5 to 80 ?m, where all values are medium values, Specific BET surface area: <1 m2/g Impurities: <50 ppm It is prepared by a) compacting pyrogenic silicon dioxide powder with a tamped density of 15 to 190 g/l to slugs, b) subsequently crushing them and removing slug fragments with a diameter of <100 ?m and >800 ?m, c) the slug fragments having a tamped density of 300 to 600 g/l, and d) subsequently treating them at 600 to 1100° C. in an atmosphere which comprises one or more compounds which are suitable for removing hydroxyl groups, and e) then sintering them at 1200° C. to 1400° C.

Abstract: Provided is a crystalline TiO2 powder in the form of aggregated primary particles having a variable sintering stability at a BET surface area of 70-100 m2/g and a rutile content of greater than 10% but less than or equal to 40%, and a process for preparing the crystalline TiO2 powder, which involves: introducing a TiCl4 vapor and, separately therefrom, H2 and a primary air into a mixing chamber to produce a gaseous mixture; igniting the gaseous mixture in a burner to produce a flame, which is burned into a reaction chamber to produce the crystalline TiO2 powder and gaseous substances; and separating the crystalline TiO2 powder from the gaseous substances, wherein the relative amounts of TiCl4 vapor, H2 and primary air are selected to provide crystalline TiO2 powder having the aforementioned BET surface area and rutile content, with the proviso that factor A has a value of 0.1-0.4 g/m2 in accordance within the following formula: factor A=105{[(TiCl4 vapor×H2)/(amount of air×gaseous mixture)]/BET]}.

Abstract: A crystalline titanium dioxide powder, containing aggregated primary particles, wherein a BET surface area of the aggregated primary particles is from 30 to 65 m2/g, and a rutile content of a sum of crystalline modifications in the crystalline titanium dioxide is from of 50-70%.

Abstract: Process for preparing an aluminium oxide powder which is present in the form of aggregated primary particles and comprises at least 85% by weight of alpha-aluminium oxide, in which an aluminium oxide powder which a) is present in the form of aggregated primary particles, b) is selected from the group consisting of gamma-aluminium oxide, theta-aluminium oxide, delta-aluminium oxide and/or X-ray amorphous aluminium oxide, and c) has a tamped density of at least 250 g/l, is subject to a heat treatment at 13000C or more and subsequently milled. Aluminium oxide powder which can be obtained by this process. Aluminium oxide powder in the form of aggregated primary particles having a BET surface area of from 3 to 30 m2/g, in which the proportion of alpha-aluminium oxide is at least 85% by weight and the ratio dgo/dio of the weight distribution of the primary particles is at least 2.8. Use as constituent of fluorescent tubes.

Abstract: Provided is a crystalline TiO2 powder in the form of aggregated primary particles having a variable sintering stability at a BET surface area of 70-100 m2/g and a rutile content of greater than 10% but less than or equal to 40%, and a process for preparing the crystalline TiO2 powder, which involves: introducing a TiCl4 vapor and, separately therefrom, H2 and a primary air into a mixing chamber to produce a gaseous mixture; igniting the gaseous mixture in a burner to produce a flame, which is burned into a reaction chamber to produce the crystalline TiO2 powder and gaseous substances; and separating the crystalline TiO2 powder from the gaseous substances, wherein the relative amounts of TiCl4 vapor, H2 and primary air are selected to provide crystalline TiO2 powder having the aforementioned BET surface area and rutile content, with the proviso that factor A has a value of 0.1-0.4·105 g/m2 in accordance within the following formula: factor A=105{[(TiCl4 vapor×H2)/(primary air×gaseous mixture)]/BET]}.

Abstract: Process for preparing a silicon dioxide granule having a specific surface area of less than 1 m2/g and a proportion of impurities of less than 50 ppm, in which a) a silicon dioxide powder with a tamped density of 15 to 190 g/l, b) is compacted to slugs which are subsequently crushed, the slug fragments having a tamped density of 210 to 800 g/l, and c) the slug fragments are treated with one or more reactive compounds at 400 to 1100° C.

Abstract: Silica glass granule having the following features: Area: 100 to 5000 ?m2, ECD: 5 to 100 ?m, Circumference: 20 to 400 ?m, Maximum diameter: 10 to 140 ?m, Minimum diameter: 5 to 80 ?m, where all values are medium values, Specific BET surface area: <1 m2/g Impurities: <50 ppm It is prepared by a) compacting pyrogenic silicon dioxide powder with a tamped density of 15 to 190 g/1 to slugs, b) subsequently crushing them and removing slug fragments with a diameter of <100 ?m and >800 ?m, c) the slug fragments having a tamped density of 300 to 600 g/l, and d) subsequently treating them at 600 to 1100° C. in an atmosphere which comprises one or more compounds which are suitable for removing hydroxyl groups, and e) then sintering them at 1200° C. to 1400° C.

Abstract: A crystalline titanium dioxide powder, containing aggregated primary particles, wherein a BET surface area of the aggregated primary particles is from 30 to 65 m2/g, and a rutile content of a sum of crystalline modifications in the crystalline titanium dioxide is from of 50-70%.