A supported catalyst, its method of preparation and use in hydrogenation methods, which catalyst contains an oxide substrate that is for the most part calcined aluminum and an active phase that contains nickel, with the nickel content between 5 and 65% by weight in relation to the total mass of the catalyst, with the active phase not containing a metal from group VIB, the nickel particles having a diameter that is less than or equal to 20 nm, the catalyst having a median mesopore diameter of between 14 nm and 30 nm, a median macropore diameter of between 50 and 200 nm, a mesopore volume that is measured by mercury porosimetry that is greater than or equal to 0.40 mL/g, and a total pore volume that is measured by mercury porosimetry that is greater than or equal to 0.42 mL/g.

A supported catalyst, its method of preparation and use in hydrogenation methods, which catalyst contains an oxide substrate that is for the most part calcined aluminum and an active phase that contains nickel, with the nickel content between 5 and 65% by weight in relation to the total mass of the catalyst, with the active phase not containing a metal from group VIB, the nickel particles having a diameter that is less than or equal to 20 nm, the catalyst having a median mesopore diameter of between 14 nm and 30 nm, a median macropore diameter of between 50 and 200 nm, a mesopore volume that is measured by mercury porosimetry that is greater than or equal to 0.40 mL/g, and a total pore volume that is measured by mercury porosimetry that is greater than or equal to 0.42 mL/g.

A process for producing alumina, the process having a seeding phase and a precipitation phase. During the seeding phase a seed mixture is produced by adding an aluminium salt to an aqueous solution and then adding an alkaline metal aluminate to the mixture while maintaining the seed mixture at generally neutral pH. The precipitation phase produces precipitated alumina by simultaneously adding aluminium salt and alkaline metal aluminate to the seed mixture while maintaining a pH from 6.9 to 7.8. The recovered precipitated alumina has at least one, preferably all the following characteristics: i) a crystallite size of 33-42 Ang.: in the (120) diagonal plane (using XRD); ii) a crystallite d-spacing (020) of between 6.30-6.59 Ang.; iii) a high porosity with an average pore diameter of 115-166 Ang.; iv) a relatively low bulk density of 250-350 kg/m.sup.3; v) a surface area after calcination for 24 hours at 1100 C. of 60-80 m.sup.2/g; and vi) a pore volume after calcination for one hour at 1000 C. 0.8-1.1 m.sup.3/g.

A process for producing alumina, the process having a seeding phase and a precipitation phase. During the seeding phase a seed mixture is produced by adding an aluminium salt to an aqueous solution and then adding an alkaline metal aluminate to the mixture while maintaining the seed mixture at generally neutral pH. The precipitation phase produces precipitated alumina by simultaneously adding aluminium salt and alkaline metal aluminate to the seed mixture while maintaining a pH from 6.9 to 7.8. The recovered precipitated alumina has at least one, preferably all the following characteristics: i) a crystallite size of 33-42 Ang.: in the (120) diagonal plane (using XRD); ii) a crystallite d-spacing (020) of between 6.30-6.59 Ang.; iii) a high porosity with an average pore diameter of 115-166 Ang.; iv) a relatively low bulk density of 250-350 kg/m.sup.3; v) a surface area after calcination for 24 hours at 1100 C. of 60-80 m.sup.2/g; and vi) a pore volume after calcination for one hour at 1000 C. 0.8-1.1 m.sup.3/g.

Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

The present disclosure relates to an alumina having a surface area in the range of 330-400 m.sup.2/g, a pore volume in the range of 1.2-1.7 cc/g, and an average pore diameter in the range of 125-160 . The present disclosure also relates to alumina extrudates having a diameter in the range of 1 mm to 3 mm, a surface area in the range of 300-360 m.sup.2/g, a pore volume in the range of 0.8-1.3 cc/g and pore diameter in the range of 90-130 with a crushing strength in the range of 1-2.5 daN/mm. Further, the present disclosure relates to a process for the preparation of alumina and alumina extrudates. The alumina extrudates can be used as a support for catalyst preparation or as a catalyst or adsorbent in various processes. The process of the present disclosure enhances metal loading capacity, has better metal dispersion, and exhibit delay in deactivation of the catalyst due to mouth pore plugging.

The present disclosure relates to an alumina having a surface area in the range of 330-400 m.sup.2/g, a pore volume in the range of 1.2-1.7 cc/g, and an average pore diameter in the range of 125-160 . The present disclosure also relates to alumina extrudates having a diameter in the range of 1 mm to 3 mm, a surface area in the range of 300-360 m.sup.2/g, a pore volume in the range of 0.8-1.3 cc/g and pore diameter in the range of 90-130 with a crushing strength in the range of 1-2.5 daN/mm. Further, the present disclosure relates to a process for the preparation of alumina and alumina extrudates. The alumina extrudates can be used as a support for catalyst preparation or as a catalyst or adsorbent in various processes. The process of the present disclosure enhances metal loading capacity, has better metal dispersion, and exhibit delay in deactivation of the catalyst due to mouth pore plugging.

A process for producing metastable nanocrystalline alpha-alumina (-Al.sub.2O.sub.3) having particle sizes smaller than 12 nm. Starting crystallites of -Al.sub.2O.sub.3 having a particle size larger than 12 nm, typically on the order of about 50 nm, are ball-milled at low temperatures to produce a nanocrystalline -Al.sub.2O.sub.3 powder having a particle size of less than 12 nm, i.e., below the theoretical room temperature thermodynamic size limit at which -Al.sub.2O.sub.3 changes phase to -Al.sub.2O.sub.3, wherein the powder remains in the -Al.sub.2O.sub.3 phase at all times.

A process for producing metastable nanocrystalline alpha-alumina (-Al.sub.2O.sub.3) having particle sizes smaller than 12 nm. Starting crystallites of -Al.sub.2O.sub.3 having a particle size larger than 12 nm, typically on the order of about 50 nm, are ball-milled at low temperatures to produce a nanocrystalline -Al.sub.2O.sub.3 powder having a particle size of less than 12 nm, i.e., below the theoretical room temperature thermodynamic size limit at which -Al.sub.2O.sub.3 changes phase to -Al.sub.2O.sub.3, wherein the powder remains in the -Al.sub.2O.sub.3 phase at all times.