Method for producing transition alumina catalyst monoliths

A method for producing a three-dimensional porous transition alumina catalyst monolith of stacked catalyst fibers, comprising the following steps:

• a) preparing a suspension paste in a liquid diluent of hydroxide precursor particles or oxy-hydroxide precursor particles of transition alumina particles or mixtures thereof and which suspension can furthermore comprise a binder material selected from organic materials in a maximum amount of 20 wt %, based on the amount of hydroxide precursor particles or oxyhydroxide precursor particles of transition alumina particles or mixtures thereof and/or a plasticizer chosen from organic materials in a maximum amount of 10 wt %, based on the amount of hydroxide precursor particles or oxyhydroxide precursor particles of transition alumina particles or mixtures thereof, all particles in the suspension having a number average particle size in the range of from 0.05 to 700 μm,
• b) extruding the paste of step a) through one or more nozzles to form fibers, and depositing the extruded fibers to form a three-dimensional porous catalyst monolith precursor,
• c) drying the porous catalyst monolith precursor to remove the liquid diluent,
• d) performing a temperature treatment of the dried porous catalyst monolith precursor of step c) at a temperature in the range of from 500 to 1000° C., to form the transition alumina catalyst monolith,
• wherein no temperature treatment of the porous catalyst monolith precursor or porous catalyst monolith at temperatures above 1000° C. is performed and
• wherein no further catalytically active metals, metal oxides or metal compounds are applied to the surface of the transition alumina precursor particles, the catalyst monolith precursor or transition alumina catalyst monolith,
• wherein no dopants are added to the suspension paste and
• wherein the amount of impurities, selected from Li2O, Na2O, K2O, CaO, MgO, BaO, B2O3, Ga2O3, SiO2, TiO2, ZrO2, ZnO, Fe2O3, as well as chlorides, nitrates and sulfates in the transition alumina particles and hydroxide precursor particles and oxyhydroxide precursor particles thereof, is not higher than 2.5 wt %, based on the transition alumina in the monolith;
• wherein the transition alumina catalyst monolith has a BET surface area in the range of from 50 to 350 m2/g.

A method for producing a three-dimensional porous transition alumina catalyst monolith of stacked catalyst fibers, comprising the following steps:

• a) preparing a suspension paste in a liquid diluent of hydroxide precursor particles or oxy-hydroxide precursor particles of transition alumina particles or mixtures thereof and which suspension can furthermore comprise a binder material selected from organic materials in a maximum amount of 20 wt %, based on the amount of hydroxide precursor particles or oxyhydroxide precursor particles of transition alumina particles or mixtures thereof and/or a plasticizer chosen from organic materials in a maximum amount of 10 wt %, based on the amount of hydroxide precursor particles or oxyhydroxide precursor particles of transition alumina particles or mixtures thereof, all particles in the suspension having a number average particle size in the range of from 0.05 to 700 μm,
• b) extruding the paste of step a) through one or more nozzles to form fibers, and depositing the extruded fibers to form a three-dimensional porous catalyst monolith precursor,
• c) drying the porous catalyst monolith precursor to remove the liquid diluent,
• d) performing a temperature treatment of the dried porous catalyst monolith precursor of step c) at a temperature in the range of from 500 to 1000° C., to form the transition alumina catalyst monolith,
• wherein no temperature treatment of the porous catalyst monolith precursor or porous catalyst monolith at temperatures above 1000° C. is performed and
• wherein no further catalytically active metals, metal oxides or metal compounds are applied to the surface of the transition alumina precursor particles, the catalyst monolith precursor or transition alumina catalyst monolith,
• wherein no dopants are added to the suspension paste and
• wherein the amount of impurities, selected from Li2O, Na2O, K2O, CaO, MgO, BaO, B2O3, Ga2O3, SiO2, TiO2, ZrO2, ZnO, Fe2O3, as well as chlorides, nitrates and sulfates in the transition alumina particles and hydroxide precursor particles and oxyhydroxide precursor particles thereof, is not higher than 2.5 wt %, based on the transition alumina in the monolith;
• wherein the transition alumina catalyst monolith has a porosity of at least 20%, determined by nitrogen physisorption.