摘要:
The selectivity and activity of a silver-based olefin epoxidation catalyst is found to be a function of the pore size distribution in the alumina carrier on which it is deposited. Specifically it is found advantageous to provide a carrier which has a minimum of very large pores, (greater than 10 micrometers) and a water absorption of 35 to 55% and a surface area of at least 1.0 m2/g. A method of making such carriers is also described.
摘要:
A carrier, which comprises non-platelet alumina and/or a bond material, has a surface area of at least 1.3 m2/g, a total pore volume and a pore size distribution such that at least 80% of the total pore volume is contained in pores with diameters in the range of from 0.1 to 10 μm, and at least 80% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm, and a process for the preparation of a carrier which comprises forming a mixture comprising: a) from 50 to 95 weight percent of a first particulate α-alumina having a median particle size (d50) of from 5 to 100 μm; b) from 5 to 50 weight percent of a second particulate α-alumina having a d50 which is less than the d50 of the first particulate α-alumina and which is in the range of from 1 to 10 μm; and c) an alkaline earth metal silicate bond material; weight percent being based on the total weight of α-alumina in the mixture; and firing the mixture to form the carrier.
摘要:
A carrier, which comprises non-platelet alumina and/or a bond material, has a surface area of at least 1.3 m2/g, a total pore volume and a pore size distribution such that at least 80% of the total pore volume is contained in pores with diameters in the range of from 0.1 to 10 μm, and at least 80% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm, and a process for the preparation of a carrier which comprises forming a mixture comprising: a) from 50 to 95 weight percent of a first particulate α-alumina having a median particle size (d50) of from 5 to 100 μm; b) from 5 to 50 weight percent of a second particulate α-alumina having a d50 which is less than the d50 of the first particulate α-alumina and which is in the range of from 1 to 10 μm; and c) an alkaline earth metal silicate bond material; weight percent being based on the total weight of α-alumina in the mixture; and firing the mixture to form the carrier.
摘要:
An improved catalyst carrier is formed by a process that comprises the use of ceramic particle components with particle sizes chosen to ensure that a desired degree of porosity is obtained without recourse to the use of organic burnout materials.
摘要:
A catalyst carrier that is comprised of relatively large alpha alumina particles dispersed in matrix that comprises an alpha alumina formed in situ by a sol-gel process and titania has excellent crush resistance while retaining good porosity and catalytic performance.
摘要:
A catalyst carrier that is comprised of relatively large alpha alumina particles dispersed in matrix that comprises an alpha alumina formed in situ by a sol-gel process has excellent crush resistance while retaining good porosity and catalytic performance.
摘要:
A catalyst for the selective reduction of nitrogen oxides to nitrogen in the presence of ammonia in the form of composite bodies formed from a mixture of anatase (5 to 40% by weight), a zeolite (50 to 90%), a bond material (0 to 30%, and, optionally, promoter selected from oxides of vanadium, molybdenum, and copper, in the amount of at least 0.1% by weight.
摘要:
A catalyst for the selective reduction of nitrogen oxides to nitrogen in the presence of ammonia in the form of composite bodies formed from a mixture of zirconia (5 to 50% by weight), a zeolite (50 to 90%), a bond material (0 to 30%), and, optionally, a promoter selected from oxides of vanadium and copper in the amount of at least 0.1% by weight.
摘要:
The invention relates to ethylene oxide catalysts containing silver, alkali metal promoters, rhenium promoters and optionally rhenium co-promoters selected from sulfur, molybdenum, tungsten, chromium and mixtures thereof supported on a carrier consisting of at least 85 percent by weight of alpha alumina, from about 0.01 to about 6 percent by weight (measured as the oxide) of an added alkaline earth metal in the form of an oxide, from about 0.01 to about 5 percent by weight (measured as the dioxide) of added silicon in the form of an oxide and from zero to about 10 percent by weight (measured as the dioxide) of added zirconium in the form of an oxide. The invention also relates to an ethylene oxide process using the above catalyst.
摘要:
The invention relates to catalyst carries for use in conjunction with silver, alkali metal promoters, rhenium promoters and optionally rhenium co-promoters selected from sulfur, molybdenum, tungsten, chromium and mixtures thereof. The carriers consisting of at least 85 and preferably 95 percent by weight of alpha alumina, from about 0.01 to about 6 percent by weight of an alkaline earth metal silicate and from about zero to about 10 percent by weight (measured as the dioxide of added zirconium in the form of an oxide.