Catalyst carriers
AssigneeSaint-Gobain Norpro Corporation
InventorsThomas Szymanski, Donald J. Remus, John R. Lockemeyer, Randall Clayton Yeates, William H. Gerdes
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Abstract
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 malting such carriers is also described.
Claims11
A carrier for a catalyst for the epoxidation of an olefin which comprises at least 95% alpha alumina with a surface area of from 1.0 to 2.6 m2/g and a water absorption of from 35 to 55%, wherein the pores are distributed such that at least 70% of the pore volume is in the form of pores having pore diameters from 0.2 to 10 micrometers and pores with diameters between 0.2 and 10 micrometers provide a volume of at least 0.27 mL/g of the carrier.
A method of making a carrier for an olefin epoxidation catalyst which comprises forming a mixture comprising:
- a) from 50 to 90% by weight of a first particulate alpha alumina having an average particle size (d50) of from 10 to 90 micrometers;
- b) from 10 to 50% by weight, based on the total alpha alumina weight, of a second particulate alpha alumina having an average particle size (d50) of from 2 to 6 micrometers;
- c) from 2 to 5% by weight of an alumina hydrate;
- d) from 0.2 to 0.8% of an amorphous silica compound, measured as silica;
- and
- e) from 0.05 to 0.3% of an alkali metal compound measured as the alkali metal oxide;
- all percentages being based on the total alpha alumina content of the mixture, and then forming the mixture into particles and firing the particles at a temperature of from 1250 to 1470° C. to form the carrier.
Dependencies are inferred from the claim text.