[0104] To this mixture were added 5%w by weight of the mixture of petrolatum oil, 9%w by weight of the mixture of burnout material and 0.1%w by weight of the mixture of boric acid. A quantity of water (about 30% w relative to the weight of the mixture) is then added such that the mixture becomes extrudable, and the mixture is then extruded to form a shaped body in the form of a hollow cylinder with dimensions of about 8 mm diameter and 8mm long. These shaped bodies were then dried and calcined in air at 1425° C. for 4 hours in a drying oven to pr...
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Abstract
A catalyst which comprises a carrier and silver deposited on the carrier, which carrier has a surface area of at least 1 m2 / g, and a pore size distribution such that pores with diameters in the range of from 0.2 to 10 mum represent at least 70% of the total pore volume and such pores together provide a pore volume of at least 0.27 ml / g, relative to the weight of the carrier; a process for the preparation of a catalyst which process comprises depositing silver on a carrier, wherein the carrier has been obtained by a method which comprises forming a mixture comprising: a) from 50 to 90% w of a first particulate alpha-alumina having an average particle size (d50) of from more than 10 up to 100 mum; and b) from 10 to 50% w of a second particulate alpha-alumina having an average particle size (d50) of from 1 to 10 mum; % w being based on the total weight of alpha-alumina in the mixture; and shaping the mixture into formed bodies and firing the formed bodies to form the carrier, and a process for the epoxidation of an olefin, which process comprises reacting an olefin with oxygen in the presence of a said catalyst.
Description
Background of the invention [0001] The present invention relates to a catalyst and the use of the catalyst in the epoxidation of olefins. [0002] In olefin epoxidation reactions, catalyst performance can be evaluated in terms of selectivity, activity and stability of operation. Selectivity is the percentage of converted olefin that yields the desired olefin oxide. As the catalyst ages, the percentage of olefins converted typically decreases with time, and in order to maintain olefin oxide production at a constant level, the reaction temperature needs to be increased. However, this would adversely affect the selectivity of conversion to the desired olefin oxide. Furthermore, the equipment used can only tolerate an increase in temperature up to a certain level, so when the reaction temperature reaches a level unsuitable for the reactor, the reaction needs to be terminated. Therefore, the longer the epoxidation reaction is carried out at a high level of selectivity and at an ...
Claims
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