| 摘要 |
1. Catalysts based on silver supported on porous artificial graphite or on porous graphite-containing materials, the catalysts being intended for the vapour phase synthesis of epoxides by reaction of an ethylenic hydrocarbon with oxygen or with gaseous mixtures containing oxygen, characterised in that the graphite-type supports have : a specific surface area of less than 10 m**2 /g, a particle size of 50 mu m to 10 mm, a total porosity volume of between 0.1 and 0.4 cm**3 /g, and a porosity distribution which is such that the pores of diameter less than 6.6 mu m represent at most 60% of the total porosity volume if the particle size of the support is greater than 0.7 mm, and at most 90% of the total porosity volume if the particle size of the support is less than or equal to 0.7 mm. |
