| 摘要 |
A Group VIII noble metal catalyst supported on an alumina carrier having an alumina content greater than 99.0%, a crystalline alpha-alumina content of greater than 96%, a theta-alumina content of less than about 3.0%, a total calcium and magnesium content of less than 750 ppm, a surface area of about 2 to 6 m2/g, an average crush strength of from about 20 to 45 lbs., a bulk density of less than about 1.35 g/cc, and an acetic acid loading of less than about 1.5% in 200 hours. The catalyst generally contains an alkali metal carboxylate activator and optionally a metal such as gold, copper, and the like. The catalyst is particularly useful for the preparation of unsaturated organic esters such as vinyl acetate and allyl acetate by a vapor phase process wherein a gaseous mixture of an olefinic compound, a lower carboxylic acid, and oxygen is contacted with the catalyst.
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