Gas phase hydrogenation of phenol to cyclohexanone - using palladium catalyst, in the presence of a gaseous basic nitrogen cpd. to increase rate of reaction

摘要

Cyclohexanone (I) is made by gas phase hydrogenation of phenol with a Pd catalyst in the presence of a basic N cpd. which is gaseous under the prevailing conditions. Pref. basic N cpds. are ammonia or aliphatic amines with 1-6C in the hydrocarbon gp. the basic cpd. is used e.g. at 0.5-100 ppm (vol.), esp. 5-200 ppm on the gas mixt. The catalyst used is pref. a Pd-on-Al2O3 catalyst and the concn. of Pd in the catalyst is pref. 0.1-10, esp. 0.2-1 wt.%. The catalyst may also contain activators such as Na2CO3 or NaOH in an amt. of 0.1-10 wt.% on the catalyst. The presence of the basic N cpd. increases the rate of reaction in the hydrogenation reaction.