PURPOSE: To prepare the titled compound stably for a long period, without increasing the gas-flow resistance of the catalyst bed, by the catalytic vapor- phase oxidation of a raw material composed of an oxygen-containing gas containing a small amount of easily handleable sulfur dioxide and naphthalene using a fixed bed comprising a stationary catalyst layer and a mixed packed layer placed at the upstream side of the stationary layer.
CONSTITUTION: 1,4-naphthoquinone is prepared by the catalytic vapor-phase oxidation of naphthalene with O2 gas using a stationary catalyst layer composed of vanadium oxide, an alkali metal sulfate, and an alkali metal pyrosulfate. In the above process, the catalytic vapor-phase oxidation of naphthalene is carried out by using a fixed bed comprising the stationary catalyst layer and a mixed packed layer composed of a mixture of a catalyst similar to the above catalyst and an inert granular material and supplying an oxygen-containing gas containing ≥1ppm of sulfur dioxide and naphthalene to the fixed bed, wherein the mixed packed layer is placed at the upstream side of the oxygen gas-inlet of the stationary catalyst layer. The sulfur dioxide is converted to sulfur trioxide in the mixed filler layer, and the increase of the gas-flow resistance of the stationary catalyst layer can be prevented.
YOSHIMURA NARIYUKI
ASANUMA YASUO
YOSHIZUMI HARUO
