PURPOSE: To prepare anthraquinone, in high yield, by the catalytic vapor-phase oxidation of 2-methyldiphenylmethane with O2 in two reaction zones containing two kinds of different catalysts, especially containing a specific compound as the catalyst for the latter reaction zone, and restricting the conversion of the raw material in each reaction zone.
CONSTITUTION: Anthraquinone is prepared by the catalytic vapor-phase oxidation of 2-methyldiphenylmethane with an O2-containing gas. In the above process, a catalyst containing a V oxide is placed to the gas-inlet side of the reaction zone, and a catalyst containing at least a compound selected from P, Al, B and Sb and added with a V oxide is placed at the gas-outlet side of the zone. The reaction is carried out by keeping the initial conversion of 2-methyldiphenylmethane to 30W98% (especially 50W98%) and the subsequent conversion to 98W100%. The catalyst in the latter stage is preferably incorporated with an alkali metal and/or Tl to improve the effect.
EFFECT: Stable for a long period.
NAKAHARA SABUROU
SUZUKI TAKEHIKO
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