PURPOSE: To separate the title compounds, useful as intermediates for dyes and pigments in high purity, by extracting an aqueous slurry catalytic oxidation product of naphthalene with a specific saturated hydrocarbon at a specific pH and temperature, and by separating insoluble substances from the solvent and aqueous layers.
CONSTITUTION: The catalytic vapor-phase oxidation product gas of naphthalene (N) is brought into contact with an aqueous medium to collect naphthoquinone and phthalic anhydride. The resulting aqueous slurry is adjusted to pH 1.2W5, and brought into contact with a solvent consisting of a chain and/or cyclic hydrocarbon at 60W110°C to extract naphthoquinone selectively into the solvent layer and to dissolve phthalic acid into the aqueous layer substantially. Resinous substances insoluble in the layers are separated to give naphthoquinone in high purity from the solvent layer and phthalic acid from the aqueous layer industrially advantageously.
KOMATSU TATSUMI
USUI KENJI
SATOU TOORU
| JPS5511520A | 1980-01-26 |