PREPARATION FOR PHTHALIC ANHYDRIDE OF HIGH PURITY

PURPOSE:To remove impurities efficiently and obtain the titled compound industrially and advantagenously, by bringing crude phthalic anhydride obtained by the catalytic vapor phase oxidation into contact with a gas containing oxygen in the presence of an alkali metallic salt of a carboxylic acid and...

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Bibliographic Details
Main Authors KITA HIROICHI, SATOU TAKAHISA, SAKAMOTO KENTAROU
Format Patent
LanguageEnglish
Published 13.05.1983
Subjects
CHEMISTRY
HETEROCYCLIC COMPOUNDS
METALLURGY
ORGANIC CHEMISTRY
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Summary:PURPOSE:To remove impurities efficiently and obtain the titled compound industrially and advantagenously, by bringing crude phthalic anhydride obtained by the catalytic vapor phase oxidation into contact with a gas containing oxygen in the presence of an alkali metallic salt of a carboxylic acid and an alloy composition containing Mn at a high temperature,and distilling the resultant mixture. CONSTITUTION:Crude phthalic anhydride prepared by the catalytic oxidation of o-xylene is treated with a gas containing molecular oxygen in the presence of one or more alkali metallic salts of carboxylic acids, e.g. maleic, succinic and benzoic acids, and an alloy composition containing Mn at a temperature as high as 150-300 deg.C for 0.5-30hr, and the resultant mixture is then distilled to give the aimed compound. Preferably, the gas containing the oxygen is brought into contact with one kg phthalic anhydride at >=1X10<-4>mol/hr flow rate expressed in terms of oxygen gas, and the alkali metallic salts are used in an amount of 10-10,000ppm (weight) expressed in terms of metallic atmos. The contact area of the alloy containing Mn is preferably >=1X10<-3>m .
Bibliography:Application Number: JP19810177808