Davy International Aktiengesellschaft

Lothar Sterck

Gerhard Keunecke

Anton Klopfer

Herbert Krimphove

John H Maude

Alfred Vilshofer

Phthalic anhydride is continuously separated from the reaction gas mixture formed by the catalytic oxidation of o-xylene and/or naphthalene, by treating said rection gas mixture in at least two absorption stages with organic absorbents. The absorbent employed in the first absorption stage is a mixture of phthalic anhydride and benzoic acid. The absorbent employed in the subsequent absorption stage(s) contains maleic anhydride and may also contain phthalic anhydride.

Process for continuously separating phthalic anhydride from the reaction

An improved process is provided for the recovery and storage of maleic anhydride from maleic anhydride-containing gases. Such gases are scrubbed with a water or maleic acid scrubbing solution in a scrubbing zone to form a maleic acid-containing solution. This maleic acid-containing solution is then concentrated and dehydrated in an evaporation zone and a dehydration zone, respectively, to form maleic anhydride. The maleic anhydride so formed is then purified by distillation in a distillation zone. The evaporation, dehydration, and distillation steps are all carried out under a vacuum maintained by withdrawing gases containing organic and water vapor from said evaporation, dehydration and distillation zones using jet pumps propelled by pressurized air. The vapor-containing gases so removed are admixed with the pressurized air pump propellant streams, and this mixture is then introduced into the scrubbing zone for the maleic anhydride-containing gases. Vapor-containing gases may also be sucked by the jet pumps from maleic anhydride storage vessels, and such vapor-containing gases may also then be introduced into the scrubbing zone.

Process for the recovery of maleic anhydride from gases containing

Apparatus for the production and catalytic oxidation of gaseous hydrocarbon/air mixtures to form dicarboxylic acid anhydride. Hydrocarbon/air mixtures are formed in an evaporator and introduced into a shell-and-tube catalytic reactor fitted with a concave reactor hood to more effectively and safely distribute the gaseous mixture to and through the catalyst-filled tubes of the reactor.

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Hurth, Germany

Lothar Sterck