Basf Aktiengesellschaft

Joachim Wagner

Friedrich Wirth

Harry Kassat

Ulrich Block

Paul Hornberger

Wolfgang Kube

Dieter Karau

Otto Leman

Klaus Nixdorf

Wolf Muff

In apparatuses for the preparation of phthalic anhydride and/or maleic anhydride by catalytic oxidation of naphthalene or o-xylene with air, reduced pressure is generated using liquid-jet pumps, and wash liquid is removed from the exit gas washer as a pump fluid for the liquid-jet pumps and is subsequently recycled to the exit gas washer.

Generation of reduced pressure in apparatuses in the preparation of

Desublimator for isolating sublimation products from reaction gases, which consists of a closed housing and a plurality of rows of finned tubes accommodated horizontally and superposedly therein, successive superposed finned tubes being supported, and mutually spaced, with limited adjustability, by means of cage-like perforated sliding shoes surrounding them in a box-like manner, the sliding shoes of the individual finned tubes being directly stacked one above the other and resting loosely on common supporting girders anchored to the housing, and the supporting girders having, in cross-section, the outline of a triangle with its apex pointing downward.

Desublimator for isolating sublimation products from reaction gases

Process for the recovery of phthalic anhydride in which gases as obtained in the catalytic atmospheric oxidation of o-xylene or naphthalene are treated with a hydrocarbon containing C.sub.26.sub.- paraffins, cooling, if necessary, the hydrocarbon laden with phthalic anhydride, separating the solid phthalic anhydride followed by melting and distillation thereof.

Recovery of phthalic anhydride

A finned tube heat exchanger for isolating sublimates, especially phthalic anhydride, in which the finned tubes arranged in parallel alongside one another and above one another and connected by headers and tube bends permit flow through them successively in the first, then the third, then the second and then the fourth row, and that the transverse fins are arranged in rows staggered laterally in opposite directions by an amount corresponding to from half the spacing to the whole spacing between adjacent fin edges.

Growing community of inventors

Ludwigshafen, Germany

Joachim Wagner