Basf Aktiengesellschaft

Walter Scheidmeir

Kaspar Bott

Matthias Schwarzmann

Herwig Hoffmann

Wilhelm Ruppel

Heinrich Aichinger

Johannes E Schmidt

Karl-Heinz Boehning

Horst Trapp

Rolf Seubert

Otto Kratzer

Bernhard Ulrich

Gerhard Hefele

Helmut Zinke-Allmang

Herwig Hoffman

In a process for preparing phthalic anhydride by catalytic gas-phase oxidation of o-xylene or naphthalene or o-xylene/naphthalene mixtures with a gas comprising molecular oxygen over a coated catalyst comprising an inert, nonporous support material on which a catalytically active composition comprising titanium dioxide and vanadium pentoxide is applied in layer form, a catalyst whose catalytically active composition comprises from 3 to 6% by weight of vanadium pentoxide, calculated as V O , from 0.3 to 0.5% by weight of a cesium compound, calculated as Cs, and the remainder to 100% by weight of titanium dioxide in the anatase modification is used in the presence or absence of a coated catalyst, differing therefrom, for the catalytic gas-phase oxidation of o-xylene or naphthalene or o-xylene/naphthalene mixtures and, in the presence of such a second catalyst, the latter is used in a combined bed with the catalyst of the above composition in the reactor.

Method for producing acid phthalic anhydride and an appropriate shell catalyst containing titanium-vanadium-cesium

Phthalic anhydride is prepared in a multiple tube reactor provided with separate salt baths, the temperature of the salt bath used for cooling the first layer of catalyst, as regarded in the direction of flow of the reaction mixture, being from 2.degree. to 20.degree. C. higher than that of the salt bath(s) associated with the following layer(s).

Preparation of phthalic anhydride from o-xylene

##STR1## where R.sup.1 is an aromatic or heterocyclic radical, R.sup.2 is a straight-chain or branched alkyl raical and R.sup.3 is hydrogen, methyl or ethyl, are prepared by reacting a secondary alcohol of the formula ##STR2## with a primary alcohol of the formula R.sup.2 OH (III) in the presence of an alkali metal hydroxide at from 150.degree. to 300.degree. C.

Preparation of alkanols which are substituted in the 1 position by

3-Arylisobutanols of the general formula I ##STR1## where R.sup.1 and R.sup.2 are each hydrogen or an alkyl or cyclo-alkyl radical of not more than 8 carbon atoms, preferably alkyl of 1 to 4 carbon atoms, are prepared by a process in which an arylcarbinol of the general formula II ##STR2## is reacted with n-propanol in the presence of a catalytic amount of an alkali metal hydroxide or an alkali metal alcoholate at from 250.degree. to 350.degree. C. in a closed reaction vessel. The process is of particular importance for the preparation of 3-arylisobutanols of the formula I, where R.sup.1 is alkyl of 1 to 4 carbon atoms and R.sup.2 is hydrogen. The p-methyl-, p-isopropyl- and p-tert-butylphenylisobutanols obtained here in very good selectivity are useful intermediates for the desirable scents jasmorange, cyclamen aldehyde and Lysmeral.RTM. (Lilial.RTM.).

Preparation of 3-arylisobutyl alcohols

Dialkyl-ketals are manufactured by reacting ketones with alkanols in the presence of an acid condensing agent and of an at least equivalent amount, based on the ketone, of anhydrous calcium sulfate.

Manufacture of dialkyl-ketals

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Walter Scheidmeir