Basf Aktiengesellschaft

Hans-Josef Wolf

Gerhard Hamprecht

Uwe Kardorff

Horst Mayer

Eberhard Ammermann

Gisela Lorenz

Hubert Sauter

Karl-Otto Westphalen

Helmut Walter

Norbert Goetz

Matthias Gerber

Christoph Kuenast

Frank Rosowski

Andreas Tenten

Elisabeth Heistracher

Ralf Klintz

Klaus Grossmann

Jochen Wild

Franz Schuetz

Peter Schaefer

Sebastian Storck

Reinhard Doetzer

Michael Baier

Process for preparing phthalic anhydride by gas-phase oxidation of xylene, naphthalene or mixtures thereof in a shell-and-tube reactor thermostatted by means of a heat transfer medium over three or more different fixed-bed catalysts arranged in zones, wherein the process is carried out so that the maximum temperature in the second catalyst zone in the flow direction is up to 50&#xb0; C. lower than the maximum temperature in the first catalyst zone and the maximum temperature in the third zone from the gas inlet is from 30 to 100&#xb0; C. lower than that in the first catalyst zone. The process of the present invention makes it possible to prepare phthalic anhydride in high yields under industrially relevant conditions.

Preparation of phthalic anhydride

A substituted 3-phenyluracil of the formula I

Substituted 3-phenyluracils

Ortho-substituted benzyl esters of cyclopropanecarboxylic acids I ##STR1## where X is N or CH and A is one of the following cyclopropane radicals: ##STR2## where R.sup.1 is CN, C.sub.2 -C.sub.8 -alkyl, CF.sub.3, C.sub.3 -C.sub.8 -alkenyl, (C.sub.1 -C.sub.4 -alkoxycarbonyl, unsubstituted or substituted phenyl-C.sub.1 -C.sub.6 -alkyl or phenyl-C.sub.3 -C.sub.6 -alkenyl, ethoxyphenyl, 2- or 3-bromophenyl, 2- or 4-trifluoromethylphenyl, 2,4- or 2,6-difluorophenyl, 2-fluoro-6-chlorophenyl, 2,4- or 2,6-dimethylphenyl, 2,3,6-trichlorophenyl or trimethylsilyl, R.sup.2 is H or halogen, R.sup.3 is unsubstituted or substituted phenyl, R.sup.4 is CH.sub.3 or halogen and Hal is halogen, with the proviso that X is CH when R.sup.1 is CF.sub.3 or trimethylsilyl, are suitable as fungicides and for controlling pests.

Ortho-substituted benzyl esters of cyclopropanecarboxylic acids

Trifluoro- and chlorodifluoromethoxy-1,3,5-triazines of the formula I ##STR1## where R.sup.1 and R.sup.2 are each, independently of one another, hydrogen, halogen or C.sub.1 -C.sub.4 -haloalkyl, and R.sup.1 is also trifluoro- or chlorodifluoromethoxy, and n is 0 or 1, excepting 2,4-dichloro-6-trifluoromethoxy-1,3,5-triazine, are prepared as described.

Trifluoro-and chlorodifluoromethoxy-1,3,5-triazines

Substituted trifluoro- and chlorodifluoromethoxypyrimidines of the formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are each, independently of one another, hydrogen, halogen or haloalkyl, and R.sup.1 and/or R.sup.2 are also trifluoromethoxy or chlorodifluoromethoxy, and n is 0 or 1, are prepared as described.

Trifluoro- and chlorodifluoromethoxypyrimidines and the preparation

Trifluoro- and chlorodifluoromethoxy-1,3,5-triazines and the preparation

Growing community of inventors

Maxdorf, Germany

Hans-Josef Wolf