Bayer Aktiengesellschaft

Rhein Chemie Rheinau Gmbh

Josef Kasbauer

Helmut Fiege

Torsten Groth

Karl-Erwin Piejko

Karlfried Wedemeyer

Bernd-Michael Konig

Michael Pies

Herbert Eichenauer

Hans-Joachim Santel

Markus Dollinger

Reinhard Lantzsch

Winfried Joentgen

Lothar Puppe

Bernd Alig

Michael Schwamborn

Wolfgang Kiel

Herbert Diehl

Ludger Heiliger

Werner Struver

Herbert Schmidt

Friedrich-Wilhelm Ullrich

Werner Bussmann

Gebhard Merz

Rudiger Herpich

Aromatic maleimides can be prepared by reacting corresponding aromatic amines with maleic anhydride in the presence of a solvent mixture of halogenated hydrocarbon and a dipolar aprotic solvent, with the addition of acid and a polymerization inhibitor.

Process for the preparation of aromatic maleimides

The invention relates to the use of the known compound 2,6-dichloro-3-fluoro-benzonitrile as active compound in selectively-herbicidal compositions, and to new preparation processes and new intermediates for the preparation of this compound.

Herbicidal compositions based on 2,6-dichloro-3-fluoro-benzonitrile, and

N-Substituted cyclic imides are obtained by reacting a cyclic acid anhydride with an amine in the presence of a solvent and an acid catalyst at 80.degree. to 200.degree. C. and with removal of the water formed, it being particularly advantageous to carry out this reaction in the presence of a stabilizer and an inert, dipolar aprotic cosolvent, optionally to add an inert organic solvent of low or zero polarity to the reaction mixture present after the reaction, to add a non-aqueous base in an amount of 0.5 to 50% by weight, based on the cyclic anhydride of the formula (II) used, and to separate off the precipitate formed to give a filtrate containing the N-substituted cyclic imide.

Process for the preparation of N-substituted cyclic imides

Thermoplastics built up from N-(2-ethyl-6-methyl)phenylmaleimide and styrene, it being possible for all or some of the styrene to be replaced by at least one other monomer component.

Thermoplastics having a high heat deflection temperature and improved

A process for the preparation of a N-)ortho-alkylphenyl)-imide of the formula ##STR1## in which R.sup.1 to R.sup.9 is defined in the specification which comprises reacting a cyclic anhydride of the formula ##STR2## wherein R.sup.6 to R.sup.9 are difined in the specification with an amine of the formula ##STR3## optionally in the presence of an acid catalyst and optionally in the presence of a solvent which is immiscible or only slightly miscible with water but can form an azeotrope with water, at a temperature between 100.degree. to 200.degree. C. under conditions so that the water formed during the reaction is removed from the reaction mixture without the addition of a polymerization inhibitor or a dipolar solvent. The final products are used as intermediates to prepare heat-stable plastics as well as intermediates to prepare pharmaceutical and agricultural chemicals.

Process for the preparation of N-(ortho-alkylphenyl)-imides

Isobenzofurandiones are obtained in particularly advantageous manner by the dehydrogenation of tetrahydroisobenzofurandiones in the presence of catalysts at elevated temperature by a process in which distilled tetrahydro-isobenzofurandiones are heated to temperatures of between 120.degree. and 300.degree. C. in the presence of supported palladium and/or platinum catalysts and in the presence of maleic acid derivatives in a trickle-phase or liquid-phase procedure, the temperature in the liquid-phase procedure being increased at a rate of 0.6.degree. to 3.degree. C. per minute above 80.degree. to 110.degree. C.

Process for the preparation of isobenzofurandiones

Halogenated benzenes are hydrodehalogenated in a particularly advantageous manner and at low temperatures by contacting them at temperatures of between 100.degree. and 250.degree. C. together with hydrogen with a catalyst prepared by application of one or more salts of palladium and/or platinum and, if desired, of copper to an alumina or titanium dioxide support.

Process for the hydrodehalogenation of halogenated benzenes

Dialkyl dicarbonates are obtained particularly advantageously from halogenoformic esters by reaction with alkalis in the presence of water-immiscible organic solvents and in the presence of a catalyst, if the catalyst used is benzylalkyldimethylammonium halides. The catalyst is then particularly easy to separate off and to recycle from the reaction mixture.

Process for the preparation of dialkyl dicarbonates

In the preparation of m-chloroaromatics by isomerizing corresponding o- and/or p-chloroaromatics in the liquid phase over zeolites, the activity of the zeolites remains at a high level for a particularly long time if the process is carried out in the presence of from 1 to 30 mol % of hydrogen, based on the chloroaromatics used.

Process for preparing m-chloroaromatics

Bis- and tris-(3-dimethylaminopropyl)-amine can be prepared by catalytic hydrogenation of 3-(dimethylamino)-propionitrile with a palladium catalyst on an Al.sub.2 O.sub.3 -containing support.

Process for the preparation of bis-and tris-(3-dimethylaminopropyl)amine

Aliphatic sulphonic acids can be prepared by reacting n-paraffins with SO.sub.2 and O.sub.2 under UV irradiation with high selectivity even at conversions of up to 12 mol % if an amount of water is added which is appropriate to ensure that after the reaction has commenced and the stationary state has been reached, the sulphoxidation proceeds in homogeneous phase.

Process for the sulphoxidation of N-paraffins

1,2-Dichlorobenzene can be prepared by reacting 1,2,4-trichlorobenzene in the gas phase with hydrogen. The reaction is carried out at a temperature from the boiling point of the starting material up to about 400.degree. C. and over a platinum-spinel catalyst.

Process for preparing 1,2-dichlorobenzene

4-Nitrophenetol is prepared by reaction of 4-chloronitrobenzene with ethanol and alkali metal hydroxides in the presence of phase-transfer catalysts by carrying out the reaction at temperatures from 60.degree. to 95.degree. C. and under pressure in the presence of oxygen-containing gases diluted with inert gases, there being at the start of the reaction 0.2 to 1.0 mol of alkali metal hydroxide metered each hour into the reaction mixture for each 1 mol of 4-chloronitrobenzene.

Process for the preparation of 4-nitrophenetol

5-Fluorotoluene-2,4-disulphochloride is prepared by chlorosulphonation of 3-fluorotoluene by first reacting the 3-fluorotoluene with chlorosulfuric acid and then with an inorganic acid chloride at temperatures up to 130.degree. C. until the evolution of gas is complete, and then heating the reaction mixture at temperatures of up to 200.degree. C. and, after the completion of the gas evolution, reacting the product at a lower temperature with further inorganic acid chloride, or reacting the 3-fluorotoluene with powerful sulphonating agents at an elevated temperature, if appropriate in the presence of inert solvents and/or diluents, to give the corresponding disulphonic acid and then treating the disulphonic acid with inorganic acid chlorides.

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Wermelskirchen, Germany

Josef Kasbauer