Bayer Aktiengesellschaft

Heinz-Ulrich Blank

Alexander Klausener

Heinz Landscheidt

Helmut Kraus

Horst Behre

Gerhard Marzolph

Helmut Fiege

Karlfried Wedemeyer

Wolfgang Bauer

Nikolaus Muller

Erich Wolters

Kaspar Hallenberger

Udo Birkenstock

Holger Heidenreich

Paul Uhrhan

Gunter Rauchschwalbe

Wolfgang Eymann

Bernd-Michael Konig

Ludwig Deibele

Gerhard Ruffert

Uwe Heinz

Volkmar Handschuh

Fritz Pohl

Gunther Rauchschwalbe

Josef Ebersberger, Deceased

4,6-diaminoresorcinol can be prepared in a plurality of steps in such a way that a) 1,3-dichlorobenzene is nitrated with a mixed acid of HNO.sub.3, H.sub.2 SO.sub.4 and SO.sub.3 at 0 to 40.degree. C. in anhydrous H.sub.2 SO.sub.4, b) the resulting 1,3-dichloro-4,6/2,4-dinitrobenzene isomeric mixture is first reacted with benzyl alcohol in the presence of a strong base at -15.degree. C. to +15.degree. C. and then at 20.degree. to 40.degree. C. to give the dibenzyloxy compound and c) the 1,3-dibenzyloxy-4,6-dinitrobenzene isomer arising in pure form in b) is converted to the 4,6-diaminoresorcinol by catalytic hydrogenation.

Process for the preparation of 4,6-diaminoresorcinol

p-Amino-phenols are advantageously prepared by catalytic hydrogenation of the aromatic nitro compounds on which they are based in a reaction medium of aqueous sulphuric acid in the sense of a Bamberger rearrangement at elevated temperature by a procedure in which the reaction medium additionally contains a water-miscible organic solvent.

Process for the preparation of p-amino-phenols

.beta.-Aminoacrylic acid esters can be prepared by reacting acetic acid esters of the formula

Process for the preparation of .beta.- aminoacrylic acid esters

Dinitro-polyalkylbenzenes can be prepared by nitration of polyalkylbenzenes using HNO.sub.3 in the presence of H.sub.2 SO.sub.4 in such a manner that at least 50% of the H.sub.2 SO.sub.4 is present as reaction medium and HNO.sub.3 and the polyalkylbenzene and any remaining H.sub.2 SO.sub.4 are added simultaneously in such a manner that the added substances polyalkylbenzene and HNO.sub.3 are in the molar ratio of 1:2-10. H.sub.2 SO.sub.4 is used at a concentration from 81 to 96% by weight and HNO.sub.3 at a concentration from 95 to 100% by weight. For the work-up, the dinitro-polyalkylbenzenes are first freed from the majority of the acids and then treated with a highly dilute aqueous solution of a dispersant for separating off residual acid.

Process for the preparation of dinitro-polyalkylbenzenes

Ortho-amides of the formula ##STR1## can be prepared by reacting salts of the formula ##STR2## with alcoholates of the formula

Process for the preparation of ortho-amides

N-acylated p-amino-phenols can be prepared by catalytical hydrogenation of the underlying aromatic nitro compounds in a reaction medium of aqueous sulfuric acid in the sense of a Bamberger type reaction at elevated temperature, optionally in the presence of a water-miscible organic solvent, and subsequent reaction of this reaction mixture with an acid chloride, optionally in the presence of an acid binder and optionally in the presence of a diluent.

Process for the preparation of N-acylated p-amino-phenols

Dialkyl carbonates can be prepared by reaction of carbon monoxide with alkyl nitrites in a continuous gas phase reaction, in which a platinum metal catalyst of oxidic or hydroxidic compounds of elements from group Vb of the Periodic Table (Mendeleev) as supports and, if desired, addition of an antimony, bismuth, aluminium, copper, vanadium, niobium, tantalum, tin, iron, cobalt, nickel compound or a mixture of a plurality thereof on this catalyst are used, and the hydrogen halide which is discharged from the reactor together with the reaction mixture is batchwise or continuously replaced in the course of the reaction. This results in the formation of dialkyl carbonates in almost quantitative selectivity; the corresponding dialkyl oxalates can, in most cases, not be detected.

Process for the preparation of dialkyl carbonates

When 2-naphthylamine-1,5-disulphonic acid is precipitated from the as-sulphonated reaction mixtures by dilution, a purer product is obtained, with a low level of adherent sulphuric acid, if the precipitation by dilution of the reaction mixture is carried out under precisely defined conditions.

Process for the isolation of 2-naphthylamine-1,5-disulphonic acid

Aminomethylene compounds of the formula ##STR1## can be prepared by reaction of C-H-acid compounds of the formula ##STR2## with salts of the formula ##STR3## in the presence of simple inorganic bases, where the radicals R.sup.1 to R.sup.4, R.sup.7, R.sup.8 and X.sup..crclbar. have the meanings given in the description.

Process for the preparation of aminomethylene compounds

Pure or substantially enriched 2,4- and 2,6-dinitrotoluene can be isolated from a mixture containing these isomers if such a mixture is distilled under a pressure of 0.5 to 20 mbar at a temperature of 80.degree. to 200.degree. C. with exclusion of reducing conditions.

Process for the isolation of pure dinitrotoluenes

Crude 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)propane (=tetramethyl-bisphenol A=TMBPA) can be purified by recrystallization, if C.sub.1 -C.sub.4 -monoalcohols with a water content of 2 to 40% by weight relative to the total weight of alcohol and water are used in an amount of 70 to 250% by weight, relative to the amount of TMBPA and the recrystallization is carried out at a temperature of 65.degree. to 150.degree. C.

Process for the purification of crude

The process for the preparation of N-methylolcaprolactam through reaction of caprolactam with formaldehyde in the presence of an alkaline catalyst at elevated temperature is essentially improved when the reaction is carried out substantially solvent-free at 70.degree. to 100.degree. C. In an advantageous fashion, the alkaline catalyst used is in heterogeneous form. In a furthermore advantageous fashion, seed crystals of pure N-methylolcaprolactam are added to the reaction batch after cooling to a temperature below the melting point of pure N-methylol-caprolactam.

Process for the preparation of N-methylol-caprolactam

Meta-chlorobenzene sulphonyl chloride and metadichlorobenzene are prepared by reacting benzene sulphonyl chloride with chlorine in the presence of a Friedel-Crafts catalyst at a temperature of from 0.degree. to 150.degree. C. After removing the catalyst, the resulting m-chlorobenzene sulphonyl chloride is reacted to form m-dichlorobenzene. The m-chlorobenzene sulphonyl chloride is preferably isolated prior to being reacted to m-dichlorobenzene. The reaction forming m-dichlorobenzene can be carried out via thermal clevage, thermal chlorolysis or chlorolysis initiated photochemically or by radicals.

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Odenthal, Germany

Heinz-Ulrich Blank