Hoechst Aktiengesellschaft

Michael Frey

Klaus Bauer

Hermann Bieringer

Lothar Willms

Heinz-Josef Loher

Hilmar Mildenberger

Rainer Liebl

Rainer Schaller

Ulrich Hertenstein

Hermann Bierigner

Process for isolating dimethyl 4,4'-biphenyldicarboxylate from residues of DMT production, which includes first distilling the residues at a pressure of at most 7 mbar at a boiler temperature from 200.degree. to 350.degree. C., subsequently treating the distillate which distills over in the range from 230.degree. to 270.degree. C. at a pressure of, for example, 0.2 mbar for from 10 to 60 minutes with 0.7 to 10 times the amount of an organic solvent at a temperature from 70.degree. to 180.degree. C., if required, separating the clear solution from undissolved components, cooling the removed clear solution to a temperature from 45.degree. to 65.degree. C. and allowing it to crystallize at this temperature, resulting in a suspension of dimethyl 4,4'-biphenyldicarboxylate crystals from which the crystals are isolated by washing one or more times with the same or a different solvent and by drying.

Isolation of dimethyl 4,4'-biphenyldicarboxylate

Sulfonylureas of the formula ##STR1## where A is a bond or a C.sub.1 -C.sub.10 -hydrocarbon radical,

Heterocyclically substituted sulfonylureas, and their use as herbicides

Sulfonylureas with heterocyclic substituents, a process for the preparation thereof, and the use thereof as herbicides or plant-growth regulators. Sulfonylureas with heterocyclic substituents, of the formula ##STR1## in which the variables are defined in the specification, as well as the salts thereof have herbicidal and plant-growth regulatory properties on mon- and dicotyledonous plants.

Sulfonylureas with heterocyclic substituents, and the use thereof as

1,2-Disubstituted piperidines of the general formula I ##STR1## in which X denotes oxygen or sulfur; R denotes alkyl, R.sup.1 and R.sup.2 denote hydrogen, alkyl or benzyl, R.sup.3 denotes hydrogen, (substituted) alkyl, (substituted) benzyl or a radical of the formulae ##STR2## Y and X denote S or O; Z denotes S, O or NR.sup.1 ; R.sup.4 denotes hydrogen, (substituted) alkyl, (substituted) phenyl, (substituted) naphthyl or (substituted) pyridyl, A denotes (substituted) phenyl or (substituted) naphthyl and m denotes 0, 1 or 2, possess advantageous herbicidal properties.

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Neusass, Germany

Michael Frey