Basf Aktiengesellschaft

Werner Praetorius

Peter Magnussen

Toni Dockner

Uwe Kempe

Herbert Krug

Volker Schumacher

Ewald Gallei

Hans Joachim Szymanski

Erich K Fehr

Heinrich Reitz

Wolfgang Gebert

Helmut Schwarz

In a process for the continuous preparation of adipic acid by hydrolysis of C.sub.1 -C.sub.4 -alkyl adipates with water at an elevated temperature in the presence of a strongly acidic ion exchanger, the improvement that the esters and excess water are fed to the middle section of a column, reaction mixture is taken off at a plurality of trays of the column below the feed point, passed over a strongly acidic ion exchanger and recycled, alkanols or alkanol/water mixtures are taken off at the top of the column and an aqueous solution of adipic acid is taken off at the bottom of the column.

Continuous preparation of adiptic acid

2-Imidazolines are prepared by reacting N,N'-diformyl-1,2-diamines in the gas phase at 200.degree.-350.degree. C., in the presence of certain amounts of an inert gas, over zinc oxide of a particular structure or over a mixture of this zinc oxide and aluminum oxide, as the catalyst. The 2-imidazolines obtainable by the process according to the invention are valuable starting materials for the preparation of dyes, crop protection agents and drugs.

Preparation of 2-imidazolines

Imidazoles are prepared by reacting 2-imidazolines at from 250.degree. to 500.degree. C. in the presence of molybdenum oxide and nickel oxide and/or cobalt oxide and aluminum oxide, silicon dioxide and/or silicates as catalysts. The imidazoles obtainable by the process according to the invention are valuable starting materials for the preparation of dyes, crop protection agents, textile auxiliaries, catalysts for polyurethanes and epoxy resins, surfactants and drugs, for example the corresponding nitroimidazoles.

Preparation of imidazoles

A novel process for the preparation of 2-imidazolines by reacting 1,2-diamines with nitriles or carbonyl compounds in the gas phase at from 200.degree. to 450.degree. C. in the presence of an oxide or phosphate of a metal of group 3 or 4 of the periodic table and/or in the presence of silicon dioxide. The 2-imidazolines obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents and drugs.

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Ludwigshafen, Germany

Werner Praetorius