Bayer Aktiengesellschaft

Bayer Healthcare Aktiengesellschaft

Hans-Peter Wirges

Hans-Josef Buysch

Johann Rechner

Gerhard Franckowiak

Carsten Hesse

Peter Fischer

Claus-Peter Reisinger

Sven Michael Hansen

Wolfram Ledwoch

Hubert Appolt

Gregor Leifker

Paul Wagner

Claus H Wulff

Peter Wachtler

Alfred Eitel

Herbert Diehl

Christine Mendoza-Frohn

Mathias Berwe

Karl-Heinz Wahl

Georg Malamet

Karl Rittner

The present invention relates to stable salts of O-acetylsalicylic acid with basic amino acids, a process for their preparation and their use as medicaments.

Stable salts of O-acetylsalicylic acid with basic amino acids

A process for the separation a substantially adduct-free diaryl carbonate from reaction solution is disclosed. The process entails obtaining a solution that contains diaryl carbonate, catalyst system components and an aromatic solvent, lowering the temperature of the solution, optionally in the presence of a nucleating agent, to produce a crystallization product, and washing the crystallization product with an anhydrous wash solution to remove catalyst residues and impurities.

Separation of impurities and/or valuable substances from solutions containing diaryl carbonate by solution crystallization

The invention relates to frost-stable aqueous alkaline solutions of highly concentrated o-phenylphenol and to their use as preservatives.

Ortho-phenylphenolate concentrates

The invention relates to a process for the preparation of nifedipine by the reaction of methyl 2-(2-nitrobenzylidene)acetoacetate and methyl 3-aminocrotonate and the use of the nifedipine thus prepared for the production of a medicament.

Process for preparing nifedipine

Catalyst systems with a content of a platinum-group-metal catalyst, a co-catalyst, a quaternary salt and a base for the oxidative carbonylation of aromatic hydroxy compounds to the corresponding diaryl carbonates are according to the invention obtained as a mother liquor by suspension crystallization and can be returned into the carbonylation reaction or worked up to valuable materials. The crystallizate, which consists predominantly of diaryl carbonate and the parent aromatic hydroxy compound, is worked up to pure diaryl carbonate and pure hydroxy compound.

Recovery of catalyst systems from diaryl carbonate-containing reaction

Catalyst systems with a content of a platinum-group-metal catalyst, a co-catalyst, a quaternary salt and a base for the oxidative carbonylation of aromatic hydroxy compounds to the corresponding diaryl carbonates are obtained according to the invention as a residual melt by melt crystallization and can be returned into the carbonylation reaction or worked up to valuable materials. The melt crystallizate, which consists predominantly of diaryl carbonate and the parent aromatic hydroxy compound, is worked up to pure diaryl carbonate and pure hydroxy compound.

Recovery of catalyst systems from diarylcarbonate-containing reaction

Ethylene glycol carbonate (EGC) can be isolated in purified form from contaminated material which contains impurities from the group comprising starting materials, by-products and/or catalysts of the preparation process in that the contaminated EGC is subjected to a fractional melt crystallization and the crystals of the purified EGC formed in this case are mechanically separated off from the remaining impurities dissolved in the residual melt.

Process for the isolation of purified ethylene glycol carbonate (EGC)

The invention relates to a special process for the production of high-purity bisphenol A from acetone and phenol in the presence of acidic catalysts.

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Krefeld, Germany

Hans-Peter Wirges