Basf Aktiengesellschaft

Hermann Dreher

Juergen Hambrecht

Adolf Echte

Johann Swoboda

Rudi W Reffert

Hans H Schuster

Eduard Heil

Peter Siebel

Herbert Naarmann

Hermann Gausepohl

Hermann Fischer

Hermann Brandt

Albert Nikles

Gerd Schwoebel

Rosemarie Berger

Polyphenylene ethers are prepared from monohydric phenols, which possess alkyl substituents in the two ortho-positions and, if desired, in the meta-position, but not in the para-position, by an oxidative coupling reaction with oxygen at from 15.degree. to 50.degree. C. and under from 1 to 10 bar in the presence of a catalyst complex, of a solvent and, if required, of an activator, by a method in which the conversion of the phenols is carried out in two more reaction zones, in which some or all of the solvent, the catalyst complex and the phenols and, where relevant, the activator is initially taken and is circulated by means of a conveying unit, and about 60-100% of the stoichiometric amount of oxygen required for the oxidative coupling is introduced into the first reaction zone and from 0 to about 40% of the said stoichiometric amount is introduced into the second reaction zone.

Preparation of polyphenylene ethers, and an apparatus for this purpose

The catalyst is removed in the preparation of high molecular weight polyphenylene ethers from monohydric phenols, which are alkyl-substituted at the two ortho-positions but not at the para-position and may or may not be alkyl-substituted at the meta-position, by an oxidative coupling reaction with oxygen at from 15.degree. to 50.degree. C. in the presence of a catalyst complex obtained from a copper salt and an organic amine, in the presence of from 1 to 20 parts by weight of a solvent per part by weight of the monomeric phenol, and in the presence or absence of an activator, and removal of the metal component of the catalyst from the polyphenylene ether solution with a complex-forming or chelate-forming compound in aqueous solution, in the presence or absence of reducing and stabilizing substances and assistants for accelerating the interphase reactions and for phase separation, by a method in which the continuous removal of the copper catalyst is carried out in one or more mixer-settler stages at a phase volume ratio of the organic phase to the aqueous phase of from 1:0.1 to 1:1.0, preferably from 1:0.4 to 1:0.6.

Continuous removal of the catalyst from polyphenylene ethers

A coherent explosive gas phase in a gas/liquid reactor comprising a tubular body which is closed at the top and into which one or more jets of liquid which are fed from a liquid circulation and are directed downward, emerge from one or more nozzles located at the highest point of the reactor, and entrain a gas phase which is to be dispersed, introduce it into the liquid and finally produce complete dispersion of the gas, is avoided by a method wherein, before start-up of the liquid circulation, the inactive reactor is charged with an amount of liquid reactant such that a gas space corresponding to the subsequent gas hold-up of dispersed bubbles under operating conditions remains at the top of the reactor, this gas space is filled with a gas, at a pressure p.sub.1, which is inert under the reaction conditions, and the gaseous reactant is fed to the reactor only when, under the action of the liquid jet or jets, the inert gas has been dispersed into a hold-up of dispersed bubbles so that a coherent gas phase no longer exists.

Avoiding an explosive gas phase in gas/liquid reactions

In the preparation of a high molecular weight polyphenylene ether from a monohydric phenol by an oxidative coupling reaction with oxygen in the presence of a catalyst complex obtained from a metal salt and an organic amine and in the presence of a solvent, and isolation of the metal ion component of the catalyst from the polyphenylene ether solution by means of a complex-forming or chelate-forming compound, the catalyst is removed by a method wherein complex formation and isolation of the metal ion component of the catalyst are carried out in an aqueous medium in the presence of from 0.1 to 5,000 mg of an anionic or non-ionic surfactant.

Removal of the catalyst from polyphenylene ethers

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Seeheim-Jugendheim, Germany

Hermann Dreher