Bayer Aktiengesellschaft

Klaus G Wilms

Helmut Waldmann

Dieter Freitag

Peter Tacke

Ludwig Bottenbruch

Werner Nouvertne

Johann Grolig

The present invention relates to thermoplastic moulding materials of (A) thermoplastic polycarbonates mixed with (B) thermoplastic polyalkylene terephthalates and, if appropriate, with (C) elastomeric polymers, which are characterized in that they contain (D) a polycarbonate-polyphenylene oxide block co-condensate.

Thermoplastic moulding materials

This invention relates to the use of polyphenylene oxides corresponding to the following general formula: ##STR1## for the production of aromatic block polyether-poly(ester) carbonates by the interfacial process and also to the block polyether-poly(ester) carbonates obtainable by the process.

Use of certain polyphenylene oxides for the production of aromatic block

2,3-Dimethylbutane-2,3-diol is prepared by a process in which 2,3-dimethylbutenes are reacted with oxygen or an oxygen-containing gas, in the presence of 0.01 to 20 parts by weight of water (relative to 2,3-dimethylbutenes employed), at temperatures of from 40.degree. to 180.degree. C. and residence times of 5 to 150 minutes, without the addition of catalysts.

Process for the preparation of 2,3-dimethylbutane-2,3-diol

In the process for decreasing the COD-content of effluent by treating with hydrogen peroxide in the presence of a transition metal compound, the improvement which comprises adding to the effluent about 50 to 65% of the calculated quantity of H.sub.2 O.sub.2 required for the total oxidation of the total COD-content of the effluent, the transition metal compound being dissolved in the effluent in an amount such that the molar ratio of H.sub.2 O.sub.2 to transition metal is from about 30:1 to 3:1, bringing the pH initially to about 2 to 9, maintaining the effluent at about 5.degree. to 100.degree. C., and separating from the effluent whatever material has flocculated. Thereafter the effluent can be subjected to conventional biological degradation such as by the activated sludge process.

Treating effluent with peroxide and iron

In the process for decreasing the COD-content of effluent by treating with hydrogen peroxide in the presence of a transition metal compound, the improvement which comprises adding to the effluent about 5 to 40% of the calculated quantity of H.sub.2 O.sub.2 required for the total oxidation of the total COD-content of the effluent, the transition metal compound being dissolved in the effluent in an amount such that the molar ratio of H.sub.2 O.sub.2 to transition metal is from about 30:1 to 3:1, bringing the pH initially to about 2 to 9, maintaining the effluent at about 5.degree. to 100.degree. C., and separating from the effluent whatever material has flocculated. Thereafter the effluent can be subjected to conventional biological degradation such as by the activated sludge process.

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Dormagen, Germany

Klaus G Wilms