1
Klaus Elfert, Hans Jurgen Rosenkranz, Hans Rudolf: Separation of aromatic hydrocarbons from mixtures, using polyurethane membranes. Bayer Aktiengesellschaft, Burgess Dinklage & Sprung, September 19, 1978: US04115465 (66 worldwide citation)

A process for separating an aromatic hydrocarbon of the general formula ##STR1## wherein R represents an alkyl group having 1 to 3 carbon atoms and


2
Klaus Elfert, Gerhard D Wolf, Francis Bentz, Hans E Kunzel: Semipermeable membranes of copolyamides. Bayer Aktiengesellschaft, Connolly and Hutz, August 12, 1980: US04217227 (18 worldwide citation)

The invention relates to semipermeable membranes with a water absorption capacity of from 4.5 to 10% by weight preferably from 4.5 to 8% by weight as measured on approximately 40.mu. thick symmetrical films at room temperature and 65% relative air humidity, with a throughflow of at least 80 1/m.sup. ...


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Klaus Elfert: Semipermeable membranes. Bayer Aktiengesellschaft, Connolly and Hutz, May 17, 1983: US04383923 (13 worldwide citation)

Semipermeable composite membranes consisting of a microporous substrate and a semipermeable layer built of polymer material containing urazole structures.


5
Klaus Elfert, Gerhard D Wolf, Hans J Rosenkranz: Semipermeable membranes of aromatic disulfimide containing polyamides. Bayer Aktiengesellschaft, Connolly and Hutz, May 26, 1981: US04269967 (10 worldwide citation)

The invention relates to membranes which consist of aromatic polyamides containing disulphimide groups and have relative viscosities .eta..sub.rel of .gtoreq.1.4 as measured on a 0.5% N-methylpyrrolidone solution at 20.degree. C., and which may be used for ultrafiltration and inverse osmosis. The me ...


6
Klaus Elfert, Jurgen Hinz, Rudolf Binsack: Semipermeable membranes of sulphonated polybenz-1,3-oxazin-2,4-diones. Bayer Aktiengesellschaft, Connolly and Hutz, January 17, 1978: US04069215 (5 worldwide citation)

Semipermeable membranes of sulphonated polybenz-1,3-oxazin-2,4-diones for separating or enriching organic sulphonates by the method of inverse osmosis or ultrafiltration.


7
Klaus Elfert, Gerhard D Wolf, Francis Bentz, Hans E Kunzel: Semipermeable membranes of heterocyclic copolyamides. Bayer Aktiengesellschaft, Connolly and Hutz, September 9, 1980: US04221903 (5 worldwide citation)

The invention relates to semipermeable membranes with a water absorption capacity of from 4.5 to 11% by weight, preferably from 4.5 to 8% by weight, as measured on approximately 40.mu. thick symmetrical films at room temperature and at 65% relative air humidity, a throughflow of 130 to 200 l/m.sup.2 ...


8
Klaus Elfert, Jurgen Hinz, Rudolf Binsack: Sulphonated polybenz-1,3-oxazin-2,4-diones. Bayer Aktiengesellschaft, Connolly and Hutz, November 22, 1977: US04059580

Novel, sulphonated polybenz-1,3-oxazin-2,4-diones are produced by reacting polybenzoxazin diones with chlorosulphonic acid in a molar ratio of from 1:1 to 1:10.