DETAILED DESCRIPTION OF THE INVENTION As hereinbefore set forth, the present invention is concerned with semipermeable membranes which are resistant to chlorine.
The membranes are prepared by casting an aqueous solution of a triaryl triamine on a porous backing support material, removing excess solution, and thereafter contacting the coated support material with an organic solvent solution of an aromatic polycarboxylic acid chloride, said organic solvent being immiscible with the aqueous solution, whereby an interfacial polymerized condensation reaction product is formed on the surface of the support material.
The resulting composite is then cured to provide a semipermeable membrane which exhibits favorable characteristics with respect to salt rejection as well as resistance to chlorine.
The triaryl triamines which comprise one component of the product of the present invention will be selected from the group consisting of 2,3-bis(p-aminobenzyl) aniline, 2,4-bis(p-aminobenzyl) aniline, 2,5-bis-(p-aminobenzyl) aniline, 2,6-bis(p-aminobenzyl) aniline, 2,3-bis(o-aminobenzyl) aniline, 2,4-bis(o-aminobenzyl) aniline, 2,5-bis(o-aminobenzyl) aniline, 2,6-bis(o-aminobenzyl) aniline, 2,3-bis(m-aminobenzyl) aniline, 2,4-bis(m-aminobenzyl) aniline, 2,5-bis(m-aminobenzyl) aniline, and 2,6-bis(m-aminobenzyl) aniline.
The aromatic polycarboxylic acid chloride which forms the other component necessary to form the interfacial polymerized condensation reaction product will comprise either a di- or tricarboxylic acid chloride such as trimesoyl chloride, 1,3,5-benzene tricarboxylic acid chloride, isophthaloyl chloride, terephthaloyl chloride, pyridine dicarboxylic acid chlorides as well as mixtures thereof.
In one embodiment, the chlorine-resistant semipermeable membranes of the present invention may be prepared by coating the porous support backing material with an aqueous solution of the triaryl triamine.
As was previously set forth, the porous support backing material comprises a polymeric material containing pore sizes which are sufficient to permit the passage of permeate therethrough but are not large enough so as to interfere with the bridging over of the resulting ultra-thin reverse osmosis membrane
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Liquid Purification 
