Monsanto Company

Cheng H Lee

Jay M Henis

A process is disclosed for quaternizing reactive substituent haloalkyl groups in hollow fiber polymer membranes wherein such haloalkyl groups are reacted with an amine quaternizing agent in the presence of an electrolyte compound and, preferably, in the presence of a cationic quaternary ammonium halide surfactant. In addition, there is disclosed a process of quaternizing the reactive haloalkyl groups in anisotropic hollow fiber polymer membranes by contacting and permeating a solution of an amine quaternizing agent from the surface of the membrane which is to be exposed to a dialysis feed solution.

Quaternization process for ion exchange membranes

Methanol is separated from formaldehyde aqueous mixtures by contacting the aqueous mixture feed with a first surface of a polymeric membrane selectively permeable to the methanol over the formaldehyde or formaldehyde and water; while maintaining a second and opposite membrane surface at a lower chemical potential than the first membrane surface for the methanol permeating a portion of the methanol into and through the membrane, and withdrawing from the second membrane surface a mixture having a higher total concentration of methanol in relationship to the formaldehyde or formaldehyde and water than in the methanol, formaldehyde aqueous feed mixtures.

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Creve Couer, MO, United States of America

Cheng H Lee