Composite polyamide membrane derived from carboxylic acid containing acyl halide monomer

A method for making a composite polyamide membrane comprising a porous support and a thin film polyamide layer, wherein the method comprises the step of applying a polyfunctional amine monomer and polyfunctional acid halide monomer to a surface of the porous support and interfacially polymerizing the monomers to form a thin film polyamide layer,

• wherein the method is characterized by applying a coating solution to the surface of the porous support comprising:
• i) a hydrocarbon solvent:
• ii) greater than 0.01 weight percent of an additional monomer comprising a carboxylic acid monomer comprising an aliphatic or aromatic moiety substituted with single carboxylic acid functional group and at least one acyl halide functional group and comprising equal to or less than 30 carbon atoms, and
• iii) a tri-hydrocarbyl phosphate compound represented by Formula (I):
• wherein R1, R2 and R3 are independently selected from hydrogen and hydrocarbyl groups comprising from 1 to 10 carbon atoms, with the proviso that no more than one of R1, R2 and R3 are hydrogen,
• wherein the interfacial polymerization is conducted in the presence of the carboxylic acid monomer and tri-hydrocarbyl phosphate compound.