Antiscalant compound and methods of making and using the same

Abstract

The antiscalant compound is a dianionic polyelectrolyte (DAPE), namely, poly[disodium 3-(N,N-diallylamino)propanephosphonate]. The cationic polyelectrolyte (CPE) polydiallyl(diethylphosphonato)propylammonium chloride is synthesized by cyclopolymerization of the monomer. The CPE contains a pendant having a three-carbon spacer separating the diethylphosphonate and NH+. Upon acidic hydrolysis of the phosphonate esters, the CPE was converted into a pH-responsive polyzwitterionic acid (PZA), poly[3-(N,N-diallylammonio)propanephosphonic acid], which was converted to DAPE poly[disodium 3-(N,N-diallylamino)propanephosphonate] and to a zwitterionic/anionic polyelectrolyte (ZAPE) poly[sodium 3-(N,N-diallylammonio)propanephosphonate]. The solution properties of the polymers were correlated to the structurally similar polyzwitterion (PZ) having monoethylphosphonate and NH+ groups. Evaluation of the antiscalant properties of the DAPE using concentrated brines revealed that the DAPE at a concentration of 10 ppm is very effective in inhibiting the formation of calcium sulfate scale, particularly in reverse osmosis plants.

Dependencies are inferred from the claim text.