A glutamic acid-based polymer keeping intact the integrity of all the three original functionalities of the amino acid

Dimethyl glutamate, on treatment with allyl bromide, afforded dimethyl N, N-diallylglutamate which upon alkaline ester hydrolysis followed by acidification with aqueous HCl gave N, N-diallylglutamic acid hydrochloride [(CH2 = CH-CH2)(2) NH+CH(CO2H)(CH2)(2)CO2 H Cl-] I. Using Butler's cyclopolymerization protocol, new monomer I underwent ammonium persulfate-initiated polymerization to give pyrrolidine ring-embedded linear cyclopolymer II i. e. -[-CH2 (C-4 H-6) NH+{CH(CO2 H)(CH2)(2) CO2 H Cl-} CH2-]-(n) retaining the integrity of all the three functionalities of glutamic acid. Under the influence of pH, the repeating units of triprotic acid (+) in II were equilibrated to those of water-insoluble diprotic polyzwitterionic acid (+/-) III, water-soluble monoprotic poly(zwitterion-anion) (+/--) IV, and its conjugate base polydianion (=) V. The critical salt concentration required to promote water solubility of (+/-) III has been determined to be 0.548 M NaCl, 0.271 M NaBr, 0.133 M NaI. The basicity constants of the carboxyl groups and trivalent nitrogen in (=) V have been determined. A 5 ppm and 20 ppm concentrations of III are effective in inhibiting the precipitation of CaSO4 from its supersaturated solution with a approximate to 100% scale inhibition efficiency at 40 degrees C for a duration of over 3 and 16 h, respectively.