Ind. Eng. Chem. Res. 1994,33, 168-170
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A New Cyclic N-Halamine Biocidal Polymer Gang Sun, Walter B. Wheatley, and S. Davis Worley' Department of Chemistry, Auburn University, Auburn, Alabama 36849 A new biocidal polymer is described. The compound, poly(l,3-dichloro-5-methyl-5-(4'-vinylphenyl)hydantoin), is prepared in a three-step synthesis from commercial polystyrene. It is insoluble in water and common organic solvents and acts as a contact biocide for contaminated water or air flowed through it. It does not leach organic impurities or levels of free chlorine greater than 1part per million into flowing water and, thus, may represent a innovation in disinfection technology. There is a need for new biocidal compounds which do not possess the limitations inherent in the disinfectants currently employed. The most common biocides in use are sources of free halogen, ozone, or chlorine dioxide; all of these materials tend to be corrosive toward water treatment equipment and may react with organic material in water to produce toxic compounds such as trihalomethanes having known or unknown health risks (Worley and Williams, 1988). An ideal biocide for water treatment should be insoluble in water and leach little or no decomposition products into water flowing through it; yet it should erradicate pathogenic microorganisms in the water upon contact. Polymeric quaternary ammonium anionic-exchangeresins (Gartner, 1983)and poly(styrenedivinylbenzene) compounds containing N-chlorinated sulfonamide moieties (Emerson, 1991) have been known for many years and have numerous potential uses. However, these biocidal polymers generally suffer the limitations of excessive solubility in water and/or the release of appreciable concentrations (over 1part per million (ppm)) of free halogen into the water (Gartner, 1983; Emerson, 1991). Work in these laboratories during the past 15 years has led to the development of several new N-halamine compounds which are biocidal and quite stable (persistent) in aqueous solution even in the presence of organic materials possessing considerablehalogen demand (Worley and Williams, 1988;Tsao et al., 1991;Barnela et al., 1987). However, all of these compounds are soluble in water and thus require extensive toxicologicalevaluations before they can be employed for disinfection of potable water. We have now developed an insoluble, polymeric N-halamine compound which exhibits outstanding potential as a biocide for a broad variety of applications including potable-water and air disinfection. The new biocidal polymer can be named poly(l,3-dichloro-5-methyl-5-(4'vinylpheny1)hydantoin); henceforth, it will be referred to as Poly-I. The synthetic procedure for Poly-I is illustrated in Scheme 1. Experimental Methods
Commercial polystyrene (0.6 mol of repeating unit) (Aldrich Chemical Co., Milwaukee, WI) having an average molecular weight as stated by the manufacturer of 280 000 (average molecular weights of 45 000 and 430 000 have been employed successfully also) was reacted with acetyl chloride (0.9 mol) in 600 mL of carbon disulfide solvent for 2 h at 46 "C in the presence of aluminum chloride (1.2 mol) in a Friedel-Crafts acylation to produce poly(4vinylacetophenone) in high yield (ca. 98% after purification in an ice/HCl mixture followed by exposure to 600
* Author to whom correspondence should be addressed. 0888-5885/94/2633-0l68$04.5OJO
KCN.(NH&CO, CH&ONH, 150 c\ 10 arm\ 24 h
t -+CH-E
R;I +
I
C1,WaOH
/N\+
d-50 22.0 18.4
Diameter in mm caused by 50 mg of Poly-I in a0.25-in.-diameter well in the center of a Tryptic Soy agar plate incubated for 24 h at 37 "C.
and Rhodoturula rubra. In fact, it has proved effective against all of the water-borne organisms which have been employed in challenge experiments to date. The organism B. thuringiensis was the most resistent one to the biocidal action of the polymer, probably because it forms resistant endospores. In addition to its biocidal action in aqueous solutions, Poly-I provided disinfection of aerosols of S. aureus flowed through a short column containing it. In this experiment a 1-in.sample of Poly-I in a 0.25-in.-diameterPasteur pipet caused complete disinfection of a nitrogen stream containing s. aureus, whereas an analogous sample of unchlorinated precursor polymer yielded confluent growth of the organism at the exit point, thus indicating that Poly-I was not acting merely as a filter material. We have also found that if Poly-I is deactivated through reduction by thiosulfate solution, it can be regenerated by exposure to aqueous free chlorine.
Conclusion We anticipate the use of Poly-I as a biocide for a variety of applications in which an insoluble material would be beneficial, and we believe that it represents an innovation in disinfection technology. Work is continuing with a goal of exploring various potential uses for the new material. In particular, experiments are under way designed to determine the efficacy of Poly-I as a function of contact time (flow rate) utilizing forced feed pumping.
Acknowledgment We thank M. Habercom and M. Wilson of Boeing, Inc., for their assistance in testing Poly-I against bacteria and for the analytical leachate studies. We also thank J. Hiller of Eastman Chemical Co. for obtaining thermal and X-ray characterization data.
Literature Cited Barnela, S. B.; Worley, S. D.; Williams, D. E. Synthesis and Antibacterial Activityof New N-Halamine Compounds. J. Pharm. Sci. 1987, 76, 245-247. Emerson, D. W. Slow Release of Active Chlorine and Bromine from Styrene-Divinylbenzene Copolymers Bearing N,N-Dichlorosulfonamide, N-Chloro-N-alkylsulfonamide, and N-Bromo-N-alkyl-
170 Ind. Eng. Chem. Res., Vol. 33, No. 1, 1994 sulfonamide Functional Groups. Polymer-Supported Reagents. 6. Ind. Eng. Chem. Res. 1991,30, 2426-2430. Gartner. W. J. Bacteriocidal Resins and Disinfection of Water Therewith. U.S. Patent 4,420,590, 1983. Tsao, T. C.; Williams, D. E.; Worley, C. G.; Worley, S. D. Novel N-Halamine Disinfectant Compounds. Biotechnol. B o g . 1991, 7. . .,R - -M -6-.
Williams, D. E.; Worley, S. D.; Barnela, S. B.; Swango, L. J. Bactericidal Activities of Selected Organic N-Halamines. Appl. Environ. Microbiol. 1987, 53, 2082-2089.
Worley, S.D.; Williams, D. E. Halamine Water Disinfectants. CRC Crit. Rev. Environ. Control 1988, 18, 133-175.
Received for review June 14,1993 Revised manuscript received September 10, 1993 Accepted September 24, 1993' e Abstract published in Advance ACS Abstracts, December 1, 1993.
