Polystyrene sulfonate

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Polystyrene sulfonate
Systematic (IUPAC) name
Poly(4-vinylbenzenesulfonic acid)
Clinical data
Trade names Sodium salt: Kayexalate, Kionex, Resonium A, sodium polystyrene sulfonate
Calcium salt: Calcium Resonium, Sorbisterit, Resikali, Calcium Resonium, Sorbisterit, Resikali
AHFS/Drugs.com monograph
MedlinePlus a682108
  • US: C (Risk not ruled out)
Legal status
  • (Prescription only)
Routes of
Oral, retention enema
Pharmacokinetic data
Bioavailability None
Metabolism None
Excretion Faeces (100%)
CAS Number 28210-41-5 YesY
ATC code V03AE01
PubChem CID: 75905
DrugBank DB01344 YesY
Chemical data
Formula [C8H8SO3]n
 YesY (what is this?)  (verify)

Polystyrene sulfonates are polymers derived from polystyrene but containing sulfonic acid or sulfonate functional groups. The linear polymer is white when very pure and is water-soluble. The crosslinked material (called a resin) does not dissolve in water and typically appears amber in color. These polymers are classified as polysalts and ionomers. They are widely used to remove ions from a solution in technical or medical applications.[1]

Medical uses[edit]

Micrograph showing sodium polystyrene sulfonate crystals (purple – at top of the image) in the biopsy of a colonic mass. H&E stain.

Polystyrene sulfonate is usually supplied in the sodium and calcium form. Its use as a potassium binders in acute and chronic kidney disease for people with hyperkalaemia (abnormal high blood serum potassium levels).[2] It however is unclear if it works and there is concern about possible side effects when it is mixed with sorbitol.[3]

Polystyrene sulfonates are administered orally (with a meal) or rectally, by retention enema.[4]


Intestinal disturbances are common, including loss of appetite, nausea, vomiting, and constipation. In rare cases, it has been associated with colonic necrosis.[5] Changes in electrolyte blood levels may occur such as hypermagnesemia, hypercalcemia, and hypokalemia.[6]

Chemical uses[edit]

Polystyrene sulfonates are useful because of their ion exchange properties.[1]

Water softening[edit]

Water softening is achieved by percolating hard water through a bed of sodium form of cross-linked polystyrene sulfonate. The hard ions such as calcium (Ca2+) and magnesium (Mg2+) adhere to the sulfonate groups, displacing sodium ions. The resulting solution of sodium ions is softened.

Idealized image of water softening process involving replacement of calcium ions in water with sodium ions donated by a cation exchange resin.

Other uses[edit]

Sodium polystyrene sulfonate is used as a superplastifier in cement, as a dye improving agent for cotton, and as proton exchange membranes in fuel cell applications. In their acid form, the resin is used as a solid acid catalyst in organic synthesis.[7]

Production and chemical structure[edit]

Polystyrene sulfonic acid has the idealized formula (CH2CHC6H4SO3H)n. The material is prepared by sulfonation of polystyrene:

(CH2CHC6H5)n + n SO3 → (CH2CHC6H4SO3H)n

Several methods exist for this conversion, which can lead to varying degree of sulfonation. Usually the polystyrene is crosslinked, which keeps the polymer from dissolving. Since the sulfonic acid group (SO3H) is strongly acidic, this polymer neutralizes bases. In this way, various salts of the polymer can be prepared, leading to sodium, calcium, and other salts:

(CH2CHC6H4SO3H)n + n NaOH → (CH2CHC6H4SO3Na)n + n H2O

These ion-containing polymers are called ionomers.

Alternative sulfonation methods[edit]

Double substitutions of the phenyl rings are known to occur, even with conversions well below 100%. Crosslinking reactions are also found, where condensation of two sulfonic acid groups yields a sulfonyl crosslink. On the other hand, the use of milder conditions such as acetyl sulfate leads to incomplete sulfonation. Recently, the atom transfer radical polymerization (ATRP) of protected styrenesulfonates has been reported,[8][9] leading to well defined linear polymers, as well as more complicated molecular architectures.[10]


  1. ^ a b François Dardel and Thomas V. Arden "Ion Exchangers" in Ullmann's Encyclopedia of Industrial Chemistry, 2008, Wiley-VCH, Weinheim. doi:10.1002/14356007.a14_393.pub2
  2. ^ MedlinePlus Encyclopedia High potassium level
  3. ^ Sterns RH, Rojas M, Bernstein P, Chennupati S (May 2010). "Ion-exchange resins for the treatment of hyperkalemia: are they safe and effective?". J. Am. Soc. Nephrol. 21 (5): 733–5. doi:10.1681/ASN.2010010079. PMID 20167700. 
  4. ^ Medicines Complete: Martindale: The Complete Drug Reference, URL: http://www.medicinescomplete.com/mc/martindale/2009/5004-l.htm; Retrieved: 27 November 2009
  5. ^ Rogers FB, Li SC (August 2001). "Acute colonic necrosis associated with sodium polystyrene sulfonate (Kayexalate) enemas in a critically ill patient: case report and review of the literature". J Trauma 51 (2): 395–7. doi:10.1097/00005373-200108000-00031. PMID 11493807. 
  6. ^ Sorbisterit – Summary of Product Characteristics; Retrieved: 27 November 2009.
  7. ^ Erik Gálvez, Pedro Romea, and Fèlix Urpí (2009). "Stereoselective Synthesis of anti α-Methyl-β-Methoxy Carboxylic Compounds". Org. Synth. 86: 81. 
  8. ^ Sikkema, FD; Comellas-Aragonès, M; Fokkink, RG; Verduin, BJ; Cornelissen, JJ; Nolte, RJ (2007). "Monodisperse polymer-virus hybrid nanoparticles". Organic & biomolecular chemistry 5 (1): 54–7. doi:10.1039/b613890j. PMID 17164905. 
  9. ^ Lienkamp, Karen; Schnell, Ingo; Groehn, Franziska; Wegner, Gerhard (2006). "Polymerization of Styrene Sulfonate Ethyl Ester by ATRP: Synthesis and Characterization of Macromonomers for Suzuki Polycondensation". Macromolecular Chemistry and Physics 207 (22): 2066. doi:10.1002/macp.200600322. 
  10. ^ Lienkamp, Karen; Ruthard, Christian; Lieser, GüNter; Berger, RüDiger; Groehn, Franziska; Wegner, Gerhard (2006). "Polymerization of Styrene Sulfonate Ethyl Ester and Styrene Sulfonate Dodecyl Ester by ATRP: Synthesis and Characterization of Polymer Brushes". Macromolecular Chemistry and Physics 207 (22): 2050. doi:10.1002/macp.200600321. 

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