Methane Sulfonic Acid Anhydrous (AMSA or MSAA)


Arkema AMSA (methane sulfonic acid anhydrous - CAS 75-75-2) enjoys wide use in the pharmaceutical industry due to its high acidity and high miscibility in aqueous and most organic media. Its uses include:


  • formation of pharmacologically acceptable API salts
  • extraction, crystallization and purification of synthetic intermediates
  • synthetic raw material
  • acid catalyst, particularly for formation and removal of protecting groups
  • dehydrating reaction solvent


AMSA is a strong organic acid (pKa-1.92). As such, it is highly corrosive in its acid form.


CAS number
Chemical name
Anhydrous methane sulfonic acid, Methansulfonsäure wasser, Acide methane sulfonique anhydre
Common name


  • strong acid
  • biodegradable
  • molecular weight 96.1

Geographic availability



  • Chemical and plastics industry
    • Pharmaceuticals
  • Food industry and agrochemicals
    • Agrochemicals

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