Used as a catalyst in organic synthesis, particularly in esterification and polymerization reactions. It is effective in promoting the formation of esters from alcohols and carboxylic acids. Also employed in the production of resins and plastics, where it helps in controlling the polymerization process. Its strong acidic nature makes it suitable for use in acid-catalyzed reactions. Additionally, it is utilized in the manufacture of dyes and pharmaceuticals, where it acts as an intermediate or a reagent in various chemical transformations.