Widely used as a catalyst in organic synthesis, especially in Friedel-Crafts reactions, where it facilitates alkylation and acylation of aromatic compounds. It plays a key role in the production of dyes, pharmaceuticals, and fragrances. Also employed in petroleum refining to promote isomerization and alkylation of hydrocarbons for high-octane fuels. In industrial settings, it serves in the manufacture of lubricants and rubber chemicals. Additionally, it finds use in water treatment and as a component in antiperspirants due to its astringent properties.