Propionyl chloride is primarily used as an acylating agent in organic synthesis. It is commonly employed in the production of pharmaceuticals, where it introduces the propionyl group into various compounds. This chemical is also utilized in the manufacture of dyes and perfumes, aiding in the synthesis of specific aromatic compounds. Additionally, it plays a role in the production of herbicides and pesticides, contributing to the development of effective agricultural chemicals. In the polymer industry, it is used to modify the properties of certain plastics and resins. Its reactivity makes it valuable in laboratory settings for creating esters, amides, and other derivatives.