A very strong halogenated derivative of acetic acid. It is used in acid catalyzed reactions, especially those where an ester is cleaved in peptide synthesis.
Derivatives of acetic acid with one or more fluorines attached. They are almost odorless, difficult to detect chemically, and very stable. The acid itself, as well as the derivatives that are broken down in the body to the acid, are highly toxic substances, behaving as convulsant poisons with a delayed action. (From Miall's Dictionary of Chemistry, 5th ed)