mesylic

Mesylic is a term that can refer to a few different things, most commonly relating to methanesulfonic acid. Methanesulfonic acid, also known as mesylic acid, is a strong organic acid with the chemical formula CH3SO3H. It is a colorless liquid and is often used as a catalyst in organic synthesis, particularly in esterification and alkylation reactions. It is also employed in various industrial processes, including metal cleaning and plating.

The mesylate anion (CH3SO3-) is the conjugate base of methanesulfonic acid. This anion is a good leaving group in organic chemistry reactions, meaning it can readily depart from a molecule during a substitution or elimination reaction. This property makes mesylate esters, formed by reacting methanesulfonic acid with an alcohol, useful intermediates in the synthesis of various organic compounds.

In some contexts, "mesylic" might also be used informally to describe something that is messy or chaotic, similar to the word "messy." However, this usage is not a formal definition and is generally understood from context. The primary and most technical meaning of mesylic relates directly to methanesulfonic acid and its derivatives.