Derivative
Definition and meaning of Derivative in chemistry.
A derivative is a compound produced from a parent compound by a chemical reaction that replaces one atom or functional group with another while preserving the parent's core molecular framework.
In more detail
Chemists make derivatives to change a compound's physical properties, solubility, volatility, crystallinity, or color, without altering its essential skeleton, which is useful for purification, identification, and analysis. In classical qualitative organic analysis, an unknown is converted into a solid crystalline derivative with a sharp, well-documented melting point (e.g., a 2,4-dinitrophenylhydrazone from an aldehyde or ketone) to confirm its identity. In modern analytical chemistry, derivatization converts poorly volatile or poorly detectable analytes into forms suitable for gas chromatography or HPLC, such as silylation prior to GC analysis.
Key facts
| Field | Organic Chemistry |
|---|---|
| Common preparation methods | Esterification, acetylation, silylation, substitution |
| Typical uses | Structure confirmation, purification, GC/HPLC detection |
| Example | Aspirin, C9H8O4, a derivative of salicylic acid |
Acetylsalicylic acid (aspirin) is a derivative of salicylic acid, made by acetylating the phenolic –OH group to form an ester.
Frequently asked questions
Why do chemists prepare solid derivatives to identify unknown compounds?
Because two different compounds can have very similar physical properties, converting an unknown into a solid derivative with a sharp, well-characterized melting point (compared against reference tables) helps distinguish it from similar substances and confirm its identity.
What is derivatization in analytical chemistry?
Derivatization is chemically converting a sample into a derivative to make it more volatile, thermally stable, or detectable, which is often necessary before analysis by gas chromatography or certain HPLC detectors.