Alkoxide Definition in Chemistry

What Is an Alkoxide?

An alkoxide forms when an alcohol is reacted with a metal.
An alkoxide forms when an alcohol is reacted with a metal. Martin Elstermann / EyeEm / Getty Images

An alkoxide is an organic functional group formed when a hydrogen atom is removed from an hydroxyl group of an alcohol when reacted with a metal. It is the conjugate base of an alcohol.

Alkoxides have the formula RO- where R is the organic substituent from the alcohol. Alkoxides are strong bases and good ligands (when R is relatively small). Generally, alkoxides are unstable in protic solvents, but they do occur as reaction intermediates. Transition metal alkoxides are used as catalysts and to prepare coatings.

Key Takeaways: Alkoxide

  • An alkoxide is the conjugate base of an acid.
  • In a chemical reaction, an alkoxide is written as RO-, where R is the organic group.
  • An alkoxide is a type of strong base.

Example

Sodium reacting with methanol (CH3OH) reacts to form the alkoxide sodium methoxide (CH3NaO).

Preparation

There are several reactions with alcohol that produce alkoxides. They may be made by reacting an alcohol with a reducing metal (e.g., any of the alkali metals), by reaction with an electrophilic chloride (e.g., titanium tetrachloride), using electrochemistry, or via a metathesis reaction between a sodium alkoxide and a metal chloride.

Alkoxide Key Takeaways

  • An alkoxide is the conjugate base of an acid.
  • In a chemical reaction, an alkoxide is written as RO-, where R is the organic group.
  • An alkoxide is a type of strong base.

Sources

  • Boyd, Robert Neilson; Morrison, Robert Thornton (1992). Organic Chemistry (6th ed.). Englewood Cliffs, N.J.: Prentice Hall. pp. 241–242. ISBN 9780136436690.
  • Bradley, Don C.; Mehrotra, Ram C.; Rothwell, Ian P.; Singh, A. (2001). Alkoxo and Aryloxo Derivatives of Metals. San Diego: Academic Press. ISBN 978-0-08-048832-5.
  • Turova, Nataliya Y.; Turevskaya, Evgeniya P.; Kessler, Vadim G.; Yanovskaya, Maria I. (2002). The Chemistry of Metal Alkoxides. Dordrecht: Kluwer Academic Publishers. ISBN 9780792375210.
  • Williamson, Alexander (1850). "Theory of Ætherification". Phil. Mag. 37 (251): 350–356. doi:10.1080/14786445008646627