Editing Williamson ether synthesis (section)

==Conditions==
Since alkoxide ions are highly reactive, they are usually prepared immediately prior to the reactions or are generated ''in situ''. In laboratory chemistry, ''in situ'' generation is most often accomplished by the use of a [[carbonate]] base or [[potassium hydroxide]], while in industrial syntheses [[phase transfer catalysis]] is very common. A wide range of solvents can be used, but protic solvents and apolar solvents tend to slow the reaction rate strongly, as a result of lowering the availability of the free nucleophile. For this reason, [[acetonitrile]] and [[N,N-dimethylformamide|''N'',''N''-dimethylformamide]] are particularly commonly used.

A typical Williamson reaction is conducted at 50&nbsp;to 100&nbsp;°C and is complete in 1&nbsp;to 8&nbsp;h. Often the complete disappearance of the starting material is difficult to achieve, and side reactions are common. Yields of 50–95% are generally achieved in laboratory syntheses, while near-quantitative conversion can be achieved in industrial procedures.

Catalysis is not usually necessary in laboratory syntheses. However, if an unreactive [[alkylating agent]] is used (e.g. an alkyl chloride) then the rate of reaction can be greatly improved by the addition of a catalytic quantity of a soluble iodide salt (which undergoes halide exchange with the chloride to yield a much more reactive iodide, a variant of the [[Finkelstein reaction]]). In extreme cases, silver compounds such as [[silver oxide]] may be added:<ref>{{OrgSynth|doi = 10.15227/orgsyn.060.0092|title = (''R'',''S'')-Mevalonolactone-2-<sup>13</sup>C (2''H''-Pyran-2-one-<sup>13</sup>C, tetrahydro-4-hydroxy-4-methyl-)|first1 = Masato|last1 = Tanabe|authorlink1 = Masato Tanabe|first2 = Richard H.|last2 = Peters|collvol = 7|collvolpages = 386|year = 1981|volume = 60|pages = 92|prep = CV7P0386}}</ref>
:[[Image:WilliamsonEtherSynth.svg|Ether synthesis with silver oxide]]

The silver ion coordinates with the halide leaving group to make its departure more facile. Finally, phase transfer catalysts are sometimes used (e.g. [[tetrabutylammonium bromide]] or [[18-crown-6]]) in order to increase the solubility of the alkoxide by offering a softer [[counterion|counter-ion]].
One more example of etherification reaction in the tri-phasic system under phase transfer catalytic conditions is the reaction of benzyl chloride and [[furfuryl alcohol]].<ref>Katole DO, Yadav GD. Process intensification and waste minimization using liquid-liquid-liquid triphase transfer catalysis for the synthesis of 2-((benzyloxy)methyl)furan. Molecular Catalysis 2019;466:112–21. https://doi.org/10.1016/j.mcat.2019.01.004</ref>