Grasping the Ether

The various formula sizes used in chemical theory during the years ca. 1820-50 maintained an uneasy coexistence at best. But problems became acute when disparate kinds of formulas were involved in one and the same chemical reaction, as in the formation of ether. 

The chemical substance simply called ether (now referred to as diethyl ether) had been known since the sixteenth century, but since it could not easily be related to a salt-forming organic acid, its formula weight could not easily be determined. But ether could be generated 

Swords, Graham, 11-15, 33-SO. He comments, Common Sense philosophy made motion and phenomena practically a tautology. Motion was the ground of all phenomena (14n). 

The following summary is much simplified, as the evolution of theories of etherification is complex. For a review, see Partington, History (1964), 262-63, 341-52, and 448-50. 

In his August 1850 paper, Williamson proposed a reaction mechanism for etherification that invoked a central chemical role for sulfuric acid. He suggested that in this reaction, ethyl radicals continuously shuttle from the alcohol, to the sulfuric acid, then to another molecule of alcohol, thereby making a molecule of ether. The alcohol molecule that is abandoned by its ethyl becomes water, one of the products the sulfuric acid molecule that acquires ethyl becomes sulfovinic acid the sulfovinic acid molecule that loses ethyl to a molecule of alcohol becomes sulfuric acid once more. The overall process ineluctably carries alcohol to ether and water, essentially doubling the size of the alcohol molecule, while the sulfuric acid remains unaltered over the course of the entire reaction. 

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