Divinyl ether

Divinyl ether is the organic compound with the formula O(CH=CH2)2. It is a colorless, volatile liquid that has mainly been of interest as an inhalation anesthetic. It is prepared by treating bis(chloroethyl) ether with base. The analytical techniques used to study its pharmacology laid the groundwork for the testing of new anesthetic agents. Vinyl ether was first prepared in 1887 by Semmler from its sulfur substituted analogue, divinyl sulfide (obtained from the essential oil of Allium ursinum L.), by reaction with silver oxide. In 1899, Knorr and Matthes obtained low yields of vinyl ether by exhaustive methylation of morpholine. Cretcher et al. reported, in 1925, what would become the foundation for one industrial method used to produce vinyl ether. It was stated that the action of heated sodium hydroxide upon β,β`-dichlorodiethyl ether produced a liquid boiling at 39 °C (among other identified products). However, in a subtly modified process Hibbert et al. reported the isolation of a product boiling at 34-35 °C, "divinyl ether". Finally, in 1929, a patent issued to Merck & Co reported isolation of vinyl ether boiling ca. 28 °C. The currently accepted boiling point of vinyl ether is 28.3 °C; the Merck patent, therefore, was the first to report the isolation of a pure product. Even before its isolation and characterization, the application of an unsaturated ether as an anesthetic interested some pharmacologists. One such pharmacologist, Chauncey Leake, was particularly captivated by the then theoretical vinyl ether. Leake predicted that vinyl ether would combine the properties of two anesthetic agents, ethyl ether, and ethylene. As an anesthetic ethylene has many favorable properties, although its very low potency often requires hypoxic conditions to achieve full anesthesia. Ethyl ether, on the other hand, is a relatively potent anesthetic but falls short of ethylene in some respects. In comparison to ether, ethylene has a much lower occurrence of post operative nausea; additionally, ethylene has faster induction and recovery times than ether.