Ethoxy group

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Ethoxy group
Ethoxy Group General Formulas V.6.png
Different spellings of the blue- marked ethoxy group (R = organyl group , e.g. alkyl group ).
Ethoxy Group General Formulas V.5b.png
Examples of molecules with a blue- marked ethoxy group, above, from left to right ethanol and tert -butyl ethyl ether , below ethyl acetate ( ethyl acetate ) and an ethoxylate anion.

The ethoxy group (ancient ethoxyl group ) is one of the simplest atomic arrangements in organic chemistry, which supplements an ethyl group with a heteroatom (oxygen).

The formula of the substituent is –OC 2 H 5 , sometimes also written as –OEt .

The ethoxy group is not an independent chemical substance, but always part of a larger molecule (see illustration). The smallest molecule in this group is ethanol , which is mostly classified as an alcohol with a hydroxyl group .

properties

Replacing a hydrogen atom in an alkane with an ethoxy group increases polarity and reactivity . For example, ethers are split into alcohols with aqueous acids at higher temperatures. As a first substituent, an ethoxy group has a moderately activating and an ortho (next to) or para (opposite) directing effect in electrophilic aromatic substitution .

Quantitative analytical determination

For the quantitative analytical determination of ethoxy groups, a sample of the substance to be examined is heated to approx. 100  ° C. with excess hydriodic acid and the resulting iodoethane is distilled off. Silver nitrate is added to the latter to an ethanolic solution and the silver iodide formed as a result of hydrolysis of the iodoalkane is determined gravimetrically.

Individual evidence

  1. ^ Siegfried Hauptmann : Organic Chemistry , 2nd revised edition, VEB Deutscher Verlag für Grundstoffindindustrie, Leipzig, 1985, ISBN 3-342-00280-8 , p. 343.