Volume 1

Recent advances in organic chemistry / by Alfred W. Stewart.

  • Alfred Walter Stewart
Date:
1931
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Recent advances in organic chemistry / by Alfred W. Stewart. Source: Wellcome Collection.

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    be expected that the other new reagents of organic chemistry will show such wide adaptability. The next to be dealt with here is ozone, which has a comparatively restricted field of application. When ozone acts upon compounds containing ethylenic or acetylenic linkages, one bond is ruptured and three oxygen atoms attach themselves to the molecule in the following way : 1 R,2C R2C R—C R—c II +03 — I /03 III +03 — II /03 RoC R2cr R—C R—Cx The fact that the double ethylenic bond is saturated by the addition of the ozone molecule is established, since the resulting ozonide does not decolorize a solution of bromine in acetic acid. The rapidity with which ozone acts upon ethylenic deriva¬ tives is influenced by constitutional factors; for ordinary ethylenic compounds are rapidly attacked, whereas when ozone reacts with substances containing conjugated double bonds, the two unsaturated groups are influenced in turn instead of being simultaneously affected. The action of ozone upon polynuclear hydrocarbons like naphthalene resembles the mode of attack of reducing agents, since one ring is completely saturated before the second ring is affected. The presence of substituents has also an influence in the case of aromatic derivatives. For example, aniline undergoes a normal oxidation process before the formation of an ozonide takes place at all. Ozonization is usually carried out in a solution, the solvent chosen being one which is itself unaffected by ozone, such as saturated hydrocarbons or simple alkyl halides. After the process is complete, the solvent is removed by evaporation, leaving the ozonide behind. The physical character of the ozonides varies according to the compounds from which they are obtained. Some are oils or syrups ; others are glassy bodies ; whilst a few can be ob- Harries have been reprinted under the title Untersuchungen uber das Ozon. A general conspectus of work done in this field up to 1915 is given in Fonrobert’s Das Ozon. 1 For some views as to the mode of action of the ozone molecules, see Engler and others, Ber., 1897, 30, 1669 ; 1899, 31, 3046 ; 1900, 33, 1090, 1097, 1109 ; 1901, 34, 2933 ; Klages and Heilmann, Ber., 1904, 57, 1449 ; Tiffeneau, Bull. Soc. chirn.. 1902, [iii], 27, 1066; Wallach, Annalen, 1905, 343, 28.