Volume 1

Chemistry in space : from J. H. van 't Hoff's 'Dix années dans l'histoire d'une théorie' / translated and edited by J.E. Marsh.

  • Jacobus Henricus van 't Hoff
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: Chemistry in space : from J. H. van 't Hoff's 'Dix années dans l'histoire d'une théorie' / translated and edited by J.E. Marsh. Source: Wellcome Collection.

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    a plane of symmetry passing through the two atoms of A which have been replaced by R and R’, this plane will remain a plane of symmetry after the substitution ; and the body obtained will be inactive. From our knowledge of the constitution of certain simple types we are able to assert that certain bodies derived from them by two replacements will be inactive. ‘Again, if it happens not only that a single substitu- tion furnishes only one derivative, but also that two and even three substitutions only furnish one and the same chemical isomer, we are obliged to admit that the four atoms A occupy the angles of a regular tetrahedron, whose planes of symmetry are identical with those of the whole molecule MA,; in this case also no bisubstituted body can have rotatory power. ‘Application to saturated bodies of the fatty series.— All the saturated bodies of the fatty series are derived from marsh gas CH, by replacement of the hydrogen by different radicals. Provided that the atoms of hydrogen are not in the same plane, a supposition on which the very existence of active trisubstituted bodies is based, we can apply the first general principle and assert that the substitution of three different radicals will furnish active bodies, and whenever in the constitutional or typical formula of a substance we meet with one carbon atom . combined with three monatomic radicals different from each other and from hydrogen, we ought to find it an active body. ‘Further, as marsh gas never furnishes more than one. derivative by two substitutions 1, we can apply the second general principle and assert that such derivatives are never active. Hence whenever we meet with a carbon atom combined with two atoms of hydrogen or with two 1 ¢Par deux et par trois substitutions.’
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