Handbook of the polariscope and its pracitcal applications / adapted from the German editon of H. Landolt, by D.C. Robb and V.H. Veley.

  • Hans Heinrich Landolt
Date:
1882
Catalogue details

Licence: Public Domain Mark

Credit: Handbook of the polariscope and its pracitcal applications / adapted from the German editon of H. Landolt, by D.C. Robb and V.H. Veley. Source: Wellcome Collection.

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    Diphenyl-succinic Acid (C6H5) — *CH(CO.OH) — [*CH(CO.OH) — 06 H6]. By comparisons of this kind, which might easily be extended, we find that up to the present no substance can be indicated with certainty2 as disproving van’t Hoff’s theory or the following state- ments based thereupon :— 1. That optically active substances invariably contain one or more asymmetrical carbon-atoms. . r^l!lt substances containing no asymmetrical carbon-atoms exhibit no optical activity. On the other hand, as van’t Hoff has pointed out, and as may be seen from the above examples, the converse is not necessarily true, that “ bodies containing asymmetrical carbon-atoms are always optically active.” There are, in fact, numerous substances which contain asymmetrical carbon-atoms and yet exhibit no optical activity, and further research is needed to decide whether or not this inactivity can be referred to the causes before specified. But, even should further inquiry prove that asymmetrical carbon-atoms are not the sole condition but merely one of the conditions of optical activitv, the foregoing statements, unless disproved by fresh discoveries, remain of great importance to chemistry, as they not only afford some sort of control over active substances, but may also yield definite indications as to the proper structural-formulae. § 15. Artificial Production of Active Substances.—The carbon- compounds m which optical activity has hitherto been observed, are all of them found in vegetable or animal organisms or as derivatives from these by simple decomposition. Many of these substances can be prepared artificially, but even when all the chemical attributes, Undetermined. Phenyl-lactic Acid Tropaic Acid (C6 H6. C H2) - *C H (0 H) — (C O . 0 H). (C6 H5)-*CH(CH2.OH)-(CO.OH). Inactive. Benzoin ( Cinnamic Acid dibromide (C6 H5. C 0) — *CH(0 H) - (C6 H5).