A manuel of the chemistry of the carbon compounds : or, Organic chemistry / [Carl Schorlemmer].

  • Schorlemmer, Carl, 1834-1892
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: A manuel of the chemistry of the carbon compounds : or, Organic chemistry / [Carl Schorlemmer]. Source: Wellcome Collection.

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    All compounds in which the carbon atoms are linked together in the same manner as in the hydrocarbons of the methane series, form one large group, which has been called the group of the fattij sub- stances, because most of the monobasic acids, belonging to it, occur in vegetable and animal fats; and these acids form a homologous series which is very complete and has been long known. The most cha- racteristic property of the members of this group is that they undergo chemical changes principally by substitiition, i.e. atoms or groups of atoms are taken out and displaced by others. A second group includes those compounds in which two or more atoms of carbon are linked together with more than one of their combining units. These bodies possess the characteristic property of combining directly with hydrogen, chlorine, &c., and thus by addition are changed into compounds belonging to the first group. This group is usually called the group of the non-saturatcd compounds, a term which, however, would imply that these bodies contained carbon atoms with free combining units, an assumption which for several reasons appears improbable. Besides these two groups there exist other groups of carbon com- pounds, which are richer in carbon than the fatty substances, but these comport themselves in most of their chemical metamorphoses like the latter, and only in a few cases form new compounds by addition, which, however, always contain less hydrogen than fatty bodies. This class of compounds is again subdivided into different groups, the best known of which is that of the aromatic substances, this name being derived from the fact that many of them are found in essential oils, .balsams, resins, &c. No compound belonging to this group contains less than six atoms of carbon, the most simple hydrocarbon of the group being benzene C^Hg, in which of the twenty- four combining units of carbon, eighteen are taken up by the union of carbon with carbon, whilst the remaining six are combined with hydrogen, thus :— HC—CH // \ HC CH \ / HC=CH This linking of the carbon atoms may figuratively be expressed by saying that they are joined together in an aimular or closed chain, whilst in the fatty and the non-saturated compounds they form an open chain. All hydrocarbons contain an even number of atoms of hydrogen; this is, as it will easily be seen, a consequence of carbon being a tetrad. From this fact it follows further that the sum of the atoms of monad and triad elements contained in the molecule of a carbon convpound must also always be an even number. The observation that by replacing in a hydrocarbon one or more