Page:Outlines of Physical Chemistry - 1899.djvu/45

 primary alcohol, if the characteristic reactions just men- tioned can be realised.

Two substances having the formula C 3 H 7 OH are known, and both are of an alcoholic nature. One of them on oxidation gives an aldehyde and an acid, consequently it contains the group — CH 2 OH. It must therefore have the constitution CH 3 — 0H 2 — CH 2 OH, and is normal propyl alcohol.

The isomeric substance yields entirely different oxida- tion products and no propionic acid. It must necessarily

H

I have the formula CH 3 — C — CH 3, the only remaining one

��OH which contains a hydroxyl group. The group — CH(OH) — thus becomes characteristic of a secondary alcohol. The substance, whose formula is given, is secondary propyl alcohol.

Similar considerations of the alcohols C 4 H 9 OH lead us to the characteristic properties and constitution of tertiary

��alcohols. These contain the -group — C(OH). For

��farther details on this subject the reader is referred to treatises on organic chemistry.

(b) The Fatty Acids. — Formic acid can only have one formula, and we know the constitution of acetic acid. These two acids contain the group — OOOH which is the characteristic of their properties. Substances which con- tain this group form salts, saponifiable esters, acid chlorides &c. We know a substance C 3 H 6 2 which is obtained by the oxidation of normal propyl alcohol and which possesses the properties characteristic of the group — COOH. Hence we conclude that this substance contains this group and has the constitution CH 3 — CH 2 — COOH (propionic acid).

It might be interesting here to refer also to the aromatic compounds, derived from the nucleus C 6 H 6, all possessed

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