Unsaturated aldehydes are also known, corresponding to the olefine alcohols; they show the characteristic properties of the saturated aldehydes and can form additive compounds in virtue of their unsaturated nature.

OLEFINE, in organic chemistry, the generic name given to open chain hydrocarbons having only singly and doubly linked pairs of carbon atoms. The word is derived from the French olefiant (from olefier, to make oil), which was the name given to ethylene, the first member of the series, by the Dutch chemists, J.

Isomerism in the olefine series does not appear until the third member of the series is reached.

They combine with hypochlorous acid to form chlorhydrins; and are easily soluble in concentrated sulphuric acid, giving rise to sulphuric acid esters; consequently if the solution be boiled with water, the alcohol from which the olefine was in the first place derived is regenerated.

The esters of the higher fatty acids, when distilled under atmospheric pressure, are decomposed, and yield an olefine and a fatty acid.

In addition to these, a series of open-chain olefine terpenes is known.

The hydrocarbon C20H42, for example, might be resolved into C5H12+C15H30, or CEH14+C14H28, or C7H16 +C13H26, &c., the general equation of the decomposition being C„1-1 27, ± 2 (paraffin) =G_rH2(, - P)+2 (paraffin)+C P H 2 n (olefine).

Energetic dehydration gives the olefine hydrocarbons, but under certain conditions ethers (see Ether) are obtained.