| 释义 |
margaric, a. Chem.|mɑːˈgærɪk|
[mod. f. Gr. µάργαρ-ον = µαργαρίτης pearl + -ic, in reference to the pearly lustre of the crystals or scales.]
In margaric acid: †a. orig. the name (acide margarique) given by Chevreul to one of the three fatty acids (oleic, margaric, stearic), the glyceryl derivatives of which (olein, margarin, stearin) were thought by him to form the chief constituents of animal fats. The composition assigned to margaric acid was (reduced to the new notation) C17H34O2. So margaric ether. Obs.
It was shown by Heintz in 1852 (Journ. Prakt. Chem. LXVI. 1) that the three fatty acids of animal fat are the oleic, palmitic, and stearic, and that the ‘margaric’ of Chevreul was really a mixture of palmitic (C16H32O2) and stearic acid (C18H36O2); and in this use the name is now obs., though it remained long in popular manuals, and its former prevalence is commemorated in the names margarine and oleo-margarine.
1819J. G. Children Chem. Anal. 314 Margaric acid was obtained from hog's lard by Chevreul in 1813. 1836Brande Chem. iii. vii. §12 (ed. 4) 962 Margaric Acid, so named from its pearly lustre,..bears a striking resemblance to stearic acid. It is obtained by decomposing the margarate of potassa. 1863Fownes Chem. (ed. 9) 533 Margaric ether is prepared by a similar mode of proceeding. c1865Letheby in Circ. Sci. I. 95/2 Margaric,..and other..Fatty Acids, are obtained from the oils.
b. By recent chemists, applied to an acid of composition C17H34O2, artificially prepared.
1865–8Watts Dict. Chem. III. 852 Margaric acid forms white crystals, melting at 59·9°, and solidifying in crystalline scales on cooling. 1891Thorpe Dict. Appl. Chem. II. 101/2 Margaric acid C16H33COOH may be formed by boiling margonitrile with alcoholic potash. 1892Morley & Muir Watts' Dict. Chem. III. 194. 1899 E. F. Smith Richter's Organ. Chem. I. 250 Margaric Acid, C17H34O2, does not apparently exist naturally in the fats. It is made in an artificial way by boiling cetyl cyanide with caustic potash. |