Volume 1

Chemical technology and analysis of oils, fats, and waxes / by J. Lewkowitsch.

  • Julius Lewkowitsch
Date:
1904
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Chemical technology and analysis of oils, fats, and waxes / by J. Lewkowitsch. Source: Wellcome Collection.

    36/454 (page 16)
    CHAP. glyceride obtained from distearin and palmitic acid (Kreis and Hafner 1). Datnrodistearin (.Distearodaturin), C3H5(0. C17H330)(0. C18H3.0),„ is obtained from lard by crystallisation from ether or petroleum ether solution. It crystallises in large laminae, appearing under the microscope as plates. In the crystalline state the melting point is 66-2° C.; in the superfused state 51‘8°C., and 66° C. (Kreis and Hafner 2). Oleodistearin, C3H,(0 . C18H330)(0 . C18H3-0)2. This is the first known mixed glyceride. It was obtained by Heise from Mkanyi fat and kokum butter, by precipitating an ethereal solution of these fats with alcohol. It has further been found in cacao butter (Fritz- weiler3). It melts at 44°-44-5° C. and solidifies at 40‘8° C. If the melted glyceride is cooled rapidly, the melting point 27°-28°C. is observed ; on further heating, the substance solidifies again, and finally melts at 37°-38°C. The specific gravity at 70° C. is 0'8928, and at 90 0'8547. The oleodistearin obtained synthetically by the action of oleic acid on a-distearin melts about 2° to 4° C. lower than the natural oleodistearin from Mkanyi fat and kokum butter (Kreis and Hafner). Elaidodistearin, C3H.(0 . C18H330)(0 . C18H350)2, is obtained by the action of nitrous acid on oleodistearin (Henriques and Kiinne 4). It melts at 61° C. Dioleostearin, C8H5(0. C18H330)2(0. C18H350), has been found recently in human fat (Partlieil and Eerie, Arch. d. Phar. 1903, 545). The occurrence of a mixed glyceride of Japanic and palmitic acids having the formula C3H5(C20H4[CO . 0]2)(0 . ClcH3102) in Japan wax is considered probable by Geitel and v. d. Want. 2. Properties of Natural Oils and Fats The natural oils and fats may, for practical purposes, be looked upon as mixtures, in varying proportions, of the triglycerides described above. The most important of the triglycerides, because most frequently occurring in nature, are tripalmitin, tristearin, and triolein. In consequence of the discovery of mixed glycerides, the question whether mixed glycerides do occur in the natural fats far more frequently than has been assumed hitherto, has become a very important one, but at present our knowledge is still too limited to justify any definite expression of opinion as to the composition of the glycerides in the oils and fats. The methods of preparing the various vegetable and animal fats (see chap, xiii.), being comparatively crude ones, the oils and fats generally contain impurities of one kind or another, such as colouring and mucilaginous matter, remnants of vegetable and 1 Berichte, 1903, 1123. 2 Ibid. 1903, 2766. 3 Arbeiten a. d. Kaiserl. Gesundheitsamte, 1902, 371. 4 Berichte, 1899, 387.