This section is from the book "A Practical Treatise On Friction, Lubrication, Fats And Oils", by Emil F. Dieterichs. Also available from Amazon: A practical treatise on friction, lubrication, fats and oils.
Peanut oil is obtained from the kernels of the peanut. They yield by pressure from thirty to forty per cent of an oil of a light yellowish, almost white, color, and of an agreeable, particularly nutty, taste and odor. When obtained by extraction the seeds furnish from forty to fifty per cent of oil. The specific gravity is 0.915, or 23° Baume, at 60° F. The older and last pressed oils have at 60° F. a specific gravity of 0.9202, or 22° Baum6. The oil is more limpid than olive oil, which it resembles much. It is a slightly drying oil. It contains palmitin, olein, stearin and archidic acids the latter being peculiar to this oil.
Mustardseed oil is obtained from the seeds of the mustard plant. The seeds yield by pressure or extraction about thirty per cent of oil of dark yellow-brownish color, of a mild taste, and when obtained by pressure, with a very slight odor of mustard. Its specific gravity at 60° F. is 0.917, or 23° Baume. It solidifies about 18° F., and is composed of stearic, palmitic and a peculiar oleic acid called mustardseed acid.
Nigerseed Oil - Is obtained from the seeds of Guizotia. It has a pale yellow color, little odor and a sweet taste. Is more limpid than rapeseed oil and of semi-drying character. Its specific gravity is 0.924, or 22° Baume.
Linseed oil is a drying fixed oil obtained from flaxseed, which yield about thirty-four per cent of oil. The seeds are roasted before being pressed or extracted, and furnish a light colored oil of best quality under cold pressure. When pressed warm or obtained by extraction with solvents it is more highly colored and more acid, has a brownish-yellow color, a disagreeable odor, a nauseous taste, and a neutral reaction. Its specific gravity is 0.932 to 0.936, or 20° Baume". It boils at 600° F., does not congeal at 0° F., and dries and solidifies on exposure to the air and acquires a strong odor and taste.
The drying property of linseed oil resides in a constituent called "linolein," to distinguish it from the olein of the non-drying oils. Spread out in thin layers and exposed to the air, it becomes thicker and resinous, and increases as much as twelve per cent of its weight, owing to the formation of linoxyn by atmospheric oxidation. Boiled with litharge, red lead, lead acetate, manganese dioxide or borate and other chemicals, so-called dryers, it absorbs oxygen still more rapidly, and increases to some fourteen per cent in weight. Its acrimony is due to the presence of a small proportion of an acrid oleoresin. It is much adulterated with other oils when used in the manufacture of printer's ink.
Linseed oil is principally used in the manufacture of paints, by printers and varnish makers, and in the manufacture of soft soaps which are used for cleaning in hotels, office buildings, factories, machine-shops, and engine rooms, and for cleaning automobiles, 3
Below a few receipts for the manufacture of "German Soft Soap" are given:
In a vessel capable of containing at least three times the quantity to be made, put one part by weight of linseed oil, heat gently and add, in two portions, three parts in all by measure, of liquor of potassa. Boil and stir frequently until the mass becomes clear which will require about five hours for 10 pounds of oil. If during this process the mass becomes too thick to stir easily add a little water.
To make Green German Soap allow the soap to become cool; but before it sets work in the coloring matter, which must be previously prepared by boiling finely powdered indigo with water until the color is formed into a thin paste. Twenty grains of indigo boiled with 1 1/2 ozs. of water until the mixture is reduced to about one drachm will answer for soap from four ounces of oil. The soap must not be too hot nor must it be reboiled after adding the coloring matter, or the green will be destroyed.
The liquor of potassa is made as follows: Dissolve one pound of carbonate of potassium in one gallon of water, boil and mix with 13 ozs. of slaked lime washed with water, boil 10 minutes stirring constantly.
Green soap is also made from hemp-seed oil. It should at least contain 5 per cent of free hydrate of potassa.
Heat linseed oil 150 lbs. and palm oil 10 lbs. together with about 150 lbs. of potash lye of 18° Be., and effect combination by crutching. When the mass has acquired a pasty consistency it is gradually fitted completely with potash lye of 28° Be. The boiling lye is prepared by dissolving in caustic potash lye of 50° Be., 18 per cent, of potash. In the case in question there are required for the saponification of the stock 65 lbs. of 50° caustic potash lye in which 12 lbs. of potash have been dissolved. The lye is then made up to 28° Be., and about one-half of it is diluted to 18° Be. in order to obtain a suitable combining lye. When the soap is correctly fitted, it is sufficiently evaporated so that it boils free from froth and breaks short from the paddle without drawing threads. It is then allowed to stand for about 2 hours, best overnight if a larger quantity of stock is used, so that its temperature does not exceed 185° F., otherwise the subsequent filling of potato-flour will form lumps. In the meanwhile the filling is prepared, it being best to heat it somewhat, otherwise the soap would be cooled too much and finally could scarcely be crutched. However, only the solutions used for the filling should be heated prior to adding the potato-flour, and at the utmost to 167° F. The filling consists of 30 lbs. water-glass (silicate of soda) mixed with 30 lbs. water, 50 lbs. potato flour stirred together with 90 lbs. potassium chloride solution of 14° Be., and 50 lbs. fitting lye of 28° Be. The mixture of water-glass and water is first crutched in small portions into the soap, some fitting lye is then added and next the potato flour stirred together with the potassium chloride solution is slowly poured over the soap, the mass being constantly crutched to effect uniform absorption of the filling. While introducing the potato flour filling some fitting lye is from time to time added to prevent the soap from becoming too long and to facilitate crutching. When the filling has been thoroughly crutched in, a sample is taken upon the glass and tested as to the fitting. If the soap is too viscous and soft some lye has to be added so that it becomes sufficiently short and shows the required firmness. When the samples prove the soap to be correctly fitted, it is at once brought into barrels, as when cooled too much it becomes very viscous and can scarcely be ladled. In case the fitting has not been too strong, the soap clears nicely in a few days and notwithstanding the large amount of filling, is quite transparent provided clear filling lyes and pure potato flour have been used.