is a common name for another fraction of the volatile distillate from petroleum, viz., that which boils between 50° and 60°C. (122° to 140° F.) and has a spec. grav. of 0.670 to 0.675°.
This liquid, which is also used as a volatile solvent for the extraction of odorous substances, must not be confounded with Benzene or Benzol, a distillate from coal tar, boiling at about 80° C. (176° F.) and having a spec. grav. of 0.878. The latter is not used for the extraction of perfumes.
Bisulphide of Carbon.
This is made by conducting vapors of sulphur over glowing charcoal or coke. The vapors of bisulphide of carbon thus formed are led into vessels filled with ice or ice-cold water, where they condense. Bisulphide of carbon is a colorless liquid, heavier than water and very refractive. It is inflammable, and possesses a peculiar odor which is not disagreeable if the liquid has been thoroughly purified. Its boiling-point is about 45° C. (113° F.) and it has great solvent power. At the present time, the market affords bisulphide of carbon of a high degree of purity.
Some manufacturers who prepare their odors by extraction, may find it advantageous to make also the bisulphide of carbon necessary for it, and this is best done in Gérard’s apparatus (Fig. 1). It consists of a cast-iron cylinder a, two metres high and one metre in diameter. This cylinder is heated on the outer surface in an oven, and two tubes, c and d, are attached to it. Tube d is connected by e with the hemispherical vessel b which is connected by the tube i with the condenser mlk. The condenser is formed of three cylinders made of sheet zinc which are surrounded with cold water. The condensed liquid escapes into the vessel p, while the gaseous products pass through n into the chimney. The cylinder a is filled with about 1,500 pounds of charcoal or coke in small pieces, after which it is closed and all tubes are carefully luted with clay; a is then heated to a strong red heat and at intervals of three minutes 3 pounds of sulphur are thrown in through c. In twenty-four hours, by the use of 478 pounds of sulphur, 568 pounds of crude bisulphide of carbon are obtained; a portion of the sulphur distils over uncombined into the vessel b.
Fig. 1.
The crude bisulphide of carbon contains about twelve per cent of sulphur and other combinations in solution and is redistilled at exactly 48° C. (118.4° F.) in a steam-heated apparatus with a long exit tube cooled with ice below and water above. In order to obtain the bisulphide of carbon absolutely pure, which is essential to render it suitable for extraction, it is again distilled at the same temperature, with the addition of two per cent of palm oil. As the vapors of bisulphide of carbon are injurious to the organism, the vessels containing it must always be kept well closed.
B. Chemical Products used for the Preparation of Perfumes.
Among all the substances belonging under this head, there is one which plays a prominent part in the manufacture of most perfumes. In handkerchief perfumes it is one of the most important substances, as it forms not only the greatest bulk, but the perfection of the perfume depends upon its quality. This substance is—