In Europe and North America the oils 2 and 3 are further fractionated, safrol being obtained as principal product. The resulting by-products enter commerce as light (low boiling), heavy (high boiling) and blue (highest boiling fraction) camphor oil.
The properties of these oils vary according to the nature of the raw material and the method of production.
The light camphor oil is used as a substitute for turpentine oil in the manufacture of varnishes, also in printing establishments for cleaning types, electroplates and cylinders. Its specific gravity varies between 0,86 and 0,900. The boiling point varies between 175 and 200° and above. The flash point fluctuates between 45 and 60°, being somewhat higher than that of turpentine oil.
Heavy camphor oil is also used in the varnish industry; for perfuming cheap soaps, more particularly soft soap, shoe polish, and hoof ointment, also for the purpose of hiding the odor of mineral oils, wagon-grease and lubricating oils. d16o about 0,95; boiling temperature about 270 to 300°.
Blue camphor oil serves similar purposes as the preceding one. d16o about 0,95 to 0,96; boiling temperature about 300°.
As to the properties of camphor leaf oil mentioned on p. 451, an oil distilled by Schimmel & Co.1), from dry leaves was completely permeated by camphor at ordinary temperature. It boiled between 170 and 270°. Two oils distilled in India from fresh leaves by D. Hooper2) showed the following properties:
1. d18o 0,9322; aD + 4° 32'; camphor content 10 to 15 p.c.
2. d 0,9314; aD + 27°; camphor content 75 p. c. Two oils distilled in Amani, likewise from fresh leaves, were examined by Schimmel & Co.3). They had the following properties: 1. d15o 0,9236; crD + 39°20'. The oil corresponded to the filtrate from the camphor which separates spontaneously from the original oil. It contained no safrol. Camphor content, as determined by distillation (see below) 75 p. c. 2. d15o0,9203; aD + 39°42'.
1) Report of Schimmel & Co. October 1892, 11.
2) Pharmaceutical Journ. 56 (1896), 21.
3) Report of Schimmel & Co. October 1906, 20; October 1910, 28.
An oil distilled from camphor roots1) was solid at ordinary temperature because of the separated camphor. When completely liquified (at 45°) d45o 0,957.
Determination of Camphor in Camphor Oil. No method is known whereby an exact determination of the amount of camphor in a volatile oil can be made2). Hence one is dependent on technical methods which are modifications of the process by which camphor is obtained on a large scale. They are based on the direct isolation of camphor by fractional distillation. The results may vary more or less, according to the greater or lesser perfection of the fractionation apparatus. Nevertheless the method described by H. Lohr3) may be looked upon as sufficiently accurate for technical purposes.
At least 300 g. of the oil to be examined are used. If the oil is rich in camphor it is first placed in a freezing mixture and the crystallized camphor separated and treated as directed below. The oil is then distilled and the distillate collected in three fractions, viz. up to 195°, 195 to 220° and above 220°. The first and third fractions contain no camphor. The second is thoroughly cooled in a freezing mixture for an hour, when the separated camphor is filtered off with the aid of a suction pump. In order to remove the adhering oil more completely, the camphor is packed in a straining cloth which is placed between filter paper under a press for half an hour. The cake is then placed between fresh filter paper and pressed for another quarter of an hour. Finally the camphor is separated and weighed. The oil which results after the camphor has been frozen out and filtered off, is again subjected to fractional distillation, fraction 205 to 220° is again separated and subjected to the same treat1) Report of Schimmel & Co. October 1892, 11. - See also p. 450.
2) The spectroscopic method proposed by Hartley (Journ. chem. Soc. 93 , 961; Report of Schimmel & Co. October 1908, 39) possesses theoretical interest only at present.
3) Chem. Ztg. 25 (1901), 292.
ment as before. However, pressure is applied but once and then only for twenty minutes. For the complete isolation of the camphor, five distillations are necessary. Each time fraction 205 to 220° is collected separately and treated for camphor as described above.
Production and Commerce. Up to the middle of the nineties of the past century, Japan was almost the only country that supplied the world's market with camphor and camphor oil. These articles were supplied principally by the Riukiu Islands between Formosa and Japan, also the islands Kiushiu, Tsushima and Shikoku. On the main island Honshiu (Hondo) the districts Totomi, Suruga, Idzu and Kii1) are principally concerned. When, after the Japanese-Chinese war, the Chinese island of Formosa (Taiwan) became a Japanese possession, it was one of the first endeavors of the new government to provide a systematic exploration of the rich camphor forests. In order to cover the great expenses caused by this action and in view also of the increasing demand for the product, the Government declared the production of camphor a state monopoly. This took effect in Japan proper in 1899, in Formosa in 1903. For the superintendence of the production a series of so-called camphor offices were established: for Japan proper in Nagasaki, Kobe, Kagoshima, Kumamoto, Fukuoka; for Formosa in Taipeh, Shiuchiku, Bioritsu, Taichu and Bato. The producers are compelled to deliver their entire output to the camphor offices at a fixed price. These in turn sell the crude camphor to refineries either at home or abroad. They also dispose of the oil after first having extracted the camphor. This oil is sold either crude or fractionated. Up to 1909 the English firm of Samuel, Samuel & Co. was entrusted with the sale of the products of the monoply; after that, the Japanese firm Mitsui & Co. Up to the middle of the first decade of the present century the market price of camphor had been driven up to three times its normal value by the management of the monopoly. This was the cause of the opening up of a series of new sources. First of all, the chemical industry took up the synthesis of camphor. This had been accomplished in a technically satisfactory manner and, with the high prices demanded, promised to be successful commercially. After that, other natural sources were looked for, particularly in China, where the southern provinces Fokien, Tshekiang, Kwangtung, Kwangsi, Kiangsi, Szetshwan, Hupeh and Hunan contributed fairly considerable quantities of camphor to the market. With the lowering of the world's market price, however, these sources again disappeared.