(2) Technical.—Various grades containing from 80 to 95 percent phenol, of which the two most important are 82-84 percent and 90-92 percent. (3) Mixtures.—Containing from 30 percent to 80 percent phenol and the remainder of the isomeric cresols. _Producers._—Natural phenol is obtained in the distillation of coal tar and to a smaller extent in the purification of ammonia liquors in coke and gas plants. In 1937 there were four producers of natural phenol with plants located at Philadelphia, Pa., Follansbee, W. Va., Indianapolis, Ind., and Pittsburgh, Pa. All these are tar distillers recovering creosote oil, pitch, cresylic acid, naphthalene, and other crudes from coal tar. Synthetic phenol is made from benzene, either by sulfonation followed by alkaline fusion, or by chlorination and subsequent heating under pressure with caustic soda. It is produced in large quantities by two firms, one at Midland, Mich., and the other at St. Louis, Mo. A third producer is building a plant at North Tonawanda, N. Y., using a process recently developed in Germany. Operation of this unit will probably start late in 1938. World production. Natural phenol is recovered in practically all European countries and in Japan. Germany and the United Kingdom are the principal producers and have also been the leading exporters. Synthetic phenol was made in Germany as early as 1900, and during the World War. Plants for synthetic phenol recently installed are now in operation in Germany, Great Britain, Belgium, and Italy. Table 60 shows the average annual world production of phenol in recent years by countries. Half of the total was produced in the United States. TABLE 60.—_Phenol: Estimated average annual production, by countries, 1933-35_ --------------+----------------- | Estimated Produced in— |annual production --------------+----------------- | _1,000 pounds_ UNITED STATES | 41,000 United Kingdom| 18,000 Germany | 10,000 Poland | 3,000 Japan | 3,000 Czechoslovakia| 1,000 Belgium | 2,000 France | 2,000 Italy | 1,500 Spain | 700 +----------------- Total | 82,200 --------------+----------------- Source: Consular reports.