In September 1916, Gibbs and Conover, working in the Color Laboratory of the Bureau of Chemistry and Soils, United States Department of Agriculture, developed a process for the synthesis of phthalic anhydride by the direct vapor phase catalytic oxidation of naphthalene. This work was done under the United States Government’s wartime investigation of the manufacture of intermediates and dyes. Gibbs and Conover were granted United States Patent No. 1,285,117 covering the basic process, and the invention was assigned to the people of the United States. This process revolutionized the manufacture of phthalic anhydride, causing the market price to drop to $2.85 per pound in 1918, to 46 cents per pound in 1920, and to 13 cents in 1930. With each decline in price new outlets were found, and domestic production increased practically every year, rising from 227,000 pounds in 1918 to 23,500,000 pounds in 1935.
By a remarkable coincidence the same basic process was developed in Germany, by Alfred Wohl, in the laboratories of the Interessen Gemeinschaft Industrie A. G. (German I. G.), at almost the same time that Gibbs and Conover made their discovery. In 1920 Wohl applied for a United States patent covering this process, claiming invention in the summer of 1916. There was some doubt whether his discovery had been made 2 months earlier or 3 days later than that of Gibbs and Conover, but in July 1934 the United States Court of Customs and Patent Appeals rendered a decision in favor of the German inventor, allowing Wohl’s claim filed with the German patent office on June 28, 1916. Therefore, Wohl’s claim covering the air oxidization process was upheld and he was granted United States Patent No. 1,971,888, issued August 28, 1934 and assigned to the German I. G.
Several domestic firms began commercial production of phthalic anhydride about 1918 under the patent of Gibbs and Conover and have since operated the process continuously. Such manufacturers are presumably protected from possible patent litigation and the payment of royalties under the Wohl patent by section 3 of the so-called Nolan Act of 1921, which states: “No patent granted or validated ... shall affect the right of any citizen of the United States or his successor in business to continue the manufacture, use, or sale commenced before the passage of this Act, nor shall the continued manufacture, use, or sale by such citizen ... constitute an infringement.”
United States production.
Table [47] shows the production and sales of phthalic anhydride from 1917 through 1937.
Table 47.—Phthalic anhydride: United States production and sales, 1917-37
| Year | Production | Sales | Unit value | |
|---|---|---|---|---|
| Quantity | Value | |||
| Pounds | Pounds | |||
| 1917 | 138,857 | 138,857 | $587,240 | $4.23 |
| 1918 | 227,414 | 227,414 | 648,650 | 2.85 |
| 1919 | 290,677 | 290,677 | 290,037 | .99 |
| 1920 | 796,210 | 796,210 | 362,431 | .46 |
| 1921 | 202,471 | 202,471 | 79,162 | .39 |
| 1922 | 1,629,182 | 1,317,625 | 461,944 | .35 |
| 1923 | 2,343,802 | 2,091,100 | 596,508 | .29 |
| 1924 | 2,787,308 | 2,277,073 | 556,265 | .24 |
| 1925 | 3,900,332 | 3,560,429 | 701,840 | .20 |
| 1926 | 4,379,108 | 3,446,175 | 604,949 | .18 |
| 1927 | 4,549,820 | 4,064,476 | 686,946 | .17 |
| 1928 | 6,030,854 | 5,445,432 | 888,156 | .16 |
| 1929 | 9,168,946 | 7,450,037 | 1,147,953 | .15 |
| 1930 | 6,693,001 | 5,614,012 | 724,909 | .13 |
| 1931 | (1) | |||
| 1932 | 6,259,000 | 5,695,000 | 663,000 | .12 |
| 1933 | 14,075,844 | 11,593,716 | 1,271,887 | .11 |
| 1934 | 20,680,379 | 13,511,253 | 1,575,787 | .12 |
| 1935 | 23,421,558 | 17,931,662 | 2,105,134 | .12 |
| 1936 | 31,244,378 | 22,905,873 | 2,824,471 | .12 |
| 1937 | 45,210,784 | 17,565,905 | 2,492,473 | .14 |
1 Not available.
Source: Compiled from annual reports of the Tariff Commission on dyes and other synthetic organic chemicals in the United States.
There are six domestic makers of phthalic anhydride, with producing units at Bridgeville, Pa., Buffalo, N. Y., Philadelphia, Pa., Deepwater Point, N. J., Saint Louis, Mo., and Detroit, Mich. Five of these firms have been producing in commercial quantities continuously for a number of years and it is therefore believed that these companies may continue to produce without the payment of royalties. New producers using this process, however, might be at a disadvantage unless licensed to operate without the payment of royalties by the owner of the patent.