EICHENGRüN, ARTHUR

(b. Aachen, Germany, 13 August 1867;

d. Bad Wiessee, Germany, 23 December 1949), macromolecular chemistry, plastics industry, pharmaceutical chemistry, photochemistry.

In the late 1890s, Eichengrün discovered protargol, a very successful drug against gonorrhea, and co-discovered aspirin. He went on to develop processes for the manufacture of cellulose acetate materials and devoted the rest of his life to the technical and economic development of plastics, lacquers, enamels, and artificial fibers based on cellulose acetate. During World War I his relatively non-inflammable synthetic cellulose acetate lacquers were important in the aircraft industry. He also pioneered the influential technique of injection molding.

Arthur Eichengrün was born in Aachen, Germany, on 13 August 1867 into a Jewish family of cloth manufacturers and was educated at the Kaiser Karl Gymnasium before entering the Aachen Technische Hochschule. He completed his undergraduate studies at Berlin under A. Wilhelm Hofmann and Carl Liebermann, then returned to Aachen in 1888 to prepare a PhD thesis titled Über das Methoxy-oxy-dihydrocarbostyril, supervised by Alfred Ein-horn (for formal reasons Eichengrün obtained his PhD from the University of Erlangen in 1890, because at that time the Technische Hochschule did not yet have the right to grant the doctorate). He remained with Einhorn in Aachen to study the degradation of cocaine, then became a private assistant to Carl Graebe at the University of Geneva. In 1892 he was invited to introduce cocaine production at the firm of C. H. Boehringer Sohn of Ingelheim am Rhein. A year later, he moved to Balzer & Co. in Grünau near Berlin, but soon transferred to L. C. Marquardt of Bonn-Beuel. In 1894 he married the American Elizabeth Fechheimer, with whom he had four children. After a divorce, in 1905 he married a Dutch woman, Madeleine Mijnssen, who gave him two children. This marriage broke up in 1921, and he married Lucie Henri-ette Gartsche in 1927.

Work at Bayer . While working at L. C. Marquardt Eichengrün developed a complex of iodoform with hexa-mine as an odorless antiseptic and investigated a silver-protein complex as an alternative to silver nitrate for the topical treatment of gonorrhea. Lacking the facilities to evaluate this, he approached Theobald Floret, company physician to the Farbenfabriken vormals Friedrich Bayer & Co. of Elberfeld. This resulted in his preparation being shown to be effective, and the rights to it were then purchased by F. Bayer & Co. On 1 October 1896, Eichengrün became employed by the company with responsibility for developing new drugs. His silver-protein complex was marketed the following year as Protargol and was the drug of choice for treating gonorrhea until the 1940s. As single inventor of this successful drug, Eichengrün received 5 percent of the net profit as a royalty. This made him a relatively wealthy man, who could start his own company when he left Bayer in 1908.

Eichengrün also produced iron somatose, another protein complex, as an oral iron preparation that would not irritate the stomach wall. These early drugs were followed by several others, including the antiseptics Helmitol (hexamethylenetetramine) and Citarin (the sodium salt of methylene citric acid), the famous drug aspirin (acetylsalicylic acid), and the odorless methyl salicylate substitute Mesotan (methoxymethyl salicylate).

The work on aspirin was carried out by Felix Hoffmann, acting under Eichengrün’s direction. For many years Hoffmann was credited with the discovery of aspirin on his own on the basis of an anecdotal footnote in an encyclopedia published in Nazi Germany in 1934. As a Jew, Eichengrün was unable to challenge this in public at that time, but he did refute it in 1944 in a long letter sent from the Theriesenstadt concentration camp to the management of I. G. Farben, into which F. Bayer & Co. had been incorporated. This was a plea for help from his former employer, in which his contributions to the success of the company were laid out. The text relating to aspirin was slightly modified for publication in Die Pharmazie shortly before Eichengrün’s death during the fiftieth anniversary year of its marketing by Bayer.

Although this detailed his claim to have co-discovered aspirin, and despite the fact that Hoffmann had never claimed credit for it in print, most authorities continued to believe that Hoffmann alone discovered it because of his synthesis of it on 10 August 1897. Yet careful examination of the text of the laboratory report reveals that this was not the first aspirin synthesis in the Bayer laboratories. It was also thought that Hoffmann discovered aspirin because his name was on the U.S. patent, but this overlooks the fact that the name of another colleague, Otto Bonhoeffer, appeared on the prior German patent application. It is not without significance that shortly after the introduction of aspirin Eichengrün, in 1901, became director of pharmaceutical and photographic research, whereas Hoffmann became director of sales. Eichengrün was the first director of pharmaceutical research at Bayer.

In his new role, Eichengrün introduced a variety of products, including the rapidly acting photographic developer Edinol (the hydrochloride salt of 3-amino salicyl alcohol), the automatic room disinfectant Autan (a complex of barium hydroxide and polymerized formaldehyde), and Cellit. The latter was the outcome of work with Theodor Becker to find a substitute for the highly flammable cellulose nitrate film being used in the rapidly expanding cinematographic industry. A process they devised in 1901 for the direct acetylation of cellulose at a low temperature to prevent its degradation also permitted the degree of acetylation to be controlled, thereby avoiding total conversion to its triacetate. This enabled Eichengrün and Becker, in 1904, to introduce a reliable synthesis of Cellit, a stable, non-brittle cellulose acetate polymer that could be dissolved in acetone for further processing. Cellit was then used to manufacture non-flammable cinematographic film, which Eastman Kodak and the Pathé Fréres began to use in 1909.

Eichengrün also devised a dry spinning process in which Cellit was sprayed into a heated chamber during production of acetate rayon fiber. This was licensed to the textile manufacturer Kunstseidenfabrik Jülich, which used it to begin production of artificial silk in 1907. Difficulties with the application of dyes to the new fabric led to its abandonment until the 1920s.

Research Laboratory and Factory . Eichengrün left Bayer in 1908 and established his own research laboratory in Berlin to manufacture materials based on cellulose acetate. Within a year or two he had devised two novel products. The first was Cellon, a flame resistant plastic that served as a replacement for celluloid. During World War I it was in considerable demand for manufacture of pilots’ goggles, windshields, and gas masks. The second product was a cellulose acetate fire-resistant substitute for the rubber-based dope applied to the fabric of aircraft wings to render them water-resistant. This was also used in Zeppelin airships to additionally prevent gas leakage. These novel products were produced under license by other companies, but in 1915 Eichengrün established his own factory in Berlin, which in 1919 was renamed the Cellon-Werke Dr. Arthur Eichengrün, with almost seventy workers. This was the year in which he pioneered injection molding, utilizing cellulose acetate to form a plastic that was initially named Lonarit. Injection molding has since been used worldwide in the manufacture of modern plastics.

The Cellon-Werke prospered, but in 1933 Eichengrün had to sell part of his share in the company to Germans of Aryan descent. In 1938 the Nazis forced him to withdraw completely from his company, and as a result he sold his firm to the Chemische Fabrik Dr. Joachim Wiernik & Co. in Berlin-Waidmannslust. Due to his reputation and influential contacts, Eichengrün remained free and continued his research at home until he was imprisoned for four months in 1943 for failing to include the statutory “Israel” as part of his name in a letter to a Reich official. In May 1944, he was deported to Theriesenstadt concentration camp until its liberation by the Red Army. He returned to Berlin after the war to continue his scientific work in private.

Eichengrün received honorary doctorates from the Technical Universities of Hannover (1929) and Berlin (1947). In 1948 he moved to Bad Wiessee in Bavaria, where he died on 23 December 1949.

BIBLIOGRAPHY

WORKS BY EICHENGRÜN

“Pharmazeutisch wissenschaftliche Abteilung.” In Geschichte und Entwicklung der Farbenfabriken vormals Friedrich Bayer & Co., Vol. 2. “Böttinger Schrift”, 409–416. Elberfeld, Germany: Farbenfabriken, 1918.

“Photographische und technische Abteilung.” In Geschichte und Entwicklung der Farbenfabriken vormals Friedrich Bayer & Co., Vol. 2. “Böttinger Schrift”, 457–462. Elberfeld, Germany: Farbenfabriken, 1918.

“Acetylcellulosen (Celluloseacetate).” In Enzyklopädie der technischen Chemie, edited by Fritz Ullmann., 2nd ed., Vol. 1. Berlin: Urban & Schwarzenberg, 1928.

“Cellit (I.G.).” In Enzyklopädie der technischen Chemie, edited by Fritz Ullmann., 2nd ed., Vol. 3. Berlin: Urban & Schwarzenberg, 1929.

“Cellon-Lacke.” In Enzyklopädie der technischen Chemie, edited by Fritz Ullmann., 2nd ed., Vol. 3. Berlin: Urban & Schwarzenberg, 1929

“50 Jahre Aspirin.” Die Pharmazie 4 (1949): 582–584.

OTHER SOURCES

Bodenbender, H. G. “A. Eichengrün zum 80. Geburtstag.” Angewandte Chemie 60 (1948): A111–A112. On Eichengrün’s contributions to the plastics industry, written on the occasion of his eightieth birthday.

Sneader, Walter. “The Discovery of Aspirin: A Reappraisal.” British Medical Journal 321 (2000): 1591–1594.

Vaupel, Elisabeth. “Arthur Eichengrün—Tribute to a Forgotten Chemist, Entrepreneur, and German Jew.” Angewandte Chemie International Edition44 (2005): 3344–3355.

———. “Cellit-Lacke und Cellon-Fenster: Die Kunstoffe des Chemikers Arthur Eichengrün und ihre Bedeutung für den Zeppelinbau.” In Wissenschaftliches Jahrbuch 2006, edited by Zeppelin Museum Friedrichshafen. Friedrichshafen, Germany: Verlag Robert Gessler, 2006. On Eichengrün’s contributions to the plastics and aircraft industry.

Wimmer, Wolfgang. Wir haben fast immer was Neues: Gesundheitswesen und Innovationen der Pharma-Industrie in Deutschland, 1880–1935. Berlin: Duncker & Humblot, 1994. An overview of the German pharmaceutical industry.

Walter Sneader