Germany's Effort to Obtain Nitrogenous Compounds

Abstract

ALTHOUGH elementary nitrogen is not only useless, but positively antagonistic, to the life of plants and animals (except to that of some bacteria which take free nitrogen from the atmosphere and convey it to theroots of leguminous plants), combined nitrogen is absolutely necessary for their metabolism. Animals obtain nitrogen from the vegetables they consume, plants from the nitrogenous constituents of the soil. The soil obtains part of its combined nitrogen from decaying vegetable matter and from the waste products of animals; the remainder has to be added. The two chief forms in which it is added are sodium nitrate and ammonium sulphate, which to a large extent are interchangeable. But for the manufacture of explosives sodium nitrate is absolutely necessary and ammonium sulphate useless. Germany, fore seeing that its supply of Chilean nitrate would be cut off by the blockade of the British Fleet, was faced with irremediable disaster unless it could lay in a sufficient stock before declaring war, or devise methods of synthesising nitric manner in which this difficulty has been overcome is described by Prof. Camille Matignon in the Revuegnrale des Sciences (January 15 and 30). Before the war Germany was the greatest consumer of corn- bined nitrogen. In 1913 the consumption amounted to 750,000 tons of Chilean nitrate, 35,000 tons of Nor-wegian nitrate, 46,000 tons of ammonium sulphate, and 30,000 tons of cyanamide. In 1913 great efforts were devoted in Germany to the preparation of mate- rials necessary for war, and no attempt was made to conceal them. The German Ammonium Sulphate Syndicate had a reserve of 43,000 tons, and on the declaration of war there was probably a stock of 100,000 tons of Chilean nitrate. Immediately after the battle of the Marne, when a long war was evidently certain, the production of artificial nitrates and of ammonium sulphate was stimulated, the Badische Aniline Company and Bayer and Co. being subsidised t the extent of 30,000,000 marks for the installation of factories to convert ammonia into nitric acid. In peace time 550,000 tons of ammonium sulphate were produced annually in Germany, but this output was reduced once war was declared. As this substance is a by-product in the manufacture of gas and cast-iron, people in Germany were instigated to use gas and coke instead of coal, and by such means an annual output of 250,000 tons of ammonium sulphate was attained. The problem of converting the ammonia into nitric acid was solved by the Frank. and Caro and the Kayser processes. A. French chemist, Kuhlmann, had discovered that ammonia is oxidised to nitrogen peroxide when mixed with air and passed over warm, finely divided platinum. The reaction was employed on a commercial scale by Ost- wald, and improved both by Kayser and by Frank and Caro. By the end of iei5 the Anhaltische Maschinenbau Society of Berlin had established thirty installations for the conversion by Frank and Caro's process, and these had a capacity of more than 100,000 tons of nitric acid per month. But this was only one of the methods adopted. Given a cheap- source of electrical energy, it was known to be cornmercially practicable to prepare nitric acid by the direct oxidation of nitrogen in the electric flame, ancb this process had been established in Norway by Birkeland and Eyde, who used the waterfalls as a source of energy. The Germans have established a factory employing Pauling's process (a modification of that of Birkeland and Eyde) at Muhlenstein, in Saxony, in the neighbourhood of the. lignite beds, which form the source of energy, and this has an annual output of 6ooo tons of nitric acid.