The Integration of the German Oil, Chemical, Rubber and Explosives Industries

The Germans waged World War II with oil, chemicals, rubber, and explosives made largely from coal, air, and water. They had searched their country thoroughly and found very little petroleum. They had imported it before the war, and they conquered important fields and captured sizable stocks during the war, but they still had to use substitutes for crude oil. Less than 15 percent of their aviation fuel and only of fourth of all their oil products made early in 1944 came from crude oil. The rest came from coal as did also nearly all of Germany's rubber, explosives and other war chemicals (Figure 10). Like oil, coal contains carbon and hydrogen. With the hydrogen derived from coal and water, nitrogen can be taken from the air and "fixed" in the form of ammonia for use in either fertilizer or explosives. Methanol (synthetic wood alcohol), the raw material for many explosives and chemicals, can be synthesized with two gases, hydrogen and carbon monoxide, both of which are obtainable from coal. Synthetic fuels be made in two ways. In the Bergius process, the complex molecules of coal are split, and hydrogen is forced into them to convert them into liquid oil molecules. In the Fischer-Tropsch process, molecules of hydrogen and carbon monoxide, obtained by breaking up molecules of coal with steam, are used to build oil molecules. The Germans employed these processes to manufacture the fuel for their war planes, submarines, and mechanized ground forces.

Germany's chemical industry was well developed long before the war. Its plants, naturally, were built in or near areas where the coal was available. One such area was in middle Germany, centering on the I.G. Farbenindustrie A.G. nitrogen and methanol plants there, at Leuna; another such area was the Ruhr, where Ruhrchemie and Victor also had nitrogen plants at Holten and Castrop-Rauxel; there was also another I.G. Farben nitrogen plant on the Rhine near Ludwigshafen and Oppau to which coal from the Ruhr could be brought by barges.

The synthetic oil industry of Germany literally grew out of this chemical industry. I.G. Farben bought the Bergius patent rights and in 1927 built at Leuna the first commercial hydrogenation plant to produce synthetic gasoline. This was a logical development because the Leuna nitrogen plant could produce more hydrogen than was needed to manufacture ammonia. The high-pressure apparatus and the experience needed to employ the Bergius process were also available at Leuna. Ruhrchemie obtained the patent rights to the Fischer-Tropsch process and built the first commercial plant of this type in its nitrogen works at Holten; other concerns in the Ruhr also favored the Fischer-Tropsch process because of the abundance of coke and coke-oven gases available there. During the war, chemical and oil plants were also established in Silesia where coal was available.

The quest for self-sufficiency prompted the Germans to develop synthetic rubber as well as synthetic fuel. The process that was developed made use of materials obtained from coal; the manufacture of synthetic rubber therefore depended on the synthetic chemical and oil plants. So I.G. Farben began producing rubber near Leuna, in another new plant in the Ruhr, and in a third at Ludwigshafen.

The oil, chemical, rubber, explosives, and other industries, in short, were interlocked not only by their mutual dependence on coal but also historically, geographically, and mechanically. They were so closely and intricately woven together, in fact, that they were needlessly vulnerable to strategic bombing - but Hitler did not complain until too late.

Synthetic Oil

The bulk of Germany's synthetic oil was made in Bergius hydrogenation plants. These used coal or coal tars and high-pressure hydrogen. The hydrogen was made from coke in water-gas generators, purified thoroughly, and used under pressures of from 3,000 to 10,000 lb per square inch. Huge, heavy compressors and reactors were needed. Aviation gasoline, motor fuels, and diesel fuels were made in this way. Germany needed so many things, however, that materials from these hydrogenation plants were soon being used to manufacture many additional products. Gases from the reactors were used as motor fuel and for the manufacture of high-octane aviation blending agents such as iso-octane and alkylate. Even synthetic aviation lubricants and important chemicals were made from these gases. Hydrogenation plant gases also were fed to nearby synthetic rubber plants.

In the Fischer-Tropsch process, gases are handled under less pressure, but complicated apparatus is required for the actual synthesis of the oil. This apparatus could not be used to produce aviation gasoline, but the products of Fischer-Tropsch synthesis had special properties for which many chemical uses were found during the war.

Chemicals

Of the thousands of products of the chemical industry, nitrogen, methanol, and calcium carbide were among the most important in the German war effort. Ammonia and methanol were produced with equipment similar to that used in synthesizing oils. Calcium carbide was manufactured from lime and coke in electric furnaces.

In addition to using ammonia and methanol to make explosives, and calcium carbide to make rubber, the Germans made an aviation blending agent (iso-octane) from methanol via isobutanol. This was apparently intended to disassociate iso-octane production from oil, but one plant was placed in the Ludwigshafen works and others were placed in new oil-chemical complexes in Silesia, where the Luftwaffe was confident they could not be attacked successfully.

Synthetic Rubber

The main materials used to make synthetic rubber are butadiene and styrene. The butadiene was obtained from acetylene, which was made mainly from calcium carbide produced by the chemical industry, except in one case where it was derived from oil plant hydrogenation gases. The styrene was made from ethylene and coking plant benzene. The largest synthetic rubber plant in Germany, at Schkopau, depended, moreover, on the Leuna synthetic oil and chemical plant for hydrogen. The rubber industry thus leaned on the oil and chemical industries. But it bolstered them by contributing an aviation gasoline blending agent - diethyl benzene, which similar to cumene - and aviation lubricants to the supplies for the Luftwaffe.

Explosives and Propellants

Nitric acid, which is made from ammonia, used in all military explosives and propellants. Production of these necessities of consequently, depended on the production of ammonia. For the new explosives, hexogen and nitro-panta, produced in Germany during the war, methanol also was required. TNT, the mainstay of the explosives industry, is made from toluene; all of which came from the Ruhr coking industry until 1940. Additional tolulene then was synthesized from methanol and benzol. Toward the end of the war, more production of toluene was planned by the employment of processes used in synthetic oil production. Ruhrchemie was also building a plant to make tolulene from normal heptane derived from the Fischer-Tropsch process. A shortage of natural glycerine, meanwhile, forced Germany to develop a substitute, diethylene glycol, which was made by series of reactions starting with acetylene, a product of the carbide industry. Germany's production of explosives and propellants was thus enmeshed with the chemical and oil industries when the war began and became more so as war continued.

Table 1 illustrates the concentration of operations. Destruction of these six industrial complexes, not only would have been a serious blow to Germany's production of synthetic liquid fuels, but also would have crippled production of chemicals, explosives, and rubber. The importance of the Leuna and Ludwigshafen plants was further augmented by the great number of additional chemical products that they turned out. These two plants, for instance, produced 76 percent of the country's ethyl chloride for tetraethyl lead.

Table 1

Examples of Integration of German Industries

* If Auschwitz had been complete and had operated at capacity, it would have contributed about 19 percent of the total.

# These figures are subject to considerable variation due to flexibility in shifting distribution of hydrogenation.

Basis taken in 1 May 1943 to I May 1944 for Leuna and Oppau. Blechhammer is on basis of April, 1944, figures only.

There were many bottlenecks, in fact, in this complicated industrial structure. Three plants produced 94 percent of Germany's synthetic rubber. Two plants produced four fifths of the cyanide used to make airplane Plexiglas. One plant made four fifths of the bydrazine hydrate used as a rocket and V-weapon propellant. And one plant made virtually all of the elemental phosphorus needed for tracer bullets and chemical warfare.

I.G. Farben at Leuna was engaged also in the production of heavy water for Germany's atomic bomb in a plant of 2 to 3 tons per year planned capacity (actually they made slightly less 1 ton than per year). The building housing this plant was reported by the Germans to have been knocked out in the first raid on Leuna on 12 May 1944, which possibly may have contributed to the delay in the German development of atomic power.

The oil, chemical, rubber, and explosives industries had been planned as a single unit, coordinated under government and military control, and harnessed to the Nazi war plans (Figure 11). The strategic bombing of the oil plants made the vulnerability of this structure so obvious that Hitler personally and publicly rebuked Dr. Krauch, his general plenipotentiary for chemical planning. Krauch contended that he had built large plants to conserve steel and make the maximum use of gas-producing facilities, utilities, etc. The misplaced confidence of the Germans in the Luftwaffe's ability to protect them from aerial attacks, however, underlay the whole plan by which they sought to free themselves from dependence on other countries for war supplies. Long after industrial leaders saw the danger of such integration and concentration of production facilities, the Luftwaffe continued to promise them complete protection.

Figure 12 shows the rise and fall of the German chemical empire as reflected in production of aviation gasoline, synthetic nitrogen, synthetic methanol, and nitrogen supplied to the Army for munitions. Production in the first four months of 1944 was taken as normal, or 100, in preparing this chart. The simplicity of the curve is striking. Aviation gasoline declined first, but decline of the others followed quickly. The first two months of strategic bombing undid the results of three years’ strenuous work by the Germans.

Forward to the Strategic Air Attack on the German Oil Industry.

Return to the Table of Contents of the United States Strategic Bombing Survey.