1. A third process, the distillation or carbonization of coal at either a high temperature (HTC) of 700–1000° C or a low temperature (LTC) of 500–700° C produces petroleum. The process is not a synthesis but a decomposition and gives small yields of only gallons per metric ton of coal rather than barrels. It is a derived process and was never a major contributor to Germany’s liquid fuel requirements. Its simplicity, distilling the petroleum from coal, not its yield, has resulted in its use.
2. F. Sherwood Taylor, A history of industrial chemistry [1957] (New York, 1972), 428–434.
3. Anthony N. Stranges, “Friedrich Bergius and the rise of the German synthetic fuel industry,” Isis, 75 (1984), 643–667
4. Friedrich Bergius, “Transformation of coal into oil by means of hydrogen,” Industrial and engineering chemistry news edition, 4 (10 Dec 1926), 9–19;
5. Friedrich Bergius, “The career of Dr. Bergius,” Journal of the institute of fuel, 8 (Dec 1934), 74–79