1. A process used to make hydrocarbon fuels from coal. It was developed by German chemist Friedrich Karl Rudolph Bergius (1884–1949) as a motor fuel in the First World War. It involves heating coal mixed with tar in the presence of a catalyst at a temperature of 450°C in hydrogen at a pressure of 200 atmospheres. There have subsequently been a number of process improvements particularly with more effective catalysts.
2. The hydrolysis of cellulose with concentrated hydrochloric acid production of sugar from wood.