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Before the first world war, Dr. Pier conducted high pressure experiments on CO-H₂ reactions in the Nernst laboratory.  Then, in 1923, he succeeded in the high pressure methanol synthesis Ludwigshafen.  A practical, quantitative conversion of water gas to methanol was obtained with the aid of catalysts at a temperature of about 400° C and pressure of, first, 1000 and then 200 atm.  Within a period of 6 months the process was applied on  an industrial scale at Leuna.  The isobutyl synthesis was also discovered at the same time.  An extensive development of synthetics, fuels, cleansers, solvents and other important products of organic chemistry followed, based on the two syntheses.

The successful high pressure hydrogenation of coal and oil to gasoline, with poison-proof catalysts, closely followed the methanol synthesis.  The basic experiment with a sulfur proof Mo-catalyst, which yielded 1 part/vol. gasoline from 1 part/vol. brown coal tar, succeeded in January 1925.  It was soon realized that the process had to be subdivided into 2 stages, the liquid and the vapor phases, in order to obtain greater catalyst effectiveness and greater thruput.

Based on small, continuous experiments, it was decided to build a larger experimental plant of 100,000 t/ann. at Leuna, which started operations in April 1927.  So many difficulties in heating and heat exchange, construction materials, etc. particularly in the liquid phase and residue processing, were encountered that in 1929 to 1932 it was decided to convert operations from direct hydrogenation of coal to the hydrogenation of tars and oils.  In 1932, however, the problem of direct hydrogenation of coal was solved by increased decomposition and consequent decreased residue processing and direct hydrogenation of coal was successfully resumed.  In 1933 the production was increased to 300,000 t/ann, which was again doubled in 1940.  This was done without building any new stalls and the originally  calculated production costs were realized.

By 1934 the hydrogenation of bituminous coal had also been developed.  In order to increase the sources of raw materials and to perfect the processing of asphalt, the 700 atm. liquid phase hydrogenation was developed.  Besides gasoline, diesel oil, lubricating oil and paraffin are produced, particularly in brown coal and brown coal tar plants, and fuel oil, particularly in plants processing bituminous coal and pitch.

In competition with the Fischer process, coal extraction, etc., hydrogenation has formed the broad basis of German motor fuel supply, in particular for practically all aviation gasoline.

The development of German aviation gasoline production generally diverged from the course followed by other countries with more abundant oil supplies.  Iso-octane is synthetically produced from CO-H₂-isobutyl oil and is also obtained from hydrogenation off-gases, just as alkyloctane.  However, most of the high grade fuels today are gasolines rich in aromatics, produced by the DHD process.

The DHD process produces products particularly rich in aromatics, from which toluol, e.g. can be obtained.  It is possible to produce considerably more toluol by bituminous coal hydrogenation than by coking.  Phenols can be obtained from the products of hydrogenation in a similar manner.

An indication of the importance of bituminous coal hydrogenation as a basis for raw materials for the chemical industry are the solid, pure aromatics are characterized by their symmetrical structure, as pyrenes, corones, carbazol and benzperylene.

With the exception of Pölitz, I.G.'s. motor fuel production is based on brown coal and its proportion of the total motor fuel production is comparatively small.  It has been repeatedly pointed out since 1933 that bituminous coal is of  greater interest to chemistry than brown coal or petroleum.  It has also been shown at Leuna that the chemical products produced from brown coal besides gasoline are steadily increasing in value.  The production coasts of processing bituminous coal at Hydrogenation Works Scholven have turned out to be very satisfactory, even without a nitrogen plant in connection with it.  The utilization by the chemical industry of the chemical by -products of bituminous coal hydrogenation is of the greatest importance today.

Change in Hydrogen Content by Liquid and
Vapor Phase Hydrogenation.

PRODUCTION OF AVIATION GASOLINE BY VARIOUS PROCESSES