1770. KINGMAN, F. E. T., AND CAWLEY, C. M. Cracking of Middle Oil From the Fischer-Tropsch Process. Petroleum (London), vol. 9, 1946, pp. 126-128; Chem. Abs., vol. 40, 1946, p. 5903.

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Literature Abstracts

Experiments were carried out on the thermal cracking of the middle oil fraction, boiling at 200°-300°, from Fischer-Tropsch product, using a vertical, electrically heated, Pyrex tube with a 35-ml. reaction space. The cracking temperature varied from 570°-635°, the throughput from 40-110 gm. per hr., and the reaction time from 30-10 sec. At 635° and a throughput of 90 gm. per hr., the total yield of liquid product was 67.6 wt. % of the original oil, with a yield of gasoline to 200° of 20.4%. Recycling the oil boiling above 200° gave a total yield of 37.8% of gasoline to 200°, Br No. 130, and a yield of gas of 39.3 l. per 100 gm. of raw material. The gasoline to 170° had a Br number of 148, and contained approximately 80-90% olefins with less than 2% aromatics. The gaseous product from thermal cracking contained only a small proportion of H₂; the olefins, which increased from 57% at 570° to 63% at 635°, consisted mainly of C₂H₄ and C₂H₆ with a smaller proportion of C₄H₈ and a very small amount of butadiene. With a catalyst of mixed alumina and silica, the yield of gas increased and the nature of the products was noticeably affected. The gasoline had a lower olefin content and a higher content of both aromatic and saturated hydrocarbons. The gas contained a greater proportion of H₂; the proportion of total olefins was not greatly changed, but the catalyst favored the production of C₃H₆ and C₄H₈ in place of C₂H₄, and the formation of butadiene was completely suppressed.