674.    ---------------.  [DAZELEY, G. H., AND HALL, C. C.]  Production of Olefins by the Cracking of Fischer-Tropsch Waxes and Their Conversion Into Lubricating Oils.  Fuel, vol. 27, No. 2, 1948, pp. 50-55; Chem. Abs., vol. 42, 1948, p. 7515.

      Total waxes, boiling above 300° at 760 mm., produced at atmospheric pressure and at 10 atm. pressure by synthesis from CO and H₂ in the presence of a Co catalyst were subjected to noncatalytic, vapor-phase cracking at temperatures ranging from 500°-640° and at a throughput of 50 gm. wax per 40 ml. of cracking space/hr.  It was found that substantial amounts of a olefins of fairly high purity can be readily recovered from the cracked products.  For example, 54 gm. of material, boiling 85°-105°, gave on distillation 36 gm. of n-heptene-1.  At a given temperature, the total yield of cracked products is less than for the diesel-oil fraction (200°-300°), but the yield of liquid products is higher.  In the range C₅-C₁₂ the liquid products from wax contain about 95% of olefins, mainly of the straight-chain a type.  The yields and composition of the liquid- and gaseous-cracked products are virtually the same for both waxes.  Approximate C-number and olefin-distribution curves for the total products of cracking have been constructed.  Polymerization of the olefins with 2-3% of AlCl₃ at 80° gives greater yields of lubricating oil with a high viscosity index than are obtained from the products of cracking the diesel-oil fraction, owing to the greater production of long-chain olefins from the waxes.  All the oils obtained had B. A. M. oxidation numbers above 2.0.