671.    DAZELEY, G. H., AND GALL, D.  Lubricating Oils From Fischer-Tropsch Olefins Using Water Gas as Raw Material.  Petroleum (London), vol. 9, 1946, pp. 208-210; Chem. Abs., vol. 41, 1947, p. 2562.

      Products obtained by the Fischer-Tropsch process using water gas (CO:H₂=1:1) have a considerably higher olefin content than products of similar boiling range obtained from synthesis gas (CO:H₂=1:2) and are therefore more promising raw materials for polymerization to lubricating oils.  The aim of this investigation was to examine the effects of chain length of olefins and of reaction temperature on the properties of the resulting lubricating oils and on the yields obtained.  For a given chain length of olefins, the absolute viscosity of the lubricating oil decreases with increase of reaction temperature, but the V.I. remains approximately constant.  Under given temperature conditions, the absolute viscosity of the oil decreases with increase in the chain length of the hydrocarbons in the starting material.  The V.I. of all oils prepared from a higher-boiling fraction of gasoline are greater than those of oils from a lower-boiling fraction.  The yield of oil calculated on the weight of starting material is less for the higher-boiling gasolines.  Calculated on the weight of olefins present, the yield appears to increase with increase in chain length of the hydrocarbons.  A marked decrease in yield occurs where a high reaction temperature is employed, but otherwise the effect of reaction temperature on yield is not significant.  Reaction temperature and chain length have very little effect on stability to oxidation.  The oils are superior in general properties to those obtained from synthesis gas.  The V.I. is higher and the oxidation numbers are lower (2.4-2.9, but still too high to comply with Government specification, which requires one below 2).  If oils of moderate viscosity and good viscosity-temperature properties are required, it would seem that the most suitable ones are obtained by polymerizing the olefins in the fraction of water-gas gasoline boiling 140°-200°, although the yield is somewhat less than with lower-boiling fractions.