UTAH ACADEMY OF SCIENCES 215 
dioxide, the saturated hydrocarbons remaining unattacked 
and forming an upper layer of immiscible oil. Dr. Rittman 
very carefully and specifically pointed out that the separa- 
tion must be made at a temperature not higher than 20 
degrees centigrade, and that if the oil contained in ex- 
cess of 25 per cent of benzene derivatives and unsaturated 
compounds the addition of liquid sulphur dioxide would 
not cause a separation into two layers. In that case it is 
necessary to add enough of an inert paraffin oil to reduce 
the content of unsaturated and benzene hydrocarbons to 
less than 25 per cent. 
In attempting to make use of Dr. Rittman’s method 
in our own work on oils and tars we quickly found that we 
were able to get satisfactory separation into two layers, 
even when 60 per cent or 80 per cent of the oil dissolved 
in the sulphur dioxide. We also found that in some 
cases repeated washing with the sulphur dioxide would 
completely dissolve the sample of oil. This suggested the 
possibility that the saturated hydrocarbons are not so in+ 
soluble in the liquid sulphur dioxide as Dr. Rittman had as- 
sumed. In following up this point we found that every 
sample of petroleum oil we could get hold of was soluble in 
the sulphur dioxide, the solubility running sometimes as 
high as 10 per cent of the weight of oil taken, and using 
an equal volume of the solvent. The oils tested included 
gasolines, kerosenes, hexane and heptane, and specially 
prepared distillates of definite boiling point range. We 
also found that as the percent of benzene derivatives in- 
creased the amount of the added diluent recovered diminish- 
ed. The maximum recovery of added diluent (gasoline or 
kerosene) is had when the amount of benzene derivatives 
does not exceed 30 per cent, but a quantitative recovery 
cannot be had in any case, due to the solubility of the added 
diluent (gasoline or kerosene) in the sulphur dioxide. This 
introduces an error into the method which it would seem 
almost impossible to overcome. 
