Effect of the Chemical Composition on Excess Volume of Mixtures with Petroleum Fractions.

 Blending of oil stocks with hydrocarbons form non-ideal mixtures, for which excess volumes can be positive or negative depending to the nature of species.Gas oil mixed with nine petroleum fractions or individual hydrocarbons consisting of aromatics, and paraffinic nature in addition to an alcohol and a ketone. The systems  have been subjected to density measurements at two temperatures. The results are reported in terms of excess volume, VE . Binary mixtures of gas oil with the paraffinic spikes, light naphtha heavy naphtha, kerosene and nhexadecane produce negative excess volume values.This
shrinkage effect is greatest for the lowest boiling spike.Nhexadecane results for in very small negative excess volume and seem to form nearly ideal volumes with gas oil.The spiking of gas oil with, toluene, xylene,MEKor reduced crude show positive excess volume, indicating that such spikes are effected as "structure breaking"materials leading to expansion. The spiked gas oil with iso-octanol shows an expansion. The excess volume values increases as the mass fraction of iso-octanol increased.Methyl ethyl ketone is used usually as solvent for dewaxing of lube oil base stocks. Its binary mixtures with
some base oil stocks of different boiling range show positive excess volume. This expansion is greatest for lowest boiling stock. Excess specific volume of ternary mixtures was studied for spiked gas oil using different nature of spices.For all spiked gas oil ternary system used in this study, the excess volumes seems to be as a result for the corresponding excess volumes of the binary mixtures.