Study On Liquid-Liquid Equilibriums Of Multicomponents Containing One Newly Utilized Petrol Additive

Adding anti-knocking additives as ethers,esters and alcohols etc to gasoline can not only enhance the octane rating of gasoline to prevent knocking in cylinder,but reduce the content of alkenes and aromatic hydrocarbons in gasoline which arouse environmental pollution.Dimethyl carbonate(DMC) is considered as a newly utilized anti-knocking additive in gasoline due to its virtues.However,it has to be investigated that the dissolution between gasoline and water as well as the effect of gasoline on water when DMC is added to gasoline.This paper investigated liquid-liquid equilibriums of two ternary systems and four quaternary systems at 298K and atmospheric pressure.The ternary systems are water+2-propanol+DMC,water+ DMC+octane,and the quaternary systems are water+2-propanol+DMC+ isooctane,water+2-propanol+DMC+heptane,water+2-propanol+DMC+ toluene,water+2-propanol+DMC+octane.The four quaternary systems all contain water,2-propanol and DMC,and also contain typical gasoline components,so experimental result can indicate the dissolution between gasoline and water when both DMC and 2-propanol are added to gasoline,and then the conclusion can be drawn that whether it is feasible to use both DMC and 2-propanol as anti-knocking additives.The experimental liquid-liquid equilibrium data is compared with the corresponding data from literature,and the comparison shows that:it is better to use DMC and 2-propanol as anti-knocking additives than to use DMC and methanol/ethanol;it is better to use DMC and 2-propanol as anti-knocking additives than to use MTBE/DIPE and 2-propanol considering preventing water from entering gasoline,and it is better to use MTBE/DIPE and 2-propanol as anti-knocking additives than to use DMC and 2-propanol considering the pollution of water from gasoline.The experimental liquid-liquid equilibrium data is calculated by Modified UNIQUAC model and Extended UNIQUAC model,providing important separating process data.The calculation shows that the experimental liquid-liquid equilibrium data can be correlated better by Modified UNIQUAC model than Extended UNIQUAC model.So Modified UNIQUAC model can be used to calculate liquid-liquid equilibriums of multicomponent systems in separating process.