Study On Multicomponent Liquid-Liquid Equilibrium Properties Of Oxygenates As Gasoline Additives

With the rapid development of the auto industry, vehicle exhaust pollution has exceededindustrial pollution. In order to improve the combustion properties of gasoline, the gasolineadditive research has attracted wide interest in recent years. Due to the leakage of MTBE willpollute the groundwater, Motor gasohol is being rapidly expanded, to its further applicationbrought resistance because gasohol need for strict measures of waterproof. And dimethylcarbonate (DMC) is an excellent solvent, and its high-octane number, higher quantituy ofoxygen content, lower Reid pressure and low price, It has been considered a good alernative toMTBE as a oxygenated additive.This paper studied multicomponent liquid-liquid equilibrium (LLE) properties of DMCor MTBE and alcohol, Gas chromatograph technique has been applied to determine LLE datafor four ternary systems and four quaternary systems composed of MTBE or DMC, Thismethod is simple, fast satisfied repetition, and the accuracy of measurements was estimatedwithin±0.001 in mole fraction. The LLE data for the four ternary mixtures of the water+methanol+DMC, water+ethanol+DMC and the water+DMC+toluene, water+MTBE+benzene systems, and the four quaternary mixtures of the water+methanol+DMC+toluene,water+ethanol+DMC+toluene, water+2-propanol+MTBE+isooctane, water+methanol+MTBE+benzene systems have been investigated at 298.15 K and atmospheric pressure.Analyzing these LLE data, the main conclusions are as following: Blended the dimethycarbonate into gasoline show that the competence of intersolubility is excel MTBE. DMC havea good character of cosolvent, as a result, in a petrol transportation and storage process, thepetrol is not susceptible to water and achieve the aim of prevent phase separation. In particular,to the prevention of phase separation in gasohol because of water infiltration and stratification,which have a profound significance. Meanwhile dimethyl carbonate is a green reagents, low intoxicity and quickly biodegradable. In other word, DMC won't cause potential conditionpollution of clean gasoline, thus the added performances of DMC are better than that of MTBE.DMC could be considered as a suitable alternative gasoline additive to MTBE, it will havegood value in use in the future.Further, the calculated results obtained from the Modified UNIQUAC model arecompared with those obtained from the Extended UNIQUAC model to verify the accuracy ofthe experimental data. The experimental ternary and quaternary LLE data have beensatisfactorily correlated by using a Modified UNIQUAC model, The correlated results given bythe Modified UNIQUAC model are in good agreement with the experiment result for all thesystems investigated here.