Study on Electric Conductivity of Quaternary Ammonium Ionic Liquids

In this paper, the effects of temperature, organic solvents (benzene and toluene) and halogen salts on the electric conductivity of the four kinds of quaternary ammonium salt-type AlCl3 ionic liquids, including phenyltrimethylammonium chloride, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyltributylammonium chloride, and tetramethylammonium chloride, were studied. The experimental results showed that the conductivity of each ionic liquid system tested rises with increasing temperature. Among all the tested systems, the TMPAC-AlCl3 system shows the highest conductivity and lowest value of apparent activation energy calculated according to the Arrhenius equation of 19.29 kJ/mol. The addition of benzene (or toluene or ethylbenzene) to ionic liquids induces a considerable increase of the electric conductivity in mixed systems with a rising volume fraction of benzene (or toluene or ethylbenzene), and then when each kind of mixed system has about 50 vol % of benzene (or toluene or ethylbenzene), its electric conductivity generally reaches the highest value of 14.5 mS/cm. Among all of the alkaline halides tested, the solubility of LiCl in TMPAC-AlCl3 has the highest value, which has a maximum value of approximately 50 g L-1. At temperatures above 60 & DEG;C, the electrolyte containing 2 g LiCl has the highest conductivity of 7.45 mS/cm, when the concentration of LiCl in the electrolyte is close to saturation.

Automated summary

This paper studies the influence of temperature, organic solvents (benzene and toluene), and halogen salts on the electric conductivity of four types of quaternary ammonium salt-type AlCl3 ionic liquids. The experimental results indicate that the conductivity of each ionic liquid system increases with temperature. The addition of benzene (or toluene or ethylbenzene) to the ionic liquids leads to a significant increase in electric conductivity, reaching a maximum value of 14.5 mS/cm when the mixed system contains about 50 vol % of benzene (or toluene or ethylbenzene).