Isobaric molar heat capacities of dimethyl carbonate and alkane binary mixtures at high pressures

Dimethyl carbonate is a promising gasoline additive for improving combustion efficiency and reducing soot formation. Isobaric molar heat capacities of binary mixtures of dimethyl carbonate + n-alkanes (C = 6,7,8) were measured over the temperature range from (314-334) K and at pressures up to 25 MPa with a flow method, while the expanded uncertainty of isobaric molar heat capacity is less than 1.0%. The accuracy of experimental system was verified by the experimental results of the isobaric molar heat capacities of pure n-hexane, n-heptane and n-octane at different temperatures and pressures. Experiment results show that dimethyl carbonate can significantly reduce the isobaric molar heat capacity, and the decrement of isobaric molar heat capacity increases as the temperature and carbon numbers in n-alkanes increases. However, pressure has no remarkable influence on the isobaric molar heat capacity. A correlation as a function of temperature, carbon numbers in n-alkanes and the mole fraction of DMC in the mixtures was established by the multiple linear regression analysis with the average absolute relative deviation of 0.25%.

Automated summary

This study measured the isobaric molar heat capacities of binary mixtures of dimethyl carbonate and n-alkanes. The results showed that dimethyl carbonate can significantly reduce the isobaric molar heat capacity, with the decrement increasing as the temperature and carbon numbers in n-alkanes increase. Pressure had no remarkable influence on the isobaric molar heat capacity.