The oxidation of asphalt is a major cause of pavement failure. At a given temperature and pressure, the asphalt oxidizes in two stages:  (1) a rapid-rate period followed by (2) a long period with constant oxidation rate. The degree of oxidation that occurs in the constant-oxidation region is asphalt-dependent and varies with oxygen pressure and with temperature. Using pavement-temperature oxidation kinetics obtained for eight asphalts in this study, it has been determined that the activation energies for the constant-rate region are dependent on the oxygen pressure and can be related to the asphaltene composition of the asphalt. An oxidation kinetic model is developed to predict the rate of oxidation in the constant-rate region knowing an initial asphaltene composition variable for the asphalt.

There are many methods to accelerate the aging process of asphalts to determine how susceptible the asphalt is to hardening. These tests use increased temperature, pressure, or both, and assume that the properties after the accelerated test match those if the asphalt is aged at lower temperature and pressure. However, the slope of the logarithm of viscosity versus carbonyl area, known as the hardening susceptibility, does not easily correlate from high-pressure to low-pressure aging conditions. The hardening susceptibility (HS) is a strong function of the oxygen pressure at which the test is run. HS is a function of pressure because the two terms that compose it—the asphaltene formation susceptibility, which determines how susceptible the asphalt is to the production of asphaltenes, and [Formula: see text], which determines how the asphaltenes are affecting the viscosity of the asphalt—are functions of pressure. The pressure dependency is hypothesized to be caused by oxygen diffusion on a molecular scale.

This paper reports on the performance of several ionic liquids for use in separating an olefin (1-octene) from a paraffin (n-octane). To quantify the effectiveness of an ionic liquid in a given separation, a measurement of the activity coefficients of the solutes in the solvent can be used as a guide. This measurement permits the calculation of selectivities and capacities that are important factors in judging the suitability and potential commercial viability of an ionic liquid for a separation application. Several different ionic liquids were tested and compared to a traditional, conventional solvent, N-methyl-pyrrolidone (NMP), and to each other. One ionic liquid tested, silver(I)/N,N-dimethylbenzoamide bis(trifluoromethylsulfonyl) imide [Ag(DMBA)2 +Tf2N−], showed selectivities 24−32 times higher than NMP while maintaining a comparable mass capacity as the nonionic solvent. The experimental data showed that this particular ionic liquid was also superior to any of the other ionic liquids tested in this series of experiments. This ionic liquid has the potential to be used in an economically viable commercial process to recover valuable olefinic components from streams where they are mixed with paraffins.