Thermophysical Studies of Dibenzyltoluene and Its Partially and Fully Hydrogenated Derivatives

Abstract

Liquid organic hydrogen carriers (LOHC) are an interesting and promising option for the storage and transport of hydrogen with reasonable energy density via a reversible hydrogenation reaction. The commercially available heat transfer oil dibenzyltoluene emerged as a potential carrier for the LOHC technology due to its availability, thermal stability, and reasonable hydrogen storage capacity. In this work, thermophysical property data (viscosity, density, surface tension, and refractive index) are measured for dibenzyltoluene and its partially and fully hydrogenated derivatives, namely, hexahydro-dibenzyltoluene, dodecahydro-dibenzyltoluene, and octadecahydro-dibenzyltoluene over a wide range of temperatures. Correlations for the temperature dependence are proposed for the measured properties. Moreover, the excess molar volume is reported within the temperature range from 293.15 K to 358.15 K for the binary mixtures of dibenzyltoluene (fully dehydrogenated form) and octadecahydro-dibenzyltoluene (fully hydrogenated form). Positive values for the excess molar volumes are observed over the entire concentration range.