Liquid Organic Hydrogen Carriers: Thermophysical and Thermochemical Studies of Benzyl- and Dibenzyl-toluene Derivatives

Abstract

The heat transfer oils dibenzyltoluene and benzyltoluene are promising materials as a new class of liquid organic hydrogen carrier compounds (LOHC). Thermophysical properties (heat capacity, density, viscosity, and surface tension) of the commercially available thermofluids Marlothem LH (benzyltoluene) and Marlotherm SH (dibenzyltoluene) and their completely hydrogenated derivatives were measured. Thermochemical properties (enthalpies of combustion and enthalpies of vaporization) were derived from experiments. Gas-phase molar enthalpies of formation were derived and validated with group-additivity and high-level quantum chemical calculations. Enthalpies of the hydrogenation/dehydrogenation reactions of the LOHC pairs under study were derived.

Hydrogenation of the liquid organic hydrogen carrier compound dibenzyltoluene – reaction pathway determination by 1H NMR spectroscopy

“…[9][10][11] Dibenzyltoluene is a commercial heat transfer oil (marketed e.g. under the trade name Marlotherm SH©) with known and very favorable toxicology (non-toxic, non-mutagenic, non-carcinogenic, not labelled as hazardous goods in transportation), high thermal stability and excellent physicochemical properties for many LOHC application scenarios.…”

Hydrogenation of the Liquid Organic Hydrogen Carrier Compound Monobenzyl Toluene: Reaction Pathway and Kinetic Effects

“…A very interesting material, combining the positive aspects of toluene and dibenzyl toluene is monobenzyl toluene (MBT) . MBT is commercially available as a heat transfer oil and exhibits favorable physicochemical properties for application as a LOHC .…”

Hydrogenation Kinetics of N‐Ethylindole on a Supported Ru Catalyst

“…This makes practical applications of the LOHC material difficult because of the poor compatibility with the existing energy infrastructure. Arlt et al . proposed a new class of liquid organic hydrogen storage materials: dibenzyltoluene and benzyltoluene, both of which are liquids at room temperature.…”