Thermophysical properties of the liquid organic hydrogen carrier system based on diphenylmethane with the byproducts fluorene or perhydrofluorene

Revealing the Effects of Weak Surfactants on the Dynamics of Surface Fluctuations by Surface Light Scattering

“…For the fully hydrogenated systems, the values for η L and σ obtained by SLS and the conventional techniques agree very well, i.e., typically within combined uncertainties. In contrast, the SLS results for η L and σ were often too large and too small for the dehydrogenated systems − and, in particular, for systems containing the partially hydrogenated intermediate cyclohexylphenylmethane (H6-DPM) . For the latter systems, it was observed that the largest deviations in σ of up to about −15% appeared at the lowest studied temperatures T close to 303 K and gradually vanished with increasing T up to 573 K. In contrast, the η L values evaluated from SLS agree well with the CV data at the lowest T , but tend to show increasing positive deviations at higher T with maximum deviations of +30%.…”

“…Additionally, theoretical values ω q,theo and Γ theo for pure H12-DPM or H0-DPM calculated from the “classical” dispersion relation without the presence of a monolayer , are represented as lines. Here, the corresponding results for η L and σ from the CV and PD measurements for pure H12-DPM or pure H0-DPM taken from ref are used as input parameters.…”

“…Upper part: Results for the interfacial tension σ of the H12-DPM-based systems (left) and the H0-DPM-based systems (right) obtained by SLS and PD method as a function of T . Lower part: Relative deviations of σ values from the T -dependent fits of PD data, σ calc,PD , for pure H12-DPM (left) and pure H0-DPM (right) taken from ref . Black circles, pure substance measured by PD method (filled symbols) and SLS (open symbols); orange diamonds, mixture with H6-DPM at x H6‑DPM = 0.01 from PD method (filled symbols) and SLS (open symbols); green triangles, H0-DPM with H6-DPM at x H6‑DPM = 0.001 from SLS.…”

“…For the investigation of the mixtures of H0-DPM or H12-DPM with H6-DPM between (303 and 473) K by SLS, CV, and the PD method, the same experimental setups as used in ref have been employed. The SLS measurements were performed under an Ar atmosphere close to 0.1 MPa inside a closed stainless-steel cell with T control via resistance heating, achieving stabilities better than ±11 mK up to 473 K. The scattered light detected in transmission direction perpendicularly to the vapor–liquid interface was superimposed with much stronger frequency-unshifted reference light in order to achieve a heterodyne detection scheme.…”

“…One class of fluids, for which such as a layer effect might not be expected at first glance, are liquid organic hydrogen carriers (LOHCs), which are currently being discussed as working fluids for the safe transport and storage of hydrogen (H 2 ). − Previous studies on the hydrocarbon-based LOHC systems relying on the dehydrogenated diphenylmethane (H0-DPM) and its hydrogenated analog dicyclohexylmethane (H12-DPM) , as well as related mixtures with process-relevant byproducts , have partly shown discrepancies in the measurement results from SLS and conventional techniques, i.e., the pendant-drop (PD) method and capillary viscometry (CV). For the fully hydrogenated systems, the values for η L and σ obtained by SLS and the conventional techniques agree very well, i.e., typically within combined uncertainties.…”