This article describes the use of Fourier transform infrared (FT-IR) spectroscopy to quantitatively measure the hydroxyl concentrations among narrow boiling shale oil cuts. Shale oil samples were from an industrial solid heat carrier retort. Reference values were measured by titration and were used to create a partial least squares regression model from FT-IR data. The model had a root mean squared error (RMSE) of 0.44 wt% OH. This method was then used to study the distribution of hydroxyl groups among more than 100 shale oil cuts, which showed that hydroxyl content increased with the average boiling point of the cut up to about 350 °C and then leveled off and decreased.

Molecular weight (MW) data for shale oils, including molecular weight distributions (MWDs) as well as average MWs, is difficult to find. A thorough literature review of MW data for shale oils from different pyrolysis processes, found scattered across a wide range of topics (or papers on various topics) and analyzed here, was carried out as part of the study. However, because the data are for oils produced under different conditions, and the exact pyrolysis conditions are sometimes not fully described, then the MW values generally are not directly comparable. Therefore, in the experimental part of the current study, average MWs and MWDs were measured for shale oils from four different oil shales (Green River in the western United States, Attarat Umm Ghudran in Jordan, Kukersite in Estonia, and Dictyonema in Estonia) obtained by retorting under identical pyrolysis conditions, using a standardized Fischer assay method. The main goal of the study, to measure the MWDs of the Fischer assay oils, was accomplished using size exclusion chromatography (SEC). The MWD data obtained was also compared to that from atmospheric solids analysis probe mass spectroscopy (ASAP MS). In addition, MWDs of industrial Kukersite shale oil from Kiviter and Galoter processes were evaluated for comparison. The MWDs of Fischer assay shale oils obtained in the current study ranged from 100 g mol–1 to 600 g mol–1. While the oils show comparable average MW values, the parameters describing the width and shape of MWDs were more dependent on the parent oil shale.

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A comparison of results of Estonian kukersite oil shale kerogen (i.e., the cross-linked macromolecular organic matter of oil shale) solvent swelling from two different methods is shown. Solvent uptakes calculated from differential scanning calorimetry (DSC) experiments are higher than those obtained by a widely used test-tube-type volumetric solvent swelling technique of fine-grained samples with swollen sample centrifugation. Solvent swelling of the kerogen sample was performed in a test tube in accordance with the common volumetric technique. Then, the swollen sample was introduced into a DSC apparatus, cooled to −120 °C, and heated at a rate of 10 °C/min. The energy of fusion of the freezable part of the solvent was used to calculate the amount of nonfreezable bound solvent that is present inside the kerogen particles and that causes swelling. The data suggest that caution should be exercised in applying the test tube volumetric method because of a possible swollen sample compaction effect.