Preparation of a Novel Chromatographic Material and Its Application for Spectroscopic Characterization of Aromatics in Crude Oil

Petroleum analysis presents many unique challenges as a result of the chemical complexity of petroleum composition. In the present work a novel chromatographic material has been developed and utilized to separate crude oils. A total number of 13 fractions have been collected using different solvent mixtures with increasing proportions of chloroform. UV and IR spectroscopy has been employed to show that the size of the aromatic ring system increases and the extent of molecular branching decreases with elution gradient. This observation suggests that intermolecular non-covalent π-π interactions between the material and the sample molecules are critical to the separation. This novel method for sequencing petroleum molecules based on the size of the aromatic ring systems has been applied to the 2D off-line analysis of crude oil samples. The 2D on-line separation (NPLC × NPLC) has been simulated by 2D off-line separation. A total number of 38 fractions have been obtained with two SPE columns based on the molecular branching and the aromatic ring system size. The chemical information obtained in this study of North Sea crude oil is complementary to standard SARA analysis. The material supports a potential solution to overcome the challenges of tandem NPLC and has demonstrated a new approach to the separation of crude oils into discrete compound classes

High-resolution synchrotron terahertz investigation of the large-amplitude hydrogen bond librational band of (HCN)2

The high-resolution terahertz absorption spectrum of the large-amplitude intermolecular donor librational band ν18 of the homodimer (HCN)2 has been recorded by means of long-path static gas-phase Fourier transform spectroscopy at 207 K employing a highly brilliant electron storage ring source.</p

Catalytic base-free transfer hydrogenation of biomass derived furanic aldehydes with bioalcohols and PNP pincer complexes

The base-free transfer hydrogenation of biomass derived furanic aldehydes with ruthenium and iridium pincer complexes was studied using bio-alcohols as the hydrogen source. The furanic substrates, such as 5-hydroxymethyl furfural (HMF) and thiophene-2-carboxaldehyde (TC), were reduced under mild conditions (35-80 °C) affording the desired alcohols with excellent conversions and yields. It was also possible to extend this methodology for the transfer hydrogenation of 5-formylfurfural (DFF) at 130 °C. Deuterium labelling of C-H functions in the furanic alcohols was also investigated in the presence of ethanol-d6 . Finally, proposed catalytic resting species derived from the interactions between one of the catalysts and furanic reagent/product as well as the solvent during the transfer hydrogenation (TH) reaction were analysed

Phase equilibria modeling of Cross-Associating systems guided by a quantum chemical Multi-Conformational framework

Cross-association between molecules may result in several conformations of weakly bound molecular complexes with different association energies. However, the conventional combining rules used in equations of state account only for one conformation. Therefore, in the present work we introduce a framework that allows one to distinguish the cross-interactions between sites of different nature and to expand the number of captured conformations coexisting in the mixture. We incorporated the proposed approach into the Cubic-Plus-Association (CPA) equation of state and applied it to model the binary Vapor-Liquid Equilibrium (VLE) of aqueous mixtures with alcohols (methanol, ethanol, propan-2-ol, tert-butanol, and phenol), acetic acid, and CO2. For the mixtures with alcohols, we report the quantum chemical association energies calculated with the benchmark Domain-Based Local Pair Natural Orbital Coupled-Cluster Single, Double, and Perturbative Triple DLPNO-CCSD(T) approach and compare these values with association energies obtained by fitting to experimental data using a distinguishable interactions approach. Based on the updated results for the binary systems, we investigated how the new cross-association parameters will affect the predictions of the ternary Liquid-Liquid Equilibrium (LLE) of water–alcohol–hydrocarbon mixtures and VLE of water–acetic acid–CO2 mixtures