Infrared Characterization of Coal-Derived Asphaltenes and Their Acidic and Basic Components

Consequences of the Mass Spectrometric and Infrared Analysis of Oils and Asphaltenes for the Chemistry of Coal Liquefaction

“…Samples were introduced into the ion sources of both mass spectrometers via all-glass inlet systems at temperatures of 300°-320° C. Data Analysis. Infrared spectra, reproduced in Reference 35, were qualita tively interpreted using compilations of vibrational frequencies for functional groups in organic substances (30,(38)(39)(40)(41)(42)(43). Calculation of functional-group concentrations using average extinction coefficients and average molecular weights (30,39,40,41) was not attempted.…”

Molecular and Colloidal Structure of Coal Asphaltenes and Other Heavy Solvent Soluble Components

“…The concentrated carbon disufide solution of an acid/neutral component of asphaltene shows a broad IR band at 3250 cm· 1 which is attributed to intermolecular hydrogen bonds between molecules of the acid/neutral component. 49 Near-IR and IH-NMR studies of hydrogen bonding between the hydroxyl group of o-phenylphenol (OPP) with asphaltenes and their acidic and basic components show that the IR band of the free OH group ofOPP at 1.44 Ilm (6944 em-I) is reduced rectilinearly when the basic component is added to its CS 2 solution, while no acidic component caused a decrease in the 1.44 Ilm absorbance, indicating the hydrogen bonding of the basic component with the OH of OPP.50 OPP was selected because their self-association is sterically hindered. 51 Interactions of model compounds, Le., OPP and pyridine, with asphaltene acid and base fractions were also studied using NMR.51 Molar enthalpy of the interaction of pentane soluble oil with asphaltene (A) and its acidic/neutral (AA) and basic (BA) components is in the order BA> A> AA, and correlates well with the IH-NMR downfield chemical shift of the OH signal of OPP as a function of added asphaltene (A, AA, BA) concentration in carbon disufide solvent.…”

The Role of Noncovalent Bonding in Coal

“…Other studies have also been reported (Brown et al, 1977;Bockrath et al, 1978a) on hydrogen bonding using IR characterization of coal-derived asphaltenes and their extractable acidic and basic components. Figure 3 shows the spectrum of the asphaltene in dilute CS 2 .…”

“…The amount of hydrogen bonding can be measured directly by infrared and proton magnetic resonance (PMR) spectroscopy, viscosity, and solubility measurements before and after derivatization of hydrogen-bonded groups (Friedel and Queiser, 1956;Friedel, 1963;Ignasiak et al, 1977a-c;Brown et al, 1977;Bockrath et al, 1978a,b;Sternberg et al, 1975a,b;Gould, 1979;Patel etal, 1980b;Thomas and Li, 1978;Schiller et al, 1977). The amount of hydrogen bonding can be measured directly by infrared and proton magnetic resonance (PMR) spectroscopy, viscosity, and solubility measurements before and after derivatization of hydrogen-bonded groups (Friedel and Queiser, 1956;Friedel, 1963;Ignasiak et al, 1977a-c;Brown et al, 1977;Bockrath et al, 1978a,b;Sternberg et al, 1975a,b;Gould, 1979;Patel etal, 1980b;Thomas and Li, 1978;Schiller et al, 1977).…”

“…Some of the most informative conclusions on IR studies come from the fractionation of asphaltenes into acid-neutral and base fractions (Brown et al, 1977). The acid-neutral fraction IR spectra are given in Fig.…”