Neil F. Woolsey

Use of acetylation and 14C-counting to quantitate hydroxyl groups in preasphaltenes and asphaltenes from coal hydrogenation

Abstract A method is described for the quantitative acetylation of coal-derived fuels primarily composed of preasphaltenes (toluene-insoluble materials) and asphaltenes (toluene-soluble, pentane-insoluble materials). The objectives of this work are to develop an acetylation procedure which renders the coal-derived material soluble in solvents suitable for nuclear magnetic resonance and infrared analysis and at the same time be quantitative in specific reactions so that hydroxyl and amine functionalities could be measured through acetylation with radio-labelled acetic anhydride. Acetylation at room temperature is thought to be able to accomplish the above objectives.

Quantitative FT 13C n.m.r. of solvent-refined coals using sym-triazine as solvent

Abstract Aromaticities (fa) determined for several solvent-refined coals (SRC) by 13C n.m.r. in sym-triazine solution and by the Brown and Ladner 1H n.m.r. technique have been found to be the same within experimental error (0.01). Use of sym-triazine to determine the fa of the soluble and insoluble fractions of a SRC in several solvents showed that the soluble fraction reflected reasonably accurately the properties of the whole sample for dioxan, carbon disulphide, chloroform and benzene extracts. The properties of the insoluble fraction varied only slightly. A more detailed analysis of the aromatic region of the 13C n.m.r. spectrum has led to some useful structural relations.

Comparison of solvent-refined lignite with solvent-refined bituminous coals

Abstract Comparison of laboratory-deashed samples of solvent-refined lignite, subbituminous and bituminous coals on the basis of gross combustion analysis, acid and basic titres, molecular weight, nuclear magnetic resonance, ultraviolet and electron spin resonance spectra including various derived parameters indicated that there is relatively little difference between the range of values for lignite- and bituminous coal-derived solvent-refined products. The probability that coal nitrogen content is reflected in the solvent-refined product was noted.

Dealkylation of N,N-dimethylaniline with sulphur and hydrogen sulphide

Abstract N , N -Dimethylaniline successively demethylates at 425 °C in the presence of hydrogen and hydrogen sulphide or sulphur to give successively N -methylaniline and aniline. For the dealkylation reaction, the rank order of promotors is S > S ue5f8 H 2 > H 2 S > H 2 S ue5f8 H 2 > H 2 .

The Role of Noncovalent Bonding in Coal

Publisher Summary The primary structure of coal is principally aromatic in nature, with about 55–90% aromatic carbon. The ring positions are mostly occupied by carbon atoms, although there are many heterocyclic rings that include sulfur, nitrogen, or oxygen atoms. Coal and coal liquids contain significant amounts of oxygen and nitrogen compounds and a high aromatic content, which suggests that hydrogen bonding is an important factor in determining the physical properties of coal. The hydrogen bonds can be either intramolecular or intermolecular. This chapter describes the measurement of hydrogen bonding in infrared (IR) spectroscopy, which is done by observing changes in the frequency, intensity, and shape of the absorption bands. Intramolecular hydrogen bonding is virtually unaffected on dilution. Thus, dilution studies offer a means of differentiating between intermolecular and intramolecular types of hydrogen bonds. Similar to IR spectroscopy, nuclear magnetic resonance spectroscopy can also be used as a diagnostic tool for hydrogen bonding. In proton magnetic resonance spectra run in a nonpolar solvent at infinite dilution, the proton resonance of the hydroxyl group in phenol is known to absorb in the range of 4–5 ppm; at higher concentrations, this signal is shifted to 6–11 ppm.

Benzophenone reduction using sulphur-based additives

Pyrite and γ-Fe2S3 are the best of the mineral promotors tried for the CO—H2O reduction of benzophenone to diphenylmethane. A mixture of ferrous sulphide and sulphur matches the promotional effect of iron pyrite, which implies that sulphur plays a role in the reaction. Both elemental sulphur and hydrogen sulphide are shown to promote CO—H2O-induced reductions.

Evaluation of solvents for carbon-13 n.m.r. analysis of solvent-refined coals. sym-Triazine a new carbon-13 n.m.r. solvent

Abstract Solvent-refined lignite (SRL) and bituminous coals (SRC) are only partially soluble in good standard carbon-13 n.m.r. solvents. A survey of other possible solvents for SRLs and SRCs showed that sym -triazine at 86 °C solvated SRL as well as pyridine, but did not absorb in the regions of interest (5–60 and 90–160 ppm relative to TMS). Model hydrocarbons, phenols and an alcohol in sym -triazine gave aromaticities ( f a ) accurate within the standard deviation (0.01 to 0.001) when proper FT carbon-13 techniques were used. An alkene and an aliphatic amine reacted with sym -triazine and gave inaccurate values of f a .

THE USE OF LIQUID SCINTILLATION COUNTING IN THE STUDIES OF COAL AND COAL DERIVED LIQUIDS

Coal and coal derived liquids were treated with radio labeled ( 14 C or 3 H) acetic acid, ethanol, methanol and water. Coal derived liquids were allowed to react with 1- 14 C-acetic anhydride in pyridine to form acetate derivatives of phenols, alcohols, primary and secondary amines. The samples were then oxidized and collected 14CO 2 or 3 H 2 O measured in a liquid scintillation counter. Good reproducibility and quantitative recovery of 14 CO 2 and 3 H 2 O were observed. The liquid scintillation counting method was very useful for quantitation of hydroxyl groups and primary and secondary amines in coal derived liquids. The amount of adsorption of acetic acid, ethanol, methanol, and water was also measured. They found it to be irreversibly adsorbed on coal. Other techniques, such as 1 H and 13 C nmr as well as titration of liberated acetic acid, are inefficient in quantitative determination of acid groups in coal. Only tracer methodology was able to determine adsorption of solvent on coal efficiently.