Richard J. Baltisberger

A study of the disproportionation of mercury(I) induced by gas sparging in acidic aqueous solutions for cold-vapor atomic absorption spectrometry

Abstract Instrumentation and procedures for the cold-vapor atomic absorption determination of mercury have been modified. Samples are analyzed by syringe injection under reducing and non-reducing conditions so as to allow mercury valence state differentiation. It is shown that chloride ion is effective in preventing mercury(I) disproportionation; in the absence of a strong mercury(II) complexing ligand, mercury(I) readily disproportionates when solutions are sparged with nitrogen. The data are consistent with the formation at the 10–500 ppb level of a Hg2Cl2 precipitate with a lower solubility product than the literature values.

The differentiation of submicrogram amounts of inorganic and organomercury in water by flameless atomic absorption spectrometry.

Abstract A method for the determination of the individual concentrations of mercury(II) and RHg(II) in aqueous solutions is described. The mercury metal produced by reduction with tin(II) is measured by flameless atomic absorption. Selective reduction of mercury(II) is achieved in the presence of RHg(II) in sulfuric acid media with tin(II). The total mercury content is then measured after oxidation with acidic hydrogen peroxide solution just before injection into the tin(II) solution of the mercury analyzer. The method is useful in the range 1–15 p.p.b. with a standard deviation of 1 p.p.b. at 15 p.p.b. The method was satisfactory for river water samples.

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  H 2 > H 2 S > H 2 S  H 2 > H 2 .

Catalytic activities and selectivities of MoO3NiSO4 supported on various oxides for hydrocracking of solvent refined lignite: Novel low surface area active catalysts

The hydrocracking of solvent refined lignite (SRL) was studied over MoO3NiSO4 catalysts supported on TiO2 ZrO2, TiO2SiO2 and three kinds of aluminas at 450°C under an initial pressure of 2500 p.s.i. hydrogen. MoO3NiSO4 supported on a fibrous alumina, Al2O3 (FF), was found to show the highest activity, the total conversion of SRL being 92%. The activities per unit surface area of the catalysts supported on TiO2 and ZrO2 were much higher than those of other catalysts. A presulfided MoO3NiSO4Al2O3(FF) gave the largest amount of total liquid fractions. The best catalysts for the formation of gasoline fractions were presulfided MoO3NiSO4Al2O3(FF) and a commercially available catalyst, MoO3NiOAl2O3(HT-100), which was also presulfided. It was shown that there is no correlation between acidic properties of the catalysts and their activities or selectivities.

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.

Gel permeation chromatographic analysis of solubilized lignite asphaltenes and preasphaltenes

Abstract GPC data have been measured for a series of acetylated solvent refined lignite (SRL) asphaltenes and preasphaltenes and model compounds. Two structural parameters, the degree of aromatic condensation ( H aru C ar ) and the molar hydrogen to carbon ratio ( H C ), were employed to correct the molecular weight of the samples for linear molecular size. For the model compounds, H aru C ar was more effective, whereas the SRL materials were better adjusted by H C . The calibration standards deemed most suitable for determination of molecular weight of SRL by GPC are the SRL samples themselves.

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.