Energy & Fuels 1991,5, [786][787][788][789][790][791] coal tar maltenes and their aromatic fractions based on the direct integration of FT-IR spectra. For the fractions of phenolic compounds, the determination of new integral absorptivities based on a much larger set of samples than in the present work is needed. ConclusionsFrom the results discussed in this work following conclusions can be drawn:1. The combination of extrography and complexation chromatography provides well-separated compound classes of coal tar. Fractions of saturates, aromatics, and polars were developed from four coal tar maltenes.2. The quantitative evaluation of FT-IR spectra was performed on the base of the determination of the integral absorptivities for aliphatic and aromatic hydrogen. The aliphatic integral absorptivities rapidly drop from saturates to polars, i.e., with increasing polarity of molecules, as the absorptivities depend simultaneously on the structure of aliphatic moieties and on the dipole moments of aliphatic C-H bonds.3. On comparing the quantitative evaluation of FT-IR and lH NMR spectra, very good agreement was obtained for maltenes and their aromatic fractions by using Solomon's integral absorptivities. However, they were not suitable for the analysis of polar fractions when the direct integration of spectral peaks was used.Acknowledgment. The author thanks J. Buchtele for providing the coal tars, and I. Lang and H. Pavlikovi for NMR measurements.A method for the determination of moisture in coals by derivatizing pyridine-extracted moisture with a 31P NMR tagging agent has been developed. Candidate derivatizing reagents which formed anhydride products (R2POPRz) possessing 31P chemical shifts that did not overlap with derivatized phenols and carboxylic acids in the coal extract included CIPOCHzCHzO (l), ClPOCMe2CMe20 (2), CIPSCHzCHzS (3), CIPPhz (9), and C1(0)PPhz (5). Because of interesting but bothersome side reactions encountered with 1-3 and 9, reagent 5 was finally selected as the reagent of choice for determining moisture contents in six Argonne Premium Coals. Advantages of reagent 5 include its clean and instantaneous reaction under very mild conditions to form Ph2(0)POP(0)Ph2 (7) which contains two 31P nuclei for NMR integration for each molecule of water reacted.

The synthesis and structure of disulfane are presented. Pure disulfane, H2S2, has been obtained by the cracking distillation of raw sulfane mixtures in a rotary evaporator, thus substituting the classical cracking column for the rotating flask of the evaporator. Pure, gaseous dideuterodisulfane could be generated by the solvolysis of bis(methyldiphenylsilyl)disulfane, (MePh2Si)2S2, with D2O in the presence of trichloroacetic acid as stabilizing agent. Partially deuterated disulfane has been prepared by H,D exchange between pure H2S2 and DCl. For the first time the molecular structure of HSSH has been determined based solely on microwave spectroscopy with the following parameters: r(SS) = 2.0564 A, r(SH) = 1.3421 A, dihedral angle γ = 90.34°, and <(SSH) = 97.88°.

The rotational spectrum of gas phase HSSSH has been recorded for the first time in absorption with the Cologne free-space-cell millimeterwave spectrometer. In the frequency region between 80 and 300 GHz a prominent series of Q-branches has been observed and assigned. The hitherto identified rotational lines unambigously arise from a perpendicular-type spectrum. In addition, successive J lines of the compact Q-branches show no indication of the easily detectable intensity alternation which arises when the molecule possesses an axis of symmetry due to nuclear spin statistical weights. Therefore the geometrical structure of the molecule does not have a C2 axis of symmetry. The present data are not complete enough for a unique structure determination. However on the basis of the present data we can definitely rule out conformations with C2 or C2v symmetry to be responsible for the strongest observed transitions of the spectrum. The molecule is not floppy as predicted from semi empirical MO calculations. On the contrary the conformation observed is rather rigidly locked into one position with no sign of possible internal rotation. We consider a sulfur triangle with the two hydrogen atoms sticking out symmetrically to the same side of the SSS-plane to be the most likely structure.

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ChemInform Abstract In a renewed effort to understand the spectra of sulfanes and the structure of the sulfur chain the rotational spectrum of gas phase H2S3 is recorded for the first time in absorption with the Cologne free-space-cell millimeterwave spectrometer. On the basis of the spectroscopic evidence a sulfur triangle with the two hydrogen atoms sticking out sym. to the same side of the SSS plane is considered to be the most likely structure.