Coal heated with naphthalene

Figure 1. EPR spectra of coal, coal-naphthalene-h8 and coal-naphthalene-d8 heated at 400°C a. unheated coal b. coal heated for 30 min c. coal heated for 10 h d. coal heated with naphthalene-d8 for 10 h e. coal heated with naphthalene-...

Figure 4. The g-factors of Illinois No. 6 coal heated for the same periods of time under different conditions Set 1,0, coal heated in sealed tubes Set 2, coal heated with naphthalene-d8 Set 3, , coal heated with naphthalene-h8 Set 4, A,...

The purpose of this experiment was to investigate the extent and the structural specificity of hydrogen exchange during the extraction of bituminous coal with naphthalene. Table I includes the data of an extraction experiment (E20) conducted with naphtha-lene-d8 using nitrogen as the cover gas. In the experiment, the reactants were heated at 380°C for 1 hour at 2200 psi the same apparatus was applied as in E19. After the run, the spent solvent was separated from the coal by distillation, and the coal and solvent were examined for deuterium and protium incorporation. 

The results described above illustrate the problem of separating effects due to catalysis provided by pyrrhotite from those due to the chemistry of the reduction of pyrite. It must also be borne in mind that reduction of pyrite produces a nearly equivalent amount of l S, which remains available to enter subsequent reactions by mechanisms now only poorly understood. In order to remove these complications, pyrrhotite was prepared by the reduction of pyrite with tetralin, isolated from the reaction residue, and then heated with fresh tetralin. Figures 4 and 5 contain the yields of naphthalene and 1-methylindan, and the ratios of trans- to cis-decalin as a function of concentration. In this case, the pyrite was a hand-picked sample of micro-crystals taken from a coal nodule. As may be seen, the yields of naphthalene and 1-methylindan, and the ratio of trans- to cis-decalin all increase with pyrite concentration. The slope of the line for naphthalene yield is 0.91. A slope of 0.53 is calculated for stoichiometric reduction of FeS to FeS by tetralin to yield naphthalene. Thus, roughly half of the naphthalene produced can be accounted for by the demand for hydrogen in the reduction of pyrite. 

Is represented byo single hydrocarbon Aoonaphthalene—— 164—produced synthetically by continuing the heating of naphthalene with ethylene, the reaction occurring in three steps. It also exists in coal-tar. 

Conversion of coal to benzene or hexane soluble form has been shown to consist of a series of very fast reactions followed by slower reactions (2 3). The fast initial reactions have been proposed to involve only the thermal disruption of the coal structure to produce free radical fragments. Solvents which are present interact with these fragments to stabilize them through hydrogen donation. In fact, Wiser showed that there exists a strong similarity between coal pyrolysis and liquefaction (5). Recent studies by Petrakis have shown that suspensions of coals in various solvents when heated to 450°C produce large quantities of free radicals (. 1 molar solutions ) even when subsequently measured at room temperature. The radical concentration was significantly lower in H-donor solvents (Tetralin) then in non-donor solvents (naphthalene) (6). 

Anthraquinone itself is traditionally available from the anthracene of coal tar by oxidation, often with chromic acid or nitric acid a more modern alternative method is that of air oxidation using vanadium(V) oxide as catalyst. Anthraquinone is also produced in the reaction of benzene with benzene-1,2-dicarboxylic anhydride (6.4 phthalic anhydride) using a Lewis acid catalyst, typically aluminium chloride. This Friedel-Crafts acylation gives o-benzoylbenzoic acid (6.5) which undergoes cyclodehydration when heated in concentrated sulphuric acid (Scheme 6.2). Phthalic anhydride is readily available from naphthalene or from 1,2-dimethylbenzene (o-xylene) by catalytic air oxidation. 

H 11.18% col pltlts(from benz or AcOH), giving a violet-red fluorescent color in soln, mp 25 0°, bp 448°, d 1.274 sol in hot benz or hot AcOH diffc sol in cold eth, CS2, AcOH or benz derived from coal-tar fractions boiling above 360° also produced by the cracking of petroleum fractions at 630-80° using catalysts, or by heating indene at 500-700° with catalysts, and by passing naphthalene coumarone thru a red-hot tube (Refs 1 to 4). Other props methods of prepn are given in the Refs... 

Naphthalene, anthracene, and phenanthrene are the three simplest members of this class. They are all present in coal tar, a mixture of organic substances formed by heating coal at about 1000°C in the absence of air. Naphthalene is bicyclic and its two benzene rings share a common side. Anthracene and phenanthrene are both tricyclic aromatic hydrocarbons. Anthracene has three rings fused in a linear fashion an angular fusion characterizes phenanthrene. The structural formulas of naphthalene, anthracene, and phenanthrene are shown along with the numbering system used to name their substituted derivatives ... 

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