Date of Award

1-1-1985

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Abstract

In this dissertation reactions of diphenyl ether, a model coal compound, with H(,2)S, S('o) and iron sulfides in the presence and absence of H(,2) and CO are described. Temperatures between 375(DEGREES)C and 525(DEGREES)C were employed. Three major types of batch autoclaves were used: Pyrex, 316 stainless steel and 1060 aluminum. The products of these reactions were quantitated by GLC, and qualified by mass spectroscopy and spiking with authentic samples using GLC.The reaction of diphenyl ether with H(,2)S in Pyrex reactors produced mainly phenol and thiophenol. An activation energy of 45.6 kcal/mole was calculated for this reaction. This reaction was enhanced by S('o) and FeS(,2), unaffected by H(,2)O, inhibited by H(,2) and Fe(,1-x)S and quenched by 316 stainless steel and tetralin. The position at which the thiol group incorporated was determined by reacting 3-phenoxytoluene with H(,2)S. A radical chain mechanism proceeding through an intermediate sigma bonded at the ipso position is proposed.Reactions of diphenylmethane with H(,2)S are also reported. The major products were toluene and thiophenol. The mechanism for this reaction is postulated to be the same as proposed for diphenyl ether.The reaction of diphenyl ether with H(,2)S in the 316 stainless steel reactors produced mostly phenol and equal amounts of benzene and thiophenol. The addition of S('o) to this reaction enhanced the conversion of diphenyl ether, as did the addition of H(,2)O.The addition of H(,2) to the reaction of H(,2)S with diphenyl ether in the steel reactors enhanced the conversion producing benzene, phenol, cyclohexane and methylcyclopentane. This reaction is postulated to proceed through the formation of pyrrhotite on the reactor surface followed by the catalytic hydrogenation of diphenyl ether over this iron sulfide. The activation energy for the conversion of diphenyl ether in a H(,2)/H(,2)S system was determined to be 29 kcal/mole.The reactivity of pyrrhotite as a function of the partial pressure of H(,2)S in a H(,2) atmosphere towards converting diphenyl ether was examined. These experiments showed that amounts of H(,2)S up to a partial pressure of 5% increased the activity of the pyrrhotite catalyst.CO had no effect on the conversion of diphenyl ether except when combined with H(,2)S and H(,2)O where the formation of H(,2) by the shift reaction was possible.

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