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Effect of zinc chloride on organic solvents and compounds modeling certain bonds in coal. [PhD thesis, 98 references]

Technical Report ·
OSTI ID:6820939

The treatment with organic solvent/zinc chloride mixtures on compounds modeling certain ether and aliphatic structures present in coal was examined at temperatures from 175 to 280/sup 0/C. In coal liquefaction, ether and aliphatic linkages between aromatic units are among the most important bonds to be broken. Treatment of diaryl ethers and alkyl-aryl ethers with a 600-fold molar excess of zinc chloride resulted in cleavage of most ethers. Cleavage of ether carbon-oxygen bonds was not achieved for those bonds in which the oxygen atom was attached directly to an aromatic ring; thus, diphenyl ether was not cleaved. For all other diaryl ethers, cleavage was rapid, with most cleavage products alkylating aromatic centers present in the treatment system; alkyl-aryl ethers were cleaved more slowly, yielding dealkylated phenols or naphthols. With treatment of diaryl alkanes under similar conditions, only diaryl methanes were cleaved, with fragments again alkylating aromatic species present. The reaction products for the ethers and diaryl alkanes confirmed previously proposed carbonium ion mechanisms. For both ether and aliphatic compounds, substituents on the aromatic rings accelerated the rate of the cleavage reaction. In related studies of behavior of solvents with zinc chloride, hydroaromatic solvents were found not significantly soluble in zinc chloride at temperatures up to 300/sup 0/C, but were degraded by zinc chloride-catalyzed cracking and polymerization reactions. Dodecane was non-reactive and insoluble.

Research Organization:
California Univ., Berkeley (USA). Lawrence Berkeley Lab.; California Univ., Berkeley (USA). Dept. of Chemical Engineering
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6820939
Report Number(s):
LBL-11395
Country of Publication:
United States
Language:
English