| 摘要 |
a : a -Diarylparaffins in which the paraffin chain contains at least two carbon atoms, are heated in the presence of water vapour and a siliceous catalyst, whereby two mononuclear aromatic compounds, one of which has an unsaturated side chain, are obtained. Starting materials mentioned are: a : a -diphenyl, phenyl tolyl, ditolyl, phenylxylyl, tolylxylyl, and dixylyl ethane and a : a -diphenyl, phenyltolyl, phenylxylyl, ditolyl and tolylxylylpropane. Benzene still residues may also be employed especially after fractionation. In examples: (1) equal volumes of a : a -p : p-ditolylethane and water are passed through a heated tube containing hydrated aluminium silicate; the resulting light oil on fractionation yields toluene and p-methyl styrene; (2) a : a -diphenylpropane similarly yielded benzene and methylstyrene; (3) fractions of benzene still residues containing a : a -phenylxylylethane and a : a -phenyl tolylethane are treated in the presence of hydrated aluminium silicate, and the unchanged hydrocarbon repassed over the catalyst; styrene, toluene and xylene are obtained. Kaolin and silica gel may also be used as catalysts. Halogen, hydroxyl and other nuclear substituents may be present in the starting materials. The diarylethanes used as starting material may be prepared from acetylene or acetaldehyde and benzene, toluene or xylene.
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