Abstract: A method for producing arylethylene comprising four steps of: (I) bringing 1,1-diarylethane into contact with an acid catalyst in the presence of an inert gas to crack said compound into arylethylenes and alkylbenzenes; (II) separating the reaction mixture obtained in the above cracking step (I) into at least a fraction mainly containing 1,1-diarylethane; (III) bringing said fraction mainly containing 1,1-diarylethane into contact with hydrogen gas in the presence of a hydrogenation catalyst; and (IV) re-cracking hydrogenated fraction obtained in the preceding hydrogenation step (III) by bringing it into said cracking step (I).Particularly, this method is useful for producing p-isobutylstyrene which is a starting material for preparing a valuable medicine of ibuprofen.

Abstract: A method for producing an aromatic hydrocarbon easily and safely without the use of carrier-supported catalyst and is characterized in that an unsaturated compound having a double bond or bonds that are conjugated with the benzene ring is allowed to coexist in the process to alkylate a substituted aromatic hydrocarbon with olefins in the presence of 5 mM or more of metallic sodium and potassium compound to provide 3 mM or more of potassium ions relative to 1 mole of the substituted aromatic hydrocarbon, said substituted aromatic hydrocarbon having at least one alkyl group or alkylene group which has at least one hydrogen atom in the .alpha.-position relative to the aromatic ring of said substituted aromatic hydrocarbon.