Process for producing biphenyl derivatives

A process for producing a halobiphenyl derivative represented by a formula (I) which comprises dehydrogenating a cyclohexylhalobenzene represented by a formula (II) in the presence of a dehydrogenating agent selected from the group consisting of (1) a catalyst selected from the group consisting of tungsten oxide, zirconium oxide and mixtures thereof as an active component supported on a refractory inorganic support and (2) sulfur under such conditions that no substantial dehalogenation occurs,

• the formula (I) being ##STR9## the formula (II) being ##STR10## wherein X represents a halogen atom, and R.sup.1 and R.sup.2 independently represent a group represented by the formula ##STR11## wherein A represents a carboxyl or alkoxycarbonyl group and R represents a hydrogen atom or lower alkyl group;
• an alkylcarbonyl;
• alkenyl;
• alkyl;
• hydroxyalkyl or cyanoalkyl.