PROBLEM TO BE SOLVED: To provide a method for synthesizing 4,4'-diisopropylbiphenyl, by which selectivity of 4,4'-diisopropylbiphenyl is improved in the isopropylation reaction of biphenyl and to obtain a catalyst.
SOLUTION: The method for synthesizing 4,4'-diisopropylbiphenyl comprises reacting biphenyl with propylene in the presence of the catalyst and carrying out the isopropylation reaction of biphenyl to synthesize 4,4'-diisopropylbiphenyl. The catalyst is SSZ-24 zeolite. In SSZ-24 zeolite containing boron (B) in the skeleton, preferably aluminum (Al) is introduced into the skeleton so as to raise activity of the SSZ-24 zeolite to the isopropylation reaction of biphenyl. In the introduction, the molar ratio of SiO2 to Al2O3 is preferably 172-768.