2,4-Di-Ter-Pentyl-Phenol Synthesis On Silica Gel Supported Phosphotungstic Acid Catalyst

The synthesis of 2,4-di-tert-amylphenol (2,4-DTAP) by the F–C alkylation reaction of phenol with 2-methyl-2-butene catalyzed by phosphotungstic acid supported on silica gel (PW/SiO₂) was studied. A series of PW/SiO₂ catalysts with various PW loading, prepared by impregnation method, were characterized by XRD, N₂ adsorption, NH₃-TPD, and SEM. The results showed that when PW loading is smaller than 40%, PW can be highly dispersed on SiO₂ surface; 2,4-DTAP has the highest yield when the PW loading of PW/SiO₂ catalyst is 40%. Afterwards, the effects of various operating parameters on 2,4-DTAP was investigated, the optimum reaction conditions were found to be: molar ratio between phenol with 2-methyl-2-butene, 1:2.2; PW/SiO₂ catalyst  amount, 0.5g/10mmol phenol; Reaction time, 70°C; Reaction time,  4 h. At the optimum conditions, the yield of 2,4-DTAP can reach up to 76.93%.