Styrene and styrene dimer derivatives, cyclohexene, tert-butylbenzene and cumene as test reactions for acid strength measurements of crystalline and amorphous silica-aluminas, sulfated oxides and Amberlyst

摘要

The minimal H-O values required for cyclohexene, alpha-methylstyrene, styrene, 2,4-diphenyl-4-methyl-1-pentene, 4-phenyl-1-butene, tert-butylbenzene and cumene to undergo the chosen test reactions over solid acids at 303 K have been established. The chosen reactions and the respective H-O min values obtained are as follows: alpha-methylstyrene and styrene oligomerization (-3.3 and -5.3), 2,4-diphenyl-4-methyl-1-pentene and 4-phenyl-1-butene oligomerization and isomerization (-6.9 and -7.9), cyclohexene oligomerization (-7.8), tert-butylbenzene disproportionation (-10.8) and cumene disproportionation (-11.5). The above mentioned test reactions were used to study the acid strength of different solid acids. The results can be presented as follows: (a) gamma-Al2O3 was practically inactive in the performed reactions due to the lack of Bronsted acid centers of H-O a parts per thousand currency sign -3.3; (b) -SO3H groups of Amberlyst XN-1010 exhibit acid strength of -7.9 < H-O a parts per thousand currency sign -7.8; (c) amorphous silica-alumina (13 and 45 % Al2O3), HY and HZSM-5 zeolites possess Bronsted acid sites of acid strength -10.8 < H-O a parts per thousand currency sign -7.9; (d) sulfated oxides: Al2O3/(8 %)SO4 (2-) and TiO2/(8 %)SO4 (2-) possesses strong protic sites of -11.5 < H-O a parts per thousand currency sign -10.8.