ISOMERIZATION AND DISPROPORTIONATION OF 1,2,4-TRIMETHYLBENZENE OVER HY ZEOLITE

The conversion of 1,2,4-trimethylbenzene (1,2,4-TMB) over HY zeolite was studied at atmosoheric pressure and 200-300-degrees-C by using a fixed-bed, integral-flow reactor. The types and initial selectivities of various products were obtained from plots of product selectivity according to the time-on-stream theory. The primary reaction included the isomerization and the disproportionation; the former led to the simultaneous formation of 1,2.3- and 1,3,5-TMB whereas the latter produced all isomers of xylene and tetramethylbenzene. The relative initial rate of disproportionation to isomerization decreased from 12.6 at 200-degrees-C to 5.47 at 300-degrees-C. The activation energies for the primary reactions were estimated and compared with those in the reaction of 1,2,3-TMB.