A comparative study of catalytic performance of rare earth metal-modified beta zeolites for synthesis of cymene

A series of zeolite (LaB, CeB, and PrB) containing rare earth metals lanthanum (La), cerium (Ce), and praseodymium (Pr) were used for transalkylation reaction. The modified beta zeolites were characterized by EDS, XRD, BET, FTIR, and TPD. The surface area and acidities of the zeolite samples modified with various rare earth metals are considerably different. The effect of various process parameters like metal loading (2–10 wt%), catalyst loading (1.44–8.63 w/w%), temperature (448–573 K), reactant ratio 1–15, and space time (3.2–9.29 kg h/kmol) on the conversion of reactant and selectivity of product was studied. Catalytic performance of praseodymium-modified beta zeolite shows highest cumene conversion (86.4 wt%) and cymene selectivity (65.7 wt%) compared to other zeolites. The maximum cumene conversion and cymene selectivity were obtained at 523 K, toluene-to-cumene ratio of 9:1, and a space time of 9.29 kg h/kmol. Kinetic modeling of the reaction was done to estimate the reaction kinetic constants and adsorption constants. The activation energy of the transalkylation was found to be 61.44 kJ/mol.