Selective alkylation of biphenyl over H-MOR and H-BEA zeolites: analysis of experimental results by computational modelling

Selectivity of a Model Zeolite Ring over Hydrocarbons with Different Symmetry, Travelling with Different Orientations and Speeds

“…Assuming no hydrocarbon cracking and no molecular collisions, the molecular simulations using model potentials show periodic behavior in energy barriers due to the diffusion of the hydrocarbons in a crystal lattice. In mordenite, the spatial periodicity occurs in an interval of approximately 7 Å . This indicates the possibility of reducing the size of the zeolite model when energetic profiles are to be investigated.…”

“…From the theoretical point of view, the computational simulations require representative models to yield accurate results. There are a number of representative models proposed by different authors ,,, taking some of the main zeolite properties into account like, for example, the molecular dimensions of the confining cavities, the presence of chemically active centers, the effects of long-distance interactions due to the atoms located relatively far away from the catalytic centers, the symmetry of the crystal structure, etc. Unfortunately, the zeolite models containing most of these features turn out to be very large, intricate, and computationally demanding.…”

“…In mordenite, the spatial periodicity occurs in an interval of approximately 7 Å. 10 This indicates the possibility of reducing the size of the zeolite model when energetic profiles are to be investigated. Also, because we are to use a computationally demanding method, the zeolite model should be not only representative of the zeolite pores but also simple enough to explore the dynamics of hydrocarbons assuming quantum interaction potentials among all the atoms taking part in the model.…”

Shape‐Selective Alkylation of Naphthalene over Zeolites: Steric Interaction of Reagents with Zeolites

“…Dealuminated H-mordenite (MOR) enhanced shape-selective formation of the smallest 2,6-diisopropylnaphthalene (2,6-DIPN) and 4,4¢-diisopropylbiphenyl (4,4¢-DIPB) in the isopropylation of NP [7][8][9][10][11][12][13][14][15][16][17][18] and BP, [19][20][21][22][23][24] respectively. On the other hand, large-pore zeolites, such as Y zeolite (FAU) and zeolite b (BEA), resulted in only low selectivities in isopropylation of NP 11,[16][17][18]25,[27][28][29][30] and BP, [27][28][29][30]31,33 and the selectivities increased in alkylation of NP 25,[34][35][36][37] and BP 32,[38][39][40] even over these zeolites by the use of bulky alkylating agents. It is interesting how zeolite channels influence catalysis, particularly steric interaction of the transition state, in the alkylation of NP and BP.…”

Alkylation of biphenyl with t-butylalcohol over modified Y zeolites

“…Mono-or dialkylated binuclear aromatic compounds such as 4-t-butylbiphenyl (4-TBB) and 4,4 -di-t-butylbiphenyl (4,4 -DTBB) are valuable industrial intermediates used for polyester fibers, engineering plastics with superior properties and for production of thermotropic liquid crystals or heat resistant polymers [1,2]. The shape selective formation of 4-and 4,4 -isomers of biphenyl in the alkylation (methylation [3,4], ethylation [5], isopropylation [6][7][8][9][10][11] and t-butylation [12][13][14]) of biphenyl was reported by various authors. In the recent years, alkylation of biphenyl in the liquid phase conditions over large pore zeolites like Y and dealuminated mordenite zeolites with propylene as alkylating agent were widely studied.…”