Alkylation of toluene with ethanol to para-ethyltoluene over MFI zeolites: Comparative study and kinetic modeling

Fabrication of Hierarchical ZSM-5 with Tailorable AlF Distribution by Metal-Containing Anions Participating in Synthesis and Their Impacts on the Alkylation of Toluene with Ethanol

“…It is commonly acknowledged that the ability of p -ET, which is the smallest molecule among the isomers, to diffuse in ZSM-5 is superior to those of ortho -ethyltoluene ( o -ET) and meta -ethyltoluene ( m -ET). Although it is speculated that p -ET is the preferential product, its continuous isomerization leads to a thermodynamic equilibrium distribution of ET isomers (23% para, 51% meta, 26% ortho) over the conventional ZSM-5 zeolite . Recently, Wang et al investigated the effect of the Al F distribution in ZSM-5 on the shape selectivity in toluene alkylation with methanol and confirmed that ZSM-5 with more Al F at sinusoidal channels can increase the para -selectivity and catalytic lifetime due to the shape/size sieving effect.…”

“…This is because the ZSM-5-3 sample exhibits lower acidic strength and quantities in comparison to the other samples, while its acidic properties it is speculated that p-ET is the preferential product, its continuous isomerization leads to a thermodynamic equilibrium distribution of ET isomers (23% para, 51% meta, 26% ortho) over the conventional ZSM-5 zeolite. 15 Recently, Wang et al 56 investigated the effect of the Al F distribution in ZSM-5 on the shape selectivity in toluene alkylation with methanol and confirmed that ZSM-5 with more Al F at sinusoidal channels can increase the para-selectivity and catalytic lifetime due to the shape/size sieving effect. There is no doubt that more Al F is located at the channels in ZSM-5-3, which with a smaller space than the channel intersecting cavity (∼0.9 nm), is not conducive to the isomerization of p-ET due to dimensional constraints.…”

“…Recently, due to the overcapacity of toluene and the inexpensive ethanol derived from the fermentation of biomass, the alkylation of toluene with ethanol has emerged as a promising route to produce ethyltoluene (ET), which is the key raw materials for producing chemical intermediates and polymers, such as p -methylstyrene and downstream poly­( p -methylstyrene). , As an important member of the zeolite family, MFI-type zeolite ZSM-5 comprises 10-membered ring channels with straight channels of 0.56 × 0.50 nm and sinusoidal channels of 0.54 × 0.54 nm and displays excellent catalytic performance in toluene alkylation with ethanol . However, the utilization of ZSM-5 zeolite is often hampered by diffusion limitation, and thus, the mass transfer to and from the acid sites is restricted, causing a rapid deactivation of catalysts .…”

Influence of modification on acidic and catalytic proper-ties of high-silica zeolites in the reaction of alkylation of toluene with isopropanol

“…In recent years, high-silica zeolites such as mordenite 14,15 and pentasil are widely used as promising catalysts for the production of para-substituted alkylaromatic hydrocarbons [16][17][18][19] . One possible way to change the catalytic and molecular-sieve properties is directional pore regulation and modification of acid sites by removing the strongest acid centres and changing their nature 6,7,16 .…”

Alkylation of Ethylbenzene by Ethanole on H-Ultrasil Zeolite Catalyst, Modified by Lantanum

“…H-ultrasil zeolite could be the best catalyst for the reaction of ethylbenzene ethylation by ethanol to p-DEB because of its special shape selectivity and surface acidity. Many processes have been developed to modify its surface property in order to promote para-selectivity for alkylation and prevent coking deposition: for example, loading with oxide of P, Mg or B [6][7][8][9][10][11][12], coking by methanol [11][12][13], silylation by silicon alkoxide [14,15] using Hultrasil zeolites of different crystal sizes [16,17] and use of metallosilicate zeolites with the MFI structure [18][19][20]. Modified H-ultrasil zeolites exhibit high para-selectivity than the parent zeolite.…”