Investigations into the origin of the remarkable catalytic performance of aged H-ferrierite for the skeletal isomerization of 1-butene to isobutene

Synthesis, Structure Solution, Characterization, and Catalytic Properties of TNU-10: A High-Silica Zeolite with the STI Topology

“…These results show that the pore structure of TNU-10 itself is not efficient for selectively isomerizing 1-butene to isobutene. Very recently, we have investigated the catalytic properties of a series of 10-ring zeolites (i.e., clinoptilolite, FER, ZSM-22, SUZ-4, ZSM-57, and ZSM-5) with different framework structures for this reaction and found that the initial isomerization activity of each zeolite catalyst can be nicely correlated with its 10-ring pore shape . When the ellipticity (ε) defined by {( b 2 − a 2 )/ b 2 } 0.5 , where a and b are the shortest and longest pore diameters, respectively, is taken as a quantitative measure of differences in the 10-ring pore shape, the ε value of 10-ring channels in H-TNU-10 was calculated to be 0.341 which is considerably lower than the value (0.629) of the analogous channels in H-FER.…”

Isomerization of 1-Butene to Isobutene at Low Temperature

“…The reason for the high isobutene selectivity of ferrierite compared to other materials is still being actively researched and debated. 18 It was necessary to confirm the ability of the C84-3 solid phosphoric acid to catalyze the skeletal isomerization of n-butenes. The smaller of the two packed-bed reactors was loaded with 30 g of catalyst diluted five times with carborundum and was operated at atmospheric pressure.…”

“…However, current commercial butene skeletal isomerization processes favor ferrierite mainly due to its near equilibrium conversion and slower deactivation rate. The reason for the high isobutene selectivity of ferrierite compared to other materials is still being actively researched and debated …”

Preferential population of Al atoms at the T4 site of ZSM-35 for the carbonylation of dimethyl ether

“…Brønsted acid sites (BASs), generated by charge balancing protons to the AlO 4/2 − unit, populated the distinct T positions in the pores and served as the active sites for catalysis. For example, the BAS at the 10-MR pore mouth catalysed the isomerization of 1-butene to isobutene; 2–5 the BAS in the 8-MR pore catalysed the carbonylation of dimethyl ether (DME) to methyl acetate (MA), as evidenced by the linearly increasing formation rate of MA with the amount of BASs in the smaller micropore. 6 Therefore, preferentially populating BASs, i.e.…”

“…38 Carbonaceous deposits were formed inside the 10-MR pore at the initial stage of the reaction, leaving the acid sites at the pore mouth that are specifically active for the formation of isobutene. 3–5 The higher 1-butene conversion over the Zeolyst sample than that on the ZSM-35-Diox sample was apparently linked to the larger fraction of the accessible BASs in the 10-MR pore, but its lower selectivity towards isobutene was associated with the higher amount of LASs that induced side-reactions such as oligomerization/cracking. 39 When tested for DME carbonylation, the ZSM-35-Diox sample outperformed the Zeolyst sample with respect to both activity and durability (Fig.…”