Mordenite MOR

Mordenite is characterized by sinusoidal channels (with limiting 8-ring windows) parallel to [010] that intersect with 1-dimensional 8- and somewhat elliptical 12-ring channels parallel to [001], which could be described by a shorthand notation of [001] 12 6.5 x 7.0 - [010]8 3.4 x 4.8 - [001] 8 2.6 x 5.7. The unit cell is orthorhombic (a = 18.3, b = 20.5, c = 7.5 A) with Cmcm symmetry. 

Mordenite ( Nag(H20)24l [AlgSi-toCLr,]) is a very important catalysis, adsorption, and separation material, widely used in petroleum refining and the fine-chemicals industry. 

The laboratory synthetic procedure described here was developed by Kim and Ahn.[127] Sodium hydroxide, sodium aluminate (32.6% Na20, 35.7% AI2O3), silica powder (91.8% Si02, 8.2% H20, Note sodium silicate can also be used as a silica source, but crystallization rates are lower), and distilled water were used to prepare the reaction gel with a composition of 6Na20 Al203 30SiO2 780 H20. The detailed procedure for the preparation of 56 g of anhydrous product is described below  

The final mixture was loaded into a Teflon-lined stainless steel autoclave and heated at 170 °C for 24 h. The solid product was filtered off, washed with distilled water until the pH of filtrate was below 10, and dried at 110 °C. Approximately 56 g of anhydrous mordenite with a size of 5 pm and irregular spherical to prismatic shape could be obtained. Powder XRD pattern of the solid product showed five characteristic strong reflections of the MOR structure at d = 3.45, 3.97, 9.02, 3.27 and 3.21 A. Elemental analysis suggested a formula of Na20 Al203 17.2 Si02. 

For most applicahons, which take advantage of the large 12-ring channels, the channel system can be considered to be one-dimensional. Since the only com- 

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Figure 1.10 Comparison of the activation energy of protonation of toluene by (a) an acidic cluster versus that of activation of the same molecule by (b) Mordenite (MOR)...

Zeolites exhibit various pore systems. Zeolitel L (LTL) has parallel one-dimensional channels, Mordenite (MOR) has two different one-dimensional parallel chan-... 

DRIFT spectroscopy was used to determine Av0h shifts, induced by adsorption of N2 and hexane for zeolite H-ZSM-5 (ZSM-a and ZSM-b, Si/Al=15.5 and 26), H-mordenite (Mor-a and Mor-b, Si/AI— 6.8 and 10) and H-Y (Y-a and Y-b, Si/Al=2.5 and 10.4) samples. Catalysts were activated in 02 flow at 773 K in situ in the DRIFTS cell and contacted than with N2 at pressures up to 9 bar at 298 K or with 6.1% hexane/He mixture at 553 K, i.e., under reaction conditions. Catalytic activities of the solids were measured in a flow-through microreactor and kapp was obtained as slope of -ln(l-X0) vs. W/F plots. The concentration of Bronsted acid sites was determined by measuring the NH4+ ion-exchange capacity of the zeolite. The site specific apparent rate constant, TOFBapp, was obtained as the ratio of kapp and the concentration of Bronsted acid sites. 

The refinement performed by Gualtieri et al. [5] evidenced that ECR-1 is formed by a strict alternation of mazzite (MAZ) and mordenite (MOR) sheets, with 4-, 5-, 6-, 8- and 12-membered tetrahedral ring forming a three dimensional ring. In the Na- form, sodium cations are distributed over 5 different extra-framework sites. The thirty-five water molecules are distributed over eleven sites. It is worth noting that the position of the cations found in ECR1 does not correspond with the site found for mazzite and mordenite. In the NH4 -exchanged form, the NH4 ions occupy three distinct extraframework sites, whereas the water molecules are distributed over the same eleven sites found for the Na-form [5],... 

Figure 4.6 View into the 12MR channels (left) and the 8MR windows of the Mordenite (MOR) structure (right).

Commercially significant zeolites include the synthetic zeolites type A (LTA), X (FAU), Y (FAU), L (LTL), mordenite (MOR), ZSM-5 (MFI), beta ( BEA/BEC), MCM-22 (MTW), zeolites E (EDI) andW (MER) and the natural zeolites mordenite (MOR), chabazite (CHA), erionite (ERl) and clinoptiloUte (HEU). Details of the structures of some of these are given in this section. Tables in each section lists the type material (the common name for the material for which the three letter code was established), the chemical formula representative of the unit cell contents for the type material, the space group and lattice parameters, the pore structure and known mineral and synthetic forms. 

As mentioned above, the main types of zeoHtes in industrial catalytic application today are Zeolite Y (FAU) and its variants, ZSM-5 and SUicahte (MFI), Mordenite (MOR) and Beta (BEA). After the first commercial synthesis of X and Y zeolites in the mid- to late 1940s by workers at the Union Carbide Corporation [21, 22],... 

The channel system for mordenite (MOR) is illustrated in Figure 7.15. Mordenite has an orthorhombic structure and two types of channels are available, governed... 

FIGURE 8 Model showing the ECR-1 connectivity between 10.5A sheets of mordenite (MOR) and 15.5A sheets of maz-zite (MAZ). The two possible structures are related by a shift of a/2 in the marked planes normal to the page. 

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