Solid Acid Zeolite H-Mordenite With More Five Membered Ring As Catalyst
Nature: also known as mordenite. One of the main mineral component of zeolite ore. Si / Al value of 4.17 to 5. Orthorhombic, needle-like crystals, fibrous aggregates for the bundle and radial. White, yellow or pink. Silk gloss or shiny glass. Hardness 3-4, density 2.15g / cm3.
In its crystal structure, not only the four-membered ring, six-membered ring and eight-membered ring, etc., but there are five-membered ring and five-membered ring a large percentage. Five-membered rings are parallel to each other in pairs, namely two five-membered rings share two tetrahedra. A pair of five-membered ring through an oxygen bridge can be paired with another five-membered ring linked, then the place linked to form a four-membered ring. If the ring and further coupled to each other, so you can enclose into eight-membered ring and twelve-membered ring and so on. Twelve yuan oval ring, the maximum and minimum diameter of 0.7nm and 0.58nm, an average of 0.66nm. Actually crystalline mordenite is overlapped by a number of such layers together by appropriate means, linked together. Thus, the crystal form mordenite in a lot of straight-shaped pores, wherein the diameter of the largest is composed of twelve-membered rings composed of straight-shaped pores, which is the main channel of mordenite, elliptical cross-section, a major axis diameter is 0.695nm, minor axis diameter of 0.581nm, they seemed like bundles of tubes, which is a, X and Y-type zeolite clathrate pores are very different. In fact, the straight-shaped pores with a certain degree of torsion, the layers are not overlapped opposite phase, but there is a certain mutual displacement. Thus, it may be reduced to an average diameter from 0.4nm 0.66nm. Between the main channel of mordenite small pores also communicate with each other, but because of these small pores aperture (about 0.39nm) small molecules generally easy to go in, only the main channel access. Mordenite crystal molecules in and out of it, can be considered as a two dimensional, and A, X, and Y-type was three-dimensional.
Because mordenite aluminosilicate ratio, five-membered ring and more, so the acid resistance and thermal stability are particularly high. Do not dissolve in acid at room temperature. Common in acidic volcanic fissures and pores, often symbiotic and clinoptilolite.
SiO2/Al2O3 Mole Ratio: 30-240
Nominal Cation Form: Sodium/Hydrogen
Surface Area, m2/g: 425
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