Homework Zeolite #2

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1. Match the unit cell showing below to the zeolite listed in Table 1 and indicate number of T-atoms in the largest pore aperture (windows) (Unit cell represented by dot-line)

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Structure A Structure B Structure C

Table 1 Chemical composition, SBU and window size of zeolites

Zeolite ZSM-23  Gmelinite  ZK-5

Unit Cell composition Nan[AlnSi24-nO48].4H2O, n<2.5 (Na2,Ca)4[Al8Si16O48].24H2O  Na30[Al30Si66O192].98H2O

SBU complex 5-1  S6R, D6R, S4R, S8R  S6R, D6R, S4R, S8R​

Window Size (Å) 5.5x5.9 7.0x7.0 3.9x3.9

2. Which zeolite possess the lowest polarity, why?

3. AlPO4-11 is an aluminophosphate having medium pore size (10 T-ring). The unit cell composition can be expressed as [Al20P20O80] If we want to synthesis SAPO-11 with Si/(Si+Al+P) ratio = 0.1 we have to add some SiO2 in the syntehsis mixture.

   What should be the unit cell composition of SAPO-11 having Si/(Si+Al+P) ratio = 0.1 Show calculatons.?

4. SAPO-11 should possess higher or lower polarity, as compared to AlPO4- 11. Why?

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