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1) The following recipe is given for a zeolite. Determine the gel composition, express your answer as ratio of oxides in the gel, where the basis is Al2O3. For a neutral template species, use just the mole ratio of this species to alumina. Percentages below are wt. % unless otherwise indicated Material Quantity (g) Comments Distilled water 290 Sodium hydroxide 6.0 50 % aqueous solution Sodium aluminate 21.5 46 % Al2O3, 31% Na2O, remainder water Silica Sol 57.0 Dupont Ludox AS-40, 40% SiO2 Tetramethyl-ammonium hydroxide 292 N(CH3)4ꞏOH 25% aqueous 3) The nitrogen isotherm isotherm below was collected for a mesoporous material. Answer the questions below regarding isotherm and what you can deduct from it. 0 50 100 150 200 250 0 0.2 0.4 0.6 0.8 1 Volume (cm3/gm) P / Po a) Identify the IUPAC type isotherm. Be as specific as possible (e.g. subcategories) b) Identify (circle on the graph or give range) the subset of the data used to calculate the sample surface area. c) Identify (label on the graph) the adsorption and desorption branches of the isotherm d) At gas uptake approaching P/P0 = 1, the isotherm takes a little uptick. What might you attribute this feature to? e) What is the approximate total pore volume (micropore + mesopore) for this sample? The volume given in the graph is the gas uptake at STP (1 atm, 273.15 K), and you may assume the liquid density of N2 at 77K is 0.807 g/cm3. Show your work for full credit. 6) a) Ammonia has recently been shown to be a significant point source pollution problem, and you wish to kinetically separate NH3 from air. Which of the following structures and Si/Al combinations would you test first? You may change cations as you see fit. Check 3 of the 11 listed. CHA 2:1 CHA 13:1 ANA 2:1 LTL 1:1 MFI 10:1 SOD 1:1 FAU 1.5:1 MOR 4:1 RHO 3:1 GIS 1:1 AEI Al/P = 1:1 b) Add one more appropriate structure and Si/Al (Al/P) to the table above. 7) Match the zeolite to the most appropriate application USY (FAU) Ion exchange Linde A (LTA) Emission control (de-NOx) Na-X (FAU) Dehydration, gas drying ZSM-5 MFI) Catalytic cracking Beta (BEA) Hydrocarbon processing, isomerization, cracking, Silicalite-1 (MFI) Hydrocarbon adsorption SSZ-13 (CHA) Gas Separation 9) The ternary diagram (adapted from Breck) below depicts the products observed for varying gel compositions in the Na2O : SiO2: Al2O3 : H2O system. Experimental conditions were crystallization temperature was 100°C, sodium silicate was the silica source, and the water content is 90-98 mol %. a) Why are all the identified structures in the left side of the diagram? An artifact of Lowenstein’s Rule There are insufficient Na+ ions to counteract Al+3 as a Tatom, therefore the alumina precipitates in octahedral coordination. No zeolite is formed. It’s an artifact of the experimental design, Breck and coworkers did not investigate that space There are insufficient OH- to fully mineralize the silica in the right half of the diagram 11) Two questions with same answer key: a) Which of the following post-synthesis treatments will be most effective against significant coke formation? b) Which of the following post-synthesis treatments will be most effective at reducing unwanted octahedral alumina? a) b) Sialylation by chemical vapor deposition (CVD) with SiCl4 Acid washing with HCl EDTA treatment (EDTA = ethylenediaminetetraacetic acid) Mild steaming A combination of mild steaming followed by acid washing 12) You discover a new low SAR, 8-ring structure. You will experiment with different cation forms for this structure. Based on your knowledge of similar structures, you expect the pore openings for kinetic gas separation will progress as follows (answer all correct): Fastest / largest opening → Slowest / smallest opening Li+ > Na+ > K+ Na+ > K+ > Ca++ Ca++ > Na+ > K+ Li+ ≈ Ca++ > K+ K+ ≈ Li+ > Ca++ Ca++ > K+ > Na+ 13) Within one framework structure, increasing the Si/ Al ratio will (check all that apply) Increase the number of acid sites Increase hydrophilicity Increase acid site strength Increase stability in caustic Increase stability in acidic media Increase hydrothermal stability Increase the T-atom density Increase the ion exchange capacity.

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Introduction To Zeolites Questions
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