Method for measuring the acidity of sapo molecular sieve with small pore cage structure
A molecular sieve and pore cage technology, which is applied in the field of solid acid characterization, and achieves the effect of being easy to be widely popularized and applied, and the method is simple and reliable.
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[0088] According to one embodiment of the present application, the method for measuring the acidity of the small-pore cage structure SAPO molecular sieve comprises:
[0089] 1) After the molecular sieve is roasted, it is loaded into a dehydration tube, and heated to 300-600° C. under vacuum conditions to obtain a sample I; the molecular sieve is a molecular sieve that removes part of the template and / or removes all the template;
[0090]2) Introduce basic molecule and auxiliary agent in the dehydration tube that sample 1 is housed in step 1), and seal the dehydration tube;
[0091] 3) Heat treatment of the sealed dehydration tube obtained in step 2) to obtain sample II;
[0092] 4) heat-treating the sample II prepared in step 3) under vacuum conditions to remove the auxiliary agent and the physically adsorbed basic probe molecules to obtain a sample enriched in the basic probe molecules in the molecular sieve cage;
[0093] 5) Put the sample obtained in step 4) into a solid N...
Embodiment 1
[0096] The SAPO-34 molecular sieve was calcined at 550°C for 4h in an air atmosphere, and the calcined SAPO-34 molecular sieve (Si / (Si+Al+P)=0.09) was put into a dehydration tube, and vacuumized at 420°C (10 -4 Pa) under the condition of dehydration 12h, cooled to room temperature. Then put the basic probe molecule trimethylphosphine (TMP) and water into the dehydration tube according to the molar ratio of 4:1, 2:1, 1:1, 1:2 or 1:4, wherein the basic probe The amount of the needle molecule substance is the same as the amount of molecular sieve B acid. Under the protection of liquid nitrogen, seal the dehydration tube to form a closed space, and put it into a muffle furnace at a temperature of 100, 200, and 300°C for 8 hours. The treated sample was vacuumized at 200°C (10 -4 Pa) was treated for another 2 h to remove the physically adsorbed basic probe molecules. Finally, solid-state NMR 31 P-spectrum determination of chemisorbed trimethylphosphine. The treatment conditions...
Embodiment 2
[0103] The SAPO-18 molecular sieve was calcined at 550°C for 4 hours in an air atmosphere, and the calcined SAPO-18 molecular sieve (Si / (Si+Al+P)=0.06) was put into a dehydration tube, and vacuumized at 420°C (10 -4 Pa) under the condition of dehydration 12h, cooled to room temperature. Then put the basic probe molecule trimethylphosphine (TMP) and water into the dehydration tube according to the molar ratio of 4:1, 2:1, 1:1, 1:2 or 1:4, wherein the basic probe The amount of the needle molecule substance is the same as the amount of molecular sieve B acid. Under the protection of liquid nitrogen, seal the dehydration tube to form a closed space, and put it into a muffle furnace at a temperature of 100, 200, and 300°C for 8 hours. The treated sample was vacuumized at 200°C (10 -4 Pa) was treated for another 2 h to remove the physically adsorbed basic probe molecules. Finally, solid-state NMR 31 P-spectrum determination of chemisorbed trimethylphosphine. The treatment condi...
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