A seed-directed fluorine-free synthesis of alpo 4 -34 method

Abstract

A seed-directed fluorine-free synthesis of AlPO 4 The method of ‑34 is characterized in that the relevant molecular sieve crystal after grinding is added as a crystal seed to an aluminum source, a phosphorus source, an organic template, and water according to the molar ratio Al 2 o 3 :P 2 o 5 :R:H 2 In the mixture formed by O=1.0:0.8~1.0:7.0~9.0:50, stir evenly to obtain a synthetic gel, then transfer it to a stainless steel kettle, hydrothermally crystallize at 170~200°C and autogenous pressure for 1~20 days, take out Naturally cool to room temperature, according to the conventional molecular sieve post-treatment method, cool, wash, dry, and collect the product.

Description

Technical field [0001] The present invention relates to an aluminum phosphate molecular sieve ALPO 4 The synthesis of -34, specifically, using suitable molecular sieves as seed substitution hydrofluoric acid, preparing high crystallinity AlPo under suitable organic template 4 -34 molecular sieve. Background technique [0002] Alpo 4 -34 consist of aluminum phosphate, similar to the rhombus, and eight-membered ring open aperture, which forms a cage structural skeleton by a double-six-membered ring, wherein 1 / 3 of Al takes a hexagonal, adjacent Al through F Or OH bridge, 2 / 3 of Al takes four coordination, forming Alo 4 Four-sided, with po 4 Tetracene is alternately coupled. Its unique structure and weak acid make it a good stability when converted to an olefin (MTO) reaction catalyst as methanol, and the catalyst reaction life is improved, which has broad application prospects. [0003] Literature Microporous and Mesoporous Materials 30 (1999) 145-153 Reported with aluminum hydroxi...

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Problems solved by technology

[0004] CN 106672990 A discloses a small grain AlPO 4 The synthetic method of -34 aluminum phosphate molecular sieve, but this method has used the highly corrosive hydrofluoric acid and the expensive tetraethylammonium hydroxide templating agent in the synthesis, and this not only has increased cost, also can be produced after the product is carried out Environmental pollution during the processing

CN 102092738 B discloses a hydrothermal fluorine-free synthesis of AlPO 4 -34 method, however, it was found that due to the fluorine-free composition of AlPO 4 The crystallization of -34 is very sensitive to the presence of water, and the interference of water in its structure formation cannot be controlled only under hydrothermal conditions, resulting in the formation of molecular sieves with other structures, and the purity of the product is not high

CN 104445244 B discloses a kind of aluminum phosphate molecular sieve AlPO 4 -34 and its fluorine-free preparation method, but this method needs to firstly mix the aluminum source, water and phosphorus source to obtain a semi-dried gel after evaporation and concentration of the gel, and then add an organic template to make a synthetic colloid. This method Not only makes the operation process complicated, but also the reaction system is difficult to stir evenly, especially in the case of large-scale synthesis

CN 102424396 A discloses a fluorine-free synthesis of AlPO by a mixed solvothermal method 4 -34 method, which is characterized in the synthesis of AlPO with isopropanol or ethylene glycol and water mixed solvent 4 -34, but the synthesis disclosed by this method requires the use of a large amount of organic solvents, which not only increases the cost, but also easily causes environmental pollution during the processing of the late synthesis products

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