High silver supported zeolite molecular sieve acetate deiodinase adsorber and preparation method thereof

Abstract

The invention belongs to the chemical technical field and relates to a high silver supported zeolite molecular sieve acetate deiodinase adsorber and a preparation method thereof. In the adsorber, the sizes of zeolite cavity openings are respectively 0.66*0.71 nanometers and 0.56*0.56 nanometers, and the adsorber is provided with characteristic X-ray diffraction lines in a BEA (Background Equivalent Activity) type zeolite structure. The deiodinase adsorber is prepared by the steps that saled sodium type zeolite molecular sieve powder with two-dimensional twelve oygen membered ring cavity openings is formed through binder, is in in-situ hydrothermal strengthening treatment to generate chemical bonds and then is treated by ion exchange sodium removal and silver carrying. The adsorber has theadvantages of high crystallization degree, strong particle strength, high silver supported and strong adsorption capacity to organic iodide, inorganic iodide and molecular iodide with different sizescontained in strong acidic medium, can enable the total iodide content in product acetic acid after deiodination treatment by the adsorber to be lower than 5ppb and is suitable for being used as raw materials for synthetizing vinyl acetate.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a deiodinated zeolite molecular sieve adsorbent used for removing iodide in the carbonylation synthesis of carboxylic acid or carboxylic anhydride product process and a preparation method thereof. Background technique [0002] In the process of carbonylation of carboxylic acid or carboxylic anhydride, iodide or its derivatives are unavoidably present in the produced carboxylic acid or carboxylic anhydride due to the use of iodide as a catalytic promoter. After traditional distillation, rectification or treatment with certain chemicals, there will still be traces of iodide (derivatives) that are difficult to remove. Its existence limits the application of the products produced by this method. In particular, it cannot be used in the production process using iodine-sensitive metals as catalysts. For example, in the process of producing vinyl acetate from acet...

AI Technical Summary

Problems solved by technology

[0007] However, due to the single pore structure of the zeolite used in the above-mentioned silver-loaded molecular sieve deiodination adsorbent, the iodide removal effect of the molecular size in the acetic acid is different, and the composition is complex.

The reason is that the intracrystalline pore diffusion resistance of large-pore zeolite is small, which is conducive to the removal of large-sized organic iodine molecules through physical adsorption, but for small-sized inorganic molecular iodine and elemental iodine, the molecular motion is violent, and the macropores Decreased adsorption capacity of zeolite

In medium pore zeolites, the organic iodide with larger molecular size is hindered in the diffusion in the pores, and the deiodination effect is poor, and it is very susceptible to the fluctuation of the iodine content concentration of the raw material, the change of the space velocity of the adsorbent bed, and the operating temperature. Due to the influence of process conditions, the deiodination effect varies greatly, so that the total iodine content of deiodoacetic acid products cannot be guaranteed to be less than 5ppb, and sometimes even exceed 10ppb

If this unstable product acetic acid is used to synthesize vinyl acetate, it will chronically poison the precious metal catalyst used, shorten its service life, and cause serious losses.

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