Preparation method, product and applications thereof of acetate deep deiodination adsorbent

Abstract

The invention relates to preparation method, product and applications thereof of an acetate deep deiodination adsorbent. The method comprises the following steps of: mixing small-pore, medium-pore and large-pore zeolite molecular sieves with different structures; forming by using an adhesive; generating chemical bonds by hydrothermal strengthening treatment; removing sodium and loading silver by ion exchange to prepare the product. The adsorbent is prepared from the following components in percentage by weight: 10-30% of small-pore zeolite, 20-50% of medium-pore zeolite and 20-70% of large-pore zeolite, and the adhesive accounts for 10-30% of the total weight of the adsorbent. The invention has the advantage that the adsorbent has strong adsorption capability on organic iodide, inorganic iodide and molecular iodine with different sizes in the strong acid medium, the total iodine content in the deep deiodination product is less than 5*10<-9>, and the adsorbent is suitable for being used as raw materials which are used for synthesizing vinyl acetate.

Description

technical field The invention belongs to the technical field of chemical industry, and in particular relates to a preparation method of a deeply deiodinated zeolite molecular sieve adsorbent used for removing iodide in the carbonylation synthesis of carboxylic acid or carboxylic anhydride product process, as well as its product and application. Background technique 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 v...

AI Technical Summary

Problems solved by technology

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 the small-sized inorganic molecular iodine and elemental iodine, the molecular thermal motion is violent, and large Decreased adsorption capacity of pore 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 easily affected by the fluctuation of the iodine content concentration in the raw material acetic acid, the space velocity of the adsorbent bed, and the operating temperature. The impact of process conditions such as changes, the deiodination effect changes greatly, making the total iodine content of the deiodoacetic acid product cannot be guaranteed to be lower than 5x10 -9 , sometimes even exceeding 10x10 -9

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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