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Method for preparing catalyst for refining of crude terephthalic acid

A crude terephthalic acid and catalyst technology, applied in the field of preparation of supported palladium/carbon catalysts, can solve problems such as unfavorable environmental protection or labor protection, difficulty in uniform distribution of carrier activated carbon, strong uncertain negative effects, etc., to achieve easy environmental protection The effect of handling, long service life and simple steps

Active Publication Date: 2008-07-16
CHINA PETROLEUM & CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because hydrogen peroxide itself is also oxidizing, it can oxidize the surface groups of activated carbon, which will change the surface physical and chemical properties of the support, that is, change the surface group structure of the support, which has a strong uncertain negative impact and will damage the catalyst. Other properties, such as palladium loading strength, catalyst life, selectivity, etc.
U.S. Patent No. 4,476,242 proposes to use organic solvents such as methanol or pyridine to prepare impregnation solutions containing Pd compounds. It is said that this is also very effective in preventing the migration of Pd and grain growth, but the production process uses methanol or pyridine, which is harmful to the human body. Harmful organic compounds are unfavorable in terms of environmental protection or labor protection
In addition, there is a patent report that by adjusting the pH value, the chloropalladium acid solution is converted into a palladium colloid, which is said to prevent the reducing groups on the surface of the activated carbon from directly reducing Pd ions to zero-valent metal Pd, but the colloid has poor stability. It is difficult to distribute evenly on the carrier activated carbon, which will also affect the dispersion of Pd

Method used

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  • Method for preparing catalyst for refining of crude terephthalic acid
  • Method for preparing catalyst for refining of crude terephthalic acid
  • Method for preparing catalyst for refining of crude terephthalic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] 100 grams of 4-8 mesh, specific surface 800-1800m 2 / g of coconut shell activated carbon is washed with 0.4mol / L nitric acid at a washing temperature of 80°C, and then washed with water until neutral.

[0043] Prepare Br with Potassium Bromide and Water - Concentration of 0.01mol / L soaking solution, impregnate activated carbon with equal volume for 2-24 hours, and dry at 80-120°C for 2-8 hours for later use.

[0044]The preparation of Pd solution, get the required amount of palladium-containing 15wt% chloropalladium acid solution, add deionized water to 40 milliliters, then add the required amount of acidic aqueous solution containing 8-hydroxyquinoline 5wt%, and add Prepare 60 ml of Pd solution with deionized water. After the Pd solution is stable for 10-200 minutes, the above treated activated carbon is impregnated with the Pd solution for 3 hours to obtain a catalyst precursor. Aging of the catalyst precursor for 24 hours, using 20 grams of 5wt% hydrazine hydrate ...

Embodiment 2~8

[0046] Different halides were selected to prepare the wetting solution containing halide ions, and the rest were the same as in Example 1. The specific halides and the concentration of halide ions in the immersion solution are listed in Table 1.

Embodiment 9~31

[0048] Select different Pd-containing compounds and complexing agents to prepare Pd solutions, and the rest are the same as in Example 1.

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Abstract

This is a kind of producing method of catalyst used for refining coarse terephthalic acid (CTA). The catalyst makes grains or molding active carbon as carrier, the content of loading active component metal Pd is 0.2 - 4wt%. It orderly includes: have acid wash to carrier active carbon; wash carrier active carbon with water to neutral; have soakage with watery solution containing nitrite ion to carrier active carbon; dry carrier active carbon to get rid of water; prepare Pd solution with water-soluble Pd compound, a kind of complexing agent and water to infuse or insufflate the carrier active carbon; the content of Pd compound in the Pd solution counted by Pd is 15 - 20wt%; the mol proportion of complexing agent and Pd is (0.01 - 1) : 1, the complexing agent is got from anyone of 8-hydroxyquinoline, 2, 3, 4-trihydroxyl-4-sulfonic azobenzol, o-phenanthroline, o-Aminophenol, o-hydroxybenzoic sodium or o-hydroxybenzaldehyde oxime; after aginged, have deoxidizing treatment with reducing agent to get activator products.

Description

technical field [0001] The invention relates to a preparation method of a supported palladium / carbon catalyst for hydrogenation reaction, in particular to a preparation method of a supported palladium / carbon catalyst for refining crude terephthalic acid through selective hydrogenation reaction. Background technique [0002] The supported palladium / carbon catalyst is mainly used for the selective hydrogenation of unsaturated organic matter, especially for the purification of crude terephthalic acid. Impurities such as p-carboxybenzaldehyde (4-CBA) in crude terephthalic acid are After the hydrogen is transformed into other compounds, it can be separated and purified by crystallization. Because the palladium / carbon catalyst usually adopts a single active component, its improvement research has always focused on the structure of the support and the distribution of metal Pd on the support in the prior art, and this will indeed have a great impact on the performance of the catalys...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/44C07C63/26C07C51/487
Inventor 钱斌吴征陈大伟
Owner CHINA PETROLEUM & CHEM CORP
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