Process for preparing catalyst Pd/TiO2 for hydrogenation of p-carboxybenzaldehyde

Abstract

The invention relates to a Pd / TiO2 catalyst used in the hydrogenation of 4-carboxybenzaldehyde; the catalyst takes TiO2 forming material, which is doped with ground alkali-free glass fibers and adopts titanium-containing precursors for surface modification, as the carrier, and is loaded with an active component, metal Pd; the content of metal Pd in the catalyst is 0.2-1.0%, the titanium-containing precursor can be any one of or the combination of tetrabutyl titanate, tetraisopropyl titanate and tetraethyl titanate. The compressive strength of the catalyst is 110-160N / cm; after reaction, the compressive strength of the catalyst is reduced by less than 13%; in the high-temperature and high-pressure water phase environment, the hydrogenation activity of the catalyst is high, and the transformation rate of 4-carboxybenzaldehyde is higher than 99.0%. The preparation method of the catalyst of the invention has simple technique, and the adopted method does not cause any negative impact on the catalyst and is suitable for the industrial production.

Description

technical field [0001] The present invention relates to a kind of Pd / TiO for hydrogenation reaction 2 Catalyst preparation method, especially related to the supported Pd / TiO used in the hydrogenation process of p-carboxybenzaldehyde under high temperature and high pressure 2 Catalyst preparation method. Background technique [0002] Purified terephthalic acid (PTA) is a very important organic chemical raw material, and its downstream processing products are mainly polyester fibers, polyester films, packaging bottles and PET engineering plastics. In the crude terephthalic acid (CTA) produced by the liquid-phase oxidation of p-xylene (PX), it generally contains 2000-3000 μg / g of p-carboxybenzaldehyde (4-CBA), the main impurity, because its aldehyde group is relatively active, It will affect the color of polyester fiber. It is necessary to convert 4-CBA into p-toluic acid, which is easily soluble in hot water, by hydrogenation and refining at a high temperature of 270-285 ° C...

AI Technical Summary

Problems solved by technology

[0006] Pd / TiO for the hydrogenation process of p-carboxybenzaldehyde in the prior art 2 The compressive strength of the catalyst is significantly reduced in a high-temperature, high-pressure aqueous environment, and the high-temperature activity of the catalyst is relatively poor. The present invention provides a Pd / TiO with high compressive strength and high activity for the hydrogenation reaction of carboxybenzaldehyde. 2 Catalyst preparation method

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