A kind of modified palladium carbon catalyst, its preparation method and application

Abstract

The invention provides a modified palladium-carbon catalyst, which comprises: a supported palladium-carbon material; and a modifier located on the surface of the supported palladium-carbon material, wherein the modifier at least comprises one selected from polyvinyl alcohol (PVA), an acrylic resin (PAA), sodium triphenylphosphine monosulfonate, polyvinylpyrrolidone (PVP) and sodium dodecyl benzenesulfonate (SDBS). The modified palladium-carbon catalyst provided by the invention is good in stability, can be applied to a method for synthesizing 1,3-cyclohexanedione multiple times, and has highselectivity.

Description

technical field [0001] The invention relates to a modified palladium-carbon catalyst, in particular to a preparation method of the modified palladium-carbon catalyst and a method for synthesizing 1,3-cyclohexanedione using the same. Background technique [0002] 1,3-cyclohexanedione has a lively β-dicarbonyl structure and is an important chemical intermediate, which is an important intermediate for many pesticides, medicines and cosmetics. [0003] At present, there are two methods for synthesizing 1,3-cyclohexanedione. One is to synthesize 1,3-cyclohexanedione by condensation with γ-acetylbutyrate as raw material and sodium methylate as a condensing agent as described in the patent US3922307 , but its raw material γ-acetylbutyrate is difficult to prepare, and sodium alkoxide is expensive, and post-processing is difficult, so it is not suitable for large-scale production. [0004] Another method is the catalytic hydrogenation method, which is currently the most commonly use...

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Problems solved by technology

For example, JP0413644A discloses the preparation of 1,3-cyclohexanedione by catalytic hydrogenation on metal catalysts (Pt, Pd, Rh, Ru) with resorcinol as raw material, neutralized by butanediamine, and the conversion rate is as high as 99%. Above, but the selectivity is only 79.6% and organic bases are used, which are expensive and cannot be used in industrial production

[0007] CN106083545A reported the preparation of 1,3-cyclohexanedione with platinum carbon as a catalyst. After the inorganic alkali treatment, it reacted for more than 5h at 95-105°C. The reaction time was long, the reaction rate was slow, the efficiency was low, and the yield was only 93%; CN108623443A discloses a method for preparing 1,3-cyclohexanedione by vapor-phase hydrogenation of resorcinol, dissolving resorcinol in benzene and directly vaporizing it and mixing it with hydrogen, the reaction temperature is 180-280°C, Reaction pressure is 1.0~2.0MPa, although yield and selectivity are all very high, organic benzene solvent is unfriendly to environment, and needs very high vaporization temperature; CN105111058A is catalyst with lanthanum chloride, palladium dichloride, under pressure The value is 4-7.5MPa, the heating temperature is 115-145°C, the conditions are harsh, the pressure requirements are high, and expensive and difficult-to-obtain rare earth metal elements are used; CN104860802A uses Pd graphene catalysts to catalyze the selective hydrogenation of resorcinol, transforming The rate is as high as 99%. Although the carrier used is a carbon-based Pd catalyst, it uses graphene. The preparation of graphene-supported Pd is cumbersome, and the oxidation synthesis is carried out twice, and the cost is expensive. At present, industrialization is difficult.

[0008] As can be seen from the above, in the existing method for synthesizing 1,3-cyclohexanedione, although the nickel catalyst used in industry is cheap, the nickel catalyst is easy to store and transport naturally, has potential safety hazards, poor stability, and few application times. ; Although the use of carbon-based noble metal catalysts has high activity, most of them have not mentioned the problem of applying them in the production process. The stability of the catalyst needs to be improved, and the reaction conditions of carbon-based noble metal catalysts are harsh, and the catalyst stability is low; Graphene Based on noble metal catalysts, it is difficult to be used in industrial production due to the high cost of catalysts

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