Hydroquinone hydrogenation catalyst, preparation method and hydrogenation reaction method

Abstract

The invention relates to a hydroquinone hydrogenation catalyst, a preparation method and a hydrogenation reaction method. The catalyst contains an active ingredient of Ru, an auxiliary agent La and a carrier, wherein the composition of the catalyst is shown as x percent Ru-y percent La / carrier, wherein the x percent Ru-y percent La / carrier, wherein the x percent represents the mass percentage of the Ru in the catalyst; the y percent represents the mass percentage of the La in the catalyst; the content of each ingredient of the catalyst is shown as follows: the mass percentage of Ru is 0.5 to 5 percent; the mass percentage of La is 0.2 to 2 percent; the rest is the carrier. Catalyst precursors are prepared by an immersion-precipitation method; then, the catalyst precursors are reduced in the hydrogen-containing atmosphere; the para-nitrotoluene hydrogenation Ru-La bimetal catalyst is obtained; in the reaction for preparing p-methyl-cyclohexylamine through nitrotoluene hydrogenation, the p-methyl-cyclohexylamine can be strongly adsorbed onto the catalyst; a great amount of tar can be further generated; the proceeding of the reaction is inhibited; through the addition of the La, the problem of strong adsorption of the catalyst on the p-methyl-cyclohexylamine is well solved; the tar generation quantity is reduced.

Description

technical field [0001] The invention relates to the technical field of catalytic hydrogenation, in particular to a catalyst preparation technology for synthesizing 1,4-cyclohexanediol by catalytic hydrogenation of hydroquinone. Background technique [0002] 1,4-Cyclohexanediol is mainly used to synthesize some anticancer drugs and biological controller markers, etc. It is a widely used pharmaceutical intermediate and new material monomer. At present, the production volume of this product in my country is very small, but its demand is very large, especially the high-purity cis and trans 1,4-cyclohexanediol and spectroscopically pure 1,4-cyclohexanediol are in short supply. Due to the large output and low price of petroleum phenol products, it is the simplest and most convenient way to synthesize 1,4-cyclohexanediol by catalytic hydrogenation of hydroquinone. At present, there is no catalyst that can synthesize 1,4-cyclohexanediol in a green and efficient manner. Therefore, i...

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Problems solved by technology

An Huajuan et al. used Raney-Ni as a catalyst to prepare 1,4-cyclohexanediol under the condition of hydrogen pressure of 6.0 MPa. The conversion rate was 99.9%, but the hydrogen pressure was too high and the reaction conditions were harsh. Requirements for reaction equipment are too high (An Huajuan, Zhejiang Chemical Industry, 2006, 37(2):5-25)

Y. Komachil prepared 1,4-cyclohexanediol by reducing hydroquinone with thorium iodide as a reducing agent in KOH solution. Due to the high price of thorium iodide, the production cost was too high (Komaehi Y, Tetrahedron Letters, 1994, 35:4169-4172)

Wang Hongjun et al. used Ru / C as a catalyst to catalyze the hydrogenation of hydroquinone to 1,4-cyclohexanediol at a temperature of 150 °C and a hydrogen pressure of 5.0 MPa. The yield was 76.8%, but there was Disadvantages of high hydrogen pressure and harsh reaction conditions (Wang Hongjun, Molecular Catalysis, 2010, 24:315-321)

Chinese patent (CN201019100011.6) reports a method for the synthesis of hydroquinone by catalytic hydrogenation, that is, hydroquinone is hydrogenated with hydrogen in the presence of a ruthenium catalyst, in the absence of a solvent or with supercritical carbon dioxide as the reaction medium 1,4-cyclohexanediol is finally obtained in the reaction, and the reaction temperature is 60~150°C. Although this method does not use toxic and harmful organic solvents, and the reaction rate is fast, the yield of 1,4-cyclohexanediol is low , only 43.5 %

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