Preparation of nitrogen-modified carbon-supported noble metal hydrogenation catalysts and their application in the hydrogenation of nitrobenzene compounds

Abstract

The invention discloses the preparation of a nitrogen-modified carbon-supported noble metal hydrogenation catalyst and its application in the hydrogenation reaction of nitrobenzene compounds. The preparation method is carried out according to the following steps: 1) the surface only contains CO 2 leaving group and CO 2 Activated carbon with a total content of leaving groups not higher than 0.8 μmol / g is oxidized with a treatment agent, and the treatment agent is a mixture of at least two of perchloric acid, sodium chlorate, and nitric acid to obtain the pretreated Activated carbon; 2) Dissolve the primary amine organic matter in water, add the pretreated activated carbon and mix well, then place it in a hydrothermal kettle under CO 2 Carrying out hydrothermal reaction in atmosphere to obtain nitrogen-modified activated carbon; 3) adopting ultraviolet light reduction method to load noble metal palladium and / or platinum on nitrogen-modified activated carbon to obtain nitrogen-modified carbon-supported noble metal hydrogenation catalyst. The catalyst is applied to catalytic hydrogenation reduction reaction of nitrobenzene compounds, and has the characteristics of high conversion rate, good selectivity, good stability and fast hydrogenation rate.

Description

(1) Technical field

[0001] The invention relates to the preparation and application of a hydrogenation catalyst, in particular to the preparation of a nitrogen-modified carbon-supported noble metal hydrogenation catalyst and its application in the hydrogenation reaction of nitrobenzene compounds.

[0002] (2) Technical background

[0003] In the field of carbon-based materials, mesoporous / microporous carbons, carbon nanotubes, fullerenes, carbon aerogels, and graphene have attracted much attention from researchers because of their unique structures and electronic properties. It is particularly interesting that due to the characteristics of carbon itself and the hybrid structure of carbon atoms, including atomic hybrid forms (sp, sp 2 and sp 3 ) and heteroatom-doped carbon structures, etc., carbon materials will present very different morphology, nanostructure, electronic properties and chemical stability. For example, the carbon atom sp 2 Hybrid hexagonal lattices can exhi...

Examples

Embodiment 1-6

[0042] Embodiment 1-6: activated carbon pretreatment

[0043] Evenly disperse 1.0g of activated carbon into 25.0mL of treatment agent solution, put its suspension in a 50mL round bottom flask, and gradually raise the temperature to 50°C under constant stirring with a magnetic stirrer at a constant temperature for 10 hours, during which time it will be condensed and condensed with alkali The liquid absorbs the exhaust gas. Then, the suspension was cooled to room temperature, filtered with suction, washed with deionized water several times until the pH value was neutral, and then placed in a vacuum oven at 110° C. for 5 h.

[0044] The obtained samples were obtained from literature ((a) J.L.Figueiredo, M.F.R.Pereira, M.M.A.Freitas, J.J.M.Orfao, Carbon 1999, 37, 1379-1389; (b) J.Xu, J.Zhao, J.Xu, T.Zhang, X. Li, X.Di, J.Ni, J.Wang, J.Cen, Ind Eng Chem Res 2014, 53, 14272-14281; (c) L.M. Jiayun Li, Xiaoian Li, Chunshan Lu, and Huazhang Liu, Ind.Eng .Chem.Res 2005,44,5478-5482; (...

Embodiment 7

[0050] 1) Normalized selective treatment of carbon surface groups

[0051] Evenly disperse 1.0g of activated carbon into 25.0mL of 20wt% oxidation treatment reagent (5wt% nitric acid + 15wt% sodium chlorate) solution, place its suspension in a 50mL round-bottomed flask, and keep stirring with a magnetic stirrer at a constant temperature Gradually raise the temperature to 35°C for 5 hours, during which the condensation is circulated and the tail gas is absorbed with lye. Then, the suspension was cooled to room temperature, filtered with suction, washed with deionized water several times until the pH value was neutral, and then placed in a vacuum oven at 110°C for 5 hours.

[0052] 2) Condensation reaction to prepare nitrogen-modified carbon

[0053] Dissolve 10 g of hexamethylenediamine in 30 mL of deionized water, gradually add 1.0 g of activated carbon obtained in step 1) under stirring, and after magnetically stirring for 2 hours, transfer to a 50 mL stainless steel hydroth...

Embodiment 22

[0074] Add 100g of nitrobenzene and 0.05g of the catalyst of Example 7 into a 500mL autoclave, close the autoclave, replace the air in the reactor with nitrogen, then replace the nitrogen with hydrogen, start stirring, the stirring speed is 1400r / min, and maintain the reaction The temperature is 50°C, and the hydrogen pressure is 1.0 MPa to carry out the reaction. When the nitrobenzene content was detected to be 0 by chromatography, the reaction was stopped and the catalyst was filtered. The filtrate is the product after phase separation, water separation and dehydration by vacuum distillation. Quantitative analysis (molar percentage) by chromatography shows that the conversion rate of hydrogenation reaction is 100%, and the selectivity is 100%. The reaction time is 25min.

(1) Technical field

[0001] The invention relates to the preparation and application of a hydrogenation catalyst, in particular to the preparation of a nitrogen-modified carbon-supported noble metal hydrogenation catalyst and its application in the hydrogenation reaction of nitrobenzene compounds.

[0002] (2) Technical background

[0003] In the field of carbon-based materials, mesoporous / microporous carbons, carbon nanotubes, fullerenes, carbon aerogels, and graphene have attracted much attention from researchers because of their unique structures and electronic properties. It is particularly interesting that due to the characteristics of carbon itself and the hybrid structure of carbon atoms, including atomic hybrid forms (sp, sp 2 and sp 3 ) and heteroatom-doped carbon structures, etc., carbon materials will present very different morphology, nanostructure, electronic properties and chemical stability. For example, the carbon atom sp 2 Hybrid hexagonal lattices can exhi...

Examples

Embodiment 1-6

[0042] Embodiment 1-6: activated carbon pretreatment

[0043] Evenly disperse 1.0g of activated carbon into 25.0mL of treatment agent solution, put its suspension in a 50mL round bottom flask, and gradually raise the temperature to 50°C under constant stirring with a magnetic stirrer at a constant temperature for 10 hours, during which time it will be condensed and condensed with alkali The liquid absorbs the exhaust gas. Then, the suspension was cooled to room temperature, filtered with suction, washed with deionized water several times until the pH value was neutral, and then placed in a vacuum oven at 110° C. for 5 h.

[0044] The obtained samples were obtained from literature ((a) J.L.Figueiredo, M.F.R.Pereira, M.M.A.Freitas, J.J.M.Orfao, Carbon 1999, 37, 1379-1389; (b) J.Xu, J.Zhao, J.Xu, T.Zhang, X. Li, X.Di, J.Ni, J.Wang, J.Cen, Ind Eng Chem Res 2014, 53, 14272-14281; (c) L.M. Jiayun Li, Xiaoian Li, Chunshan Lu, and Huazhang Liu, Ind.Eng .Chem.Res 2005,44,5478-5482; (...

Embodiment 7

[0050] 1) Normalized selective treatment of carbon surface groups

[0051] Evenly disperse 1.0g of activated carbon into 25.0mL of 20wt% oxidation treatment reagent (5wt% nitric acid + 15wt% sodium chlorate) solution, place its suspension in a 50mL round-bottomed flask, and keep stirring with a magnetic stirrer at a constant temperature Gradually raise the temperature to 35°C for 5 hours, during which the condensation is circulated and the tail gas is absorbed with lye. Then, the suspension was cooled to room temperature, filtered with suction, washed with deionized water several times until the pH value was neutral, and then placed in a vacuum oven at 110°C for 5 hours.

[0052] 2) Condensation reaction to prepare nitrogen-modified carbon

[0053] Dissolve 10 g of hexamethylenediamine in 30 mL of deionized water, gradually add 1.0 g of activated carbon obtained in step 1) under stirring, and after magnetically stirring for 2 hours, transfer to a 50 mL stainless steel hydroth...

Embodiment 22

[0074] Add 100g of nitrobenzene and 0.05g of the catalyst of Example 7 into a 500mL autoclave, close the autoclave, replace the air in the reactor with nitrogen, then replace the nitrogen with hydrogen, start stirring, the stirring speed is 1400r / min, and maintain the reaction The temperature is 50°C, and the hydrogen pressure is 1.0 MPa to carry out the reaction. When the nitrobenzene content was detected to be 0 by chromatography, the reaction was stopped and the catalyst was filtered. The filtrate is the product after phase separation, water separation and dehydration by vacuum distillation. Quantitative analysis (molar percentage) by chromatography shows that the conversion rate of hydrogenation reaction is 100%, and the selectivity is 100%. The reaction time is 25min.

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