A kind of phosphorus-modified carbon-supported palladium catalyst and application thereof

A palladium catalyst and phosphorus modification technology, which is applied in the field of catalytic hydrogenation of halogenated aromatic nitro compounds to synthesize halogenated aromatic amines, can solve the problem of reducing the dispersion of active group components, reducing catalytic activity and reaction rate, and reducing the effective utilization of precious metals efficiency and other issues, to achieve the effects of inhibiting dehalogenation, improving product production efficiency and utilization of production equipment, and significant technological progress

Active Publication Date: 2019-06-14
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method reduces the dispersion of active group components and greatly reduces the effective utilization of precious metals
At the same time, the catalytic activity and reaction rate are reduced

Method used

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  • A kind of phosphorus-modified carbon-supported palladium catalyst and application thereof
  • A kind of phosphorus-modified carbon-supported palladium catalyst and application thereof
  • A kind of phosphorus-modified carbon-supported palladium catalyst and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～ Embodiment 17

[0049] The content, proportion and preparation conditions of the catalyst active components are provided (as shown in Table 1).

[0050] Catalyst concrete preparation process is as follows (taking embodiment 1 as example):

[0051] (a) Set the specific surface area to 1300m 2 / g, 0.80mL / g pore volume, 3.5% ash content coconut shell activated carbon, vacuum drying and dehydration at 110°C for 5h;

[0052] (b) Weigh 1.4194g of sodium hypophosphite solid (5wt% load) and add it to 30mL of ethylene glycol, stir until completely dissolved to obtain system A; then immerse 10g of activated carbon dried and dehydrated in step (a) in system A , after stirring evenly, let stand at room temperature for 2 days, and then dry at 120°C for 8 hours. Then put the sample in a quartz boat and place it in a tube furnace, replace the air and fill it with nitrogen, then raise the temperature to 350°C at a rate of 5°C / min in nitrogen, then keep the temperature at 350°C for 4 hours, Take out after ...

Embodiment 18

[0076] Add the phosphorus-modified carbon-supported palladium supported catalyst prepared by 200g p-chloronitrobenzene and 1.0g embodiment 1 in the 500mL autoclave, close the autoclave, replace the air in the reactor with nitrogen, then replace the nitrogen with hydrogen, Start the stirring, the stirring speed is 1200r / min, the reaction temperature is maintained at 90°C, and the hydrogen pressure is 1.0MPa to carry out the reaction. When the content of p-chloronitrobenzene 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 99.99%.

[0077] The operating condition of embodiment 19~embodiment 36 is the same as embodiment 18, is respectively the hydrogenation catalyst that the embodi...

Embodiment 55

[0090] Add the phosphorus-modified carbon-supported palladium supported catalyst prepared by 200g 6-chloro-2-nitrotoluene and 1.0g embodiment 1 in the 500mL autoclave, close the reactor, replace the air in the reactor with nitrogen, and then use The nitrogen gas was replaced by hydrogen, the stirring was started, the stirring speed was 1200r / min, the reaction temperature was maintained at 50°C, and the hydrogen pressure was 0.5MPa for the reaction. When the content of 6-chloro-2-nitrotoluene 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 99.97%.

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Abstract

The invention discloses a phosphor-modified palladium-supported carbon catalyst and an application thereof. The phosphor-modified palladium-supported carbon catalyst is prepared according to a method which comprises the following steps: (a) taking activated carbon, drying and dewatering; (2) adding hypophosphite into glycol and stirring till full dissolution, thereby obtaining a system A; soaking the dried and dewatered activated carbon into the system A, uniformly stirring, and then standing by for 1-3 days under room temperature and then drying for 6-12h at 100-150 DEG C; placing the sample in a chemical inert gas, increasing the temperature to 350-650 DEG C, keeping constant temperature for 2-10h and lastly reducing temperature to the room temperature, thereby obtaining a phosphor-modified carbon material; (c) preparing a palladium solution; (d) soaking the phosphor-modified carbon material into the palladium solution, stirring and dipping, regulating pH value to 8-10, and then adding a reducing agent for reduction reaction, thereby obtaining the phosphor-modified palladium-supported carbon catalyst. The invention provides the application of the phosphor-modified palladium-supported carbon catalyst in catalytic hydrogenation synthesis of arylamine from aromatic nitro compound. Under the effect of the phosphor-modified palladium-supported carbon catalyst, the selectivity of the arylamine is still above 99.9% under the condition of higher reaction rate and 100% conversion rate of hydrogenation reaction.

Description

(1) Technical field [0001] The invention relates to a phosphorus-modified carbon-supported palladium catalyst and its application. The catalyst can be applied to the catalytic hydrogenation of aromatic nitro compounds to synthesize aromatic amines, and is especially suitable for the catalytic hydrogenation of halogenated aromatic nitro compounds to synthesize halogenated aromatic amines. . (2) Technical background [0002] Halogenated aromatic amines are widely used in the synthesis of fine chemicals such as pigments, spices, medicines, pesticides, photosensitive materials, liquid crystal materials, textiles, synthetic fibers, plasticizers and flame retardants, and are an important class of organic synthesis intermediates . The synthetic route of halogenated aromatic amines is mainly prepared by reducing the corresponding halogenated aromatic nitro compounds. At present, the widely used process is the liquid-phase catalytic hydrogenation reduction method. This process is a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/185C07C209/36C07C211/52
CPCB01J27/1856C07C209/365C07C211/52
Inventor 卢春山李小年王梦君齐亚妮冯振龙丰枫马磊张群峰
Owner ZHEJIANG UNIV OF TECH
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