A kind of supported spherical nanoparticle palladium catalyst and its preparation method and application

A nanoparticle and palladium catalyst technology, applied in the field of supported spherical nanoparticle palladium catalyst and its preparation, can solve the problems that hinder the breakthrough of industrial production technology, the requirements of improving precision and difficulty, and the reaction end point is not obvious, and reach the reaction end point Ease of use, easy operation, and many times of application

Active Publication Date: 2019-02-01
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the generated nitroarylamine can hardly stay stably in the reaction system, and it will continue to hydrogenate quickly to form aromatic amine. The end point of the reaction is not obvious and difficult to determine. The reaction process can only be controlled by the theoretical hydrogen consumption.
This greatly increases the requirements for the accuracy and difficulty of the hydrogenation reaction process, hindering the breakthrough of its industrial production technology

Method used

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  • A kind of supported spherical nanoparticle palladium catalyst and its preparation method and application
  • A kind of supported spherical nanoparticle palladium catalyst and its preparation method and application
  • A kind of supported spherical nanoparticle palladium catalyst and its preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～ Embodiment 15

[0048] The content, proportion and preparation conditions of the catalyst active components are provided (as shown in Table 1).

[0049] Catalyst concrete preparation process is as follows (taking embodiment 1 as example):

[0050] 1) Dry and dehydrate the activated carbon made from coconut shell in vacuum at 120°C for 3 hours;

[0051] 2) Dissolve palladium chloride in concentrated ammonia water (25-28wt%) in an amount that just dissolves (1.0 times the theoretical amount), stir at room temperature until completely dissolved, and then dilute with water to prepare a concentration of 0.05g / ml of palladium solution.

[0052] 3) Take 25ml of ethylene glycol solution with a mass content of 80% in a 100ml hydrothermal synthesis kettle, and control the temperature at -8.0°C. Finally, pour 10 g of activated carbon that has been vacuum-dried and dehydrated into the synthesis kettle, and stir until the temperature of the slurry reaches -8.0°C; drop in 10ml of the palladium solution ...

Embodiment 16～32

[0061] 50g m-dinitrobenzene, 100ml methyl alcohol and 0.5g embodiment 1~15 or the loaded catalyst prepared by comparative example 1~2 are added in the 500mL autoclave, close the reactor, replace the air in the reactor with nitrogen, and then The nitrogen is replaced with hydrogen, the stirring is started, the stirring speed is 1000r / min, the reaction temperature is maintained at 25-70°C, and the hydrogen pressure is 1.0-1.5MPa to carry out the reaction. When the hydrogen gas no longer drops within 5 minutes, it is considered that the reaction is terminated, the reaction is stopped, and the catalyst is filtered. The filtrate is the product after phase separation, water separation and dehydration by vacuum distillation, and it is quantitatively analyzed by chromatography (mole percentage).

Embodiment 33

[0063] The catalyst prepared in Example 10 is selected, the carrier particle size is 0.5-1.0 mm, and the fixed bed is 8 cm. The gas space velocity of the sum of hydrogen and m-dinitrobenzene is 2.0*10 4 h -1 , the molar ratio of hydrogen to m-dinitrobenzene is 40:1; the temperature is 70°C, and the hydrogen pressure is 2.0MPa. The product was analyzed by chromatography, and the conversion and selectivity were both 100%.

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Abstract

The invention discloses a supported spherical nano particle palladium catalyst and a preparation method and application thereof .The catalyst is composed of a carrier and an active component supported by the carrier, wherein the carrier is active carbon, alumina, silicon dioxide or titanium dioxide, the active component is elemental palladium, the elemental palladium is a spherical particle in shape, and the particle size ranges from 5 nm to 50 nm .Based on the mass of the carrier, the capacity of the elemental palladium is 0.10-15.0wt% .The application of the catalyst in catalytic hydrogenation reaction of polynitroaromatics shown in formula (I) selectively synthesizing nitro aromatic amine shown in formula (II) is provided .In formula (I), at least two of R1, R2, R3, R4, R5 and R6 are nitryls, and the other groups are independent H, Cl, F, CH3, OH, CH2CH3, NH2, OCH3, OCH2CH3, C6H5, COOH or COOCH3; in formula (II), only one nitryl is reduced into amino, the other groups correspond to the groups in formula (i) in a one-to-one mode and do not change before and after reaction .Please see formula (I) and formula (II) in the description.

Description

(1) Technical field [0001] The invention relates to a supported spherical nanoparticle palladium catalyst and its preparation method and application. The catalyst can be applied to the catalytic hydrogenation reaction of polynitroaromatic compound to selectively synthesize nitroarylamine. (2) Technical background [0002] Nitroarylamine is an important class of organic synthesis intermediates, widely used in the synthesis of fine chemicals such as pigments, dyes, medicines, pesticides and rubber additives, resins, and photosensitive materials. At present, nitroarylamines are mainly prepared by partial reduction of corresponding polynitroaromatic compounds. The more mature process is the chemical reduction method. This method uses alkali sulfide, iron powder, etc. to partially reduce the nitro group in an acidic medium to obtain nitroarylamine. This process is easy to operate, but it will produce a large amount of waste residue containing organic poisons, which is difficult ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/44B01J35/08C07C209/36C07C211/52C07C227/04C07C229/64C07C229/60
CPCB01J23/44B01J35/08C07C209/36C07C209/365C07C227/04C07C211/52C07C229/64C07C229/60
Inventor 卢春山马磊张群峰丰枫李小年
Owner ZHEJIANG UNIV OF TECH
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