Catalytic hydrogenation catalyst as well as preparation thereof and application thereof to selective hydrogenation reaction of aromatic nitro compound

A catalytic hydrogenation and catalyst technology, applied in catalyst activation/preparation, metal/metal oxide/metal hydroxide catalyst, physical/chemical process catalyst, etc., can solve the problem of reducing catalyst activity and service life, easily poisoning catalyst, Complicated post-treatment process and other issues, to avoid steric hindrance effect, good catalytic performance, and improve metal utilization

Active Publication Date: 2019-02-15
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of the catalytic hydrogenation method is that it needs to use an excessive amount of additives to control the selectivity, and the additives are easy to poison the catalyst, reducing the activity and service life of the catalyst, and some additives are similar in nature to aromatic hydroxylamine, with a higher boiling point, resulting in complicated post-treatment process

Method used

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  • Catalytic hydrogenation catalyst as well as preparation thereof and application thereof to selective hydrogenation reaction of aromatic nitro compound
  • Catalytic hydrogenation catalyst as well as preparation thereof and application thereof to selective hydrogenation reaction of aromatic nitro compound
  • Catalytic hydrogenation catalyst as well as preparation thereof and application thereof to selective hydrogenation reaction of aromatic nitro compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Weigh 1.5g of methyl orthosilicate and 0.05g of n-butyl titanate and add them to the distillation flask, add 20g of activated carbon after fully stirring, and then add dropwise an aqueous solution of tetramethylammonium hydroxide (containing tetramethylammonium hydroxide) with a mass concentration of 20%. Hydroxyl ammonium hydroxide 0.075g), distill and separate the hydrolyzate at 95°C, and then heat the solid matter in the flask at 180°C for 12h to obtain activated carbon coated with a modified coating.

[0037] Get the gac (70% of mesopore ratio after detection, 30% of micropore ratio, size is not more than 1cm) 1g and 15ml of deionized water and 3ml of methyl alcohol that are coated with modified coating that the above-mentioned method makes and make mixed slurry, stir 15min, take 10mL palladium concentration of 0.002g / mL chloropalladium acid solution dropwise into the mixed solution, put it under the ultraviolet lamp, and carry out light stirring for 40min under the ...

Embodiment 14

[0048] The catalyst prepared in Example 1 was loaded into a tubular reactor with an inner diameter of 20 cm, and the air was replaced with nitrogen, and then the nitrogen was replaced with hydrogen. According to the total volume of the reaction solution composed of p-chloronitrobenzene and methanol to the volume ratio of hydrogen is 1:1, the ratio of p-chloronitrobenzene to methanol is 2g:5ml, and the p-chloronitrobenzene is dissolved in methanol solvent to obtain the reaction The liquid is pumped into the mixing tube in front of the reaction tube by a high-pressure liquid pump, mixed with hydrogen, and then enters the tubular reactor loaded with catalyst. The hydrogen pressure is set at 1MPa, the temperature is 50°C, and the liquid space velocity is 8min. -1 , turn on the lighting device, set the light power to 325nm, the power to 225W, and the radiation intensity to 3820μW / cm 2 , start the reaction, pass through the gas-liquid separation device after the one-way reaction, th...

Embodiment 15～27

[0050] Examples 15-27 are based on the fixed-bed catalytic evaluation operation steps in Example 14. The fixed-bed catalytic hydrogenation catalysts prepared in Examples 1-13 and Comparative Examples 1-2 are selected for catalyst reaction. The specific parameters are shown in Table 2.

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Abstract

The invention discloses a catalytic hydrogenation catalyst as well as a preparation thereof and application thereof to the selective hydrogenation reaction of an aromatic nitro compound. The catalystcomprises an activated carbon carrier coated with a modified coating layer and metal quantum dots loaded on the carrier; metal is palladium, and the particle size range of each of the metal quantum dots is between 4 mm and 7 nm; activated carbon is irregular or molded granular activated carbon, and the size is not greater than 1 cm; a pore structure of the activated carbon coated with the modifiedcoating layer is dominated by a mesopore, the micro-pore ratio is reduced to below 10 percent, and the composition materials of the modified coating layer are titanium dioxide, silicon dioxide and titanium silicate. The invention discloses the application of the catalytic hydrogenation catalyst to the reaction of aromatic hydroxylamine shown as a selective catalytic hydrogenation synthesis formula II of the aromatic nitro compound shown as a formula I; the catalytic hydrogenation catalyst has the characteristics of no additive requirement, high conversion rate, good selectivity, high hydrogenation reaction rate, good stability, long catalyst service life and hydrogen recycling.

Description

(1) Technical field [0001] The invention relates to a catalytic hydrogenation catalyst and its preparation and application, in particular to the application of the catalyst in catalytic selective hydrogenation of aromatic nitro compounds. (2) Technical background [0002] Aromatic hydroxylamine (also known as aromatic hydroxylamine) is an important intermediate in organic synthesis, and is widely used in polymerization inhibitors, antioxidants, pesticides, medicines, cosmetics, etc. Synthesis, such as the use of Bamberger rearrangement to transform into p-aminophenol, an important intermediate of substituted aromatics such as medicines, dyes, and spices; BASF has also successfully developed pyraclostrobin (BAS 500F) fungicide products with aromatic hydroxylamine as the key intermediate. However, during the reduction process of aromatic nitro compounds, the intermediate aromatic hydroxylamine will be rapidly converted into the corresponding amine, which is not only difficult ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/44B01J35/00B01J37/02B01J37/34C07C239/10C07B43/00
CPCB01J23/44B01J35/004B01J35/0046B01J35/006B01J37/0217B01J37/345C07B43/00C07C239/10Y02P20/584
Inventor 卢春山王昊张雪洁周烨彬朱倩文季豪克赵佳丰枫张群峰马磊许孝良李小年
Owner ZHEJIANG UNIV OF TECH
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