Palladium/carbon nanotube catalyst for hydrogenation of cinnamaldehyde and preparation method thereof

A carbon nanotube and catalyst technology, which is applied in the field of palladium/carbon nanotube catalyst preparation, can solve the problem of C=C double bond hydrogenation selectivity decline, and achieve the effect of small particle size and high selectivity

Inactive Publication Date: 2010-05-12
葛昌华 +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Catalysts for the selective catalytic hydrogenation of cinnamaldehyde are commonly group VIII elements. As we all know, palladium is a typical C=C hydrogenation catalyst. Due to the conjugated structure of cinnamaldehyde, in the process of palladium-catalyzed hydrogenation, the C=O double bond Hydrogenation becomes easier, reducing the selectivity of C=C double bond hydrogenation

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Use a pipette to pipette 0.5 mL of chloropalladium acid aqueous solution with a concentration of 0.05 mol / L and add it to a 100 mL three-necked bottle, then add 30 mL of deionized water, add 263 mg of carbon nanotubes under the action of magnetic stirring, and ultrasonically disperse for 1 h. The carbon nanotubes are uniformly dispersed. Then, under the action of magnetic stirring, 10 mL of potassium borohydride solution with a concentration of 0.005 mol / L was added dropwise, and stirring was continued for 1.5 h after the dropwise addition, so that the chloropalladium acid solution was completely reduced to palladium nanoparticles. Finally, stirring was continued for 1.5 h in an 80°C oil bath until no bubbles were generated. The mixture was cooled to room temperature and filtered, washed thoroughly with deionized water and absolute ethanol, and dried at 80°C. A palladium / carbon nanotube catalyst (mass fraction of palladium is 1%) is obtained. The transmission electron...

Embodiment 2

[0019] Use a pipette to pipette 2.5 mL of chloropalladium acid aqueous solution with a concentration of 0.1 mol / L and add it to a 100 mL three-necked bottle, then add 40 mL of deionized water, add 505 mg of carbon nanotubes under the action of magnetic stirring, and ultrasonically disperse for 2 hours. The carbon nanotubes are uniformly dispersed. Then, under the action of magnetic stirring, 10 mL of potassium borohydride solution with a concentration of 0.05 mol / L was added dropwise, and after the dropwise addition, stirring was continued for 2 h to completely reduce the chloropalladium acid solution to palladium nanoparticles. Finally, stirring was continued for 2 h in an oil bath at 80 °C until no bubbles were generated. The mixture was cooled to room temperature and filtered, washed thoroughly with deionized water and absolute ethanol, and dried at 80°C. The obtained palladium / carbon nanotube catalyst (the mass fraction of palladium is 5%) transmission electron microscope...

Embodiment 3

[0024] Use a pipette to pipette 1.0 mL of chloropalladium acid aqueous solution with a concentration of 0.03 mol / L and add it to a 100 mL three-necked bottle, then add 30 mL of deionized water, add 396 mg of carbon nanotubes under the action of magnetic stirring, and ultrasonically disperse for 2 hours. The carbon nanotubes are uniformly dispersed. Then, under the action of magnetic stirring, 10 mL of formaldehyde solution with a concentration of 0.006 mol / L was added dropwise, and stirring was continued for 1.5 h after the dropwise addition, so that the chloropalladium acid solution was completely reduced to palladium nanoparticles. Finally, stirring was continued for 1.5 h in an oil bath at 80 °C. The mixture was cooled to room temperature and filtered, washed thoroughly with deionized water and absolute ethanol, and dried at 80°C. The obtained palladium / carbon nanotube catalyst (the mass fraction of palladium is 0.8%) is shown by transmission electron microscopy that palla...

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PUM

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Abstract

The invention discloses a palladium/carbon nanotube catalyst for the hydrogenation of cinnamaldehyde and a preparation method thereof. The carrier of the catalyst is carbon nanotubes, and the active ingredient of the catalyst is noble metal palladium nanoparticles with an average particle size of 5 to 6 nanometers. The catalyst contains 0.1 to 5 mass percent of palladium and the balance of the carbon nanotubes. The preparation method of the catalyst comprises: 1) dissolving a palladium salt in deionized water to prepare 0.01 to 0.2 mol/L aqueous solution of the palladium salt, adding the carbon nanotubes into the aqueous solution of the palladium salt and subjecting the solution to ultrasonic dispersion for 0.5 to 1 hour; 2) with magnetic stirring, dripping reducer-containing aqueous solution till the ratio of the reducer and the palladium is 1:1 to 2:1, and continuously stirring for 1 to 2 hours after the dripping is finished; and 3) finally, stirring the solution in an oil bath for 1 to 2 hours, and obtaining the palladium/carbon nanotube catalyst by filtering, washing and drying. Compared with active carbon supported palladium catalyst, the palladium/carbon nanotube catalyst has high selectivity for the preparation of benzenepropana by the hydrogenation of cinnamaldehyde.

Description

technical field [0001] The invention relates to a catalyst and a preparation method in the reaction of preparing phenylpropionaldehyde by hydrogenation of cinnamaldehyde, in particular to a preparation method of a palladium / carbon nanotube catalyst used to catalyze the hydrogenation of cinnamaldehyde to prepare phenylpropionaldehyde. Background technique [0002] The selective catalytic hydrogenation of α,β-unsaturated aldehydes is an important reaction in the fine chemical and pharmaceutical industries. α, β unsaturated aldehyde hydrogenation chooses a suitable catalyst, and the reaction product can be unsaturated aldehyde or saturated alcohol. Cinnamaldehyde is a typical representative of α, β unsaturated aldehydes. It has a benzene ring, C=O double bond and C=C double bond, forming a conjugated system, which increases the selective hydrogenation of C=C double bond to a certain extent. difficulty. In recent years, it has been found that phenylpropionaldehyde is an import...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/44B01J21/18C07C47/228C07C45/62
Inventor 葛昌华赵杰李艳周仁贤
Owner 葛昌华
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