Method for preparing monofluoromethane by Pd-M alloy supported catalyst

A supported catalyst, a technology of monofluoromethane, which is applied in the fields of dehalogenation preparation, chemical instruments and methods, metal/metal oxide/metal hydroxide catalysts, etc. Methane has no economic value, and the catalyst life is not ideal. It achieves the effects of environmental protection in the synthesis process route, moderate hydrogenation capacity, and moderate acid-base performance.

Active Publication Date: 2019-05-31
ZHEJIANG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this method is simple and convenient, the use of carbon nanotubes as a catalyst carrier has high production costs and unsatisfactory catalyst life, making it difficult to realize industrialization
[0006] The above process route for synthesizing HFC-41 has the following defects. The conversion rate of the gas phase fluorination synthesis route is low, and it is more dangerous to use HF. Once it leaks, it may cause serious consequences, and the heavy metal chromium-based catalyst is used. Eliminated Heavy Metal Catalysts
In the existing hydrodechlorination synthesis route, under the condition of using noble metal catalysts, the selectivity of HFC-41 is below 60%, which increases the cost of separation in the later stage, and the generated by-products such as methane have basically no economic value, resulting in waste of resources

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 39mL of 0.02mol / L Cu(NO 3 ) 2 ·3H 2 O aqueous solution, 50mL of 0.01mol / L PVP aqueous solution and 50mL of 0.1mol / L ascorbic acid aqueous solution were mixed and placed under nitrogen atmosphere and stirred for 0.5h. Then add 10 mL of 0.1 mol / L sodium borohydride aqueous solution dropwise to the mixed solution, and continue stirring for 0.5 h; then add 1 g of AlF to the above solution 3 powder, continue to stir for 0.5~1h, ultrasonic for 5 minutes; filter, dry for 12h, and then place the dried solid in air at 300°C for 4h to obtain Cu / AlF 3 ; The above-baked Cu / AlF 3 After calcination and reduction at 250°C under a hydrogen atmosphere for 2 hours, passivation was calcined at 250°C for 1 hour under a nitrogen atmosphere, cooled to room temperature, and then placed in 9.4mL palladium nitrate aqueous solution (the concentration of palladium element is 0.0001mol / L) under a nitrogen atmosphere Continue to stir for 0.5~1h, the temperature of the mixed solution is 50°C, an...

Embodiment 2

[0029] Mix 18mL of 0.02mol / L ZnCl aqueous solution, 50mL of 0.01mol / L PVP aqueous solution and 50mL of 0.1mol / L sodium citrate aqueous solution and stir for 2h under a nitrogen atmosphere. The flow rate is 10mL / min. Then, 10 mL of 0.1 mol / L sodium borohydride aqueous solution was added dropwise to the mixture, and stirring was continued for 1 h; then 1 g of MgF 2 powder, continue to stir for 0.5~1h, ultrasonic for 5 minutes; filter, dry for 12h, and then place the dried solid in air at 300°C for 4h to obtain Zn / MgF 2 ; The above-mentioned roasted Zn / MgF 2 After calcination and reduction at 250°C under a hydrogen atmosphere for 2 hours, passivation was calcined at 250°C for 1 hour under a nitrogen atmosphere, cooled to room temperature, and then placed in 9.4mL aqueous solution of chloropalladium acid under a nitrogen atmosphere (the concentration of palladium element is 0.0001mol / L) Stirring was continued for 0.5~1h, the temperature of the mixture was 50°C, and the flow rate...

Embodiment 3

[0032] Mix 18mL of 0.02mol / L ZnCl aqueous solution, 50mL of 0.01mol / L PVP aqueous solution and 50mL of 0.1mol / L sodium citrate aqueous solution and stir under a nitrogen atmosphere for 0.5~1h. The temperature of the mixed solution is 50°C. The flow rate of nitrogen is 10mL / min. Then add 10mL of 0.1mol / L sodium borohydride aqueous solution to the mixture dropwise, and continue to stir for 0.5~1h; then add 1g of MgF to the above solution 2 powder, continue to stir for 0.5~1h, ultrasonic for 5 minutes; filter, dry for 12h, and then place the dried solid in air at 300°C for 4h to obtain Zn / MgF 2 ; The above-mentioned roasted Zn / MgF 2 After being reduced for 2 hours under a hydrogen atmosphere at 250°C, passivation was calcined at 250°C for 1 hour under a nitrogen atmosphere, cooled to room temperature, and then placed in 9.4mL palladium nitrate aqueous solution (the concentration of palladium element is 0.0001mol / L) under a nitrogen atmosphere to continue Stir for 0.5~1h, the te...

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Abstract

The invention discloses a method for preparing monofluoromethane by using a Pd-M alloy supported catalyst. The preparation method of the catalyst comprises the following steps: firstly, loading metalM nanoparticles on a carrier, then mixing and stirring a Pd precursor aqueous solution, preparing monodisperse Pd atoms on metal M through displacement reaction, and combining the Pd atoms with the Mmetal through roasting to form a Pd-M alloy to obtain the monodisperse Pd-M alloy supported catalyst, wherein the metal M can be Cu, Zn, Ni, Ru, Sn or Fe. Compared with single, double and multi-component non-alloy catalysts, the Pd-M alloy supported catalyst has higher selectivity to monofluoromethane (HFC-41) when used for catalyzing hydrogenation dechlorination of chloro-monofluoromethane to prepare monofluoromethane, can reach about 95%, is not prone to carbon deposition, and has longer service life (within 10% of activity reduction and within 5% of selectivity reduction within 1000h); andmoreover, the process route for preparing the monofluoromethane is simple, environment-friendly and safe.

Description

technical field [0001] The invention relates to the technical field of preparation of a single-atom alloy catalyst, in particular to a method for preparing monofluoromethane with a Pd-M alloy supported catalyst. Background technique [0002] Monofluoromethane (HFC-41) is a colorless, flammable gas with low greenhouse effect potential and zero ozone depletion potential. It is one of the few saturated hydrofluorocarbons that meets EU standards for use. In addition, it can be used as a selective fluoromethylation reagent for organic molecules in organic synthesis and drug synthesis, and is also used as a raw material for the production of important pesticide intermediates, bromofluoromethane. High-purity HFC-41 gas is a green, high-efficiency new etching gas (ODP value 0, GWP value 97), which can be used for etching semiconductor and electronic products, such as selectively etching silicon compound films. [0003] Patent CN200580031247.9 discloses using monochloromethane as a ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/23C07C19/08B01J27/13B01J23/62B01J23/89B01J23/58
Inventor 唐浩东周楠张庆韩文锋李瑛刘宗健
Owner ZHEJIANG UNIV OF TECH
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