WO2022121398A1 - Hydrodechlorination catalyst and application thereof in preparation of chlorotrifluoroethylene - Google Patents

Abstract

Disclosed in the present invention are two hydrodechlorination catalysts and an application thereof in preparation of chlorotrifluoroethylene. The hydrodechlorination catalyst comprises a carrier, an active component, and an auxiliary agent. A first hydrodechlorination catalyst takes activated carbon as the carrier, the active metal component comprises Pd and Cu, and the auxiliary agent comprises Zn; by taking the total weight of the catalyst as a reference, the mass percentage content of the active metal component is 0.5-3%, and the mass percentage content of the auxiliary agent is 0.2-2%. The carrier of a second hydrodechlorination catalyst is activated carbon, Al2O3 or SiO2, a main catalyst and the auxiliary agent are loaded on the carrier, the main catalyst comprises Pd and Cu, and the auxiliary agent comprises Sn and/or Mn. The catalysts provided by the present invention are good in stability, high in reaction selectivity, less liable to carbon deposition and long in service life, and is more beneficial to industrial scale production when being used for preparing chlorotrifluoroethylene.

Description

Hydrodechlorination catalyst and its application in the preparation of chlorotrifluoroethylene technical field

The invention belongs to the field of chemical industry, and specifically relates to two hydrodechlorination catalysts, their preparation methods and their application in the preparation of chlorotrifluoroethylene.

Background technique

Chlorotrifluoroethylene is a very important intermediate compound and polymerized monomer in industry. It is widely used in the preparation of various high value-added downstream products, including trifluoroethylene, hexafluorobutadiene, high-performance fluoropolymers, etc. . The synthesis cost, purity and industrial feasibility of chlorotrifluoroethylene are the main factors affecting the development of chlorotrifluoroethylene and fluoropolymer materials. Therefore, it is of great significance to develop a high-purity, low-cost and environmentally friendly preparation process for chlorotrifluoroethylene.

At present, the preparation methods of chlorotrifluoroethylene with industrial application value are mainly:

1) Trifluorotrichloroethane (CFC-113) zinc powder reductive dechlorination method. This method generally has large production equipment, low efficiency, and difficult to control production rate. In the reaction process, it needs to use a large amount of alcohol substances and zinc powder that are difficult to recover. The by-products include trifluoroethylene, difluoroethylene, difluorochloroethylene, etc. Difficult to recycle, high cost of pollution treatment, etc.

2) Trifluorotrichloroethane catalytic hydrodechlorination method. This method has the advantages of continuous production, no zinc chloride residue and no solvent, and has become the main industrial synthesis method. Hydrodechlorination catalysts are the technical core of the hydrodechlorination process, mainly including Ni-based, supported precious metals, metal carbides and other heterogeneous catalysts and homogeneous catalysts. Supported noble metal catalysts are a hotspot in research and application due to their high activity and easy recovery.

CN1460549A discloses the catalyst used for preparing chlorotrifluoroethylene and trifluoroethylene by catalytic hydrodechlorination of 1,1,2-trifluoro-2,2,1-trichloroethane (CFC-113). Precious metal palladium and metal copper are the main active components, alkali metal lithium and rare earth metal (or metal lanthanum) are added as modification aids, and coconut shell activated carbon (referred to as coconut shell carbon) is used as the carrier. In the hydrodechlorination reaction test of trifluorotrichloroethane (CFC-113), the catalyst was operated continuously for more than 800 hours at a reaction temperature of 180-290 °C, and the average result obtained was: the conversion rate of CFC-113 was 81.07 %, the CTFE selectivity was 88.95%.

CN106140193A discloses a preparation method of a catalyst for hydrodechlorination of CFC and HCFC. The catalyst precursor includes main active components and auxiliary agents, the main active components are Pd and Cu, and the auxiliary agents are selected from transition metals, alkali metals, alkaline earths One, two or more combinations of metals and rare earth metals. As a preferred mode, the auxiliary agent is selected from one, two or a combination of three or more of Mg, Ca, Ba, Co, Mo, Ni, Sm and Ce. The main active ingredients and auxiliary agents are supported on a carrier, and the carrier is preferably activated carbon, aluminum fluoride or aluminum oxide. When the catalyst prepared by the method is used for the hydrodechlorination of CFC-113 to prepare chlorotrifluoroethylene, the conversion rate of CFC-113 is up to 96.50%.

CN105457651 discloses a hydrodechlorination catalyst, which consists of a main catalyst, an auxiliary agent and a carrier; the main catalyst is Pd and Cu; the auxiliary agent is selected from one of Mg, Ca, Ba, Co, Mo, Ni, Sm and Ce One, two or three or more combinations; the main catalyst and the auxiliary agent are supported on the activated carbon carrier. Its preparation method: adding activated carbon into an acid or alkali solution, refluxing in a water bath for 2-4 hours at 60-90 DEG C, washing and drying; using the soluble salt solution of the main catalyst and auxiliary agent used to separate it under vacuum or normal pressure conditions. Step-impregnated or co-impregnated activated carbon; drying the impregnated activated carbon at a drying temperature of 90-120°C; reducing the dried activated carbon to obtain a catalyst. A metal alloy phase is formed on the surface of the carrier between the selected first active component and the second active component, and the activity is moderate, which is beneficial to improve product selectivity and prolong catalyst life. The raw material conversion rate can reach 97.8%, and the CTFE selectivity is up to 96.2%.

The hydrodechlorination catalysts in the prior art still have problems such as the conversion rate and selectivity need to be further improved, the catalysts are prone to carbon deposition, and the long-term stability is poor.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, the present invention proposes two hydrodechlorination catalysts with high stability, high selectivity, not easy to deposit carbon and long service life, which are applied to the hydrodechlorination of trifluorotrichloroethane to produce chlorotrifluoroethylene The reaction has high activity, selectivity and stability.

The purpose of this invention is to realize through the following technical solutions:

In a first aspect, the present invention provides the first hydrodechlorination catalyst, which is specifically as follows:

A hydrodechlorination catalyst, the catalyst uses activated carbon as a carrier, the active metal components include Pd and Cu, the auxiliary agent includes Zn, and the mass percentage of the active metal components is 0.5-3% based on the total weight of the catalyst, It is preferably 0.5-2%, more preferably 0.6-1%, the mass percentage of the auxiliary agent is 0.2-2%, preferably 0.4-1%, more preferably 0.6-0.8%, and the specific surface area of the catalyst is 800-1500m ² /g, the total acid content of the catalyst is 0.2-1.5 mmol/g, preferably 0.4-1.2 mmol/g.

The acid strength of the catalyst is -5.6<H ₀ ≤-3.0, the acid content is ≥90%, the acid content is 0-10% within the range of H ₀ ≤-5.6, and the acid content is within the range of H ₀ >-3.0. 0-10%. The catalyst acid strength was measured by n-butylamine titration.

Preferably, the amount of acid in the range of acid strength of the catalyst -5.6<H ₀ ≤-3.0 is ≥95%, the amount of acid in the range of H ₀ ≤-5.6 accounts for 0-5%, and the amount of acid in the range of H ₀ >-3.0 The proportion is 0-5%.

The ratio of catalyst B acid/L acid center is 1:(5-50), preferably 1:(10-40), more preferably 1:(20-35). The ratio of Catalyst B acid/L acid sites was measured by pyridine adsorption.

The amount of acid B and acid L of the catalyst of the present invention is controlled within an appropriate range, so that the hydrodechlorination capacity of the catalyst is improved.

In the active metal components, the mass ratio of Pd and Cu is (1-7):(1-4).

The catalyst activated carbon carrier is pretreated activated carbon obtained by sequentially treating with hydrofluoric acid and ammonia water.

The auxiliary agent of the present invention is more concentrated on the catalyst surface. The high abundance of Zn atoms on the catalyst surface adjusted the acidity of the catalyst surface and enhanced the anti-carbon deposition performance.

The abundance of Zn atoms on the catalyst surface reaches 60-90 wt%, preferably 70-85 wt%.

The atomic mass ratio of Pd/Zn on the catalyst surface was 1:(5-20), and the atomic mass ratio of Cu/Zn was 1:(5-20).

The average pore size of the catalyst measured by mercury porosimetry is 2-10 nm, preferably 4-8 nm. The pores of the catalyst with a diameter of 5-10 nm account for 50-80% of the total pore volume, preferably 60-75%. The catalyst pore structure is reasonable and the heat transfer effect is good.

Hydrodechlorination catalyst is used for hydrodechlorination of trifluorotrichloroethane to produce chlorotrifluoroethylene.

The preparation method of the first hydrodechlorination catalyst of the present invention comprises the following steps:

(1) pretreatment with activated carbon;

(2) supporting active metal components on the pretreated activated carbon carrier;

(3) introducing auxiliary components;

(4) Roasting.

The step of pretreating the activated carbon in step (1) includes: adding the activated carbon into a hydrofluoric acid solution with a mass concentration of 5-20%, the mass ratio of activated carbon:hydrofluoric acid solution is 1:(1-2), and at 50-20% Reflux treatment at 100°C for 2-24 hours, washed with deionized water, dried, and then added to ammonia water with a mass concentration of 10-30%, the mass ratio of activated carbon: ammonia water is 1: (1-2), stirring at room temperature for 1-10 hours , washed with deionized water and dried.

The pretreated activated carbon of the present invention has improved acid strength distribution, specific surface area and pore structure, high dispersion degree of active components and auxiliary agents on the surface of the carrier, high bonding strength between the carrier and active components and auxiliary agents, and high catalyst activity and stability. Sex is high.

The step of supporting the active metal component on the pretreated activated carbon carrier in step (2) includes: adding the pretreated activated carbon carrier to a solution containing soluble Pd salt and soluble Cu salt, and immersing it for 2-24 hours, Wash and dry.

The soluble Pd salt is selected from palladium chloride, palladium nitrate and the like. The soluble Cu salt is selected from copper chloride, copper nitrate and the like.

In the solution comprising the soluble Pd salt and the soluble Cu salt, the molar concentration of the soluble Pd salt is 1-2 mol/L, and the molar concentration of the soluble Cu salt is 1-2 mol/L.

The step of introducing the auxiliary component in step (3) includes: adding the carrier carrying the active metal component into the zinc acetate aqueous solution with a mass percentage of 5-20%, and immersing it at 60-80 ° C for 2-8 hours, It is then filtered and dried under vacuum at 80-100°C for 6-24 hours.

The roasting step in step (4) includes: roasting in a nitrogen atmosphere at a temperature of 250-500° C. for 2-5 hours, and then roasting at a temperature of 150-300° C. in a hydrogen atmosphere for 1-3 hours.

During the roasting in nitrogen atmosphere of the present invention, the heating rate when rising from room temperature to 300-500 DEG C is 20-50 DEG C/min, and the temperature is naturally lowered to room temperature after the roasting.

When calcining in hydrogen atmosphere, the heating rate from room temperature to 150-300 ℃ is 10-20 ℃/min, and the temperature is naturally lowered to room temperature after the calcination.

The control of the roasting process of the present invention further adjusts the size and distribution of the catalyst specific surface area, the catalyst acid content and the acid strength, promotes the conversion of the B acid center to the L acid center, and the distribution of the acid sites is uniform.

The hydrodechlorination of trifluorotrichloroethane to chlorotrifluoroethylene is a strong exothermic process, and carbon deposition is the main reason for the deactivation of the hydrodechlorination catalyst. By adjusting the acid property, pore structure and the like of the catalyst, the invention reduces the carbon deposition active center of the catalyst, makes the catalyst less prone to carbon deposition, suppresses the occurrence of side reactions, and prolongs the life of the catalyst.

In a second aspect, the present invention provides a second hydrodechlorination catalyst, which is specifically as follows:

A hydrodechlorination catalyst comprising a carrier, a main catalyst and an auxiliary;

The carrier is activated carbon, Al ₂ O ₃ or SiO ₂ , and the main catalyst and auxiliary agent are supported on the carrier;

The main catalysts are Pd and Cu;

As a preferred solution, the amount of Pd accounts for 0.5-3% of the total mass of the catalyst, the amount of Cu accounts for 2.0-10.5% of the total mass of the catalyst, and the amount of the auxiliary agent is 0.2-3.0% of the total mass of the catalyst.

As a further preferred solution, the auxiliary agent is Sn and/or Mn, and the amount of Sn and/or Mn accounts for 0.2-3.0% of the total mass of the catalyst.

As a further preferred solution, in addition to Sn and/or Mn, the auxiliary agent also includes one to three kinds of Zn, Zr, Ag, Ti, Cd, Hg, In, Pb, and Bi; the amount of the auxiliary agent is the total mass of the catalyst 0.2-3.0%, and the amount of Sn and/or Mn accounts for 0.1-2.0% of the total mass of the catalyst. The addition of Zn, Zr, Ag, Ti, Cd, Hg, In, Pb, Bi and other auxiliary components further adjusts the surface properties of the catalyst and improves the dispersion and binding of Sn and/or Mn, Pd, and Cu on the carrier sex.

Optionally, the auxiliary agents are Sn and Zn. Optionally, the auxiliary agents are Mn and Zn. Optionally, the auxiliary agent is Sn, Mn, Zn.

Optionally, the auxiliary agent is Sn, Zn, Ti. Optionally, the auxiliary agent is Mn, Zn, Ti. Optionally, the auxiliary agent is Sn, Mn, Zn, Ti.

Optionally, the auxiliary agent is Sn, Zr, Cd, Bi. Optionally, the auxiliary agent is Mn, Zr, Cd, Bi. Optionally, the auxiliary agent is Sn, Mn, Zr, Cd, Bi.

Optionally, the auxiliary agent is Sn, Ag, Hg, In. Optionally, the auxiliary agent is Mn, Ag, Hg, In. Optionally, the auxiliary agent is Sn, Mn, Ag, Hg, In.

The preparation method of the catalyst of the present invention comprises: impregnating the carrier in the impregnation liquid of the active component and the auxiliary agent.

As a further preferred solution, the active component and auxiliary agent immersion liquid includes active component and auxiliary agent soluble salt; the pH value of the immersion liquid is in the range of 3-9.5. As a further preferred solution, the pH value of the impregnation solution is in the range of 7-9.

As a further preferred solution, the soluble salt of the active component and the auxiliary agent can be chloride or nitrate.

As a further preferred solution, the carrier is activated carbon, and the activated carbon is subjected to high temperature pretreatment, acid washing/alkali washing pretreatment before impregnating the active components and auxiliary agents. High temperature pretreatment, acid washing/alkali washing pretreatment can improve the stability of the activated carbon support and the binding ability with the supporting components.

As a further preferred solution, when activated carbon is used as a carrier, the specific surface area of the activated carbon is 800-1500 m ² /g.

As a further preferred solution, when activated carbon is used as a carrier, nitric acid, hydrochloric acid, sulfuric acid, perchloric acid and hydrofluoric acid are used for pickling pretreatment.

As a further preferred solution, when activated carbon is used as a carrier, ammonia water, potassium hydroxide, etc. are used for alkaline washing pretreatment.

As a further preferred solution, when activated carbon is used as a carrier, high temperature is used to perform high temperature pretreatment on the activated carbon, and the temperature can be set to 1700-2000 °C. High temperature pretreatment time is 2-6 hours, vacuum environment.

The present invention also protects a method for preparing chlorotrifluoroethylene, which selects the above hydrodechlorination catalyst, and reacts trifluorotrichloroethane, hydrogen and the hydrodechlorination catalyst at 150-300° C. to obtain trifluorotrifluoroethylene vinyl chloride.

As a further preferred solution, the reaction pressure is controlled to be 1-1.5MPa.

As a further preferred solution, the residence time is controlled to be 15-25s.

As a further preferred solution, in order to make the reactant and the catalyst fully contact and react sufficiently, the hydrogen gas velocity is 30-60ml/min.

As a further preferred solution, the molar ratio of hydrogen to trifluorotrichloroethane is (1.5-3.1):1.

As a further preferred solution, the raw material space velocity is 10-1300h ^-1 , more preferably 10-1100h ^-1 .

Compared with the prior art, the beneficial effects of the present invention include:

1. Both of the two hydrodechlorination catalysts of the present invention have the advantages of good stability, high activity, high reaction selectivity, friendly applicable reaction temperature, long service life, etc. When used in the preparation of chlorotrifluoroethylene, it can realize green environmental protection, The beneficial effect of cost reduction is more conducive to industrial scale production.

2. The first hydrodechlorination catalyst of the present invention reduces the carbon deposit active center of the catalyst by adjusting the acidity, pore structure, etc. of the catalyst, so that the catalyst is not easy to deposit carbon, suppresses the occurrence of side reactions, and prolongs the catalyst life. life.

3. The second hydrodechlorination catalyst of the present invention is based on the Pd-Cu system catalyst, and Sn or Mn is added to suppress the agglomeration and improve the catalyst performance. When used for preparing chlorotrifluoroethylene, it can achieve green environmental protection and cost reduction The beneficial effect is better to meet the market demand.

Detailed ways

The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should realize that the present invention covers all alternatives, modifications and equivalents that may be included within the scope of the claims.

(First aspect), the preparation and application of the first hydrodechlorination catalyst in the embodiment of the present invention.

Example 1.1

The activated carbon was added to the hydrofluoric acid solution with a mass concentration of 20%, the mass ratio of activated carbon: hydrofluoric acid solution was 1:2, refluxed at 80 ° C for 10 hours, washed with deionized water, dried, and then added with a mass concentration of 28%. In ammonia water, the mass ratio of activated carbon: ammonia water is 1:2, stirring at room temperature for 5 hours, washing with deionized water, and drying. The pretreated activated carbon support was added to a solution containing palladium chloride and cupric chloride, soaked for 6 hours, washed and dried. In the solution containing palladium chloride and cupric chloride, the molar concentration of palladium chloride is 1 mol/L, and the molar concentration of cupric chloride is 1 mol/L. The carrier carrying the active component was added to a zinc acetate aqueous solution with a mass percentage of 10%, immersed at 70° C. for 6 hours, then filtered and vacuum-dried at 80° C. for 12 hours. Under a nitrogen atmosphere, the temperature was increased from room temperature to 400 °C at a heating rate of 20 °C/min, and calcined at 400 °C for 3 hours, then naturally lowered to room temperature, switched to a hydrogen atmosphere, and the temperature was increased from room temperature at a heating rate of 15 °C/min. Raised to 250°C and calcined at 250°C for 2 hours, then naturally cooled to room temperature.

In the prepared catalyst, Pd is 0.5wt%, Cu is 1wt%, Zn is 1wt%, the specific surface area of the catalyst is 882m ² /g, and the total acid content of the catalyst is 1.1mmol/g. The acid strength of the catalyst measured by n-butylamine titration method is 95% in the range of -5.6<H ₀ ≤-3.0, the proportion of acid in the range of H ₀ ≤-5.6 is 2%, and the range of H ₀ >-3.0 The proportion of acid inside is 3%. The ratio of catalyst B acid/L acid sites measured by pyridine adsorption was 1:20. The abundance of Zn atoms on the catalyst surface reaches 75wt%. The atomic mass ratio of Pd/Zn on the catalyst surface was 1:7.5, and the atomic mass ratio of Cu/Zn was 1:5. The average pore size of the catalyst measured by mercury porosimetry was 5.8 nm. The catalyst pores with a diameter of 5-10 nm accounted for 64% of the total pore volume.

When the prepared catalyst catalyzes the reaction of trifluorotrichloroethane and hydrogen under the conditions of a reaction temperature of 300°C, a space velocity of 300h ^-1 and a molar ratio of trifluorotrichloroethane to hydrogen of 1:3, trifluorotrichloroethane will react with hydrogen. The conversion rate of ethane reaches 100%, and the selectivity of chlorotrifluoroethylene reaches 99.46%. After 500 hours of reaction, the conversion rate of trifluorotrichloroethane was still 100%, and the selectivity of trifluorochloroethylene was 99.38%.

Comparative Example 1.1

Different from Example 1.1, the activated carbon was directly loaded with active metal components without pretreatment. The specific surface area of the catalyst was 554 m ² /g, and the total acid content of the catalyst was 1 mmol/g. The acid strength of the catalyst measured by n-butylamine titration method is 81% in the range of -5.6<H ₀ ≤-3.0, the acid content in the range of H ₀ ≤-5.6 is 6%, and the range of H ₀ >-3.0 The proportion of acid inside is 13%. The ratio of catalyst B acid/L acid sites measured by pyridine adsorption was 1:73. The abundance of Zn atoms on the catalyst surface reaches 53wt%. The atomic mass ratio of Pd/Zn on the catalyst surface was 1:3, and the atomic mass ratio of Cu/Zn was 1:2. The average pore size of the catalyst measured by mercury porosimetry was 2.5 nm. The catalyst pores with a diameter of 5-10 nm accounted for 38% of the total pore volume.

When the prepared catalyst catalyzes the reaction of trifluorotrichloroethane and hydrogen under the conditions of a reaction temperature of 300°C, a space velocity of 300h ^-1 and a molar ratio of trifluorotrichloroethane to hydrogen of 1:3, trifluorotrichloroethane will react with hydrogen. The ethane conversion was 100% and the chlorotrifluoroethylene selectivity was 97.24%. After 500 hours of reaction, the conversion rate of trifluorotrichloroethane was 98.45%, and the selectivity of chlorotrifluoroethylene was 93.78%.

Comparative Example 1.2

Unlike Example 1.1, no auxiliary Zn was added. The specific surface area of the catalyst was 875 m ² /g, and the total acid content of the catalyst was 2.1 mmol/g. The acid strength of the catalyst measured by n-butylamine titration method is 79% in the range of -5.6<H ₀ ≤-3.0, the acid content in the range of H ₀ ≤-5.6 is 15%, and the range of H ₀ >-3.0 The proportion of acid inside is 6%. The ratio of Catalyst B acid/L acid sites measured by pyridine adsorption was 2:1. The average pore size of the catalyst measured by mercury porosimetry was 6.3 nm. The catalyst pores with a diameter of 5-10 nm accounted for 52% of the total pore volume.

When the prepared catalyst catalyzes the reaction of trifluorotrichloroethane and hydrogen under the conditions of a reaction temperature of 300°C, a space velocity of 300h ^-1 and a molar ratio of trifluorotrichloroethane to hydrogen of 1:3, trifluorotrichloroethane will react with hydrogen. The ethane conversion was 100% and the chlorotrifluoroethylene selectivity was 96.49%. After 500 hours of reaction, the conversion rate of trifluorotrichloroethane was 97.73%, and the selectivity of chlorotrifluoroethylene was 92.46%.

(Second aspect), the preparation and application of the second hydrodechlorination catalyst in the embodiment of the present invention.

Example 2.1 Activated carbon pretreatment

Take a certain amount of activated carbon, the specific surface area of activated carbon is 910m ² /g. Treated under vacuum at 1800°C for 2 hours, immersed in pre-diluted 20% dilute nitric acid after cooling, heated to 100°C with stirring, and refluxed in a constant temperature water bath at 90°C for 5h. After the constant temperature water bath, washed with deionized water until neutral, and dried at 110 °C for 8 h to obtain the pretreated activated carbon carrier for use.

Example 2.2 Catalyst preparation

Configure the immersion solution: After mixing the active ingredient and the auxiliary soluble chloride salt solution, adjust the pH value to 9 with ammonia water.

The carrier was immersed in the impregnation solution, immersed at 60°C for 2 hours, and then dried at 90°C for 12 hours. The catalyst was reduced by hydrogen at 200 °C for 2 h before use.

The components of the catalyst are shown in Table 1.

Table 1 Catalyst components

serial number	Active ingredient	Auxiliary	carrier
1	0.5wt%Pd-8wt%Cu	1wt% Sn	Example 2.1 Activated carbon
2	0.8wt%Pd-6wt%Cu	2wt%Mn	Al 2 O 3
3	1.2wt%Pd-10wt%Cu	0.5wt%Sn-1wt%Mn	SiO2
4	1wt%Pd-8wt%Cu	0.2wt%Sn-0.3wt%Zn	Al 2 O 3
5	1wt%Pd-6wt%Cu	0.5wt%Sn-0.5wt%Mn-0.4wt%Zn-0.2wt%Ti	Example 2.1 Activated carbon
6	2.5wt%Pd-6wt%Cu	0.1wt%Mn-0.1wt%Zr-0.1wt%Cd-0.1wt%Bi	SiO2
7	0.5wt%Pd-6wt%Cu	0.2wt%Sn-0.2wt%Mn-0.1wt%Ag-0.1wt%Hg-0.1wt%In	Example 2.1 Activated carbon
8	0.5wt%Pd-6wt%Cu	——	Example 2.1 Activated carbon

Example 2.3

The catalyst prepared in Example 2.2 is carried out to the hydrodechlorination of trichlorotrichloroethane, and the catalytic reaction temperature is controlled to be 280 ° C and then feed hydrogen and trichlorotrichloroethane, and the mol ratio of hydrogen and trichlorotrichloroethane It is 1.8:1, the reaction pressure is 1.1Mpa, the residence time is 20 seconds, the hydrogen gas velocity is 40ml/min, and the raw material space velocity is 500h ^-1 . The reaction product is subjected to rapid cooling, alkali washing, water washing, drying, compression and rectification to obtain chlorotrifluoroethylene,

The reaction results are shown in Table 2 below.

Table 2 Catalyst test results

Claims (20)

1. A hydrodechlorination catalyst is characterized in that: the catalyst takes activated carbon as a carrier, the active metal components include Pd and Cu, the auxiliary agent includes Zn, and the mass percentage of the active metal components is 0.5 based on the total weight of the catalyst. -3%, the mass percentage of the auxiliary agent is 0.2-2%, the specific surface area of the catalyst is 800-1500m2/g, and the total acid content of the catalyst is 0.2-1.5mmol/g.
2. The hydrodechlorination catalyst according to claim 1, characterized in that: the acid amount in the range of catalyst acid strength -5.6<H ₀ ≤-3.0 is ≥90%.
3. The hydrodechlorination catalyst according to claim 1, characterized in that: in the active metal component, the mass ratio of Pd and Cu is (1-7):(1-4).
4. The hydrodechlorination catalyst of claim 1, wherein the hydrodechlorination catalyst is used for the hydrodechlorination of trifluorotrichloroethane to produce chlorotrifluoroethylene.
5. The preparation method of hydrodechlorination catalyst as claimed in claim 1, is characterized in that: comprises the following steps:

   (1) pretreatment with activated carbon;

   (2) supporting active metal components on the pretreated activated carbon carrier;

   (3) introducing auxiliary components;

   (4) Roasting.
6. The preparation method according to claim 5, wherein the step of pre-processing the activated carbon in step (1) comprises: adding the activated carbon into a hydrofluoric acid solution with a mass concentration of 5-20%, at 50-100° C. Reflux treatment for 2-24 hours, washing and drying, then adding ammonia water with a mass concentration of 10-30%, stirring at room temperature for 1-10 hours, washing and drying.
7. The preparation method according to claim 5, characterized in that: in step (2), the step of supporting the active metal component on the pretreated activated carbon carrier comprises: adding the pretreated activated carbon carrier to a material containing soluble Pd salts and soluble Cu salt solution, immersed for 2-24 hours, washed and dried.
8. The preparation method according to claim 5, characterized in that: the step of introducing an auxiliary component in step (3) comprises: adding the carrier carrying the active metal component into zinc acetate with a mass percentage content of 5-20% In an aqueous solution, soak at 60-80°C for 2-8 hours, then filter and vacuum dry at 80-100°C for 6-24 hours.
9. The preparation method according to claim 5, wherein the roasting step in step (4) comprises: roasting in a nitrogen atmosphere at a temperature of 250-500° C. for 2-5 hours, and then roasting in a hydrogen atmosphere at 150-300° C. calcined at the same temperature for 1-3 hours.
10. Application of the hydrodechlorination catalyst of claim 1 in the preparation of chlorotrifluoroethylene by hydrodechlorination of trifluorotrichloroethane.
11. A hydrodechlorination catalyst, the hydrodechlorination catalyst comprises a carrier, a main catalyst and an auxiliary, the carrier is activated carbon, Al ₂ O ₃ or SiO ₂ , the main catalyst and the auxiliary are supported on the carrier, and the main catalyst is Pd and Cu, characterized in that the additives include Sn and/or Mn.
12. The catalyst according to claim 11, wherein the auxiliary agent further comprises one to three kinds of Zn, Zr, Ag, Ti, Cd, Hg, In, Pb and Bi.
13. The catalyst according to claim 11 or 12, wherein the amount of Pd accounts for 0.5-3% of the total mass of the catalyst, the amount of Cu accounts for 2.0-10.5% of the total mass of the catalyst, and the amount of the auxiliary agent is the total amount of the catalyst. 0.2 to 3.0% of the mass.
14. The catalyst according to claim 11, wherein the amount of Sn and/or Mn accounts for 0.2-3.0% of the total mass of the catalyst.
15. The catalyst according to claim 12, wherein the amount of Sn and/or Mn accounts for 0.1-2.0% of the total mass of the catalyst.
16. The catalyst of claim 11, wherein when activated carbon is used as a carrier, the specific surface area of the activated carbon is 800-1500 m ² /g.
17. A preparation method of chlorotrifluoroethylene, the method adopts the catalyst according to any one of claims 11-16, wherein, trifluorotrichloroethane, hydrogen and the hydrodechlorination catalyst are mixed at 150 React at ~300°C to obtain chlorotrifluoroethylene.
18. The preparation method according to claim 17, wherein the reaction pressure is controlled to be 1-1.5MPa.
19. The preparation method of claim 17, wherein the residence time is controlled to be 15-25s.
20. The preparation method of claim 17, wherein the hydrogen gas velocity is 30-60 mL/min.