WO2019237723A1

WO2019237723A1 - Catalyst for producing 1,1,1-trifluoro-2,2-dichloroethane by gas-phase chlorination, and preparation and application methods therefor

Info

Publication number: WO2019237723A1
Application number: PCT/CN2019/000121
Authority: WO
Inventors: 洪江永; 杨波; 张彦; 赵阳; 欧阳豪; 周华东
Original assignee: 浙江衢化氟化学有限公司
Priority date: 2018-06-11
Filing date: 2019-06-11
Publication date: 2019-12-19
Also published as: CN108993553A

Abstract

A catalyst for producing 1,1,1-trifluoro-2,2-dichloroethane by gas-phase chlorination, and preparation and application methods therefor. The catalyst takes activated carbon as a carrier, and a metal chloride containing one or two of zinc, copper, nickel, manganese, and iron as an active component. In the process of preparing HCFC-123 by reacting HCFC-133a with chlorine as raw materials by a gas phase method, the catalyst shows high activity and selectivity at a low reaction temperature, and has long service life.

Description

Catalyst for gas-phase chlorination production of 1,1,1-trifluoro-2,2-dichloroethane, and preparation and use method thereof

Technical field

The invention relates to the technical field of hydrochlorofluorocarbons, in particular to a catalyst for producing 1,1,1-trifluoro-2,2-dichloroethane by gas-phase chlorination, and a method for preparing and using the same.

Background technique

1,1,1-trifluoro-2,2-dichloroethane is abbreviated as HCFC-123 (R-123), and its molecular formula is CF ₃ CHCl ₂ , which can be used as a refrigerant. The good comprehensive performance of R-123 refrigerant makes it It has become an effective and safe alternative refrigerant for R-11 (R11, Freon 11, F-11, CFC-11, chlorotrichloromethane, Freon 11) refrigerant in large central air-conditioning (centrifugal chiller). HCFC-123 can also be used for foaming of foam plastics, cleaning agents, chemical solvents and other raw materials of chemical products.

There are two main preparation routes for HCFC-123: trichloroethylene (TCE) route and tetrachloroethylene (PCE) route. The PCE route is a one-step reaction of PCE and hydrogen fluoride to synthesize HCFC-123. The disadvantage is that HCFC-123a, an isomer of HCFC-123, is formed, which is difficult to separate. The TCE route is divided into two steps. In the first step, TCE and hydrogen fluoride are catalyzed to synthesize 1,1,1-trifluoro-2-chloroethane (HCFC-133a). In the second step, HCFC-133a is chlorinated to HCFC-123. . Currently, most of the industrial production of HCFC-123 uses the trichloroethylene (TCE) route. However, the disadvantage of the trichloroethylene (TCE) route is that the reaction temperature is high when HCFC-133a is rechlorinated to HCFC-123, generally at 350 to 500 ° C, which results in the catalyst being easily carbonized and deactivated, and the selectivity of HCFC-123 is low In order to improve the selectivity of HCFC-123, a diluent needs to be added when HCFC-133a is rechlorinated, which increases the generation of by-products, resulting in the need to increase the separation process and increase the complexity of the process.

Such as US5171899, the name of the invention: a method for preparing 1,1,1-trifluoro-2,2-dichloroethane. In the invention, HCFC-133a is prepared by reacting HCFC-133a with chlorine gas (Cl ₂ ). The active component of the catalyst is NiCl ₂ , CuCl ₂ , FeCl ₂ , and the support is AlF ₃ or CrF ₃ . The reaction conditions are: 350 to 400 ° C, normal pressure, contact time of 0.5 to 30 s, Cl ₂ / HCFC-133a molar ratio of 0.05 to 0.5: 1, conversion rate of 10 to 40%, and selectivity of HCFC-123 of 77 to 91%. The disadvantage is that the high reaction temperature causes the catalyst to be easily decarbonized and deactivated, and there are many by-products.

Another example is US5132473, the invention name: a method for preparing 1,1,1-trifluoro-2,2-dichloroethane. In the invention, HCFC-133a is prepared by reacting HCFC-133a with HCl and O ₂ . In this invention, NiCl ₂ , CuCl ₂ , FeCl _{2 is} selected as the active component of the catalyst, and AlF _{3 is} selected as the support. The reaction conditions are: 350 to 500 ° C, normal pressure, contact time of 0.5 to 30s, conversion rate of 8 to 42%, and R-123 selectivity of 73 to 89%. The disadvantage is that the high reaction temperature causes the catalyst to be easily decarbonized and deactivated, and other diluents need to be passed in, which increases the complexity of the process.

Another example is US5414166, the invention name: a method for preparing 1,1,1-trifluoro-2,2-dichloroethane. The invention uses HCFC-133a, Cl ₂ and H ₂ to prepare HCFC-123 under the action of activated carbon. Reaction conditions: 350-450 ° C, contact time 15-45s, Cl ₂ / HCFC-133a molar ratio 1 to 5: 1, H ₂ / HCFC-133a molar ratio 0.5 to 3: 1, pressure 8 to 10 atm, reactor material 600 or Hastelloy or nickel, conversion rate of 42 to 79%, selectivity of 76 to 92%. The purpose of introducing H ₂ in this invention is to reduce the formation of trifluorotrichloroethane (HCFC-113a) and improve the selectivity of HCFC-123. The disadvantage is that the high reaction temperature causes the catalyst to be easily decarbonized and deactivated, and other diluents need to be passed in, which increases the complexity of the process.

Summary of the Invention

Aiming at the shortcomings of the prior art, the present invention provides a catalyst for gas phase chlorination production of 1,1,1-trifluoro-2,2-dichloroethane with simple process, mild reaction and good catalytic activity, and Its preparation and use methods.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a catalyst for producing 1,1,1-trifluoro-2,2-dichloroethane by gas-phase chlorination, wherein the catalyst uses activated carbon as a carrier, A metal chloride supporting one or two of zinc, copper, nickel, manganese, and iron is an active component.

The loading amount of the metal chloride is preferably 5 to 30 wt.% (Wt.%, Mass percentage).

The loading amount of the metal chloride is more preferably 10 to 20 wt.%.

The activated carbon is preferably coal-based activated carbon or coconut shell activated carbon.

The invention also provides a method for preparing the catalyst, including the following steps:

(1) The activated carbon is placed in a 10-30 wt.% Nitric acid solution, and the water bath is refluxed for 3 to 5 hours at 40 to 80 ° C, washed to neutrality, and then dried at 100 to 120 ° C for 10 to 15 hours to obtain a dried product. Activated carbon, spare

(2) disposing one or two chlorides of zinc, copper, nickel, manganese, and iron into a 10-20 wt.% Solution, and immersing the dried activated carbon obtained in step (1) in the solution, After stirring for 20 to 40 minutes, suction filtration, washing to neutrality, and then drying at 100 to 120 ° C for 5 to 15 hours, heat treatment at 300 to 400 ° C for 3 to 8 hours under a nitrogen atmosphere to prepare a catalyst.

The invention also provides a method for producing 1,1,1-trifluoro-2,2-dichloroethane by using the catalyst in gas phase chlorination. In the presence of the catalyst, 1,1,1-trifluoro-2 -Chloroethane and chlorine gas react to obtain 1,1,1-trifluoro-2,2-dichloroethane, the reaction temperature is 200-300 ° C, chlorine gas and 1,1,1-trifluoro-2- The molar ratio of ethyl chloride is 0.1 to 0.8: 1, and the space velocity is 100 to 800 h ^-1 .

The reaction temperature is preferably 220 to 250 ° C, the molar ratio of chlorine gas to 1,1,1-trifluoro-2-chloroethane is preferably 0.3 to 0.5: 1, and the space velocity is preferably 300 to 500 h ^-1 .

The catalyst carrier of the present invention is selected from activated carbon. Activated carbon is prepared by carbonization and activation treatment of various carbonaceous materials. Therefore, the properties of activated carbon produced by different raw materials in the industry are quite different, especially the pore structure of activated carbon is critical to its performance. Important role. The pores of the carbonaceous material are voids generated after the various carbon-containing compounds and disordered carbon are eliminated between the basic crystallites of the amorphous carbon during the preparation process. The void structure of the carbonaceous material has large pores leading directly to the outer surface of the carbonaceous material. The mesopores are branches of the macropores, and the micropores are branches of the mesopores. The pore structure and surface groups of activated carbon are two basic factors that determine its performance. The pore structure mainly affects the adsorption capacity and adsorption rate of activated carbon. Coal activated carbon or coconut shell activated carbon generally has the advantages of a dense pore structure, low content of inorganic impurities, and high mechanical strength. Therefore, the catalyst support in the present invention is preferably coal activated carbon or coconut shell activated carbon.

Activated carbon nitric acid pretreatment has a great influence on pore structure parameters and ash content. The nitric acid pretreatment can remove the impurities blocking the pores of the activated carbon and increase the specific surface area. The micropores and specific surface area of the coal charcoal and coconut shell char increase after the pretreatment, and the ash content decreases to only about 0.23wt.%.

Since the carbon material is easily decomposed under high temperature and oxygen-containing conditions, the heat treatment needs to be performed in a nitrogen atmosphere, during which the active components are redistributed on the carbon support. The heat treatment temperature affects the activity of the catalyst. If the heat treatment temperature is too low, the interaction between the active component and the support is not strong, and the catalyst is easily deactivated during the reaction. However, if the heat treatment temperature is too high, the active component will be sintered. The degree of dispersion decreases. After repeated tests, the temperature of 300-400 ° C for 3-8 hours, the prepared catalyst has the highest activity.

The choice of active ingredients has a direct effect on the conversion and selectivity of the reaction. 1,1,1-trifluoro-2-chloroethane and chlorine are used as raw materials to produce 1,1,1-trifluoro-2,2-dichloroethane by gas-phase chlorination. The active components are selected from zinc, copper, A metal chloride of one or both of nickel, manganese, and iron. Metal elements are supported on activated carbon in the form of chlorides. The loading of metal chloride components also has an important impact on the performance of the catalyst. The loading is too low and the catalytic activity is not enough; the loading is high and the activity is good, but the amount of by-product HCFC-113a is large. Therefore, the loading amount of the metal chloride component in the present invention is preferably 5 to 30 wt.%, And more preferably 10 to 20 wt.%.

When the catalyst of the present invention is used to prepare HCFC-123 using HCFC-133a and chlorine gas as raw materials, the reaction conditions have a great influence on the effect of generating HCFC-123, especially temperature and molar ratio. The temperature is too high, there are many HCFC-113a, and many other impurities, and the selectivity of HCFC-123 decreases; the temperature is too low, and the overall conversion of HCFC-133a is not high. According to experimental verification, the reaction temperature is 200-300 ° C, preferably 220 ~ 250 ° C. The molar ratio of chlorine gas and HCFC-133a is large, and the reaction moves in the direction of generating HCFC-113a. Therefore, in the present invention, the molar ratio of chlorine gas and HCFC-133a is selected from 0.1 to 0.8: 1, preferably 0.3 to 0.5: 1.

Compared with the prior art, the present invention has the following advantages:

1. The catalyst has good activity. Using the catalyst of the present invention to prepare HCFC-123 using HCFC-133a and chlorine gas as raw materials, a better reaction effect can be achieved at a lower temperature. When the reaction temperature is 200-300 ° C, HCFC-133a The conversion rate is above 22.6%, up to 48.5%; the selectivity of HCFC-123 is above 81.1%, up to 95.3%;

2. The process is simple. Using the catalyst of the present invention, HCFC-123 is prepared by using HCFC-133a and chlorine gas as raw materials in a gas-phase method. It does not need to pass in other diluents to achieve a good reaction effect, reduces the generation of by-products, and reduces waste. Less, which significantly simplifies the production process;

3. The catalyst has a long service life. Using the catalyst of the present invention can prepare HCFC-123 at a lower temperature, which delays the carbon deposition rate of the catalyst and extends the life of the catalyst.

detailed description

The present invention is described in further detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

Example 1

Catalyst preparation:

(1) Put 300 ml of coal-based activated carbon in a 30 wt.% Nitric acid solution, and treat it under reflux in a water bath at 50 ° C for 3h, wash it with distilled water to neutrality, and then dry it at 110 ° C for 15h to obtain dried activated carbon for future use;

(2) Weigh zinc chloride and copper chloride to prepare a solution with a concentration of 20 wt.%, Immerse the dried activated carbon obtained in step (1) in the solution, magnetically stir for 30 min, and then suction filter and wash with distilled water until Neutral, then dried at 110 ° C for 10 hours, and heat-treated at 350 ° C for 5 hours under a nitrogen atmosphere to prepare a catalyst. After analysis, the catalyst contains 8 wt.% Zinc chloride and 15 wt.% Copper chloride.

The catalyst prepared above was charged into a reactor, and HCFC-133a and chlorine gas were introduced for reaction. Samples were taken from the reactor outlet for analysis. The results are shown in Table 1.

Table 1 Analysis data of reactor outlet of Example 1

Example 2

Catalyst preparation:

(1) Put 300ml of coal-based activated carbon in a 20wt.% Nitric acid solution, and treat it under reflux in a water bath at 70 ° C for 3.5h, wash it with distilled water to neutrality, and then dry it at 105 ° C for 12h to obtain a dried activated carbon for future use. ;

(2) Weigh nickel chloride and copper chloride to prepare a solution with a concentration of 18 wt.%, Immerse the dried activated carbon obtained in step (1) in the solution, magnetically stir for 20 minutes, and then suction filter and wash with distilled water to Neutral, then dried at 100 ° C for 15h, and heat-treated at 300 ° C for 7 hours in a nitrogen atmosphere to prepare a catalyst. After analysis, the catalyst contains 7 wt.% Nickel chloride and 20 wt.% Copper chloride.

The catalyst prepared above was charged into a reactor, and HCFC-133a and chlorine gas were introduced for reaction. Samples were taken at the reactor outlet for analysis. The results are shown in Table 2.

Table 2 Analysis data of reactor outlet of Example 2

Example 3

Catalyst preparation:

(1) Put 300 ml of coal-based activated carbon in a 10 wt.% Nitric acid solution, reflux the water bath at 60 ° C for 3h, wash it with distilled water to neutrality, and then dry it at 115 ° C for 14h to obtain dried activated carbon for future use;

(2) Weigh manganese chloride and ferric chloride to prepare a solution with a concentration of 14wt.%, Immerse the dried activated carbon obtained in step (1) in the solution, magnetically stir for 25min, suction filter, and wash with distilled water until Neutral, then dried at 105 ° C for 8 hours, and heat-treated at 320 ° C for 8 hours under a nitrogen atmosphere to prepare a catalyst. After analysis, the catalyst contains 11 wt.% Manganese chloride and 6 wt.% Ferric chloride.

The catalyst prepared above was charged into a reactor, and HCFC-133a and chlorine gas were introduced for reaction. Samples were taken at the reactor outlet for analysis. The results are shown in Table 3.

Table 3 Analysis data of reactor outlet of Example 3

Example 4

Catalyst preparation:

(1) Put 300 ml of coconut shell activated carbon in a 30 wt.% Nitric acid solution, and treat it under reflux in a water bath at 80 ° C for 5h, wash it with distilled water to neutrality, and then dry it at 100 ° C for 12h to obtain dried activated carbon for future use;

(2) Weigh nickel chloride and ferric chloride to prepare a solution with a concentration of 10 wt.%, Immerse the dried activated carbon obtained in step (1) in the dry solution, magnetically stir for 30 minutes, and then suction filter and wash with distilled water to Neutral, then dried at 120 ° C for 10h, and heat-treated at 350 ° C for 5 hours in a nitrogen atmosphere to prepare a catalyst. After analysis, the catalyst contained 10 wt.% Of nickel chloride and 20 wt.% Of ferric chloride.

The catalyst prepared above was charged into a reactor, and HCFC-133a and chlorine gas were introduced for reaction. Samples were taken at the reactor outlet for analysis. The results are shown in Table 4.

Table 4 Example 4 reactor outlet analysis data

Example 5

Catalyst preparation:

(1) Put 300ml of coconut shell activated carbon in a 15wt.% Nitric acid solution, and treat it under reflux in a water bath at 55 ° C for 3h, wash it with distilled water to neutrality, and then dry it at 110 ° C for 13h to obtain a dried activated carbon for future use:

(2) Weigh copper chloride, prepare a solution with a concentration of 20wt.%, Immerse the dried activated carbon obtained in step (1) in the solution, magnetically stir for 35min, suction filter, wash with distilled water to neutrality, and then It was dried at 115 ° C for 12 hours and heat-treated at 370 ° C for 6 hours under a nitrogen atmosphere. After analysis, a catalyst was prepared, and the catalyst contained 10% by weight of copper chloride.

The catalyst prepared above was charged into a reactor, and HCFC-133a and chlorine gas were introduced for reaction. Samples were taken at the reactor outlet for analysis. The results are shown in Table 5.

Table 5 Example 5 reactor outlet analysis data

Example 6

Catalyst preparation

(1) Put 300 ml of coal-based activated carbon in a 30 wt.% Nitric acid solution, reflux the water bath at 40 ° C for 4h, wash it with distilled water to neutrality, and then dry it at 110 ° C for 10h to obtain dried activated carbon for future use;

(2) Weigh ferric chloride, prepare a solution with a concentration of 15 wt.%, Immerse the dried activated carbon obtained in step (1) in the solution, magnetically stir for 30 minutes, suction filter, wash with distilled water to neutrality, and then The catalyst was dried at 110 ° C for 10 hours, and heat-treated at 350 ° C for 5 hours under a nitrogen atmosphere. After analysis, the catalyst contained 5 wt.% Of ferric chloride.

The catalyst prepared above was charged into a reactor, and HCFC-133a and chlorine gas were introduced for reaction. Samples were taken at the reactor outlet for analysis. The results are shown in Table 6.

Table 6 Example 6 reactor outlet analysis data

Example 7

Catalyst preparation:

(1) 300 ml of coal-based activated carbon was placed in a 25 wt.% Nitric acid solution, and the water bath was refluxed at 75 ° C for 4.5h, washed with distilled water to neutrality, and then dried at 120 ° C for 11h to obtain dried activated carbon, which was reserved ;

(2) Weigh zinc chloride to prepare a solution with a concentration of 20wt.%, Immerse the dried activated carbon obtained in step (1) in the solution, magnetically stir for 40min, suction filter, wash with distilled water to neutrality, and then It was dried at 110 ° C for 5 hours, and heat-treated at 400 ° C for 3 hours under a nitrogen atmosphere to prepare a catalyst. After analysis, the catalyst contained 20 wt.% Zinc chloride.

The catalyst prepared above was charged into a reactor, and HCFC-133a and chlorine gas were introduced for reaction. Samples were taken at the reactor outlet for analysis. The results are shown in Table 7.

Table 7 Example 7 reactor outlet analysis data

Claims

A catalyst for producing 1,1,1-trifluoro-2,2-dichloroethane by gas-phase chlorination, characterized in that the catalyst uses activated carbon as a carrier and supports zinc, copper, nickel, manganese, and iron One or both of the metal chlorides are active ingredients.
The catalyst for gas-phase chlorination production of 1,1,1-trifluoro-2,2-dichloroethane according to claim 1, characterized in that the loading amount of the metal chloride is 5 to 30wt. %.
The catalyst for producing 1,1,1-trifluoro-2,2-dichloroethane for gas-phase chlorination according to claim 1, characterized in that the loading amount of the metal chloride is 10 to 20wt. %.
The catalyst for gas-phase chlorination production of 1,1,1-trifluoro-2,2-dichloroethane according to claim 1, wherein the activated carbon is coal-based activated carbon or coconut shell activated carbon.
The method for preparing a catalyst for producing 1,1,1-trifluoro-2,2-dichloroethane by gas-phase chlorination according to claim 1, comprising the following steps:

(1) The activated carbon is placed in a 10-30 wt.% Nitric acid solution, and the water bath is refluxed for 3 to 5 hours at 40 to 80 ° C, washed to neutrality, and then dried at 100 to 120 ° C for 10 to 15 hours to obtain a dried product. Activated carbon, spare

(2) disposing one or two chlorides of zinc, copper, nickel, manganese, and iron into a 10-20 wt.% Solution, and immersing the dried activated carbon obtained in step (1) in the solution, After stirring for 20 to 40 minutes, suction filtration, washing to neutrality, drying at 100 to 120 ° C for 5 to 15 hours, heat treatment at 300 to 400 ° C under a nitrogen atmosphere for 3 to 8 hours, to prepare a catalyst.
The method for using the catalyst for gas-phase chlorination production of 1,1,1-trifluoro-2,2-dichloroethane according to claim 1, characterized in that in the presence of the catalyst, 1,1 1,1-trifluoro-2-chloroethane and chlorine are reacted to obtain 1,1,1-trifluoro-2,2-dichloroethane. The temperature of the reaction is 200-300 ° C. Chlorine and 1,1, The molar ratio of 1-trifluoro-2-chloroethane is 0.1 to 0.8: 1, and the space velocity is 100 to 800 h -1 .
The method for using a catalyst for gas phase chlorination production of 1,1,1-trifluoro-2,2-dichloroethane according to claim 6, wherein the reaction temperature is 220-250 ° C The molar ratio of chlorine gas and 1,1,1-trifluoro-2-chloroethane is 0.3 to 0.5: 1, and the space velocity is 300 to 500 h -1 .