A catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to 2-chloro-3,3,3-trifluoropropene

Abstract

This invention discloses a catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to prepare 2-chloro-3,3,3-trifluoropropylene, the catalyst being designated M. x O y / Fe p O q -MgF2, in which Fe p O q -MgF2 as support, Fe p O q It is a mixture of Fe2O3 and Fe3O4, M x O y M is the active component. x O y It consists of one or more of Al2O3, CuO, ZnO, and La2O3. The catalyst preparation method includes: adding a polyamine to an aqueous solution of a soluble magnesium salt at 30℃~60℃ with stirring, then adding hydrofluoric acid dropwise, and continuing stirring for 10min~60min after the addition is complete; adding a soluble iron salt to the above solution, and continuing stirring for 30min~90min; adding ammonia dropwise to adjust the pH to 8~10, and continuing stirring for 60min~180min; filtering, washing the filter cake with deionized water until the pH of the filtrate is ~7, drying at 80℃~120℃, and calcining at 200℃~260℃ to obtain the supported Fe. p O q The precursor salt of the active component is loaded onto a support using an impregnation method, dried at 80℃~120℃, and calcined at 260℃~320℃ to obtain the desired catalyst. The catalyst in this invention does not involve chromium or antimony compounds, and exhibits high selectivity and yield for 2-chloro-3,3,3-trifluoropropylene, making it valuable for industrial applications.

Description

Technical Field

[0001] This invention relates to a catalyst, specifically a catalyst for the preparation of 2-chloro-3,3,3-trifluoropropylene from 1,1,1,3-tetrachloropropane via a chlorofluorination reaction. Background Technology

[0002] Fluorinated olefins, especially hydrofluoroolefins, such as 2,3,3,3-tetrafluoropropene (HFO-1234yf), are novel organofluorine compounds with zero ozone depletion potential (ODP) and low global warming potential (GWP). They are considered the best alternative to currently widely used hydrofluorocarbons (HFCs) and can be used as refrigerants, fluoropolymer monomers, etc. 2-Chloro-3,3,3-trifluoropropene (HCFO-1233xf) is an important intermediate in the preparation of HFO-1234yf.

[0003] The current process of preparing HCFO-1233xf using 1,1,1,3-tetrachloropropane (TCP) has the following problems: low selectivity and yield of HCFO-1233xf; the chromium-based catalyst used can be harmful to the human body, especially high-valent chromium, which is a strong carcinogen and may cause serious harm; multiple reaction steps are required, the process is lengthy, and the antimony-containing compounds used in the preparation process bring inconvenience to the reaction operation and post-processing, generating a large amount of waste and increasing treatment costs. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to prepare 2-chloro-3,3,3-trifluoropropene. This catalyst is a TCP catalyst for the preparation of HCFO-1233xf with short reaction steps, no involvement of chromium or antimony compounds, and high selectivity and yield.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to prepare 2-chloro-3,3,3-trifluoropropene is a supported catalyst, denoted as M. x O y / Fe p O q -MgF2, where Fe p O q -MgF2 is used as the support, Fe p O q It is a mixture of Fe2O3 and Fe3O4, M x O y The active component is M; x O yIt consists of one or more of Al2O3, CuO, ZnO, and La2O3; the preparation steps of this catalyst are as follows:

[0007] Step 1: While stirring, add polyamine to an aqueous solution of soluble magnesium salt at 30℃~60℃, then add hydrofluoric acid dropwise. After the addition is complete, continue stirring for 10min~60min.

[0008] Step 2: Add the soluble iron salt to the above solution and continue stirring for 30 min to 90 min;

[0009] Step 3: Add ammonia water dropwise to adjust the pH to 8-10, and continue stirring for 60-180 minutes.

[0010] Step 4: Filter by suction, wash the filter cake with deionized water until the pH of the filtrate reaches 7, dry at 80℃~120℃, and calcine at 200℃~260℃ to obtain the Fe support. p O q -MgF2;

[0011] Step 5: The precursor salt of the active component is loaded onto the support by impregnation, dried at 80℃~120℃, and calcined at 260℃~320℃ to obtain a catalyst for the preparation of 2-chloro-3,3,3-trifluoropropylene by chlorofluorination of 1,1,1,3-tetrachloropropane.

[0012] The present invention also includes the following technical features:

[0013] Specifically, the soluble magnesium salt is magnesium chloride, magnesium nitrate, or magnesium sulfate.

[0014] Specifically, the polyamine is ethylenediamine, 1,2-propanediamine, or 1,3-propanediamine.

[0015] Specifically, the molar ratio of the polyamine to the soluble magnesium salt is 0.1 to 0.6:1.

[0016] Specifically, the molar ratio of the hydrofluoric acid to the soluble magnesium salt is 2 to 3:1.

[0017] Specifically, the soluble iron salt is ferric chloride, ferric nitrate, or ferric sulfate.

[0018] Specifically, the molar ratio of the soluble iron salt to the soluble magnesium salt is 0.05 to 0.25:1.

[0019] Specifically, the precursor salt of the active component is aluminum chloride, aluminum nitrate, aluminum sulfate, copper chloride, copper nitrate, copper sulfate, zinc chloride, zinc nitrate, zinc sulfate, lanthanum chloride, or lanthanum nitrate.

[0020] Specifically, the molar ratio of the precursor salt and the soluble magnesium salt of the active component is 0.01 to 0.15:1.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] (1) The existing TCP preparation process for HCFO-1233xf involves long reaction steps, a lot of waste, and complicated post-treatment. The catalyst in this invention can realize the one-step chlorofluorination synthesis of HCFO-1233xf from TCP.

[0023] (2) Existing catalysts involve chromium and antimony compounds, and the selectivity and yield of HCFO-1233xf are low. The catalyst in this invention does not involve chromium and antimony compounds, and the selectivity and yield of HCFO-1233xf are high, both reaching over 92.0%. Detailed Implementation

[0024] This invention provides a catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to prepare 2-chloro-3,3,3-trifluoropropene. By selecting a suitable support and active component, the selectivity and yield of HCFO-1233xf are improved through their synergistic effect. Specifically, a polyamine is introduced during the support preparation process. On the one hand, the polyamine adjusts the pH value of the soluble magnesium salt aqueous solution to generate magnesium hydroxide precipitate. On the other hand, the nitrogen in the polyamine can coordinate with Mg to change the properties of the generated magnesium hydroxide. Then, hydrofluoric acid is added dropwise to the newly generated magnesium hydroxide precipitate to convert the magnesium hydroxide into magnesium fluoride sol. Soluble iron salt is introduced into the magnesium fluoride sol, allowing magnesium and iron to mix uniformly. After precipitation with ammonia, a support with uniform magnesium and iron mixing and a high specific surface area is obtained. The active component can regulate the acidity, alkalinity, and redox properties of the catalyst surface, giving the catalyst suitable acidity, alkalinity, and redox properties, thereby improving the selectivity and yield of HCFO-1233xf.

[0025] The catalyst used in this invention for the TCP chlorofluorination preparation of HCFO-1233xf is a supported catalyst, denoted as M. x O y / Fe p O q -MgF2, where Fe p O q -MgF2 is used as the support, Fe p O q It is a mixture of Fe2O3 and Fe3O4, M x O y The active component; active component M x O y It consists of one or more of Al2O3, CuO, ZnO, and La2O3.

[0026] The catalyst preparation steps are as follows: Under stirring, a polyamine is added to an aqueous solution of a soluble magnesium salt at 30℃~60℃, followed by the dropwise addition of hydrofluoric acid. After the addition is complete, stirring continues for 10min~60min. A soluble iron salt is then added to the above solution, and stirring continues for 30min~90min. Ammonia water is added dropwise to adjust the pH to 8~10, and stirring continues for 60min~180min. The solution is then filtered, and the filter cake is washed with deionized water until the pH of the filtrate reaches ~7. The filtrate is dried at 80℃~120℃ and calcined at 200℃~260℃ to obtain the Fe support. p O q -MgF2; The precursor salt of the active component was loaded onto the support by impregnation, dried at 80℃~120℃, and calcined at 260℃~320℃ to obtain the catalyst for the preparation of HCFO-1233xf by TCP chlorofluorination.

[0027] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0028] Evaluation of the catalyst performance involved in this invention: 60 mL of catalyst was measured and loaded into a fixed-bed tubular reactor with a diameter of Φ38 mm. The temperature was raised to 200 °C and dried for at least 2 h. Hydrogen fluoride gas was introduced for fluorination for 4–8 h. Then the temperature was raised to 300 °C and fluorination was continued for 12–24 h. The temperature was lowered to 240 °C and Cl2 and TCP were introduced. The molar ratio of HF, Cl2 and HCFO-1233xf was 10:0.6:1, the contact time was 8 s, and the reaction was run for 24 h. The reaction product was washed with water and alkali to absorb HF, HCl and Cl2, and then analyzed by gas chromatography. Peak area normalization was used for quantification to obtain TCP conversion rate and HCFO-1233xf selectivity data.

[0029] Example 1:

[0030] This embodiment provides a catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to prepare 2-chloro-3,3,3-trifluoropropene. Under stirring, 6.01 g of ethylenediamine was added to 500 mL of a 2 mol / L magnesium nitrate aqueous solution at 30 °C, followed by the dropwise addition of 100.00 g of hydrofluoric acid. After the addition was complete, stirring was continued for 10 min. 13.51 g of ferric chloride was added to the above solution, and stirring was continued for 30 min. Ammonia water was added dropwise to adjust the pH to 8, and stirring was continued for 60 min. The solution was filtered, and the filter cake was washed with deionized water until the pH of the filtrate was ~7. The filtrate was dried at 80 °C and calcined at 200 °C to obtain the support Fe. p O q-MgF2; 3.75 g of aluminum nitrate was loaded onto a support using an impregnation method, dried at 90 °C, and calcined at 270 °C to prepare the catalyst. Evaluation showed that the TCP conversion rate was 100%, and the HCFO-1233xf selectivity was 94.1%.

[0031] Example 2:

[0032] This embodiment provides a catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to prepare 2-chloro-3,3,3-trifluoropropene. Under stirring, 22.24 g of 1,2-propanediamine was added to 600 mL of a 1 mol / L magnesium chloride aqueous solution at 60°C. Then, 72.00 g of hydrofluoric acid was added dropwise, and stirring continued for 30 min after the addition was complete. 48.48 g of ferric nitrate was added to the above solution, and stirring continued for 60 min. Ammonia water was added dropwise to adjust the pH to 9, and stirring continued for 90 min. The solution was filtered, and the filter cake was washed with deionized water until the pH of the filtrate was ~7. The filtrate was dried at 100°C and calcined at 230°C to obtain the support Fe. p O q -MgF2; 10.23 g of copper chloride was loaded onto a support using an impregnation method, dried at 80 °C, and calcined at 260 °C to prepare the catalyst. Evaluation showed that the TCP conversion rate was 100%, and the HCFO-1233xf selectivity was 92.5%.

[0033] Example 3:

[0034] This embodiment provides a catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to prepare 2-chloro-3,3,3-trifluoropropene. Under stirring, 26.28 g of 1,3-propanediamine was added to 600 mL of a 1 mol / L magnesium sulfate aqueous solution at 40 °C. Then, 90.00 g of hydrofluoric acid was added dropwise, and stirring continued for 60 min after the addition was complete. 84.30 g of ferric sulfate was added to the above solution, and stirring continued for 90 min. Ammonia water was added dropwise to adjust the pH to 10, and stirring continued for 180 min. The solution was filtered, and the filter cake was washed with deionized water until the pH of the filtrate was ~7. The filtrate was dried at 120 °C and calcined at 260 °C to obtain the support Fe. p O q -MgF2; 25.88 g of zinc sulfate was loaded onto a support using an impregnation method, dried at 120 °C, and calcined at 320 °C to prepare the catalyst. Evaluation showed that the TCP conversion rate was 100%, and the HCFO-1233xf selectivity was 93.2%.

[0035] Example 4:

[0036] This embodiment provides a catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to prepare 2-chloro-3,3,3-trifluoropropene. Under stirring, 14.82 g of 1,2-propanediamine was added to 500 mL of a 2 mol / L magnesium nitrate aqueous solution at 50°C. Then, 120.00 g of hydrofluoric acid was added dropwise, and stirring continued for 40 min after the addition was complete. Next, 80.80 g of ferric nitrate was added to the solution, and stirring continued for another 80 min. Ammonia water was then added dropwise to adjust the pH to 9, and stirring continued for 120 min. The solution was filtered, and the filter cake was washed with deionized water until the pH of the filtrate was ~7. The filtrate was dried at 90°C and calcined at 240°C to obtain the Fe support. p O q -MgF2; 21.65 g of lanthanum nitrate was loaded onto a support using an impregnation method, dried at 100 °C, and calcined at 300 °C to prepare the catalyst. Evaluation showed that the TCP conversion rate was 100%, and the HCFO-1233xf selectivity was 95.4%.

Claims

1. A catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to 2-chloro-3,3,3-trifluoropropene, characterized in that, The catalyst is a supported catalyst, denoted as M x O y / Fe p O q -MgF2, wherein Fe p O q -MgF2 is the carrier, Fe p O q is a mixture of Fe2O3, Fe3O4, M x O y is the active component; the active component M x O y is composed of one or several of Al2O3, CuO, ZnO, La2O3; the catalyst is prepared as follows: Step 1, under stirring, a polyamine is added to a water solution of a soluble magnesium salt at 30-60℃, then hydrofluoric acid is added dropwise, and the stirring is continued for 10-60 minutes after the addition is completed; Step 2, a soluble iron salt is added to the above solution, and the stirring is continued for 30-90 minutes; Step 3, ammonia is added dropwise to adjust the pH to 8-10, and the stirring is continued for 60-180 minutes; Step 4, suction filtration, washing the filter cake with deionized water until the filtrate pH is 7, drying at 80-120°C, calcining at 200-260°C to obtain the carrier Fe p O q -MgF2; Step 5, a precursor salt of an active component is loaded onto a carrier by impregnation, dried at 80-120℃, and calcined at 260-320℃ to obtain a catalyst for the chlorofluorination of 1,1,1,3-tetrachloropropane to produce 2-chloro-3,3,3-trifluoropropene.

2. The catalyst for the production of 2-chloro-3,3,3-trifluoropropene by chlorofluorination of 1,1,1,3-tetrachloropropane according to claim 1, characterized in that, The soluble magnesium salt is magnesium chloride, magnesium nitrate or magnesium sulfate.

3. The catalyst for the production of 2-chloro-3,3,3-trifluoropropene by the chlorofluorination of 1,1,1,3-tetrachloropropane according to claim 1, characterized in that, The polyamine is ethylenediamine, 1,2-propanediamine or 1,3-propanediamine.

4. The catalyst for the production of 2-chloro-3,3,3-trifluoropropene by the chlorofluorination of 1,1,1,3-tetrachloropropane according to claim 1, characterized in that, The molar ratio of the polyamine to the soluble magnesium salt is 0.1-0.6:

1.

5. The catalyst for the production of 2-chloro-3,3,3-trifluoropropene by the chlorofluorination of 1,1,1,3-tetrachloropropane according to claim 1, characterized in that, The molar ratio of the hydrofluoric acid to the soluble magnesium salt is 2-3:

1.

6. The catalyst for the production of 2-chloro-3,3,3-trifluoropropene by the chlorofluorination of 1,1,1,3-tetrachloropropane according to claim 1, characterized in that, The soluble iron salt is ferric chloride, ferric nitrate or ferric sulfate.

7. The catalyst for the production of 2-chloro-3,3,3-trifluoropropene by the chlorofluorination of 1,1,1,3-tetrachloropropane according to claim 1, characterized in that, The molar ratio of the soluble iron salt to the soluble magnesium salt is 0.05-0.25:

1.

8. The catalyst for the production of 2-chloro-3,3,3-trifluoropropene by the chlorofluorination of 1,1,1,3-tetrachloropropane according to claim 1, characterized in that, The precursor salt of the active component is aluminum chloride, aluminum nitrate, aluminum sulfate, copper chloride, copper nitrate, copper sulfate, zinc chloride, zinc nitrate, zinc sulfate, lanthanum chloride or lanthanum nitrate.

9. The catalyst for the production of 2-chloro-3,3,3-trifluoropropene by the chlorofluorination of 1,1,1,3-tetrachloropropane according to claim 1, characterized in that, The molar ratio of the precursor salt of the active component to the soluble magnesium salt is 0.01-0.15:1.