A resource utilization method of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane

Abstract

The present invention relates to a resource utilization method of low value-added by-products, and in particular to a resource utilization method of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane. The resource utilization method comprises the following steps: filling a bimetallic fluoride catalyst, sequentially performing a dehydration treatment and a reduction treatment on the bimetallic fluoride catalyst, then heating up and passing a mixed gas of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and hydrogen, performing a selective hydrodechlorination reaction, and obtaining 1,2-dibromo-1,2,2-trifluoroethane. The resource utilization method converts 1,2-dibromo-1-chloro-1,2,2-trifluoroethane, a by-product in the production process of bromotrifluoroethylene, into 1,2-dibromo-1,2,2-trifluoroethane, so that the by-product can continue to be used in the synthesis step of subsequent bromotrifluoroethylene, and the overall yield of bromotrifluoroethylene is improved.

Description

Technical Field

[0001] The invention relates to a method for resource utilization of low value-added by-products, and specifically to a method for resource utilization of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane. Background Art

[0002] Bromotrifluoroethylene, also known as trifluoroethylene bromide, molecular formula: C2BrF3, molecular weight: 160.921, CAS number: 598-73-2, DOT number: UN2419, boiling point: -2.5 ℃ (101.325kPa), relative vapor density 5.6, easily soluble in DMF and DMSO. Trifluoroethylene bromide is a colorless gas with a musty odor. It is easy to spontaneously ignite in the air and easily polymerize at room temperature. In order to prevent its self-polymerization, it is usually stored at low temperature or with an inhibitor (0.1% tributylamine). The inhibitor can be simply removed by passing the mixed gas through silica gel in subsequent use.

[0003] Bromotrifluoroethylene has the properties of fluorinated olefins, including halogenation, hydrogenation, and nucleophilic reactions. It is mainly used in polymerization reactions and can also be used as a chemical intermediate. Its metal organic intermediates are important reagents for the synthesis of trifluoroethylene compounds. The telomeres can be used as floating liquids and damping liquids for high-precision navigation system liquid-floating gyroscopes and accelerometers, and are used in the aerospace industry. Bromotrifluoroethylene is often used to prepare a variety of polymers and copolymers, and is also used in the preparation of fluorinated styrenes. For example, the thermoplastic resin homopolymer of trifluoroethylene has a wide range of commercial and use values. At the same time, bromotrifluoroethylene is also one of the three monomers (tetrafluoroethylene, perfluoromethyl perfluorovinyl ether, and bromotrifluoroethylene) required for the preparation of cured fluororubber.

[0004] At present, the synthesis route of trifluoroethylene bromide is mainly trifluorochloroethylene hydrobromination, but since 1,2-dibromo-1-chloro-1,2,2-trifluoroethane will inevitably be produced in the process, the overall yield of trifluoroethylene bromide will be reduced, and the purity of trifluoroethylene bromide will also be greatly affected. Therefore, how to remove the production of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane or utilize it as a resource is an urgent problem to be solved in this process route. Summary of the invention

[0005] The technical problem to be solved by the present invention is: how to realize the resource utilization of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for resource utilization of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane, comprising the following steps: filling a bimetallic fluoride catalyst, sequentially performing a dehydration treatment and a reduction treatment on the bimetallic fluoride catalyst, then heating and introducing a mixed gas of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and hydrogen to perform a selective hydrodechlorination reaction to obtain 1,2-dibromo-1,2,2-trifluoroethane.

[0007] The beneficial effect of the present invention is that the present invention converts 1,2-dibromo-1-chloro-1,2,2-trifluoroethane, a by-product in the production process of bromotrifluoroethylene, into 1,2-dibromo-1,2,2-trifluoroethane, so that the by-product can be continuously used in the subsequent synthesis step of bromotrifluoroethylene, thereby improving the overall yield of bromotrifluoroethylene and realizing the resource utilization of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane. DETAILED DESCRIPTION

[0008] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes.

[0009] A method for resource utilization of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane comprises the following steps: filling a bimetallic fluoride catalyst, sequentially performing a dehydration treatment and a reduction treatment on the bimetallic fluoride catalyst, then heating and introducing a mixed gas of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and hydrogen to perform a selective hydrodechlorination reaction to obtain 1,2-dibromo-1,2,2-trifluoroethane. The entire catalytic reaction process is detected online by GC-MS to calculate the conversion rate and target product selectivity.

[0010] From the above description, it can be seen that the beneficial effect of the present invention is that the present invention converts the by-product 1,2-dibromo-1-chloro-1,2,2-trifluoroethane in the production process of bromotrifluoroethylene into 1,2-dibromo-1,2,2-trifluoroethane by utilizing a bimetallic fluoride catalyst, and 1,2-dibromo-1,2,2-trifluoroethane can be further used in the subsequent synthesis steps of bromotrifluoroethylene, thereby effectively improving the overall yield of bromotrifluoroethylene, achieving the process production goal of green chemistry, and having excellent industrial application prospects.

[0011] In one or more embodiments, the first metal of the bimetallic fluoride catalyst is one of Zn, Pb, Ba, Ca, Sr and Mg, preferably Zn, Pb or Ba, and the second metal is one of Co, Cu and Ni, preferably Cu or Ni.

[0012] From the above description, it can be seen that the first metal is selected from Zn, Pb, Ba, Ca, Sr or Mg, especially Zn, Pb and Ba can effectively and selectively activate the C-Cl bond in 1,2-dibromo-1-chloro-1,2,2-trifluoroethane without breaking the C-Br bond, which greatly improves the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane. At the same time, the hydrogenation metal is selected from base metals such as Cu or Ni, which makes the catalyst cheap, easy to industrially apply, and has extremely high economic benefits.

[0013] In one or more embodiments, the molar ratio of the first metal to the second metal of the bimetallic fluoride catalyst is 10:1 to 50:1, preferably 10:1 to 30:1.

[0014] In one or more embodiments, the fluorine source of the bimetallic fluoride catalyst is excess ammonium fluoride.

[0015] In one or more embodiments, the atmosphere of the dehydration treatment is nitrogen, the temperature of the dehydration treatment is 300° C., and the time is 3 h.

[0016] From the above description, it can be seen that the adsorbed water and surface hydroxyl groups of the catalyst are removed by dehydration treatment, and the dehydration temperature should not be too high, which will cause catalyst sintering.

[0017] In one or more embodiments, the atmosphere of the reduction treatment is a mixed gas of nitrogen and hydrogen, with a volume ratio of N2 / H2 of 3:1, and the temperature of the reduction treatment is 400°C and the time is 6 h.

[0018] It can be seen from the above description that conventional reduction treatment temperature and time are sufficient, and too high a reduction temperature will cause the active metal to sinter and agglomerate.

[0019] In one or more embodiments, the temperature of the selective hydrodechlorination reaction is 350-600°C, preferably 400-500°C.

[0020] In one or more embodiments, the reaction space velocity of the selective hydrodechlorination reaction is 200 to 1200 h -1 , preferably 300~800 h -1 .

[0021] In one or more embodiments, the particle size of the bimetallic fluoride catalyst is 20-40 mesh.

[0022] In one or more embodiments, the volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane to hydrogen is 1:1 to 1:3.

[0023] In one or more embodiments, a method for preparing a ZnCu bimetallic fluoride catalyst comprises the following steps: weighing zinc nitrate hexahydrate, copper nitrate trihydrate and ammonium fluoride, dissolving them in deionized water, stirring, washing and filtering the resulting precipitate with deionized water, and then drying it at 120°C for 12 h, and finally calcining it in a muffle furnace at 500°C for 4 h to obtain a ZnCu bimetallic fluoride catalyst; wherein the Zn / Cu molar ratio is 10:1~50:1, preferably 10:1~30:1.

[0024] Embodiment 1: Weigh 29.7 g of zinc nitrate hexahydrate, 2.42 g of copper nitrate trihydrate and 37 g of ammonium fluoride and dissolve them in 1000 mL of deionized water. After stirring for 2 h, wash the obtained precipitate with deionized water and filter it, then dry it at 120 °C for 12 h, and finally calcine it in a muffle furnace at 500 °C for 4 h to obtain a ZnCu bimetallic fluoride catalyst. Then, the catalyst is pressed into tablets to obtain a ZnCu bimetallic fluoride catalyst with a particle size of 20-40 mesh.

[0025] In a fixed bed reactor with an online detection system for GC-MS, 10 mL of ZnCu bimetallic fluoride catalyst with a particle size of 20-40 mesh was first loaded, and then 100 mL / min of N2 was introduced and the temperature was raised to 300 °C for dehydration treatment for 3 h, and then the temperature was raised to 400 °C, and the gas was switched to a mixture of N2 and H2, with a volume ratio of N2 / H2 of 3:1 and a total flow rate of 100 mL / min. The catalyst was reduced for 6 h. Then the temperature was kept constant and the atmosphere was switched to a mixture of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2, with a volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2 of 1:1.3, and a reaction space velocity of 300 h -1 .

[0026] After online detection by GC-MS, the conversion rate of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 87.4%, the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane was 97.8%, and the catalyst remained stable after 30 h (i.e., the conversion rate of the reactants and the selectivity of the target product remained basically unchanged).

[0027] Embodiment 2: 23.6 g of calcium nitrate tetrahydrate, 2.91 g of cobalt nitrate hexahydrate and 37 g of ammonium fluoride were weighed and dissolved in 1000 mL of deionized water. After stirring for 2 h, the obtained precipitate was washed with deionized water and filtered, and then dried at 120 °C for 12 h, and finally calcined in a muffle furnace at 500 °C for 4 h to obtain a CaCo bimetallic fluoride catalyst. The catalyst was then pressed into tablets to obtain a CaCo bimetallic fluoride catalyst with a particle size of 20-40 mesh.

[0028] In a fixed bed reactor with an online detection system for GC-MS, 10 mL of CaCo bimetallic fluoride catalyst with a particle size of 20-40 mesh was first loaded, and then 100 mL / min of N2 was introduced and the temperature was raised to 300 °C for dehydration treatment for 3 h, and then the temperature was raised to 400 °C, and the gas was switched to a mixture of N2 and H2, with a volume ratio of N2 / H2 of 3:1 and a total flow rate of 100 mL / min. The catalyst was reduced for 6 h. Then the temperature was cooled to 350 °C, and the atmosphere was switched to a mixture of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2, with a volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2 of 1:1, and the reaction space velocity was 200 h -1 .

[0029] After online detection by GC-MS, the conversion rate of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 83.9%, the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane was 91.7%, and the catalyst remained stable after 35 h.

[0030] Embodiment 3: Weigh 21.2 g of strontium nitrate, 0.58 g of nickel nitrate hexahydrate and 37 g of ammonium fluoride and dissolve them in 1000 mL of deionized water. After stirring for 2 h, wash the obtained precipitate with deionized water and filter it, then dry it at 120 °C for 12 h, and finally calcine it in a muffle furnace at 500 °C for 4 h to obtain a SrNi bimetallic fluoride catalyst. Then, press the catalyst into tablets to obtain a SrNi bimetallic fluoride catalyst with a particle size of 20-40 mesh.

[0031] In a fixed bed reactor with an online detection system for GC-MS, 10 mL of SrNi bimetallic fluoride catalyst with a particle size of 20-40 mesh was first loaded, and then 100 mL / min of N2 was introduced and heated to 300 °C for dehydration treatment for 3 h, and then the temperature was raised to 400 °C, and the gas was switched to a mixture of N2 and H2, with a volume ratio of N2 / H2 of 3:1 and a total flow rate of 100 mL / min. The catalyst was reduced for 6 h. Then the temperature was raised to 600 °C, and the atmosphere was switched to a mixture of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2, with a volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2 of 1:3, and the reaction space velocity was 1200 h -1 .

[0032] After GC-MS online detection, the conversion rate of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 91.2%, the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane was 89.9%, and the catalyst remained stable after 40 h.

[0033] Embodiment 4: Weigh 25.6 g of magnesium nitrate hexahydrate, 1.2 g of copper nitrate trihydrate and 37 g of ammonium fluoride and dissolve them in 1000 mL of deionized water. After stirring for 2 h, wash the obtained precipitate with deionized water and filter it, then dry it at 120 °C for 12 h, and finally calcine it in a muffle furnace at 500 °C for 4 h to obtain a MgCu bimetallic fluoride catalyst. Then, the catalyst is pressed into tablets to obtain a MgCu bimetallic fluoride catalyst with a particle size of 20-40 mesh.

[0034] In a fixed bed reactor with an online detection system for GC-MS, 10 mL of MgCu bimetallic fluoride catalyst with a particle size of 20-40 mesh was first loaded, and then 100 mL / min of N2 was introduced and heated to 300 °C for dehydration treatment for 3 h, and then the temperature was raised to 400 °C, and the gas was switched to a mixture of N2 and H2, with a volume ratio of N2 / H2 of 3:1 and a total flow rate of 100 mL / min. The catalyst was reduced for 6 h. The temperature was then raised to 550 °C, and the atmosphere was switched to a mixture of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2, with a volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane to H2 of 1:2.5, and a reaction space velocity of 1000 h -1 .

[0035] After online detection by GC-MS, the conversion rate of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 82.4%, the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane was 91.9%, and the catalyst remained stable after 40 h.

[0036] Embodiment 5: 33.1 g of lead nitrate, 2.9 g of nickel nitrate hexahydrate and 37 g of ammonium fluoride were weighed and dissolved in 1000 mL of deionized water. After stirring for 2 h, the obtained precipitate was washed with deionized water and filtered, and then dried at 120 °C for 12 h. Finally, it was calcined in a muffle furnace at 500 °C for 4 h to obtain a PbNi bimetallic fluoride catalyst. The catalyst was then pressed into tablets to obtain a PbNi bimetallic fluoride catalyst with a particle size of 20-40 mesh.

[0037] In a fixed bed reactor with an online detection system for GC-MS, 10 mL of a 20-40 mesh PbNi bimetallic fluoride catalyst was first loaded, and then 100 mL / min of N2 was introduced and heated to 300 °C for dehydration for 3 h, and then the temperature was raised to 400 °C, and the gas was switched to a mixture of N2 and H2, with a volume ratio of N2 / H2 of 3:1 and a total flow rate of 100 mL / min. The catalyst was reduced for 6 h. The temperature was then raised to 450 °C, and the atmosphere was switched to a mixture of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2, with a volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane to H2 of 1:1.5, and a reaction space velocity of 600 h -1 .

[0038] After online detection by GC-MS, the conversion rate of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 88.4%, the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane was 98.1%, and the catalyst remained stable after 50 h.

[0039] Embodiment 6: Weigh 26.1 g of barium nitrate, 0.8 g of copper nitrate trihydrate and 37 g of ammonium fluoride and dissolve them in 1000 mL of deionized water. After stirring for 2 h, wash the obtained precipitate with deionized water and filter it, then dry it at 120 °C for 12 h, and finally calcine it in a muffle furnace at 500 °C for 4 h to obtain a BaCu bimetallic fluoride catalyst. Then, press the catalyst into tablets to obtain a BaCu bimetallic fluoride catalyst with a particle size of 20-40 mesh.

[0040] In a fixed bed reactor with an online detection system for GC-MS, 10 mL of BaCu bimetallic fluoride catalyst with a particle size of 20-40 mesh was first loaded, and then 100 mL / min of N2 was introduced and heated to 300 °C for dehydration treatment for 3 h, and then the temperature was raised to 400 °C, and the gas was switched to a mixture of N2 and H2, with a volume ratio of N2 / H2 of 3:1 and a total flow rate of 100 mL / min. The catalyst was reduced for 6 h. Then the temperature was raised to 500 °C, and the atmosphere was switched to a mixture of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2, with a volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2 of 1:2, and the reaction space velocity was 800 h -1 .

[0041] After online detection by GC-MS, the conversion rate of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 86.9%, the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane was 97.9%, and the catalyst remained stable after 35 h.

[0042] Embodiment 7: 29.7 g of zinc nitrate hexahydrate, 1.45 g of nickel nitrate hexahydrate and 37 g of ammonium fluoride were weighed and dissolved in 1000 mL of deionized water. After stirring for 2 h, the obtained precipitate was washed with deionized water and filtered, and then dried at 120 °C for 12 h. Finally, it was calcined in a muffle furnace at 500 °C for 4 h to obtain a ZnNi bimetallic fluoride catalyst. The catalyst was then pressed into tablets to obtain a ZnNi bimetallic fluoride catalyst with a particle size of 20-40 mesh.

[0043] In a fixed bed reactor with an online detection system for GC-MS, 10 mL of ZnNi bimetallic fluoride catalyst with a particle size of 20-40 mesh was first loaded, and then 100 mL / min of N2 was introduced and heated to 300 °C for dehydration treatment for 3 h, and then the temperature was raised to 400 °C, and the gas was switched to a mixture of N2 and H2, with a volume ratio of N2 / H2 of 3:1 and a total flow rate of 100 mL / min. The catalyst was reduced for 6 h. Then the temperature was raised to 450 °C, and the atmosphere was switched to a mixture of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2, with a volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2 of 1:1.8, and the reaction space velocity was 500 h -1 .

[0044] After online detection by GC-MS, the conversion rate of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 87.8%, the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane was 98.4%, and the catalyst remained stable after 50 h.

[0045] Embodiment 8: 33.1 g of lead nitrate, 2.42 g of copper nitrate trihydrate and 37 g of ammonium fluoride were weighed and dissolved in 1000 mL of deionized water. After stirring for 2 h, the obtained precipitate was washed with deionized water and filtered, and then dried at 120 °C for 12 h. Finally, it was calcined in a muffle furnace at 500 °C for 4 h to obtain a PbCu bimetallic fluoride catalyst. The catalyst was then pressed into tablets to obtain a PbCu bimetallic fluoride catalyst with a particle size of 20-40 mesh.

[0046] In a fixed bed reactor with an online detection system for GC-MS, 10 mL of a 20-40 mesh PbCu bimetallic fluoride catalyst was first loaded, and then 100 mL / min of N2 was introduced and heated to 300 °C for dehydration for 3 h, and then the temperature was raised to 400 °C, and the gas was switched to a mixture of N2 and H2, with a volume ratio of N2 / H2 of 3:1 and a total flow rate of 100 mL / min. The catalyst was reduced for 6 h. Then, the temperature was kept constant, and the atmosphere was switched to a mixture of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and H2, with a volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane to H2 of 1:1.6, and a reaction space velocity of 550 h -1 .

[0047] After online detection by GC-MS, the conversion rate of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 88.3%, the selectivity of the target product 1,2-dibromo-1,2,2-trifluoroethane was 99.1%, and the catalyst remained stable after 50 h.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for resource utilization of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane, characterized in that: The following steps are involved: The bimetallic fluoride catalyst is filled, and the bimetallic fluoride catalyst is sequentially subjected to a dehydration treatment and a reduction treatment, and then the temperature is increased and a mixed gas of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and hydrogen is introduced to carry out a selective hydrogenation dechlorination reaction to obtain 1,2-dibromo-1,2,2-trifluoroethane.

2. The resource utilization method according to claim 1, characterized in that: The first metal of the bimetallic fluoride catalyst is one of Zn, Pb, Ba, Ca, Sr and Mg, and the second metal is one of Co, Cu and Ni.

3. The resource utilization method according to claim 1 or 2, characterized in that: The molar ratio of the first metal to the second metal of the bimetallic fluoride catalyst is 10:1 to 50:

1.

4. The resource utilization method according to claim 1, characterized in that: The fluorine source of the bimetallic fluoride catalyst is ammonium fluoride.

5. The resource utilization method according to claim 1, characterized in that: The atmosphere for the water removal treatment is nitrogen.

6. The resource utilization method according to claim 1, characterized in that: The atmosphere for the reduction treatment is a mixed gas of nitrogen and hydrogen.

7. The resource utilization method according to claim 1, characterized in that: The temperature of the selective hydrodechlorination reaction is 350-600°C.

8. The resource utilization method according to claim 1, characterized in that: The reaction space velocity of the selective hydrodechlorination reaction is 200-1200 h -1 .

9. The resource utilization method according to claim 1, characterized in that: The particle size of the bimetallic fluoride catalyst is 20-40 meshes.

10. The resource utilization method according to claim 1, characterized in that: The volume ratio of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane to hydrogen is 1:1~1:3.