A method for preparing perfluorooctyl bromide by catalytic bromination of perfluorooctyl iodide

Abstract

The present invention discloses a method for preparing perfluorooctyl bromide by catalytic bromination of perfluorooctyl iodide. First, fluorosilicic acid reacts with aluminum hydroxide, and after filtering to remove silicon dioxide, a mixed solution of fluoroaluminate and fluorosilicic acid is obtained. Then, a soluble metal salt additive and graphite powder are added thereto. After coprecipitation, granulation, and sintering, metal oxide-doped aluminum-based catalyst particles are obtained, which are loaded into a fixed-bed reactor. After fluorination with an N2 / HF mixed gas, perfluorooctyl iodide and bromine are vaporized and mixed and then enter the fixed-bed reactor, and perfluorooctyl bromide is prepared by reaction. In the present invention, the reaction raw materials are easily available; the reaction conditions are mild, and materials and equipment matching the process can be found in the existing equipment and material system to support the long-term stable operation of production; through the efficient catalysis of the catalyst and the continuous progress of the reaction gas phase, the reaction efficiency is improved and the consumption of bromine is reduced, so that the whole process has good atom economy and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of pharmaceutical synthesis, and particularly relates to a method for catalytic bromination of perfluorooctyl iodide to prepare perfluorooctyl bromide, an important alternative material for artificial blood. Background Art

[0002] Perfluorooctyl bromide (C8F 17 Br) has important medical and social significance as an artificial blood substitute material. The unique bromine atom in its molecule endows it with high lipophilicity and excellent biocompatibility. It can be efficiently emulsified by lecithin-based emulsions to form a stable oxygen carrier, and has the characteristic of rapid excretion, which can significantly reduce the accumulation risk of traditional perfluorocarbons in the body. Compared with the problems of vasoconstriction and nephrotoxicity easily caused by hemoglobin-based artificial blood, perfluorooctyl bromide can achieve a physiological-level oxygen dissociation curve without complex chemical modification, and has high chemical stability and temperature tolerance, which can greatly simplify the preparation process and improve clinical applicability. At the application level, its characteristic of not requiring blood type matching can completely solve the blood transfusion problem of patients with rare blood types; its ability to be stored at room temperature for several years and the 75% savings in cold chain costs are particularly suitable for extreme scenarios such as battlefield first aid and disaster relief. In addition, its high oxygen solubility and rapid oxygen release characteristics have also been extended to the fields of tumor radiotherapy sensitization and organ transplantation preservation, further highlighting its multi-dimensional medical value. With the successful research and development of medical-grade products, perfluorooctyl bromide has become one of the most promising artificial blood solutions for industrialization at present.

[0003] The main methods for preparing perfluorooctyl bromide reported in the current literature are as follows: First, CN112341310A reported that perfluorooctyl iodide reacts with bromine under photocatalysis at 70 °C to prepare perfluorooctyl bromide. This method is carried out under liquid-phase conditions, the reaction temperature exceeds the boiling point of bromine, and the reaction is carried out under positive pressure, which poses a very severe test to the sealing material of the equipment. It is difficult for the equipment to operate stably for a long time. In addition, since iodine tribromide will be generated, a large amount of excessive bromine needs to be consumed, and the atom economy is not good. Second, RU2739762C1 reported that perfluorooctanesulfonyl fluoride and hydrazine hydrate are used to produce perfluorooctanesulfonyl hydrazide and then react with bromine by heating to remove sulfur dioxide to prepare perfluorooctyl bromide. This method, like EP519808A1, requires the use of PFOS raw materials that have been comprehensively prohibited from production and does not have the feasibility of industrial production. Third, EP519808A1 reported that perfluorooctanesulfonyl chloride reacts with hydrogen bromide under the catalysis of a catalyst and heating conditions to prepare perfluorooctyl bromide. On the one hand, this method requires the use of PFOS, which has been comprehensively prohibited from production, and on the other hand, the yield is not high. Fourth, US5455373A reported that silver perfluorononanoate reacts with bromine by heating to undergo a decarboxylation reaction to prepare perfluorooctyl bromide. The raw material silver carbonate used in this method is a precious metal, and perfluorononanoic acid is also an uncommon industrial raw material, and the costs are all relatively high, so it is not economical. Fifth, JP60184033A reported that perfluorooctyl iodide and bromine react under photocatalysis in a 1,1,2-trichloro-1,2,2-trifluoroethane solvent to prepare perfluorooctyl bromide, with a yield of 42%. The cost is too high, and a large amount of three wastes are generated, so it does not have good technical economy. Sixth, CN102992944A reported that perfluorooctanesulfonyl chloride reacts with quaternary ammonium bromide to prepare perfluorooctyl bromide. This method, like EP519808A1, requires the use of PFOS raw materials that have been comprehensively prohibited from production and does not have the feasibility of industrial production. Seventh, JP2019014655A reported that perfluorooctyl iodide and bromine undergo a gas-phase bromination reaction at 350 °C to prepare perfluorooctyl bromide. This method has harsh conditions. At 350 °C, almost no materials can withstand the corrosion of bromine except for materials such as ceramics and quartz. However, the sealing of hard equipment such as ceramics and quartz has always been a difficult problem, and there are almost no sealing materials that can support the normal operation of the process under such harsh conditions, so it does not have the feasibility of mass production. Eighth, CN116903433A reported that perfluorooctane and bromine react under photocatalysis to prepare perfluorooctyl bromide. The perfluorooctane raw material used in this method is not easily available and the cost is relatively high. Summary of the Invention

[0004] In view of the disadvantages of the existing perfluorooctyl bromide production methods, such as difficult availability of raw materials, harsh reaction conditions making it difficult to match suitable equipment and processes, large consumption of bromine, a large amount of three wastes, and high costs, the present invention aims to provide a method for catalytic bromination of perfluorooctyl iodide to prepare perfluorooctyl bromide, an important alternative material for artificial blood. The reaction raw materials are easily available; the reaction conditions are mild, and materials and equipment that match the process can be found in the existing equipment and material systems to support the long-term stable operation of production; through the efficient catalysis of the catalyst and the continuous gas phase of the reaction, the reaction efficiency is improved and the bromine consumption is reduced, making the entire process have good atom economy and good application prospects.

[0005] To achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for catalytic bromination of perfluorooctyl iodide to prepare perfluorooctyl bromide, comprising the following steps:

[0007] Step 1: React fluorosilicic acid with aluminum hydroxide, filter to remove silicon dioxide to obtain a mixed solution of fluoroaluminum acid and fluorosilicic acid, then add a soluble metal salt auxiliary agent and graphite powder thereto, stir evenly, add ammonia water to adjust the pH to 14, and obtain metal oxide-doped aluminum-based catalyst particles after coprecipitation, granulation, and sintering; the metal in the soluble metal salt auxiliary agent is selected from at least three of titanium, copper, cerium, calcium, lanthanum, manganese, cobalt, and nickel;

[0008] Step 2: Load the above metal oxide-doped aluminum-based catalyst particles into a fixed-bed reactor, slowly fluorinate with an N2 / HF mixed gas to obtain a partially fluorinated, metal-doped aluminum-based catalyst; then pump perfluorooctyl iodide and bromine into a heated mixing tank respectively to vaporize and mix the two, and finally enter the fixed-bed reactor together with the carrier gas, and carry out bromination reaction under normal pressure to obtain perfluorooctyl bromide.

[0009] Preferably, in Step 1, when there is a titanium salt auxiliary agent in the soluble metal salt auxiliary agent, the titanium salt is tetraethyl titanate; when there are other non-titanium salt auxiliary agents in the soluble metal salt auxiliary agent, it is one of their chlorides and nitrates.

[0010] Preferably, in Step 1, the sintering temperature is 250~300°C and the time is 12~36h.

[0011] Preferably, in Step 1, the molar ratio of aluminum in the aluminum hydroxide to graphite powder is 1:40~60.

[0012] Preferably, in Step 1, the molar ratio of aluminum in the aluminum hydroxide to the metal in the soluble metal salt auxiliary agent is 80~99:1~20; more preferably 85~95:5~15.

[0013] Preferably, in step one, the metals in the soluble metal salt additive are titanium, copper and cerium, where the molar ratio of titanium, copper and cerium is 2:2:1, and the total molar amount of titanium, copper and cerium to the molar amount of aluminum is 10:90.

[0014] Preferably, in step two, the fluorination is carried out by gradient fluorination of the aluminum-based catalyst particles doped with metal oxides using N2 / HF mixed gases with different concentrations. During the gradient fluorination process, the volume ratio of N2 to HF decreases gradually in a gradient manner. For example, the volume ratios of N2 to HF are 20:1, 10:1, 5:1, 3:1, 1:1, 0:1 in sequence.

[0015] Preferably, in step two, in the bromination reaction, the molar ratio of bromine to perfluorooctyl iodide is not less than 1, and more preferably 1.2 - 2.0.

[0016] Preferably, in step two, in the bromination reaction, the space velocity is 100 - 500 h -1 , and more preferably 150 - 350 h -1 .

[0017] Preferably, in step two, in the bromination reaction, the reaction temperature is 100 - 210 °C, and more preferably 180 - 200 °C.

[0018] The advantages of the present invention are as follows:

[0019] (1) For the perfluorooctyl bromide preparation method provided by the present invention, the raw material used is perfluorooctyl iodide which is currently produced on a large scale in industrialization, and it well solves the problem of difficult availability of raw materials;

[0020] (2) For the perfluorooctyl bromide preparation method provided by the present invention, the consumption of bromine is within 1.8 equivalents, and the total yield based on perfluorooctyl iodide can be as high as 95%. It well solves the problem of poor atom economy caused by the need for a large excess of bromine due to the formation of iodine tribromide from bromine and iodine;

[0021] (3) For the perfluorooctyl bromide preparation method provided by the present invention, it greatly reduces the difficulty of the bromination reaction, enables the reaction to proceed smoothly optimally at about 190 °C, with both good conversion rate and yield. At this temperature, the mature PTFE-lined metal pipes widely used industrially can well withstand the corrosion of bromine, and the sealing problem can be solved by using PTFE gaskets between pipelines. It well solves the matching problem between equipment materials and equipment structure;

[0022] (4)The method for preparing perfluorooctyl bromide provided by the present invention has the whole reaction process continuously carried out under normal pressure. A relatively small tubular continuous reaction equipment can be used for continuous production for a long time. Both the process safety and process stability are good, which well solves a series of problems such as continuous production process. Large-scale production can be carried out with very small equipment and little floor area, and it has good application prospects.

[0023] (5)The method for preparing perfluorooctyl bromide provided by the present invention can also respectively obtain corresponding perfluorobutyl bromide and perfluorohexyl bromide for raw materials such as perfluoroiodobutane and perfluoroiodohexane in the same series. Description of the Drawings

[0024] Figure 1 It is the gas chromatogram of the reaction material in Comparative Example 1 after being condensed and collected and washed with sodium hydroxide to remove bromine and then sampled.

[0025] Figure 2 It is the gas chromatogram of the reaction material in Comparative Example 2 after being condensed and collected and washed with sodium hydroxide to remove bromine and then sampled.

[0026] Figure 3 It is the gas chromatogram of the reaction material in Example 1 after being condensed and collected and washed with sodium hydroxide to remove bromine and then sampled.

[0027] Figure 4 It is the gas chromatogram of the sample after the reaction in Example 1 lasted for 150 h and was washed with sodium hydroxide to remove bromine.

[0028] Figure 5 It is the gas chromatogram of the perfluorooctyl bromide product after rectification and purification in Example 1.

[0029] Figure 6 It is the gas chromatogram of the reaction material in Example 2 after being condensed and collected and washed with sodium hydroxide to remove bromine and then sampled.

[0030] Figure 7 It is the gas chromatogram of the reaction material in Example 3 after being condensed and collected and washed with sodium hydroxide to remove bromine and then sampled.

[0031] Figure 8 It is the gas chromatogram of the reaction material in Example 4 after being condensed and collected and washed with sodium hydroxide to remove bromine and then sampled.

[0032] Figure 9 It is the gas chromatogram of the reaction material in Example 5 after being condensed and collected and washed with sodium hydroxide to remove bromine and then sampled.

[0033] Figure 10It is the gas chromatogram of the reaction materials in Comparative Example 3 after being condensed and collected and washed with sodium hydroxide to remove bromine, and then sampled.

[0034] Figure 11 It is the gas chromatogram of the reaction materials in Comparative Example 4 after being condensed and collected and washed with sodium hydroxide to remove bromine, and then sampled. Specific Embodiments

[0035] Comparative Example 1

[0036] Perfluorooctyl iodide was added to the perfluorooctyl iodide vaporization tank from the perfluorooctyl iodide feeding port at a speed of 3.3 g / min by a peristaltic pump for vaporization. The temperature of the perfluorooctyl iodide vaporization tank was controlled at 190 °C. Nitrogen was introduced into the perfluorooctyl iodide vaporization tank at a speed of 88 ml / min to be mixed with perfluorooctyl iodide, and then the mixed gas entered the mixing tank to be mixed with bromine together; bromine was added to the bromine vaporization tank from the bromine feeding port at a speed of 1.56 g / min by an injection pump for vaporization. The temperature of the bromine vaporization tank was controlled at 180 °C. Nitrogen was introduced into the bromine vaporization tank at a speed of 88 ml / min to be mixed with bromine together, and then the mixed gas entered the mixing tank to be mixed with perfluorooctyl iodide; the temperature of the vaporization tank was controlled at 180 °C. The perfluorooctyl iodide, bromine and nitrogen that were uniformly mixed in the vaporization tank entered the inner-lined tetrafluoro fixed-bed reactor for reaction without adding a catalyst. The temperature in the reactor was 190 °C, the pressure was atmospheric pressure, and the overall space velocity was 320. After the reaction materials were condensed and collected and washed with sodium hydroxide to remove bromine, samples were taken for gas chromatographic analysis. The results are as Figure 1 shown. The content of perfluorooctyl bromide was 10.2%, and almost all the remaining components were unreacted perfluorooctyl iodide raw materials.

[0037] Comparative Example 2

[0038] 100 g of aluminum hydroxide was reacted with 570 g of 18% fluosilicic acid to obtain a mixture of fluoroaluminum acid and silicon dioxide. After filtering to remove silicon dioxide, a clear and transparent mixed solution of fluoroaluminum acid and fluosilicic acid was obtained. Then, 761 g of graphite powder with a particle size of 400 mesh and 8 L of pure water were added thereto. Ammonia water was slowly added thereto until the pH value reached 14, and the reaction was continued to stir for 30 min. Then, it was left to stand and age for 24 h, filtered, and the filter cake was washed with pure water until neutral to obtain a fluoride catalyst precursor powder mainly composed of ammonium fluoroaluminate. It was granulated with a granulator to obtain fluoride catalyst precursor particles mainly composed of ammonium fluoroaluminate. The obtained fluoride catalyst precursor particles mainly composed of ammonium fluoroaluminate were placed in a muffle furnace and sintered at 280 °C for 24 h, and then the catalyst precursor particles mainly composed of aluminum fluoride were taken out and cooled for use.

[0039] Place 105 ml of the obtained catalyst precursor particles mainly composed of aluminum fluoride in a Teflon-lined fixed-bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm. First, pass nitrogen with a flow rate of 100 ml / min, turn on the heating, heat to 100 °C first and hold at 100 °C for 30 min, then raise the temperature to 200 °C and hold at 200 °C for 30 min, and then raise the temperature to 300 °C to dry the catalyst precursor particles mainly composed of aluminum fluoride. After 12 h, the drying is completed. Cool down to 190 °C. First, pass a mixed gas with a volume ratio of N2 / HF of 20:1 and a gas flow rate of 100 ml / min to further fluorinate the catalyst precursor mainly composed of aluminum fluoride for 2 h; then adjust the volume ratio of N2 / HF to 10:1 and the gas flow rate remains 100 ml / min to continue partial fluorination of the catalyst precursor mainly composed of aluminum fluoride for 2 h; then adjust the volume ratio of N2 / HF to 5:1 and the gas flow rate remains 100 ml / min to continue further fluorination of the catalyst precursor mainly composed of aluminum fluoride for 2 h; then adjust the volume ratio of N2 / HF to 3:1 and the gas flow rate remains 100 ml / min to continue further fluorination of the catalyst precursor mainly composed of aluminum fluoride for 2 h; then adjust the volume ratio of N2 / HF to 1:1 and the gas flow rate remains 100 ml / min to continue partial fluorination of the catalyst precursor mainly composed of aluminum fluoride for 2 h; then adjust the volume ratio of N2 / HF to 0:1 and the gas flow rate remains 100 ml / min to continue further fluorination of the catalyst precursor mainly composed of aluminum fluoride for 2 h; after the fluorination is completed, a partially porous aluminum fluoride catalyst is obtained. After the catalyst activation is completed, the reactor temperature is maintained at 190 °C and the nitrogen flow rate is maintained at 100 ml / min, waiting for feeding.

[0040] Perfluorooctyl iodide is added to the perfluorooctyl iodide vaporization tank from the perfluorooctyl iodide feeding port by a peristaltic pump at a speed of 3.3 g / min for vaporization. The temperature of the perfluorooctyl iodide vaporization tank is controlled at 190 °C. Nitrogen is introduced into the perfluorooctyl iodide vaporization tank at a speed of 88 ml / min to mix with perfluorooctyl iodide, and then the mixed gas enters the mixing tank to mix with bromine; bromine is added to the bromine vaporization tank from the bromine feeding port by an injection pump at a speed of 1.56 g / min for vaporization. The temperature of the bromine vaporization tank is controlled at 190 °C. Nitrogen is introduced into the bromine vaporization tank at a speed of 88 ml / min to mix with bromine, and then the mixed gas enters the mixing tank to mix with perfluorooctyl iodide; the temperature of the vaporization tank is controlled at 190 °C. The perfluorooctyl iodide, bromine and nitrogen that are uniformly mixed in the vaporization tank enter a Teflon-lined fixed-bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm filled with catalyst for reaction. The temperature in the reactor is 190 °C, the pressure is atmospheric pressure, and the overall space velocity is 320 h -1, after the reaction materials were condensed and collected and washed with sodium hydroxide to remove bromine, a sample was taken for gas chromatography analysis, and the results were as Figure 2 shown. The perfluorooctyl bromide content reached 33.78%, and 65.68% of the perfluorooctyliodide had not been converted.

[0041] Example 1

[0042] 100 g of aluminum hydroxide was reacted with 570 g of 18% fluorosilicic acid to obtain a mixture of fluoroaluminum acid and silicon dioxide. After filtering to remove silicon dioxide, a clear and transparent mixed solution of fluoroaluminum acid and fluorosilicic acid was obtained. Then, 10.69 g of copper nitrate, 13 g of tetraethyl titanate, 9.29 g of cerium nitrate, 761 g of graphite powder with a particle size of 400 mesh, and 8 L of pure water were added thereto. Ammonia water was slowly added thereto until the pH value reached 14, and the mixture was continuously stirred and reacted for 30 min, then left to stand and age for 24 h, filtered, and the filter cake was washed with pure water until neutral to obtain a fluoride catalyst precursor powder mainly composed of ammonium fluoroaluminate. After granulation with a granulator, it was placed in a muffle furnace and sintered at 280 °C for 24 h to obtain aluminum fluoride catalyst particles doped with titanium copper cerium oxides.

[0043] 105 ml of the obtained aluminum fluoride catalyst particles doped with titanium copper cerium oxides was placed in a fixed-bed reactor lined with tetrafluoroethylene with an inner diameter of 1.5 cm and a heating zone length of 60 cm. First, nitrogen was passed through, and the nitrogen flow rate was 100 ml / min. Heating was started, and it was first heated to 100 °C and maintained at 100 °C for 30 min, then heated to 200 °C and maintained at 200 °C for 30 min, and then heated to 300 °C to dry the aluminum fluoride catalyst particles doped with titanium copper cerium oxides. After 12 h, the drying was completed. The temperature was lowered to 190 °C. First, a mixed gas with a volume ratio of N2 / HF of 20:1 and a gas flow rate of 100 ml / min was passed through to fluorinate the aluminum fluoride catalyst particles doped with titanium copper cerium oxides for 2 h; then the volume ratio of N2 / HF was adjusted to 10:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 5:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 3:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 1:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 0:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; after the fluorination was completed, a partially fluorinated aluminum fluoride catalyst doped with titanium copper cerium was obtained. After the catalyst activation was completed, the reactor temperature was maintained at 190 °C, and the nitrogen flow rate was maintained at 100 ml / min, waiting for feeding.

[0044] Perfluorooctyl iodide was added into the perfluorooctyl iodide vaporization tank through a peristaltic pump at a rate of 3.3 g / min from the perfluorooctyl iodide feeding port for vaporization. The temperature of the perfluorooctyl iodide vaporization tank was controlled at 190 °C. Nitrogen was introduced into the perfluorooctyl iodide vaporization tank at a rate of 88 ml / min to mix with perfluorooctyl iodide. Then the mixed gas entered the mixing tank to mix with bromine. Bromine was added into the bromine vaporization tank through an injection pump at a rate of 1.56 g / min from the bromine feeding port for vaporization. The temperature of the bromine vaporization tank was controlled at 190 °C. Nitrogen was introduced into the bromine vaporization tank at a rate of 88 ml / min to mix with bromine. Then the mixed gas entered the mixing tank to mix with perfluorooctyl iodide. The temperature of the vaporization tank was controlled at 190 °C. The perfluorooctyl iodide, bromine and nitrogen that were uniformly mixed in the vaporization tank entered a lined tetrafluoro fixed bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm filled with catalyst for reaction. The temperature in the reactor was 190 °C, the pressure was atmospheric pressure, and the overall space velocity was 320 h -1 , After the reaction materials were condensed and collected and washed with sodium hydroxide to remove bromine, samples were taken for gas chromatography analysis. The results were as Figure 3 shown. The content of perfluorooctyl bromide reached 98.5%, and all the raw material perfluorooctyl iodide was converted.

[0045] In order to investigate the catalyst life and accumulate and separate and purify the materials, the whole reaction lasted for 150 h. After 150 h, samples were taken, washed with sodium hydroxide to remove bromine, and then subjected to gas chromatography analysis. The results were as Figure 4 shown. The content of perfluorooctyl bromide decreased to 65%, and 34.4% of the raw material perfluorooctyl iodide remained.

[0046] The total raw materials consumed in the whole process were 30 Kg. The crude perfluorooctyl bromide obtained was rectified and purified after washing the bromine with sodium hydroxide. The results were as Figure 5 shown. 22.7 Kg of perfluorooctyl bromide product with a purity of 99.68% was obtained, and the total yield was 83.6%.

[0047] Example 2

[0048] 105 ml of the titanium-copper-cerium oxide-doped aluminum fluoride catalyst particles obtained in Example 1 were placed in a PTFE-lined fixed-bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm. First, nitrogen was passed through at a flow rate of 100 ml / min. Heating was started, and the temperature was first raised to 100 °C and maintained at 100 °C for 30 min, then raised to 200 °C and maintained at 200 °C for 30 min, and then raised to 300 °C to dry the titanium-copper-cerium oxide-doped aluminum fluoride catalyst particles. The drying was completed after 12 h. The temperature was lowered to 190 °C. First, a mixed gas with a volume ratio of N2 / HF of 20:1 was passed through at a gas flow rate of 100 ml / min to fluorinate the titanium-copper-cerium oxide-doped aluminum fluoride catalyst particles for 2 h; then the volume ratio of N2 / HF was adjusted to 10:1, and the gas flow rate remained 100 ml / min for further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 5:1, and the gas flow rate remained 100 ml / min for further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 3:1, and the gas flow rate remained 100 ml / min for further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 1:1, and the gas flow rate remained 100 ml / min for further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 0:1, and the gas flow rate remained 100 ml / min for further fluorination for 2 h; after the fluorination was completed, a partially fluorinated, titanium-copper-cerium-doped aluminum fluoride catalyst was obtained. After the catalyst activation was completed, the reactor temperature was maintained at 190 °C, and the nitrogen flow rate was maintained at 100 ml / min, waiting for the feed.

[0049] Perfluorooctyl iodide was vaporized by a peristaltic pump at a rate of 4.5 g / min from the perfluorooctyl iodide feed port and added to the perfluorooctyl iodide vaporization tank. The temperature of the perfluorooctyl iodide vaporization tank was controlled at 190 °C. Nitrogen was introduced into the perfluorooctyl iodide vaporization tank at a rate of 120 ml / min and mixed with perfluorooctyl iodide, and then the mixed gas entered the mixing tank to be mixed with bromine; bromine was vaporized by an injection pump at a rate of 2.14 g / min from the bromine feed port and added to the bromine vaporization tank. The temperature of the bromine vaporization tank was controlled at 190 °C. Nitrogen was introduced into the bromine vaporization tank at a rate of 120 ml / min and mixed with bromine, and then the mixed gas entered the mixing tank to be mixed with perfluorooctyl iodide; the temperature of the vaporization tank was controlled at 190 °C. The perfluorooctyl iodide, bromine, and nitrogen that were uniformly mixed in the vaporization tank entered a PTFE-lined fixed-bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm filled with the catalyst and reacted. The temperature in the reactor was 190 °C, the pressure was atmospheric pressure, and the overall space velocity was 436.5 h -1 , after the reaction materials were condensed and collected and washed with sodium hydroxide to remove bromine, samples were taken for gas chromatography analysis, and the results were asFigure 6 As shown, the perfluorooctyl bromide content reaches 91.09%, and 7.27% of the raw material perfluorooctyl iodide has not been completely converted.

[0050] Example 3

[0051] 105 ml of the titanium-copper-cerium oxide-doped aluminum fluoride catalyst particles obtained in Example 1 were placed in a fixed-bed reactor lined with tetrafluoroethylene with an inner diameter of 1.5 cm and a heating zone length of 60 cm. First, nitrogen was passed through, and the nitrogen flow rate was 100 ml / min. Heating was started, and it was first heated to 100 °C and maintained at 100 °C for 30 min, then heated to 200 °C and maintained at 200 °C for 30 min, and then heated to 300 °C to dry the titanium-copper-cerium oxide-doped aluminum fluoride catalyst particles. After 12 h, the drying was completed. The temperature was lowered to 190 °C. First, a mixed gas with a volume ratio of N2 / HF of 20:1 and a gas flow rate of 100 ml / min was passed through to fluorinate the aluminum-titanium-copper-cerium fluoride catalyst precursor for 2 h; then the volume ratio of N2 / HF was adjusted to 10:1 and the gas flow rate remained 100 ml / min for further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 5:1 and the gas flow rate remained 100 ml / min for further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 3:1 and the gas flow rate remained 100 ml / min for further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 1:1 and the gas flow rate remained 100 ml / min for further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 0:1 and the gas flow rate remained 100 ml / min for further fluorination for 2 h; after the fluorination was completed, a partially fluorinated, titanium-copper-cerium-doped aluminum fluoride catalyst was obtained. After the catalyst activation was completed, the reactor temperature was maintained at 190 °C and the nitrogen flow rate was maintained at 100 ml / min, waiting for feeding.

[0052] Perfluorooctyl iodide was added into the perfluorooctyl iodide vaporization tank from the perfluorooctyl iodide feeding port at a speed of 2 g / min by a peristaltic pump for vaporization. The temperature of the perfluorooctyl iodide vaporization tank was controlled at 190 °C. Nitrogen was introduced into the perfluorooctyl iodide vaporization tank at a speed of 54 ml / min to be mixed with perfluorooctyl iodide, and then the mixed gas entered the mixing tank to be mixed with bromine. Bromine was added into the bromine vaporization tank from the bromine feeding port at a speed of 0.95 g / min by an injection pump for vaporization. The temperature of the bromine vaporization tank was controlled at 190 °C. Nitrogen was introduced into the bromine vaporization tank at a speed of 54 ml / min to be mixed with bromine, and then the mixed gas entered the mixing tank to be mixed with perfluorooctyl iodide. The temperature of the vaporization tank was controlled at 190 °C. The perfluorooctyl iodide, bromine and nitrogen that were uniformly mixed in the vaporization tank entered a lined tetrafluoro fixed bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm filled with a catalyst for reaction. The temperature in the reactor was 190 °C, the pressure was atmospheric pressure, and the overall space velocity was 193.9 h -1 , after the reaction materials were condensed and collected and washed with sodium hydroxide to remove bromine, samples were taken for gas chromatography analysis, and the results were as Figure 7 shown. The content of perfluorooctyl bromide reached 98.59%, and the raw material perfluorooctyl iodide was completely converted.

[0053] Example 4

[0054] 490 ml of the titanium-copper-cerium oxide-doped aluminum fluoride catalyst particles obtained in Example 1 were placed in a tetrafluoro-lined fixed-bed reactor with an inner diameter of 2.5 cm and a heating zone length of 100 cm. First, nitrogen was passed through at a flow rate of 100 ml / min. Heating was started, and the temperature was first raised to 100 °C and maintained at 100 °C for 30 min, then raised to 200 °C and maintained at 200 °C for 30 min, and then raised to 300 °C to dry the titanium-copper-cerium oxide-doped aluminum fluoride catalyst particles. After 12 h, the drying was completed. The temperature was lowered to 190 °C. First, a mixed gas with a volume ratio of N2 / HF of 20:1 was passed through at a gas flow rate of 100 ml / min to fluorinate the titanium-copper-cerium oxide-doped aluminum fluoride catalyst particles for 2 h; then the volume ratio of N2 / HF was adjusted to 10:1 and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 5:1 and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 3:1 and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 1:1 and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 0:1 and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; after the fluorination was completed, a partially fluorinated, titanium-copper-cerium-doped aluminum fluoride catalyst was obtained. After the catalyst activation was completed, the reactor temperature was maintained at 190 °C and the nitrogen flow rate was maintained at 100 ml / min, waiting for the feed.

[0055] Perfluorooctyl iodide was added to the perfluorooctyl iodide vaporization tank from the perfluorooctyl iodide feed port by a peristaltic pump at a speed of 15.3 g / min for vaporization. The temperature of the perfluorooctyl iodide vaporization tank was controlled at 190 °C. Nitrogen was passed into the perfluorooctyl iodide vaporization tank at a speed of 410 ml / min to mix with perfluorooctyl iodide, and then the mixed gas entered the mixing tank to mix with bromine; bromine was added to the bromine vaporization tank from the bromine feed port by an injection pump at a speed of 7.26 g / min for vaporization. The temperature of the bromine vaporization tank was controlled at 190 °C. Nitrogen was passed into the bromine vaporization tank at a speed of 410 ml / min to mix with bromine, and then the mixed gas entered the mixing tank to mix with perfluorooctyl iodide; the temperature of the vaporization tank was controlled at 190 °C. The perfluorooctyl iodide, bromine, and nitrogen that were uniformly mixed in the vaporization tank entered a tetrafluoro-lined fixed-bed reactor with an inner diameter of 2.5 cm and a heating zone length of 100 cm filled with a catalyst for reaction. The temperature in the reactor was 190 °C, the pressure was atmospheric pressure, and the overall space velocity was 320 h -1 , after the reaction materials were condensed and collected and washed with sodium hydroxide to remove bromine, samples were taken for gas chromatography analysis, and the results were asFigure 8 As shown, the perfluorooctyl bromide content reaches 98.28%, and all the raw material perfluorooctyl iodide is converted.

[0056] Example 5

[0057] 100 g of aluminum hydroxide was reacted with 570 g of fluosilicic acid with a concentration of 18% to obtain a mixture of fluoroaluminum acid and silicon dioxide. After filtering to remove silicon dioxide, a clear and transparent mixed solution of fluoroaluminum acid and fluosilicic acid was obtained. Then, 10.69 g of copper nitrate, 7.4 g of cobalt chloride, 9.26 g of lanthanum nitrate, 761 g of graphite powder with a particle size of 400 mesh, and 8 L of pure water were added thereto. Ammonia water was slowly added thereto until the pH value reached 14, and the reaction was continued with stirring for 30 min. Then, it was allowed to stand for aging for 24 h, filtered, and the filter cake was washed with pure water until neutral to obtain a fluoride catalyst precursor powder mainly composed of ammonium fluoroaluminate. After granulation with a granulator, it was placed in a muffle furnace and sintered at 280 °C for 24 h to obtain copper-cobalt-lanthanum oxide-doped aluminum fluoride catalyst particles.

[0058] 105 ml of the obtained copper-cobalt-lanthanum oxide-doped aluminum fluoride catalyst particles were placed in a fixed-bed reactor lined with tetrafluoroethylene with an inner diameter of 1.5 cm and a heating zone length of 60 cm. First, nitrogen was passed, and the nitrogen flow rate was 100 ml / min. Heating was started, and it was first heated to 100 °C and maintained at 100 °C for 30 min, then heated to 200 °C and maintained at 200 °C for 30 min, and then heated to 300 °C to dry the copper-cobalt-lanthanum oxide-doped aluminum fluoride catalyst particles. After 12 h, the drying was completed. The temperature was lowered to 190 °C. First, a mixed gas with a volume ratio of N2 / HF of 20:1 and a gas flow rate of 100 ml / min was passed to fluorinate the copper-cobalt-lanthanum oxide-doped aluminum fluoride catalyst particles for 2 h; then the volume ratio of N2 / HF was adjusted to 10:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 5:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 3:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 1:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 0:1, and the gas flow rate remained 100 ml / min to continue further fluorination for 2 h; after the fluorination was completed, a partially fluorinated, copper-cobalt-lanthanum-doped aluminum fluoride catalyst was obtained. After the catalyst activation was completed, the reactor temperature was maintained at 190 °C, and the nitrogen flow rate was maintained at 100 ml / min, waiting for feeding.

[0059] Perfluorooctyl iodide was added into the perfluorooctyl iodide vaporization tank from the perfluorooctyl iodide feeding port at a speed of 3.3 g / min by a peristaltic pump for vaporization. The temperature of the perfluorooctyl iodide vaporization tank was controlled at 190 °C. Nitrogen was introduced into the perfluorooctyl iodide vaporization tank at a speed of 88 ml / min to be mixed with perfluorooctyl iodide, and then the mixed gas entered the mixing tank to be mixed with bromine. Bromine was added into the bromine vaporization tank from the bromine feeding port at a speed of 1.56 g / min by an injection pump for vaporization. The temperature of the bromine vaporization tank was controlled at 190 °C. Nitrogen was introduced into the bromine vaporization tank at a speed of 88 ml / min to be mixed with bromine, and then the mixed gas entered the mixing tank to be mixed with perfluorooctyl iodide. The temperature of the vaporization tank was controlled at 190 °C. The perfluorooctyl iodide, bromine and nitrogen that were uniformly mixed in the vaporization tank entered a lined tetrafluoro fixed-bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm filled with a catalyst for reaction. The temperature in the reactor was 190 °C, the pressure was atmospheric pressure, and the overall space velocity was 320 h -1 , after the reaction materials were condensed and collected and washed with sodium hydroxide to remove bromine, samples were taken for gas chromatography analysis, and the results were as Figure 9 shown. The content of perfluorooctyl bromide reached 92.17%, and the content of perfluorooctyl iodide was 6.52%.

[0060] Comparative Example 3

[0061] 100 g of aluminum hydroxide was reacted with 570 g of 18% fluorosilicic acid to obtain a mixture of fluoroaluminum acid and silicon dioxide. After filtering to remove silicon dioxide, a clear and transparent mixed solution of fluoroaluminum acid and fluorosilicic acid was obtained. Then 10.69 g of copper nitrate, 13 g of tetraethyl titanate, 761 g of graphite powder with a particle size of 400 mesh and 8 L of pure water were added thereto. Ammonia water was slowly added thereto until the pH value reached 14, and the reaction was continued to stir for 30 min, and then left to age for 24 h. After filtration, the filter cake was washed with pure water until neutral to obtain a fluoride catalyst precursor powder mainly composed of ammonium fluoroaluminate. After granulation with a granulator, it was sintered in a muffle furnace at 280 °C for 24 h to obtain titanium copper oxide-doped aluminum fluoride catalyst particles.

[0062] Place 105 ml of the obtained titanium copper oxide-doped aluminum fluoride catalyst particles into a tetrafluoro-lined fixed-bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm. First, pass nitrogen with a flow rate of 100 ml / min. Turn on the heating, first heat to 100 °C and hold at 100 °C for 30 min, then raise the temperature to 200 °C and hold at 200 °C for 30 min, and then raise the temperature to 300 °C to dry the titanium copper oxide-doped aluminum fluoride catalyst particles. After 12 h, the drying is completed. Cool down to 190 °C. First, pass a mixed gas with a volume ratio of N2 / HF of 20:1 and a gas flow rate of 100 ml / min to fluorinate the titanium copper oxide-doped aluminum fluoride catalyst particles for 2 h; then adjust the volume ratio of N2 / HF to 10:1 and still maintain the gas flow rate at 100 ml / min to continue further fluorination for 2 h; then adjust the volume ratio of N2 / HF to 5:1 and still maintain the gas flow rate at 100 ml / min to continue further fluorination for 2 h; then adjust the volume ratio of N2 / HF to 3:1 and still maintain the gas flow rate at 100 ml / min to continue further fluorination for 2 h; then adjust the volume ratio of N2 / HF to 1:1 and still maintain the gas flow rate at 100 ml / min to continue further fluorination for 2 h; then adjust the volume ratio of N2 / HF to 0:1 and still maintain the gas flow rate at 100 ml / min to continue further fluorination for 2 h; after the fluorination is completed, a partially fluorinated, titanium copper-doped aluminum fluoride catalyst is obtained. After the catalyst activation is completed, the reactor temperature is maintained at 190 °C and the nitrogen flow rate is maintained at 100 ml / min, waiting for feeding.

[0063] Perfluorooctyl iodide is vaporized by a peristaltic pump at a rate of 3.3 g / min from the perfluorooctyl iodide feeding port and added to the perfluorooctyl iodide vaporization tank. The temperature of the perfluorooctyl iodide vaporization tank is controlled at 190 °C. Nitrogen is introduced into the perfluorooctyl iodide vaporization tank at a rate of 88 ml / min to mix with perfluorooctyl iodide, and then the mixed gas enters the mixing tank to mix with bromine; bromine is vaporized by an injection pump at a rate of 1.56 g / min from the bromine feeding port and added to the bromine vaporization tank. The temperature of the bromine vaporization tank is controlled at 190 °C. Nitrogen is introduced into the bromine vaporization tank at a rate of 88 ml / min to mix with bromine, and then the mixed gas enters the mixing tank to mix with perfluorooctyl iodide; the temperature of the vaporization tank is controlled at 190 °C. The perfluorooctyl iodide, bromine, and nitrogen that are uniformly mixed in the vaporization tank enter a tetrafluoro-lined fixed-bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm filled with the catalyst for reaction. The temperature in the reactor is 190 °C, the pressure is atmospheric pressure, and the overall space velocity is 320 h -1 , after the reaction materials are condensed and collected and washed with sodium hydroxide to remove bromine, a sample is taken for gas chromatography analysis, and the results are as Figure 10As shown, the perfluorooctyl bromide content reaches 70.73%, and the perfluorooctyl iodide content is 28.63%.

[0064] Comparative Example 4

[0065] 100 g of aluminum hydroxide was reacted with 570 g of fluorosilicic acid with a concentration of 18% to obtain a mixture of fluoroaluminum acid and silicon dioxide. After filtering to remove silicon dioxide, a clear and transparent mixed solution of fluoroaluminum acid and fluorosilicic acid was obtained. Then, 10.69 g of copper nitrate, 9.29 g of cerium nitrate, 761 g of graphite powder with a particle size of 400 mesh, and 8 L of pure water were added thereto. Ammonia water was slowly added thereto until the pH value reached 14, and the reaction was continued with stirring for 30 min. Then, it was left to stand and age for 24 h, filtered, and the filter cake was washed with pure water until neutral to obtain a fluoride catalyst precursor powder mainly composed of ammonium fluoroaluminate. After granulation with a granulator, it was placed in a muffle furnace and sintered at 280 °C for 24 h to obtain copper-cerium oxide-doped aluminum fluoride catalyst particles.

[0066] 105 ml of the obtained copper-cerium oxide-doped aluminum fluoride catalyst particles were placed in a fixed-bed reactor lined with tetrafluoroethylene with an inner diameter of 1.5 cm and a heating zone length of 60 cm. First, nitrogen was passed through, and the nitrogen flow rate was 100 ml / min. Heating was started, and it was first heated to 100 °C and maintained at 100 °C for 30 min, then heated to 200 °C and maintained at 200 °C for 30 min, and then heated to 300 °C to dry the copper-cerium oxide-doped aluminum fluoride catalyst particles. After 12 h, the drying was completed. The temperature was lowered to 190 °C. First, a mixed gas with a volume ratio of N2 / HF of 20:1 was passed through at a gas flow rate of 100 ml / min to fluorinate the copper-cerium oxide-doped aluminum fluoride catalyst particles for 2 h; then the volume ratio of N2 / HF was adjusted to 10:1 and the gas flow rate was still 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 5:1 and the gas flow rate was still 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 3:1 and the gas flow rate was still 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 1:1 and the gas flow rate was still 100 ml / min to continue further fluorination for 2 h; then the volume ratio of N2 / HF was adjusted to 0:1 and the gas flow rate was still 100 ml / min to continue further fluorination for 2 h; after the fluorination was completed, a partially fluorinated, copper-cerium-doped aluminum fluoride catalyst was obtained. After the catalyst activation was completed, the reactor temperature was maintained at 190 °C and the nitrogen flow rate was maintained at 100 ml / min, waiting for feeding.

[0067] Perfluorooctyl iodide was added to the perfluorooctyl iodide vaporization tank from the perfluorooctyl iodide feeding port at a rate of 3.3 g / min by a peristaltic pump for vaporization. The temperature of the perfluorooctyl iodide vaporization tank was controlled at 190 °C. Nitrogen was introduced into the perfluorooctyl iodide vaporization tank at a rate of 88 ml / min to be mixed with perfluorooctyl iodide, and then the mixed gas entered the mixing tank to be mixed with bromine. Bromine was added to the bromine vaporization tank from the bromine feeding port at a rate of 1.56 g / min by an injection pump for vaporization. The temperature of the bromine vaporization tank was controlled at 190 °C. Nitrogen was introduced into the bromine vaporization tank at a rate of 88 ml / min to be mixed with bromine, and then the mixed gas entered the mixing tank to be mixed with perfluorooctyl iodide. The temperature of the vaporization tank was controlled at 190 °C. The perfluorooctyl iodide, bromine and nitrogen that were uniformly mixed in the vaporization tank entered a lined tetrafluoro fixed-bed reactor with an inner diameter of 1.5 cm and a heating zone length of 60 cm filled with a catalyst for reaction. The temperature in the reactor was 190 °C, the pressure was atmospheric pressure, and the overall space velocity was 320 h -1 , after the reaction materials were condensed and collected and washed with sodium hydroxide to remove bromine, samples were taken for gas chromatography analysis, and the results were as Figure 11 shown. The content of perfluorooctyl bromide reached 80.93%, and the content of perfluorooctyl iodide was 18.43%.

Claims

1. A method for preparing perfluorooctyl bromide by catalytic bromination of perfluorooctyl iodide, characterized in that, It includes the following steps: Step 1: React fluosilicic acid with aluminum hydroxide, filter to remove silicon dioxide to obtain a mixed solution of fluoaluminate and fluosilicic acid, then add a soluble metal salt additive and graphite powder thereto, stir evenly, add ammonia water to adjust the pH to 14, and obtain metal oxide-doped aluminum-based catalyst particles after coprecipitation, granulation and sintering; the metal in the soluble metal salt additive is selected from titanium, copper and cerium; or copper, lanthanum and cobalt; Step 2: Load the above-mentioned metal oxide-doped aluminum-based catalyst particles into a fixed-bed reactor, slowly fluorinate with an N2 / HF mixed gas to obtain a partially fluorinated and metal-doped aluminum-based catalyst; then pump perfluorooctyl iodide and bromine into a heated mixing tank respectively to vaporize and mix them, and finally enter the fixed-bed reactor together with the carrier gas, and carry out a bromination reaction under normal pressure to prepare perfluorooctyl bromide.

2. The method according to claim 1, characterized in that, In Step 1, when there is a titanium salt additive in the soluble metal salt additive, the titanium salt is tetraethyl titanate; when there are other non-titanium salt additives in the soluble metal salt additive, it is one of their chlorides and nitrates.

3. The method according to claim 1, wherein In Step 1, the sintering temperature is 250-300 °C and the time is 12-36 h.

4. The method according to claim 1, wherein In Step 1, the molar ratio of aluminum in the aluminum hydroxide to graphite powder is 1:40-60.

5. The method according to claim 1, wherein In Step 1, the molar ratio of aluminum in the aluminum hydroxide to the metal in the soluble metal salt additive is 80-99:1-20.

6. The method according to claim 5, characterized in that, In Step 1, the molar ratio of aluminum in the aluminum hydroxide to the metal in the soluble metal salt additive is 85-95:5-15.

7. The method according to any one of claims 1-6, characterized in that, In Step 1, the metal in the soluble metal salt additive is titanium, copper and cerium, and the molar ratio of titanium, copper and cerium is 2:2:1, and the total molar amount of titanium, copper and cerium to aluminum is 10:

90.

8. The method according to claim 1, characterized in that In Step 2, the fluorination is to carry out gradient fluorination on the metal oxide-doped aluminum-based catalyst particles with N2 / HF mixed gases of different concentrations. During the gradient fluorination process, the volume ratio of N2 to HF decreases in a gradient manner.

9. The method according to claim 1, characterized in that, In Step 2, in the bromination reaction, the molar ratio of bromine to perfluorooctyl iodide is not less than 1; the space velocity is 100 - 500 h -1 ; the reaction temperature is 100 - 210 °C.

10. The method according to claim 9, characterized in that, In Step 2, in the bromination reaction, the molar ratio of bromine to perfluorooctyl iodide is 1.2 to 2.0; the space velocity is 150 to 350 h -1 ; the reaction temperature is 180 to 200 °C.

Images