Manufacturing method of 1,2-dichlorohexafluorocyclopentene

Abstract

Disclosed is a manufacturing method of 1,2-dichlorohexafluorocyclopentene. The first reaction uses dicyclopentadiene as a starting material and nitrogen gas or another inert gas as a diluting agent in a gas-phase thermal cracking reaction to obtain cyclopentadiene. The second reaction uses cyclopentadiene as a starting material in a liquid phase chlorination reaction with chlorine gas to obtain 1,2,3,4-tetrachlorocyclopentane. The third reaction uses 1,2,3,4-tetrachlorocyclopentane as a starting material in a gas-phase chlorination and fluorination reaction with hydrogen fluoride and chlorine gas in the presence of a chromium-based catalyst to obtain 1,2-dichlorohexafluorocyclopentene. The method uses easily acquired starting material and a stable fluorination catalyst, provides a high yield for a target product, and is applicable for large-scale continuous gas-phase production of 1,2-dichlorohexafluorocyclopentene.

Claims

1. A method for preparing 1,2 dichlorohexafluorocyclopentene, comprising: in step one: pyrolysing dicyclopentadiene, as raw material, to obtain cyclopentadiene, with nitrogen or other inert gas as a diluent in a molar ratio of the diluent to dicyclopentadiene of 1:0.5 to 3, wherein the pyrolysing is at a reaction pressure of 0.1 MPa to 1.5 MPa, a reaction temperature of 300 C. to 450 C. and a contact time of 5 s to 30 s; in step two: subjecting cyclopentadiene, as raw material, to a chlorination reaction in a liquid phase with chlorine to obtain 1,2,3,4-tetrachlorocyclopentane, in a molar ratio of chlorine to cyclopentadiene of 1 to 3:1, wherein the chlorination reaction is at a reaction temperature of 0 C. to 40 C., and a reaction time of 1 h to 10 h; in step three: subjecting 1,2,3,4-tetrachlorocyclopentane, as raw material, to a chlorofluorination reaction with hydrogen fluoride and chlorine in a gas phase in the presence of a chromium-based catalyst to obtain 1,2-dichlorohexafluorocyclopentene, in a molar ratio of 1,2,3,4-tetrachlorocyclopentane, hydrogen fluoride and chlorine of 1:5 to 20:5, wherein the chlorofluorination reaction is at a reaction pressure of 0.1 MPa to 1.5 MPa, a reaction temperature of 370 C. to 450 C. and a contact time of 2 s to 30 s.

2. The method according to claim 1, wherein the chromium-based catalyst is prepared by calcinating a catalyst precursor at a high temperature, the catalyst precursor is a mixture of a trivalent chromium compound and a metal powder, and based on the total mass of the catalyst precursor, the trivalent chromium compound represents 95% to 99.9% by mass, and the metal powder represents 0.1% to 5% by mass.

3. The method according to claim 2, wherein the trivalent chromium compound is chromium hemitrioxide or chromium hydroxide, and the metal powder is one or more of tungsten powder, molybdenum powder, and indium powder.

4. The method according to claim 2, wherein the calcinating at a high temperature is performed at 300 C. to 500 C. for 6 h to 15 h under a nitrogen atmosphere.

5. The method according to claim 4, wherein the chromium-based catalyst is activated at 60 C. to 450 C. in a gas mixture of a nitrogen and a hydrogen fluoride gas in a molar ratio of 10:1 for 6 h to 15 h before use.

6. The method according to claim 1, wherein in step one, the molar ratio of the diluent to dicyclopentadiene is 1:1 to 2, the reaction temperature is 330 C. to 370 C., the reaction pressure is 0.1 MPa to 1.5 MPa, and the contact time is 10 s to 20 s.

7. The method according to claim 1, wherein in step two, the molar ratio of chlorine to cyclopentadiene is 1.5 to 1:1, the reaction temperature is 20 C. to 30 C., and the reaction time is 3 h to 7 h.

8. The method according to claim 1, wherein in step three, the molar ratio of 1,2,3,4-tetrachlorocyclopentane, hydrogen fluoride and chlorine is 1:10 to 15:5, the reaction pressure is 0.1 MPa to 1.5 MPa, and the contact time is 10 s to 20 s.

Description

DETAILS OF THE INVENTION

(1) In order to make the objects, technical solutions, and advantages of the present invention more comprehensible, the present invention will be further described in detail below by way of examples. It is apparent that the described examples are only a part of the examples of the invention, and not all of them. Based on the examples in the present application, any other examples obtained by the ordinary skilled person in the art without creative work are within the protection scope of the present invention.

Example 1

(2) 30 ml of inert alumina was charged into a tubular reactor made of Inconel alloy with an inner diameter of inch and a length of 30 cm. The reactor was heated to 370 C., and nitrogen and dicyclopentadiene were simultaneously introduced into the reactor. The molar ratio of nitrogen to dicyclopentadiene was controlled to be 1:1.5, the contact time was controlled to be 15 seconds, and the reaction pressure was controlled to be 0.1 MPa. The reaction product was cooled in an ice bath at 0 C. to obtain cyclopentadiene. The yield of cyclopentadiene was determined by gas chromatography, and the results are shown in Table 1.

(3) The conditions for the gas chromatography include: Analytical instruments: chromatographic instrument GC-930 from Shanghai Haixin Group Co., Ltd., hydrogen flame detector, the column of capillary column Al.sub.2O.sub.3/S 50 m0.320 mm0.25 m (manufactured by the Chromatography Technology Research and Development Center, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences).

(4) Gas Chromatographic Analysis Method: high purity nitrogen (99.999%) was used as a carrier gas. The detection conditions are as follows: the temperature in vaporization chamber was 250 C., the temperature of auxiliary furnace 2 was 250 C., the temperature of detector was 250 C., the initial temperature of column furnace was 40 C. for 10 minutes, the heating rate was 15 C./min, the final temperature was 230 C. for 3 minutes, and the split ratio was 20:1.

(5) It should be noted that the yields of the products were determined by the same gas chromatographic conditions as in Example 1 in the following examples.

Example 2

(6) The same operation as in Example 1 was performed, except that the reaction temperature was 300 C., and the results are shown in Table 1.

Example 3

(7) The same operation as in Example 1 was performed, except that the reaction temperature was 330 C., and the results are shown in Table 1.

Example 4

(8) The same operation as in Example 1 was performed, except that the reaction temperature was 410 C., and the results are shown in Table 1.

Example 5

(9) The same operation as in Example 1 was performed, except that the reaction temperature was 450 C., and the results are shown in Table 1.

Example 6

(10) The same operation as in Example 1 was performed, except that the contact time was 2 s, and the results are shown in Table 1.

Example 7

(11) The same operation as in Example 1 was performed, except that the contact time was 10 s, and the results are shown in Table 1.

Example 8

(12) The same operation as in Example 1 was performed, except that the contact time was 20 s, and the results are shown in Table 1.

Example 9

(13) The same operation as in Example 1 was performed, except that the contact time was 30 s, and the results are shown in Table 1.

Example 10

(14) The same operation as in Example 1 was performed, except that the molar ratio of nitrogen to dicyclopentadiene was 1:0.5, and the results are shown in Table 1.

Example 11

(15) The same operation as in Example 1 was performed, except that the molar ratio of nitrogen to dicyclopentadiene was 1:1, the results are shown in Table 1.

Example 12

(16) The same operation as in Example 1 was performed, except that the molar ratio of nitrogen to dicyclopentadiene was 1:2, and the results are shown in Table 1.

Example 13

(17) The same operation as in Example 1 was performed, except that the molar ratio of nitrogen to dicyclopentadiene was 1:3, and the results are shown in Table 1.

Example 14

(18) The same operation as in Example 1 was performed, except that the reaction pressure was 0.5 MPa, and the results are shown in Table 1.

Example 15

(19) The same operation as in Example 1 was performed, except that the reaction pressure was 1.0 MPa, and the results are shown in Table 1.

Example 16

(20) The same operation as in Example 1 was performed, except that the reaction pressure was 1.5 MPa, and the results are shown in Table 1.

(21) TABLE-US-00001 TABLE 1 Temper- Pres- Molar cyclo- ature/ sure/ Contact ratio of pentadiene Examples C. MPa time/s N.sub.2:C.sub.10H.sub.20 Yield/% Example 1 370 0.1 15 1:1.5 99.4 Example 2 300 0.1 15 1:1.5 87.9 Example 3 330 0.1 15 1:1.5 90.9 Example 4 410 0.1 15 1:1.5 79.3 Example 5 450 0.1 15 1:1.5 68.5 Example 6 370 0.1 2 1:1.5 39.2 Example 7 370 0.1 10 1:1.5 83.7 Example 8 370 0.1 20 1:1.5 92.6 Example 9 370 0.1 30 1:1.5 80.4 Example 10 370 0.1 15 1:0.5 95.1 Example 11 370 0.1 15 1:1.sup. 96.4 Example 12 370 0.1 15 1:2.sup. 95.2 Example 13 370 0.1 15 1:3.sup. 75.3 Example 14 370 0.5 15 1:1.5 90.1 Example 15 370 1.0 15 1:1.5 83.6 Example 16 370 1.5 15 1:1.5 59.8

Example 17

(22) Cyclopentadiene and chlorine were simultaneously added into the autoclave; the molar ratio of cyclopentadiene to chlorine was controlled to 1:1.5, the temperature in autoclave was controlled to 20 C., and the reaction time was controlled to 5 h. The product was washed with water and alkali, and then dried with 4A molecular sieves, to obtain 1,2,3,4-tetrachlorocyclopentane; the yield of 1,2,3,4-tetrachlorocyclopentane was determined by gas chromatography, and the results are shown in Table 2.

Example 18

(23) The same operation as in Example 17 was performed, except that the molar ratio of cyclopentadiene to chlorine was 1:1, and the results are shown in Table 2.

Example 19

(24) The same operation as in Example 17 was performed, except that the molar ratio of cyclopentadiene to chlorine was 1:2, and the results are shown in Table 2.

Example 20

(25) The same operation as in Example 17 was performed, except that the molar ratio of cyclopentadiene to chlorine was 1:3, and the results are shown in Table 2.

Example 21

(26) The same operation as in Example 17 was performed, except that the reaction temperature was 0 C. and the reaction time was 10 h, and the results are shown in Table 2.

Example 22

(27) The same operation as in Example 17 was performed, except that the reaction temperature was 10 C. and the reaction time was 7 h, and the results are shown in Table 2.

Example 23

(28) The same operation as in Example 17 was performed, except that the reaction temperature was 30 C. and the reaction time was 3 h, and the results are shown in Table 2.

Example 24

(29) The same operation as in Example 17 was performed, except that the reaction temperature was 40 C. and the reaction time was 1 h, and the results are shown in Table 2.

(30) TABLE-US-00002 TABLE 2 Reaction 1,2,3,4- Temper- Molar tetrachloro- ature/ Reaction ratio of cyclopentane Examples C. Time/h C.sub.5H.sub.6:Cl.sub.2 Yield/% Example 17 20 5 1:1.5 98.2 Example 18 20 5 1:1.sup. 78.2 Example 19 20 5 1:2.sup. 93.3 Example 20 20 5 1:3.sup. 90.6 Example 21 0 10 1:1.5 73.8 Example 22 10 7 1:1.5 82.5 Example 23 30 3 1:1.5 93.4 Example 24 40 1 1:1.5 90.2

(31) Methods for preparing chromium-based catalysts involved in Examples 25 to 28 are as follows.

(32) The chromium nitrate was dissolved in water, added with a precipitant of aqueous ammonia at 60 C. The resulted solution was adjusted to pH 7.5 to 8.5, so that the precipitate was fully separate out under stirring. The formed slurry was filtered and washed with deionized water until it was neutral, and then dried at 150 C. for 12 hours to obtain chromium hydroxide.

(33) The obtained chromium hydroxide and metal powder (the metal powder is tungsten powder, molybdenum powder and/or indium powder) were mixed uniformly in the mass percentage ratio of 95% to 99.9%:0.1% to 5%, and shaped under pressure to obtain a catalyst precursor. Then, the catalyst precursor was calcinated at 450 C. for 10 hours under a nitrogen atmosphere, and then activated at 60 C. to 450 C. for 12 hours under a mixing atmosphere composed of hydrogen fluoride gas and nitrogen at a molar ratio of 1:10, to obtain a chromium-based catalyst.

Example 25

(34) 10 ml of a chromium-based catalyst was charged into a tubular reactor made of Inconel alloy with an inner diameter of inch and a length of 30 cm. The chromium-based catalyst precursor was prepared by mixing chromium hydroxide and tungsten powder in the mass percentage ratio of 97%:3% and shaping the mixture under pressure, with the temperature for activation of 300 C. The reactor was heated to 370 C., and anhydrous hydrogen fluoride, 1,2,3,4-tetrachlorocyclopentane and chlorine were simultaneously introduced into the reactor. The molar ratio of anhydrous hydrogen fluoride, 1,2,3,4-tetrachlorocyclopentane and chlorine was controlled to 12:1:5, the contact time was controlled to 15 seconds, and the reaction pressure was controlled to 0.1 MPa. After 20 hours of reaction, the reaction product was washed with water and alkali, and separated to obtain an organic material. The organic material was dried to remove water, so as to obtain a product. The product was characterized by gas chromatography-mass spectrometry (GC-MS) technique and nuclear magnetic resonance (.sup.19F NMR) as follows:

(35) GC-MS:

(36) Instruments and conditions: GC-MS-QP2010 Ultra (Shimadzu), column: DB-5 with an inner diameter of 0.25 mm and a length of 30 m (J&W Scientific Inc.); programmed temperature: 40 C. for 4 min; raised to 230 C. at a rate of 10 C./min, for 5 min; the inlet temperature and detector temperature were maintained at 200 C., and the carrier gas He was maintained at 10 mL/min.

(37) Test Results:

(38) m/z:244 (M.sup.+); 225 (M.sup.+-F); 209 (M.sup.+-Cl); 194 (M.sup.+-CF.sub.2); 175 (M.sup.+-CF.sub.3); 159 (M.sup.+-CF.sub.2Cl); 155 (M.sup.+-FCl.sub.2); 140 (M.sup.+-CF.sub.3Cl); 125 (M.sup.+-CF.sub.2Cl.sub.2); 109 (M.sup.+-C.sub.2F.sub.4Cl); 90 (M.sup.+-C.sub.2F.sub.5Cl); 85 (M.sup.+-C.sub.4F.sub.4Cl); 69 (M.sup.+-C.sub.4F.sub.3Cl.sub.2); 55 (M.sup.+-C.sub.2F.sub.5Cl.sub.2); 31 (M.sup.+-C.sub.4F.sub.5Cl.sub.2); 18 (M.sup.+-C.sub.5F.sub.5Cl.sub.2).

(39) .sup.19F NMR: Fluorine spectrum (.sup.19F NMR) of the product was tested at 25 C., the internal standard was CFCl.sub.3, and the solvent was CDCl.sub.3; the test results: 113.75 (dt, 4F); 129.73 (ddt, 2F).

(40) The product of Example 25 was determined to be 1,2-dichlorohexafluorocyclopentene by the above-mentioned GC-MS and NMR data; the yield of 1,2-dichlorohexafluorocyclopentene was determined by gas chromatography, and the results are shown in the Table 3.

Example 26

(41) The same operation as in Example 25 was performed, except that the chromium-based catalyst precursor was prepared by uniformly mixing chromium hydroxide and indium powder in the mass percentage ratio of 97%:3% and shaping the mixture under pressure, and the reaction temperature was 300 C. The results are shown in Table 3.

Example 27

(42) The same operation as in Example 25 was performed, except that the chromium-based catalyst precursor was prepared by uniformly mixing chromium hydroxide and tungsten powder in the mass percentage ratio of 99.9%:0.1% and shaping the mixture under pressure, and the reaction temperature was 330 C. The results are shown in Table 3.

Example 28

(43) The same operation as in Example 25 was performed, except that the tungsten powder in the chromium-based catalyst precursor was replaced by molybdenum powder, the temperature for activation was 60 C. and the reaction temperature was 410 C. The results are shown in Table 3.

(44) TABLE-US-00003 TABLE 3 1,2- Tem- dichloro- pera- Pres- Con- Molar hexafluoro- ture/ sure/ tact ratio of cyclopentene Examples C. MPa time/s HF:C.sub.5Cl.sub.4H.sub.6:Cl.sub.2 Yield/% Example 25 370 0.1 15 12:1:5 48.1 Example 26 300 0.1 15 12:1:5 4.3 Example 27 330 0.1 15 12:1:5 10.9 Example 28 410 0.1 15 12:1:5 39.2

(45) The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalents, improvements, etc., which are made within the spirit and principles of the present invention, should be included within the protection scope of the present invention.