METHOD FOR INHIBITING FLASH POINT OF TRANS-1,2-DICHLOROETHYLENE (T-1,2-DCE) AND USE OF T-1,2-DCE

Abstract

A method for inhibiting a flash point of trans-1,2-dichloroethylene (T-1,2-DCE) and a use of T-1,2-DCE are provided. The T-1,2-DCE has an excellent cleaning effect and is environmental friendly but cannot be used alone because of huge safety hazard caused by its low flash point. 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) is used to inhibit the flash point of T-1,2-DCE. However, because the actual boiling points of these two substances are quite different, the two substances are easily separated at a slightly-high ambient temperature. Because a boiling point of HCFO-1233zd is extremely low, HCFO-1233zd will escape rapidly, resulting in the loss of inhibition on the flash point. In the present disclosure, T-1,2-DCE and 1-chloro-2,3,3-trifluoropropene are mixed to prepare a mixed solution, and the mixed solution can effectively maintain the inhibition on the flash point of T-1,2-DCE in various ambient temperatures, such that the T-1,2-DCE can be heated to generate a steam for cleaning.

Claims

1. A method for inhibiting a flash point of trans-1,2-dichloroethylene (T-1,2-DCE), comprising: mixing the T-1,2-DCE with 1-chloro-2,3,3-trifluoropropene to obtain a mixed solution, wherein the 1-chloro-2,3,3-trifluoropropene accounts for 3% to 90% by weight of the mixed solution.

2. The method for inhibiting the flash point of the T-1,2-DCE according to claim 1, comprising: mixing the T-1,2-DCE with the 1-chloro-2,3,3-trifluoropropene to obtain the mixed solution, wherein the 1-chloro-2,3,3-trifluoropropene accounts for 5% to 50% by weight of the mixed solution.

3. The method for inhibiting the flash point of the T-1,2-DCE according to claim 2, comprising: mixing the T-1,2-DCE with the 1-chloro-2,3,3-trifluoropropene to obtain the mixed solution, wherein the 1-chloro-2,3,3-trifluoropropene accounts for 10% to 20% by weight of the mixed solution.

4. The method for inhibiting the flash point of the T-1,2-DCE according to claim 1, wherein a preparation method of the 1-chloro-2,3,3-trifluoropropene comprises the following steps: 1) subjecting 1,1,2,3,3-pentachloropropane and hydrogen fluoride to a reaction at a temperature of 200° C. to 350° C. and a space velocity of 60 h.sup.−1 to 570 h.sup.−1 under a catalysis of a chromium-based catalyst to generate 1,2-dichloro-3,3-difluoropropene, wherein a ratio of the hydrogen fluoride to the 1,1,2,3,3-pentachloropropane is (5-25):1; and 2) subjecting the 1,2-dichloro-3,3-difluoropropene and hydrogen fluoride to a reaction at a temperature of 250° C. to 400° C. and a space velocity of 50 h.sup.−1 to 550 h.sup.−1 under a catalysis of a catalyst to generate the 1-chloro-2,3,3-trifluoropropene, wherein the catalyst comprises a main catalyst and a cocatalyst, wherein the main catalyst is a chromium-based catalyst treated with hydrogen fluoride and the cocatalyst is one selected from the group consisting of Zn, Co, Ni, and Cu; and a ratio of the hydrogen fluoride to the 1,2-dichloro-3,3-difluoropropene is (1-8):1.

5. The method for inhibiting the flash point of the T-1,2-DCE according to claim 1, wherein the mixed solution has no flash point before boiling.

6. The method for inhibiting the flash point of the T-1,2-DCE according to claim 1, wherein the 1-chloro-2,3,3-trifluoropropene is trans-1-chloro-2,3,3-trifluoropropene.

7. A use of T-1,2-DCE, comprising: using the mixed solution obtained by the method for inhibiting the flash point of the T-1,2-DCE according to claim 1 to prepare a cleaning agent.

8. The use of the T-1,2-DCE according to claim 7, wherein the cleaning agent is placed in a closed space and heated to 45° C. to 50° C., and then an object to be cleaned is placed above a liquid level for a steam cleaning.

9. The use of the T-1,2-DCE according to claim 8, wherein the object to be cleaned is a mechanical component and an electronic device.

10. The use of the T-1,2-DCE according to claim 7, wherein the method comprises mixing the T-1,2-DCE with the 1-chloro-2,3,3-trifluoropropene to obtain the mixed solution, wherein the 1-chloro-2,3,3-trifluoropropene accounts for 5% to 50% by weight of the mixed solution.

11. The use of the T-1,2-DCE according to claim 10, wherein the method comprises mixing the T-1,2-DCE with the 1-chloro-2,3,3-trifluoropropene to obtain the mixed solution, wherein the 1-chloro-2,3,3-trifluoropropene accounts for 10% to 20% by weight of the mixed solution.

12. The use of the T-1,2-DCE according to claim 7, wherein a preparation method of the 1-chloro-2,3,3-trifluoropropene comprises the following steps: 1) subjecting 1,1,2,3,3-pentachloropropane and hydrogen fluoride to a reaction at a temperature of 200° C. to 350° C. and a space velocity of 60 h.sup.−1 to 570 h.sup.−1 under a catalysis of a chromium-based catalyst to generate 1,2-dichloro-3,3-difluoropropene, wherein a ratio of the hydrogen fluoride to the 1,1,2,3,3-pentachloropropane is (5-25):1; and 2) subjecting the 1,2-dichloro-3,3-difluoropropene and hydrogen fluoride to a reaction at a temperature of 250° C. to 400° C. and a space velocity of 50 h.sup.−1 to 550 h.sup.−1 under a catalysis of a catalyst to generate the 1-chloro-2,3,3-trifluoropropene, wherein the catalyst comprises a main catalyst and a cocatalyst, wherein the main catalyst is a chromium-based catalyst treated with hydrogen fluoride and the cocatalyst is one selected from the group consisting of Zn, Co, Ni, and Cu; and a ratio of the hydrogen fluoride to the 1,2-dichloro-3,3-difluoropropene is (1-8):1.

13. The use of the T-1,2-DCE according to claim 7, wherein the mixed solution has no flash point before boiling.

14. The use of the T-1,2-DCE according to claim 7, wherein the 1-chloro-2,3,3-trifluoropropene is trans-1-chloro-2,3,3-trifluoropropene.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] Example 10 is the optimal example of the present disclosure, and the present disclosure will be further described below with reference to examples.

[0024] The main component T-1,2-DCE is manufactured by China Ningxia Purui Chemical Co., Ltd., and a main content thereof is higher than or equal to 99.9%.

EXAMPLES 1 TO 8 AND COMPARATIVE EXAMPLES 1 TO 3

[0025] A preparation method of 1-chloro-2,3,3-trifluoropropene was provided, including the following steps: 1) 1,1,2,3,3-pentachloropropane and hydrogen fluoride were subjected to a reaction at a temperature of 275° C. and a space velocity of 240 h.sup.−1 under the catalysis of a F-Cr.sub.2O3 catalyst produced by Shandong Zibo Feiyuan Chemical Co., Ltd. to generate 1,2-dichloro-3,3-difluoropropene (E/Z) (CHCl=CCl—CHF.sub.2) (HCFO-1232aa), where a ratio of the hydrogen fluoride to the 1,1,2,3,3-pentachloropropane was 15:1; and 2) the 1,2-dichloro-3,3-difluoropropene and hydrogen fluoride were subjected to a reaction at a temperature of 300° C. and a space velocity of 220 h.sup.−1 under the catalysis of a catalyst to generate the 1-chloro-2,3,3-trifluoropropene (E/Z) (CHCl=CF—CHF.sub.2) (HCFO-1233yd), where the catalyst was a Cr—Co—Zn composite catalyst produced by Shandong Zibo Feiyuan Chemical Co., Ltd.; and a ratio of the hydrogen fluoride to the 1,2-dichloro-3,3-difluoropropene was 4:1.

[0026] A method for inhibiting a flash point of T-1,2-DCE was provided, including: mixing the T-1,2-DCE with 1-chloro-2,3,3-trifluoropropene to obtain a mixed solution in which the 1-chloro-2,3,3-trifluoropropene accounted for 3% to 90% by weight. A mixing ratio of the T-1,2-DCE and 1-chloro-2,3,3-trifluoropropene in each example is shown in Table 1 below. T-1,2-DCE is trans-1,2-dichloroethylene, 1233yd is a cis/trans-1-chloro-2,3,3-trifluoropropene mixture prepared by the above-mentioned preparation method of 1-chloro-2,3,3-trifluoropropene, and T-DEC/1233yd is a weight ratio of the T-1,2-DCE to the 1-chloro-2,3,3-trifluoropropene.

[0027] A use of T-1,2-DCE was provided. The mixed solution of T-1,2-DCE and 1-chloro-2,3,3-trifluoropropene (E/Z) obtained in Example 1 was placed in a closed constant-temperature box, heated, and kept at 47° C. A volume of the mixed solution was about 30% of a volume of the box and a weight ratio of the T-1,2-DCE to the 1-chloro-2,3,3-trifluoropropene (E/Z) was 90:10. A hollow steel pipe with a bend angle of 90°, a diameter of 1 mm, and a length of 15 cm was fixed at an inner top of the box with a distance of 30 cm from a liquid level, which was blocked by organic oil dirt inside. The steel pipe was cooled and kept at temperature lower than 25° C. to undergo steam cleaning for 1 h and then taken out and observed. It was found that the organic oil inside the steel pipe was mostly dissolved and two ends of the steel pipe were connected.

[0028] With the volume of the mixed solution being only 30% of the volume of the box, the whole process did not require liquid supplementation, indicating that the 1-chloro-2,3,3-trifluoropropene did not escape. The prominent steam cleaning effect proved that the T-1,2-DCE and 1-chloro-2,3,3-trifluoropropene (E/Z) in the steam did not separate and the excellent approximate azeotropic effect was still maintained. Thus, the T-1,2-DCE can be used for thorough cleaning of special components or machinery on a large scale.

TABLE-US-00001 TABLE 1 Mixing ratio Comparative Comparative Comparative Example Example Example Example Example Example Example Example Example Example Example 1 2 3 4 5 6 7 8 1 2 3 T-1,2- 97/3 96/4 90/10 80/20 70/30 60/40 50/50 10/90 100/0 99/1 98/2 DCE/1233yd

[0029] Examples 9 to 13 A method for inhibiting a flash point of T-1,2-DCE was provided. The preparation method of 1-chloro-2,3,3-trifluoropropene in Example 1 was repeated. The prepared 1-chloro-2,3,3-trifluoropropene was subjected to rectification to obtain trans-1-chloro-2,3,3-trifluoropropene with a boiling point of 47.67° C., and the T-1,2-DCE was mixed with the obtained trans-1-chloro-2,3,3-trifluoropropene to obtain a mixed solution in which the trans-1-chloro-2,3,3-trifluoropropene accounted for 3% to 90% by weight. A mixing ratio in each example was shown in Table 2 below. 1233yd (E) is trans-1-chloro-2,3,3-trifluoropropene.

TABLE-US-00002 TABLE 2 Mixing ratios of T-1,2-DCE and 1233yd (E) Exam- Exam- Exam- Exam- Exam- ple 9 ple 10 ple 11 ple 12 ple 13 T-1,2-DCE/ 97/3 90/10 80/20 70/30 60/40 1233yd (E)

[0030] Performance test 1 According to the national standard GB/T 5208-2008/ISO 3679: 2004, a closed cup flash point of the mixed solution of T-1,2-DCE and 1-chloro-2,3,3-trifluoropropene was determined. The samples obtained in the above examples and comparative examples were each placed in a room at 0° C., then the temperature of the room was lowered to −18° C., and the humidity of the room was set to 45%. The flash point was determined 3 times at each temperature test point, and test results were recorded in Table 3, where N/A means that the flash point had been reached and thus the test was stopped.

TABLE-US-00003 TABLE 3 Flash point test results Flash point of T-1,2-DCE: 1233yd (yes/no) Test Comparative Comparative Comparative temperature/ Example Example Example Example Example Example Example Example Example ° C. 1 2 3 1 2 3 4 5 8 −15 No No No No No No No No No −12 No No No No No No No No No −10 No No No No No No No No No −8 No No No No No No No No No −4 Yes Yes Yes No No No No No No 0 N/A N/A N/A No No No No No No 10 N/A N/A N/A No No No No No No 20 N/A N/A N/A No No No No No No 30 N/A N/A N/A No No No No No No 47 N/A N/A N/A No No No No No No 50 N/A N/A N/A Yes No No No No No

[0031] According to the results in Table 3, when the 1-chloro-2,3,3-trifluoropropene in the mixed solution prepared by the method for inhibiting the flash point of T-1,2-DCE of the present disclosure accounts for 3% to 90% by weight, the mixed solution can exhibit an excellent effect of inhibiting the flash point. When the 1-chloro-2,3,3-trifluoropropene accounts for only 1% to 2% by weight, the effect of inhibiting the flash point drops sharply. It is known that the boiling point of T-1,2-DCE is about 47° C. to 48° C., and thus it can be known from Examples 2 to 8 that the mixed solution still can exhibit the effect of inhibiting the flash point of T-1,2-DCE when the boiling point is reached. When 1-chloro-2,3,3-trifluoropropene accounts for 90% or higher by weight in the mixed solution, the cleaning effect will be significantly reduced due to the too-low T-1,2-DCE content.

[0032] Performance test 2 The azeotropic point of the mixed solution of T-1,2-DCE and 1-chloro-2,3,3-trifluoropropene was determined by an azeotropic point test device designed by Qilu Petrochemical Research Institute of China Petroleum & Chemical Corporation. The azeotropic point test device was composed of a rectification balance kettle, a pure water boiling point meter, a mercury manometer, a condenser, two buffer bottles, an automatic balance controller, two relays, two solenoid valves, and several glass tubes. The azeotropic point test device was used in combination with a gas chromatograph and a data processor to obtain test data and integration results thereof. The above Examples 1 to 13 and Comparative Examples 2 to 3 were subjected to approximate azeotropic distillation on this device, and test result were shown in table 4.

TABLE-US-00004 TABLE 4 Approximate azeotropic temperature test results Ratio of components Approximate Mixing ratio of Humidity (%)/ at distillation azeotropic raw materials Corrected gas tower top temperature (T-1,2-DCE:1233yd) pressure (kPa) (T-1,2-DCE:1233yd) (° C.) Comparative 45/101.3 98.33:1.67  40.6 Example 2 Comparative 45/101.3 97.53:2.47  41.1 Example 3 Example 1 45/101.3 97.16:2.84  45.3 Example 2 45/101.3 95.49:4.51  46.5 Example 3 45/101.3 89.89:10.11 47.1 Example 4 45/101.3 79.81:20.19 46.1 Example 5 45/101.3 69.71:30.29 45.3 Example 6 45/101.3 58.24:41.76 44.8 Example 7 45/101.3 48.78:51.22 44.2 Example 9 45/101.3 96.89:3.11  47.1 Example 10 45/101.3 89.87:10.13 47.3 Example 11 45/101.3 79.78:20.22 46.5 Example 12 45/101.3 69.69:30.31 45.6 Example 13 45/101.3 59.49:40.51 45.1

[0033] According to Table 4, when the mixed solution of T-1,2-DCE and 1-chloro-2,3,3-trifluoropropene prepared by the method for inhibiting the flash point of T-1,2-DCE of the present disclosure reaches its boiling point, namely, the approximate azeotropic point, a ratio of the two components in a steam at a tower top remains similar to that in the mixed solution, which can prove that the 1-chloro-2,3,3-trifluoropropene can still exhibit a stable effect of inhibiting the flash point when the T-1,2-DCE is boiled and evaporated at an ambient temperature, and thus a steam of the mixed solution can be used for cleaning or other special purposes. Under the same mixing ratio of raw materials, when the pure trans-1-chloro-2,3,3-trifluoropropene is used as a flash point inhibitor, a mixing ratio of the T-1,2-DCE and the trans-1-chloro-2,3,3-trifluoropropene in a steam obtained from the evaporation of the mixed solution is close to a mixing ratio of the two components in the mixed solution, and thus an effect close to approximate azeotropism can be achieved, that is, a superior effect of inhibiting the flash point can be achieved.

[0034] The above are merely preferred examples of the present disclosure and are not intended to limit the present disclosure in other forms. Any person skilled in the art may make changes or modifications based on the technical contents disclosed above to obtain equivalent examples. Any simple amendments or equivalent changes and modifications made to the above examples according to the technical essence of the present disclosure without departing from the content of the technical solutions of the present disclosure should fall within the protection scope of the technical solutions of the present disclosure.