A styrene polymerization inhibitor and its application in styrene production process

Abstract

The present invention relates to the technical field of styrene polymerization inhibition, specifically to a styrene polymerization inhibitor and its application in a styrene production process, the structure of which is shown in the following formula (1): #imgabs0# wherein R1-R 12 Each independently selected from hydrogen, hydroxyl, amino, C1-C4 alkyl, C6-C 30 Aromatic group, the styrene polymerization inhibitor prepared by the present invention has good polymerization inhibition effect and can be applied to styrene production processes such as distillation processes.

Description

Technical Field

[0001] The present invention relates to the technical field of styrene polymerization inhibition, in particular to a styrene polymerization inhibitor and application thereof in a styrene production process. Background Art

[0002] Styrene monomer is commonly used as a raw material for several important commodities, such as acrylonitrile-butadiene-styrene (ABS), styrene-butadiene rubber (SBR), and polystyrene composites. It is widely used in industries such as pharmaceuticals, dyes, pesticides, and mineral processing. It enjoys a wide range of applications and is in high demand in industrial production. Styrene production is a crucial process in industrial production.

[0003] Styrene, on the other hand, is thermally self-polymerizable. Even without an initiator, styrene polymerization can occur at relatively low temperatures. Typically, as the polymerization reaction proceeds, thickening and polymerization heat are generated. This polymerization process automatically accelerates as the reaction proceeds, and when the temperature is above 70°C, the polymerization rate increases rapidly. Furthermore, the polymerization reaction of styrene is exothermic, generating approximately 71 kJ / mol of heat. Improper handling of styrene polymerization not only results in decreased yields and reduced economic benefits, but can also cause the polymer to clog equipment and pipelines in the production process, necessitating shutdowns for maintenance in severe cases, significantly reducing work efficiency. Summary of the Invention

[0004] Purpose of the invention: In order to solve the above technical problems, the present invention provides a styrene polymerization inhibitor and its application in the styrene production process.

[0005] The technical solutions adopted are as follows:

[0006] A styrene polymerization inhibitor, the structure of which is shown in the following formula (1):

[0007]

[0008] Among them, R1-R 12 Each independently selected from hydrogen, hydroxy, amino, C1-C4 alkyl, C6-C 30 Aromatic group.

[0009] Furthermore, at least one of R1 and R2 is a hydroxyl group.

[0010] Furthermore, one of R1 and R2 is hydrogen and the other is hydroxyl.

[0011] Furthermore, at least one of R3-R7 is an amino group.

[0012] Furthermore, R8-R 12 At least one of them is an amino group.

[0013] Furthermore, at least one of R3-R7 is a C1-C4 alkyl group.

[0014] Furthermore, R8-R 12 At least one of them is a C1-C4 alkyl group.

[0015] Furthermore, R3-R7 contain an amino group and two C1-C4 alkyl groups, R8-R 12 It contains one amino group and two C1-C4 alkyl groups.

[0016] Furthermore, it is any one or more combinations of the following compounds:

[0017]

[0018] The present invention also provides the use of the polymerization inhibitor in the production process of styrene, wherein the addition amount of the polymerization inhibitor in styrene is 50-5000 ppm.

[0019] Beneficial effects of the present invention:

[0020] The present invention provides a styrene polymerization inhibitor, which combines the advantages of aromatic amine and phenol polymerization inhibitors. Phenol is oxidized to quinone, and the quinone combines with chain free radicals to capture free radicals and prevent rapid consumption of oxygen, thereby extending the inhibition period and exerting its inhibition effect. The styrene polymerization inhibitor prepared by the present invention has a good inhibition effect and can be applied to styrene production processes such as distillation processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a curve showing the change in the inhibition effect of the styrene polymerization inhibitor over time in Example 1 of the present invention. DETAILED DESCRIPTION

[0022] Unless otherwise specified, the following examples and comparative examples were conducted in parallel, using the same processing steps and parameters.

[0023] Example 1:

[0024] A method for synthesizing a styrene polymerization inhibitor:

[0025]

[0026] S1: Compound 1-A (42.37 g, 423.69 g / mol, 0.1 mol), (Boc)2O (45.83 g, 218.25 g / mol, 0.21 mol), and triethylamine (60.71 g, 101.19 g / mol, 0.6 mol) were added to 250 mL of methanol and stirred at room temperature for 18 h. The reaction solution was concentrated under reduced pressure to remove methanol, and 1 L of water was added. The solution was extracted with 250 mL × 3 of dichloromethane. The dichloromethane phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain compound 1-B in a yield of 91.2%;

[0027] S2: Compound 1-B (50 g, 623.92 g / mol, 0.08 mol) and 4-chlorocatechol (12.14 g, 144.55 g / mol, 0.084 mol) were dissolved in 500 mL of toluene, and palladium acetate (0.05 eq, 0.89 g, 224.51 g / mol, 0.004 mol), X-phos (0.05 eq, 1.91 g, 476.72 g / mol, 0.004 mol), sodium tert-butoxide (1.2eq, 9.23g, 96.103g / mol, 0.096mol), 250mL of ethanol and 150mL of water were added, and the reaction was stirred at 100°C for 8h. The reaction was stopped and cooled to room temperature. 2.5L of ethanol was added and stirred for 8h. The precipitated solid was filtered off, and the collected solid was dissolved in an appropriate amount of hot toluene. The solid was passed through silica gel and activated carbon while hot, and the filtrate was collected and cooled for crystallization to obtain compound 1-C with a yield of 50.8%;

[0028] S3: Compound 1-C (10 g, 732.02 g / mol, 13.66 mmol) was added to 200 mL of dichloromethane and stirred to dissolve. Trifluoroacetic acid (9.35 g, 114.02 g / mol, 81.96 mmol) was added dropwise under ice bath and stirred for 8 h. 200 mL of water was added to the reaction solution, and the solution was separated by extraction. The dichloromethane phase was washed with 200 mL of water for 3 times, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain the target compound 1 (yield 85.2%). ESI-MS (m / z) (M + ): Theoretical value 531.79, measured value 531.20, elemental analysis results (molecular formula C 34 H 49 N3O2): theoretical values ​​C, 76.79; H, 9.29; N, 7.90; O, 6.02; found values ​​C, 76.88; H, 9.13; N, 7.56; O, 6.14.

[0029] Example 2:

[0030] A method for synthesizing a styrene polymerization inhibitor:

[0031]

[0032] The synthesis method is basically the same as that of Example 1, except that compound 2-A is used instead of compound 1-A. The target compound 2 (yield 83.7%) was obtained by ESI-MS (m / z) (M + ): Theoretical value 475.68, measured value 475.06, elemental analysis results (molecular formula C 30 H 41 N3O2): theoretical values ​​C, 75.75; H, 8.69; N, 8.83; O, 6.73; found values ​​C, 75.43; H, 8.75; N, 8.77; O, 6.60.

[0033] Example 3:

[0034] A method for synthesizing a styrene polymerization inhibitor:

[0035]

[0036] The synthesis method is basically the same as that of Example 1, except that compound 3-A is used instead of compound 1-A. The target compound 3 (yield 88.1%) was obtained by ESI-MS (m / z) (M + ): Theoretical value 363.46, measured value 363.50, elemental analysis results (molecular formula C 22 H 25 N3O2): theoretical value C, 72.70; H, 6.93; N, 11.56; O, 8.80; found value C, 72.94; H, 6.80; N, 11.44; O, 8.82.

[0037] Example 4:

[0038] A method for synthesizing a styrene polymerization inhibitor:

[0039]

[0040] The synthesis method is basically the same as that of Example 1, except that compound 4-A is used instead of compound 1-A. The target compound 4 (yield 86.1%) was obtained by ESI-MS (m / z) (M + ): Theoretical value 419.57, measured value 419.69, elemental analysis results (molecular formula C 26 H 33 N3O2): Theoretical values ​​C, 74.43; H, 7.93; N, 10.02; O, 7.63; Found values ​​C, 74.25; H, 7.78; N, 10.10; O, 7.60.

[0041] Performance testing:

[0042] The styrene polymerization inhibitors prepared in Examples 1-4 of the present invention and the commercially available styrene polymerization inhibitor TBC were used as samples;

[0043] A certain amount of styrene was placed in a separatory funnel and repeatedly washed with 5% sodium hydroxide solution (to react with the phenolic polymerization inhibitor in styrene). During the process, attention was paid to oscillation and degassing. The washed styrene solution was colorless or slightly yellow. It was then washed with distilled water until the water layer was neutral. After separating the water layer, anhydrous sodium sulfate was added to dry it, and it was allowed to stand until transparent. The desiccant was removed by filtration, and then it was placed in a distillation flask and distilled under reduced pressure. The fraction at 44-45°C / 2666.44Pa (20mmHg) was collected to obtain pure styrene monomer. A clean stoppered colorimetric tube was taken, 50g of the purified styrene was weighed, and a certain amount of sample was accurately injected with a microinjector (no polymerization inhibitor was added to the blank group, and a commercially available styrene polymerization inhibitor TBC was added to the control group). After thorough mixing, it was placed in a 120°C oil bath and the timer was started. Every 0.5h, an appropriate amount of the reaction liquid was taken to measure the styrene content in the system using a gas chromatography internal standard method, and then the amount of polymer produced was calculated.

[0044] The test results are shown in Table 1 below:

[0045] Table 1:

[0046]

[0047] As can be seen from Table 1 above, the styrene polymerization inhibitor prepared by the present invention has a good polymerization inhibition effect and can be applied to the styrene production process.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A styrene polymerization inhibitor, characterized in that Its structure is shown in the following formula (1): ； Among them, one of R1 and R2 is hydrogen and the other is hydroxyl; R3-R7 contains one amino group and two C1-C4 alkyl groups, and the rest are hydrogen; R8-R 12 It contains one amino group and two C1-C4 alkyl groups, and the rest are hydrogen.

2. The styrene polymerization inhibitor according to claim 1, wherein It is any one or more combinations of the following compounds: 。 3. Use of the polymerization inhibitor according to claim 1 in a styrene production process, characterized in that: The addition amount of the polymerization inhibitor in styrene is 50-5000ppm.

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