High-efficiency polymerization inhibitor for styrene rectification and preparation method thereof

Abstract

The present application provides a kind of high-efficiency polymerization inhibitor for styrene rectification, by weight parts, including following each component: 20-40 parts of radical scavenger, 15-25 parts of modified alkylamine and 50-100 parts of composite alcohol solution, 2-4 parts of sodium citrate and 1-3 parts of sodium oxalate;The radical scavenger is porous calcium carbonate microspheres loaded with nitroxyl radical and plant extract;The modified alkylamine is layered double hydroxide LDH loaded with alkylamine;The composite alcohol solution is ethylene glycol, glycerol and polyvinyl alcohol;It is applied to styrene rectification, and the polymerization inhibition capacity is obviously improved by efficient capture of free radical.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of petroleum chemical polymerization inhibitor, and particularly relates to a high-efficiency polymerization inhibitor for styrene rectification and a preparation method thereof. BACKGROUND

[0002] Styrene is an important chemical raw material, which is widely used in plastic, rubber, paint, resin and other industries. It is a colorless to light yellow liquid with special aromatic flavor, which can self-polymerize to polystyrene (PS) resin and easily copolymerize with other unsaturated compounds containing double bonds. Industrially, styrene is mainly produced by catalytic dehydrogenation of ethylbenzene in gas phase. The mixed liquid after dehydrogenation of ethylbenzene will be polymerized into polystyrene in the rectification separation, which is easy to block the equipment and process pipelines, so it is necessary to add a polymerization inhibitor in the rectification process.

[0003] At present, the polymerization inhibitors developed at home and abroad are mainly divided into true polymerization inhibitors and retarders. The true polymerization inhibitors such as nitrogen-oxygen free radical compounds have high inhibition efficiency and can produce a long induction period, and almost no polymer is produced during the induction period, but they have the shortcomings of being easily consumed by free radicals and short service life. The retarders such as nitrophenol compounds have stable chemical properties, less failure in the inhibition process, and can reduce the polymerization rate, but cannot produce an obvious induction period, so the content of the polymer is always slowly increasing.

[0004] CN 101440286A develops a polymerization inhibitor compounded by 2,2,6,6-tetramethylpiperidine nitrogen-oxygen free radical compound, 4,6-dinitroalkyl phenol compound and dimethyl sulfide benzene diamine compound, which is suitable for the production or refining process of styrene, divinylbenzene, p-chloromethylstyrene and other high-boiling olefin monomers or cross-linking agents, and the compounded polymerization inhibitor is in liquid state at low temperature; CN 102249842A discloses a high-efficiency environmentally friendly polymerization inhibitor for styrene, which is composed of nitrogen-oxygen free radical compounds, hydroxylamine compounds, nitrophenol compounds and phosphite compounds. The compound system utilizes the synergistic effect between the components, overcomes the respective shortcomings of the retarder and the true polymerization inhibitor, and improves the inhibition effect.

[0005] However, researches show that the polymerization mechanism of styrene monomer is thermal polymerization and free radical polymerization, and the factors for initiating polymerization are heat, oxygen and metal impurities. Styrene will generate free radicals under the catalysis of metal impurities at a higher temperature, and once free radicals are generated, polymerization reaction will occur. The higher the concentration of free radicals, the faster the polymerization reaction speed. Therefore, a free radical capturing agent is developed to improve the inhibition capacity by efficiently capturing free radicals. SUMMARY

[0006] The application aims to provide a high-efficiency polymerization inhibitor for styrene rectification and a preparation method thereof.

[0007] To achieve the above-mentioned purpose, the application provides the following technical solutions.

[0008] The high-efficiency polymerization inhibitor for styrene rectification comprises the following components in parts by weight: 20-40 parts of a free radical trapping agent, 15-25 parts of a modified alkyl amine, and 50-100 parts of a composite alcohol solution.

[0009] Preferably, the free radical trapping agent is porous calcium carbonate microspheres loaded with nitroxyl radicals and plant extract; the modified alkyl amine is layered double hydroxide (LDH) loaded with alkyl amine; and the composite alcohol solution is ethylene glycol, glycerol, and polyvinyl alcohol, with a molar ratio of 1:0.3-0.6:0.5-0.8.

[0010] Preferably, the nitroxyl radical is 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxyl radical.

[0011] Preferably, the alkyl amine is one or a mixture of triethylamine or diethylamine.

[0012] Preferably, 2-4 parts of sodium citrate and 1-3 parts of sodium oxalate are further included.

[0013] The preparation method of the high-efficiency polymerization inhibitor for styrene rectification comprises the following steps:

[0014] S1: mix porous calcium carbonate microspheres and plant extract according to a solid-liquid ratio of 1g:8-15ml, then add nitroxyl radicals, stir and react at a temperature of 65-75℃ for 1-3h to obtain a free radical trapping agent;

[0015] S2: mix layered double hydroxide (LDH) and alkyl amine according to a solid-liquid ratio of 1g:10-20ml, then stir and react at a temperature of 95-115℃ for 50-80min to obtain a modified alkyl amine;

[0016] S3: mix ethylene glycol, glycerol, and polyvinyl alcohol according to a molar ratio of 1:0.3-0.6:0.5-0.8, then stir at room temperature for 25-35min to obtain a composite alcohol solution;

[0017] S4: mix 20-40 parts of the free radical trapping agent obtained in step S1, 15-25 parts of the modified alkyl amine obtained in step S2, and 50-100 parts of the composite alcohol solution obtained in step S3, then stir at a temperature of 50-80℃ for 35-55min; subsequently, add 2-4 parts of sodium citrate and 1-3 parts of sodium oxalate, and perform ultrasonic treatment to obtain a high-efficiency polymerization inhibitor.

[0018] Preferably, the preparation process of the porous calcium carbonate microspheres in step S1 is as follows: 80-100 parts of deionized water, 30-50 parts of phosphogypsum, 2-4 parts of potassium sorbate, 15-25 parts of cyclohexane, 3-6 parts of dodecyltrimethylammonium chloride, and 1-3 parts of citric acid are uniformly mixed, then 8-12 parts of calcium bicarbonate is added, and grinding is performed for 1-2 hours, followed by separation and drying; and then heat preservation is performed at 250-350 DEG C for 8-12 min, to obtain the porous calcium carbonate microspheres.

[0019] Preferably, the preparation process of the plant extract in step S1 is as follows: 2-5 parts of peppermint, 2-6 parts of grapefruit, and 20-40 parts of ethanol are mixed, and then supercritical carbon dioxide is used for extraction, with the temperature being controlled at 80-100 DEG C and the pressure being controlled at 100-150 bar, to obtain the plant extract.

[0020] Preferably, the preparation process of the layered composite metal hydroxide in step S2 is as follows: 3-6 parts of lithium hydroxide and 5-10 parts of aluminum hydroxide are mixed and dissolved in water, then 20-30 parts of 0.3-0.6 mol / L sodium salicylate aqueous solution is added, and then stirring reaction is performed at a temperature of 150-180 DEG C for 2-4 hours, followed by separation and filtration, and then the filter residue is dried to obtain the layered composite metal hydroxide.

[0021] Preferably, the ultrasonic treatment in step S4 is performed at a power of 800-1000 W, at a temperature of 75-85 DEG C, and for a time of 20-30 min.

[0022] Compared with the prior art, the application has the following advantages and beneficial effects:

[0023] In the application, the porous calcium carbonate microspheres are used to load nitrogen-oxygen free radicals and plant extract as free radical capturing agents, so that the 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine nitrogen-oxygen radical molecules are difficult to be orderly stacked to form crystals in the environment of the porous calcium carbonate microspheres, and the viscosity of the whole system is obviously reduced; meanwhile, the free radical capturing agent performance is improved together with the synergistic effect of the free radical elimination components in the plant extract; the layered composite metal hydroxide LDH is used to load alkyl amine, and the layered composite metal hydroxide LDH is used together with the free radical capturing agent; the citrate and oxalate ions dissociated from sodium citrate and sodium oxalate can form complexes with iron ions, so that the catalytic activity of the iron ions can be effectively reduced, the polymerization reaction of styrene catalyzed by the iron ions can be prevented, and the styrene polymerization inhibition effect can be improved. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0025] The raw materials used in the present application are as follows:

[0026] The phosphogypsum is from Wuhu Zhonglei Building Material Co., Ltd. with the product code S156; the potassium sorbate is from Shanghai Yuan Ye Biological Technology Co., Ltd. with the product code S11114; the cyclohexane is from Shandong Zhengxing New Material Co., Ltd. with the product code 345; the dodecyl trimethyl ammonium chloride is from Shanghai Xuejie Chemical Co., Ltd. with the product code 134; the citric acid is from Henan Zun Ting Biological Technology Co., Ltd. with the product code 645; and the polyvinyl alcohol is from Sichuan Lai Te Poly Xin Pharmaceutical Auxiliary Co., Ltd. with the product code 40.

[0027] Embodiment 1

[0028] The present embodiment provides a preparation method of a high-efficiency polymerization inhibitor for styrene rectification, comprising the following steps:

[0029] S1: 80g of deionized water, 30g of phosphogypsum, 2g of potassium sorbate, 15g of cyclohexane, 3g of dodecyl trimethyl ammonium chloride, and 1g of citric acid are uniformly mixed, 8g of calcium bicarbonate is then added, and grinding is performed for 1h, followed by separation and drying; and the porous calcium carbonate microspheres are obtained by incubating at 250℃ for 8min;

[0030] 2g of mint, 2g of grapefruit, and 20g of ethanol are mixed, and supercritical carbon dioxide is used for extraction, with the temperature being controlled at 80℃ and the pressure being controlled at 100bar, to obtain a plant extract;

[0031] The porous calcium carbonate microspheres and the plant extract are mixed according to a solid-liquid ratio of 1g:8ml, and a nitrogen-oxygen free radical is then added, and stirring is performed at a temperature of 65℃ and a rate of 500r / min for 1h, to obtain a free radical trapping agent;

[0032] S2: 3g of lithium hydroxide and 5g of aluminum hydroxide are mixed and dissolved in water, 20g of a 0.3mol / L sodium salicylate aqueous solution is then added, and stirring is performed at a temperature of 150℃ and a rate of 500r / min for 2h, followed by separation and filtration, and the filter residue is dried to obtain a layered composite metal hydroxide;

[0033] The layered composite metal hydroxide LDH and triethylamine are mixed according to a solid-liquid ratio of 1g:10ml, and stirring is performed at a temperature of 95℃ and a rate of 600r / min for 50min, to obtain a modified alkyl amine;

[0034] S3: Ethylene glycol, glycerol and polyvinyl alcohol are mixed in a molar ratio of 1:0.3:0.5 and stirred at 600 r / min for 25 min at room temperature to obtain a composite alcohol solution.

[0035] S4: Take 20g of the free radical scavenger described in step S1, 15g of the modified alkylamine described in step S2, and 50g of the composite alcohol solution described in step S3, mix them, and stir at 50℃ and 550r / min for 35min; then add 2g of sodium citrate and 1g of sodium oxalate, and sonicate at 800W and 75℃ for 20min to obtain a high-efficiency polymerization inhibitor.

[0036] Example 2

[0037] This embodiment provides a method for preparing a high-efficiency polymerization inhibitor for styrene distillation, comprising the following steps:

[0038] S1: Take 100g of deionized water, 50g of phosphogypsum, 4g of potassium sorbate, 25g of cyclohexane, 6g of dodecyltrimethylammonium chloride, and 3g of citric acid, mix them evenly, then add 12g of calcium bicarbonate, grind for 2 hours, separate and dry; keep warm at 350℃ for 12 minutes to obtain porous calcium carbonate microspheres.

[0039] Mix 5g of peppermint, 6g of grapefruit and 40g of ethanol, and extract using supercritical carbon dioxide at a controlled temperature of 100℃ and a pressure of 150 bar to obtain plant extract.

[0040] Porous calcium carbonate microspheres and plant extract were mixed at a solid-liquid ratio of 1g:15ml, and then nitrogen oxide free radicals were added. The mixture was stirred at 75℃ and 500r / min for 3h to obtain a free radical scavenger.

[0041] S2: Mix 6g of lithium hydroxide and 10g of aluminum hydroxide and dissolve them in water. Add 30g of sodium salicylate aqueous solution with a molar concentration of 0.6mol / L. Stir and react at 180℃ for 4h. After separation and filtration, take the filter residue and dry it to obtain a layered composite metal hydroxide.

[0042] Layered composite metal hydroxide LDH and triethylamine were mixed at a solid-liquid ratio of 1g:20ml and stirred at 115℃ for 80min at a rate of 600r / min to obtain modified alkylamine.

[0043] S3: Ethylene glycol, glycerol and polyvinyl alcohol are mixed in a molar ratio of 1:0.6:0.8 and stirred at 400 r / min for 35 min at room temperature to obtain a composite alcohol solution.

[0044] S4: Take 40g of the free radical scavenger described in step S1, 25g of the modified alkylamine described in step S2, and 100g of the composite alcohol solution described in step S3, mix them, and stir at 80℃ and 550r / min for 55min; then add 4g of sodium citrate and 3g of sodium oxalate, and sonicate at 1000W and 85℃ for 30min to obtain a high-efficiency polymerization inhibitor.

[0045] Example 3

[0046] This embodiment provides a method for preparing a high-efficiency polymerization inhibitor for styrene distillation, comprising the following steps:

[0047] S1: Take 85g of deionized water, 40g of phosphogypsum, 3g of potassium sorbate, 22g of cyclohexane, 4g of dodecyltrimethylammonium chloride, and 2g of citric acid, mix them evenly, then add 10g of calcium bicarbonate, grind for 1.5h, separate and dry; keep warm at 320℃ for 10min to obtain porous calcium carbonate microspheres.

[0048] Mix 4g of peppermint, 3g of grapefruit and 35g of ethanol, and extract using supercritical carbon dioxide at a controlled temperature of 90℃ and a pressure of 120 bar to obtain plant extract.

[0049] Porous calcium carbonate microspheres and plant extract were mixed at a solid-liquid ratio of 1g:13ml, and then nitrogen oxide free radicals were added. The mixture was stirred at 70℃ and 500r / min for 2.5h to obtain a free radical scavenger.

[0050] S2: Mix 5g of lithium hydroxide and 8g of aluminum hydroxide and dissolve them in water. Add 25g of sodium salicylate aqueous solution with a molar concentration of 0.45mol / L. Stir the mixture at 170℃ and 600r / min for 3.5h. After separation and filtration, dry the filter residue to obtain a layered composite metal hydroxide.

[0051] Layered composite metal hydroxide LDH and triethylamine were mixed at a solid-liquid ratio of 1g:15ml and stirred at 100℃ for 70min at a rate of 600r / min to obtain modified alkylamine.

[0052] S3: Ethylene glycol, glycerol and polyvinyl alcohol are mixed in a molar ratio of 1:0.5:0.6 and stirred at room temperature at a rate of 550 r / min for 30 min to obtain a composite alcohol solution.

[0053] S4: Take 35g of the free radical scavenger described in step S1, 20g of the modified alkylamine described in step S2, and 80g of the composite alcohol solution described in step S3, mix them, and stir at 75℃ and 550r / min for 45min; then add 3g of sodium citrate and 2g of sodium oxalate, and sonicate at 850W and 80℃ for 25min to obtain a high-efficiency polymerization inhibitor.

[0054] Comparative Example 1

[0055] The difference between this comparative example and Example 1 is that step S1 is missing, meaning that the nitrile radicals are not modified; the other steps are the same.

[0056] Comparative Example 2

[0057] The difference between this comparative example and Example 1 is that porous calcium carbonate microspheres are missing in step S1, while the other steps are the same.

[0058] Comparative Example 3

[0059] The difference between this comparative example and Example 1 is that the plant extract is missing in step S1, while the other steps are the same.

[0060] Comparative Example 4

[0061] The difference between this comparative example and Example 1 is that the layered composite metal hydroxide LDH is missing in step S2, while the other steps are the same.

[0062] Comparative Example 5

[0063] The difference between this comparative example and Example 1 is that only ethylene glycol is used in step S3, while the other steps are the same.

[0064] Comparative Example 6

[0065] The difference between this comparative example and Example 1 is that sodium citrate and sodium oxalate are missing in step S4, while the other steps are the same.

[0066] Performance testing:

[0067] The polymerization inhibitors prepared in the examples and comparative examples were applied to styrene distillation. 100g of styrene and 0.06g of polymerization inhibitor sample were added to a four-necked flask equipped with nitrogen purging, a thermometer, a reflux condenser, and mechanical or magnetic stirring. After purging the system with nitrogen, the mixture was heated at 120°C for 2 hours with the same amount of polymerization inhibitor. Samples were then taken to analyze the polystyrene content. The amount of polymerization inhibitor sample was 0.06% of the total styrene. The results are shown in Table 1 below.

[0068] Table 1 Performance Test Results

[0069]

[0070] The performance test results above show that the polymer content of Examples 1-3 is significantly reduced, which can effectively inhibit and slow down the polymerization of styrene; in particular, the comprehensive performance of Example 3 is the most outstanding. Comparative Examples 1-6, however, did not employ the necessary technical solutions, resulting in significantly worse performance than the Examples in the corresponding tests. These experimental results further demonstrate the importance of the technical solutions defined in this invention for its technical effect.

[0071] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A polymerization inhibitor for styrene distillation, characterized in that, The product comprises, by weight, the following components: 20-40 parts free radical scavenger, 15-25 parts modified alkylamine, 50-100 parts composite alcohol solution, 2-4 parts sodium citrate, and 1-3 parts sodium oxalate; the free radical scavenger is porous calcium carbonate microspheres loaded with nitric oxide free radicals and plant extract; the modified alkylamine is layered composite metal hydroxide LDH-loaded alkylamine; the composite alcohol solution is ethylene glycol, glycerol, and polyvinyl alcohol, with a molar ratio of 1:0.3-0.6:0.5-0.8; the preparation process of the plant extract is as follows: by weight, 2-5 parts peppermint, 2-6 parts grapefruit, and 20-40 parts ethanol are mixed and extracted using supercritical carbon dioxide, with the temperature controlled at 80-100 degrees Celsius and the pressure at 100-150 bar, to obtain the plant extract.

2. The polymerization inhibitor for styrene distillation according to claim 1, characterized in that, The nitroxide free radical is a 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide free radical.

3. The polymerization inhibitor for styrene distillation according to claim 2, characterized in that, The alkylamine is one or a mixture of triethylamine or diethylamine.

4. A method for preparing a polymerization inhibitor for styrene distillation, characterized in that, Includes the following steps: S1: Mix porous calcium carbonate microspheres and plant extract at a solid-liquid ratio of 1g:8-15ml, then add nitrogen and oxygen free radicals, and stir the reaction at 65-75℃ for 1-3 hours to obtain a free radical scavenger. S2: Take layered composite metal hydroxide LDH and alkylamine at a solid-liquid ratio of 1g:10-20ml, mix them, and stir at 95-115℃ for 50-80min to obtain modified alkylamine; S3: Mix ethylene glycol, glycerol and polyvinyl alcohol in a molar ratio of 1:0.3-0.6:0.5-0.8 and stir at room temperature for 25-35 minutes to obtain a composite alcohol solution. S4: Take 20-40 parts of the free radical scavenger described in step S1, 15-25 parts of the modified alkylamine described in step S2, and 50-100 parts of the composite alcohol solution described in step S3, mix them, and stir at 50-80℃ for 35-55 minutes; then add 2-4 parts of sodium citrate and 1-3 parts of sodium oxalate, and sonicate to obtain a high-efficiency polymerization inhibitor; The preparation process of the plant extract in step S1 is as follows: by weight, take 2-5 parts of peppermint, 2-6 parts of grapefruit and 20-40 parts of ethanol, mix them, and extract them with supercritical carbon dioxide, controlling the temperature at 80-100 degrees Celsius and the pressure at 100-150 bar to obtain the plant extract.

5. The method for preparing a polymerization inhibitor for styrene distillation according to claim 4, characterized in that, The preparation process of porous calcium carbonate microspheres in step S1 is as follows: by weight, take 80-100 parts of deionized water, 30-50 parts of phosphogypsum, 2-4 parts of potassium sorbate, 15-25 parts of cyclohexane, 3-6 parts of dodecyltrimethylammonium chloride, and 1-3 parts of citric acid and mix them evenly. Then add 8-12 parts of calcium bicarbonate, grind for 1-2 hours, separate and dry; keep warm at 250-350℃ for 8-12 minutes to obtain porous calcium carbonate microspheres.

6. The method for preparing a polymerization inhibitor for styrene distillation according to claim 4, characterized in that, The preparation process of the layered composite metal hydroxide in step S2 is as follows: by weight, 3-6 parts of lithium hydroxide and 5-10 parts of aluminum hydroxide are mixed and dissolved in water, and 20-30 parts of 0.3-0.6 mol / L sodium salicylate aqueous solution are added. The mixture is stirred and reacted at 150-180℃ for 2-4 hours. After separation and filtration, the filter residue is dried to obtain the layered composite metal hydroxide.

7. The method for preparing a polymerization inhibitor for styrene distillation according to claim 4, characterized in that, In step S4, the ultrasonic treatment power is 800-1000W, the temperature is 75-85℃, and the time is 20-30min.

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