阅读说明：本技术 一种苯乙烯阻聚剂及其制备方法 (Styrene polymerization inhibitor and preparation method thereof ) 是由 杜炳明 于 2020-06-16 设计创作，主要内容包括：本发明属于阻聚剂技术领域,具体涉及一种苯乙烯阻聚剂及其制备方法。一种苯乙烯阻聚剂,包括氮氧自由基化合物、醚类化合物和苯类溶剂,且所述阻聚剂在40℃下的运动粘度小于20mm<Sup>2</Sup>/s。该阻聚剂巧妙地利用了组份间的协同作用,克服了其各自的缺点,使得阻聚效果明显提高,增大了在苯乙烯或乙苯中的溶解度,从而有效地延长苯乙烯装置的运行时间,降低了苯乙烯精馏过程的能耗,提高了产品的质量,特别适用于负压高温精馏过程,且能同各种缓阻剂进行复配使用。(The invention belongs to the technical field of polymerization inhibitors, and particularly relates to a styrene polymerization inhibitor and a preparation method thereof. The styrene polymerization inhibitor comprises a nitroxide free radical compound, an ether compound and a benzene solvent, and the kinematic viscosity of the polymerization inhibitor at 40 ℃ is less than 20mm 2 And s. The polymerization inhibitor skillfully utilizes the synergistic effect among the components, overcomes the respective defects, obviously improves the polymerization inhibition effect, increases the solubility in styrene or ethylbenzene, effectively prolongs the running time of a styrene device, reduces the energy consumption of the styrene rectification process, improves the product quality, is particularly suitable for the negative pressure high temperature rectification process, and can be used together with various resistance-reducing agents.)

1. The styrene polymerization inhibitor is characterized by comprising a nitroxide free radical compound, an ether compound and a benzene solvent, and the kinematic viscosity of the polymerization inhibitor at 40 ℃ is less than 20mm²/s。

2. The styrene polymerization inhibitor according to claim 1, wherein the nitroxide radical compound is a piperidine nitroxide radical compound.

3. The styrene polymerization inhibitor according to claim 2, wherein the piperidine nitroxide radical is a tetramethylpiperidine radical compound.

4. The styrene polymerization inhibitor according to any one of claims 1 to 3, wherein the ether compound is an etherified aliphatic diol.

5. The styrene polymerization inhibitor according to claim 4, wherein the aliphatic diol is a C2-10 chain aliphatic diol.

6. The styrene polymerization inhibitor according to claim 5, wherein the ether-based compound has a flash point of 70 ℃ or lower.

7. The styrene polymerization inhibitor according to any one of claims 1 to 6, wherein the content of the nitroxide radical compound in the polymerization inhibitor is 15 to 20 wt%.

8. The styrene polymerization inhibitor according to any one of claims 1 to 6, wherein the content of the ether-based compound in the polymerization inhibitor is 15 to 25 wt%.

9. The styrene polymerization inhibitor according to any one of claims 1 to 6, wherein the benzene-based solvent is contained in the inhibitor in an amount of 55 to 65 wt%.

10. A method for preparing a styrene polymerization inhibitor according to any one of claims 1 to 9, comprising the steps of: injecting half of ether compound and half of benzene solvent into a reaction kettle, heating to 40-60 ℃, pouring all nitroxide free radical compounds into the reaction kettle, stirring until all nitroxide free radical compounds are dissolved, finally adding all the remaining ether compound and benzene solvent into the reaction kettle, stirring to dissolve uniformly, and cooling to normal temperature to obtain the product.

Technical Field

The invention belongs to the technical field of polymerization inhibitors, and particularly relates to a styrene polymerization inhibitor and a preparation method thereof.

Background

Styrene (styrene) is a basic raw material in petrochemical industry, can generate Polystyrene (PS) resin by self polymerization, and is easy to copolymerize with other unsaturated compounds containing double bonds. For example, styrene is copolymerized with butadiene and acrylonitrile, and the copolymer can be used for producing ABS engineering plastics; copolymerizing acrylonitrile into AS resin; copolymerization with butadiene to give latex (SBL) or synthetic rubber (SBR), styrene may also be used to give other resins; in addition, styrene is widely used in pharmaceutical, coating, textile and other industries.

Styrene has the property of vinyl olefin, has strong reactivity, can generate self-polymerization at normal temperature, and can be polymerized in each stage of refining, storing and using, especially in the refining process, so that monomer loss and pipeline blockage can be caused, and the production cost of the monomer is increased. In order to inhibit the self-polymerization of styrene and ensure the quality of the monomer, a polymerization inhibitor must be added into the monomer.

The current polymerization inhibitor developed at home and abroad is mainly divided into a real polymerization inhibitor and a retarder, the polymerization inhibition efficiency of the real polymerization inhibitor such as nitroxide free radical compounds is high, a long induction period can be generated, almost no polymer is generated during the induction period, but the defects of easy free radical consumption and short service life exist; retarders such as nitrophenol compounds are chemically stable, have little failure during polymerization inhibition, can reduce the polymerization rate, but cannot generate an obvious induction period, so that the content of the polymer is slowly increased all the time.

In order to combine the advantages of retarder and real polymerization inhibitor and overcome the disadvantages of single polymerization inhibitor, research on compound polymerization inhibitor has been carried out at home and abroad. For example, US 20050113626a uses a polymerization inhibitor in which a nitroxide radical and a hydrogen donor or electron acceptor are combined, wherein the hydrogen donor or electron acceptor can be selected from hydroxylamine, oxime, thiol, anthracene substitute, etc., which is effective in preventing the prepolymerization of vinyl monomers; US 20060122341a discloses a polymerization inhibiting system compounded by aromatic sulfonic acid compounds, amines, nitrophenol and nitroxide free radical compounds or nitrosoaniline, which is a high-efficiency polymerization inhibitor for vinyl unsaturated monomers; CN 1962572A proposes a compound polymerization inhibitor, the effective components of which contain nitrite, quinone compounds, nitrophenol and derivatives thereof, mainly solving the problem of cracking C from steam by adopting the extractive distillation technology₈A problem of a decrease in the recovery rate due to polymerization of styrene when styrene is recovered from the fraction; the polymerization inhibitor is generally used in an oxygen-free vacuum environment, and the energy consumption is large at the moment. At present, an energy-saving process is adopted in the industry, refining is carried out under normal pressure, and the temperature of a tower kettle of a crude styrene tower in a styrene device can reach about 120 ℃, so that the requirement on a polymerization inhibitor is stricter.

Disclosure of Invention

The words "preferred", "more preferred", and the like, in the present invention refer to embodiments of the invention that may provide certain benefits, under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

When a range of values is disclosed herein, the range is considered to be continuous and includes both the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range-describing features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range from "1 to 10" should be considered to include any and all subranges between the minimum value of 1 and the maximum value of 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, and the like.

Unless otherwise explicitly stated, the following abbreviations in this specification have the following meanings: min is minutes; DEG C is centigrade; wt% ═ weight percent; all numerical ranges are inclusive and combinable with each other in any order so long as the sum of the numerical ranges is limited, logically, to 100%.

In order to solve the above problems, a first aspect of the present invention provides a styrene polymerization inhibitor comprising a nitroxide radical compound, an ether compound and a benzene-based solvent, and having a kinematic viscosity at 40 ℃ of less than 20mm²/s。

The kinematic viscosity, i.e. the ratio of the dynamic viscosity of the fluid to the density p of the fluid at the same temperature, is measured by the experimental method GB/T265 at 40 ℃.

The nitroxide free radical compound is a compound with unique oxidation resistance and stable free radicals, and the molecular structure of the nitroxide free radical compound generally contains elements such as carbon, nitrogen, oxygen, hydrogen and the like and spin single electrons; common nitroxide free compounds include imidazole nitroxide free compounds, ferrocene nitroxide free compounds, and piperidine nitroxide free compounds.

In a preferred embodiment, the nitroxide compound is a piperidine nitroxide compound; more preferably, the piperidine nitroxide radical is a tetramethylpiperidine radical compound. Suitable tetramethylpiperidine-based free radical compounds include, but are not limited to, 2,6, 6-tetramethyl-piperidinyloxy, 4-hydroxy-2, 2,6, 6-tetramethyl-piperidinyloxy, 4-oxo-2, 2,6, 6-tetramethyl-piperidinyloxy, 4-dimethylamino-2, 2,6, 6-tetramethyl-piperidinyloxy, 4-amino-2, 2,6, 6-tetramethyl-piperidinyloxy, 4-ethanoxy-2, 2,6, 6-tetramethyl-piperidinyloxy, 2,5, 5-tetramethyl-piperidinyloxy, 3-amino-2, 2,5, 5-tetramethyl-piperidinyloxy, 2,5, 5-tetramethyl-1-oxo-3-piperidinyl-1-oxo-3-carboxylic acid; wherein, the more preferable one comprises 4-oxo-2, 2,6, 6-tetramethyl-piperidyl oxy, also called nitroxide radical piperidone, and the addition amount is 15 to 20 weight percent of the total weight of the raw materials of the polymerization inhibitor, and the more preferable one is 16 to 19 weight percent.

In a preferred embodiment, the ether compound is an etherified aliphatic diol; wherein the aliphatic diol is preferably a C2-10 chain aliphatic diol; specific examples of the chain aliphatic diol having C2 to 10 include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1, 3-propanediol, 1, 10-decanediol, 1, 4-butanediol, and 1, 6-hexanediol.

In a more preferred embodiment, the ether compound has a flash point of less than or equal to 100 ℃; in particular, ether compounds with high flash points generally have high viscosity, the range of viscosity change of the ether compounds is large under the influence of temperature, and the ether compounds are easy to stick a one-way valve marble in a device to influence the operation of the device, so that the suitable ether compounds in the invention are preferably chain aliphatic diol with the flash point of less than or equal to 100 ℃ and C2-10; the suitable ether compounds comprise ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether and dipropylene glycol monobutyl ether, and the ether compounds can be used singly or mixed with more than two; specifically, the addition amount of the ether compound is preferably 15 to 25 wt% of the total weight of the raw materials of the polymerization inhibitor, and more preferably 17 to 25 wt%.

In the research, on one hand, the screening of ether compounds considers the solubility with nitroxide radical piperidone and the cooperativity involved in polymerization inhibition, on the other hand, the screening of ether compounds considers the cooperativity with the inhibition, and on the other hand, the screening of ether compounds considers the cooperativity with nitroxide radical piperidone, and on the other hand, the screening of ether compounds considers the cooperativity with the inhibition, the screening of ether compounds considers the cooperativity with nitroxide radical piperidone, the screening of ether compounds considers that the cooperativity with nitroxide radical piperidone is best when C2-10 chain fatty diol with the flash point of less than or equal to 100 ℃, particularly ethylene glycol monobutyl ether is used, the generation of polymers in the polymerization of styrene leads to the increase of viscosity, ethylene glycol monobutyl ether has the flash point of 60.1 ℃, has relatively lower flash point, the effect; the chain-initiated endothermic reaction also leads to a further increase in viscosity, but experiments finally show that ethylene glycol monobutyl ether and nitroxide piperidone can be synergistically used to deprive active hydrogen atoms thereon, so that new free radicals are formed or the free radicals react with free radicals further to prevent polymerization.

In a preferred embodiment, the benzene-based solvent includes one or more selected from the group consisting of benzene, toluene, xylene, ethylbenzene, mesitylene, cyclohexylbenzene, dichlorobenzene, diphenyl ether, benzaldehyde, tetramethylbenzene; more preferably, the benzene solvent is tetramethylbenzene, and the addition amount of the benzene solvent is 55-65 wt% of the total weight of the raw materials of the polymerization inhibitor.

In view of the need to improve the solubility and stability of nitroxide piperidone, it is clear from the examples described later that the combination of tetramethylbenzene and ethylene glycol monobutyl ether provides excellent solubility and stability of nitroxide piperidone, and it is confirmed that this synergistic effect has an effect of suppressing the decrease in the blocking ability of nitroxide piperidone. The interaction of the formed II bond and the hydrogen bond of the tetramethylbenzene is equivalent to the hydrogen bond acting force of the diluted nitroxide radical piperidone, so the synergy is optimal under a certain proportion, while the synergistic effect cannot be obtained by the single tetramethylbenzene or the single ethylene glycol monobutyl ether, and the particularly preferred mass ratio of the ethylene glycol monobutyl ether to the tetramethylbenzene is (15-30): (50-70).

The second aspect of the present invention provides a method for preparing the styrene polymerization inhibitor as described above, comprising the steps of: injecting half of ether compound and half of benzene solvent into a reaction kettle, heating to about 50 ℃, pouring all the nitroxide free radical compounds into the reaction kettle, stirring until all the nitroxide free radical compounds are dissolved, finally adding all the remaining ether compound and benzene solvent into the reaction kettle, stirring to dissolve uniformly, and cooling to normal temperature to obtain the product.

In a third aspect of the present invention, there is provided a distillation and purification apparatus for producing ethylene, for illustrating the injection point of the polymerization inhibitor of the present invention, as shown in FIG. 1, the distillation and purification apparatus comprises 1a pre-fractionating column T401, 2a crude styrene column T402, 3 a refined styrene column T403, 4 a thin film evaporator E-414; the pre-separation tower T401, the crude styrene tower T402, the refined styrene tower T403 and the film evaporator E-414 are sequentially connected through pipelines, each pipeline is provided with a liquid outlet pump, and the liquid can be pumped from the last tower kettle into the next tower kettle for continuous rectification; the pre-fractionating tower T401, the crude styrene tower T402 and the refined styrene tower T403 are respectively provided with a reboiler 5, and the figure shows that the injection points of the polymerization inhibitor of the invention are two and are respectively represented by A, B, and finally generated tar is discharged through a liquid outlet pump 6 connected with a thin film evaporator E-414.

Has the advantages that: the invention provides a styrene polymerization inhibitor, which skillfully utilizes the synergistic effect among components, overcomes the respective defects, obviously improves the polymerization inhibition effect, increases the solubility in styrene or ethylbenzene, effectively prolongs the running time of a styrene device, reduces the energy consumption in the styrene rectification process, improves the product quality, is particularly suitable for the negative pressure high temperature rectification process, and can be compounded with various resistance-reducing agents for use. In addition, the polymerization inhibitor has the advantages of less addition amount in styrene, easily obtained raw materials, low cost, high efficiency, energy conservation and environmental protection, and no adverse effect on styrene, and in view of the excellent effect of the polymerization inhibitor in styrene, the polymerization inhibitor can be expected to be popularized to the production, treatment, transportation and use processes of vinyl aromatic monomers, can greatly improve the purity of the monomers, and can reduce the cost.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly described below, the drawings described below are only some embodiments of the present invention, and it is obvious to those skilled in the art that other drawings can be obtained based on the drawings without creative efforts.

FIG. 1 is a diagram of a distillation purification apparatus for producing styrene;

the numbering in the figure is as follows:

1. a pre-separation tower T401; 2. a crude styrene column T402; 3. a refined styrene column T403; 4. a thin film evaporator E-414; 5. a reboiler; 6. a liquid outlet pump.

Detailed Description

The technical features of the technical solutions provided by the present invention are further clearly and completely described below with reference to specific embodiments, but the scope of protection is not limited thereto. In addition, the starting materials used are all commercially available, unless otherwise specified.