CN113307719A

CN113307719A - Compound polymerization inhibitor and application thereof in styrene rectification process

Info

Publication number: CN113307719A
Application number: CN202110653422.9A
Authority: CN
Inventors: 徐海军; 杨文梁; 董洁灵; 田红; 杨卫娟; 王乐; 麻永强
Original assignee: Tangshan Xuyang Chemical Co ltd
Current assignee: Tangshan Xuyang Chemical Co ltd
Priority date: 2021-06-11
Filing date: 2021-06-11
Publication date: 2021-08-27
Anticipated expiration: 2041-06-11
Also published as: CN113307719B

Abstract

The invention relates to a compound polymerization inhibitor and application thereof in a styrene rectification process. The polymerization inhibitor comprises 4-10% of nitroxide free radical compounds by mass based on the total mass of the polymerization inhibitor; 5 to 15 mass percent of quinone methyl compound; 1-5% of hydroxylamine compound; 70-90% by mass of an ether compound having a boiling point of 200 ℃ or higher and a viscosity of 10cp (20 ℃) or lower. The polymerization inhibitor applied to the styrene rectification process has good polymerization inhibition effect, small kinematic viscosity, low toxicity and convenient storage and transportation, has good solubility in the styrene rectification process, can effectively improve the rectification yield of the styrene, reduce the viscosity of discharged tar, prevent the blockage of tar pipelines, and is more suitable for the industrialized production requirement.

Description

Compound polymerization inhibitor and application thereof in styrene rectification process

Technical Field

The invention belongs to the technical field of styrene polymerization inhibitors, relates to a styrene compound polymerization inhibitor and a preparation method and application thereof, and particularly relates to a styrene compound polymerization inhibitor used in a styrene rectification process and a preparation method and application thereof.

Background

Styrene is a basic raw material product of petrochemical industry and is also an important raw material for synthesizing polymers such as Polystyrene (PS) resin, ABS resin, styrene butadiene rubber and the like. In addition, styrene is widely used in pharmaceutical, coating, textile and other industries. Styrene has extremely high reactivity and can generate self-polymerization at normal temperature, and the higher the temperature is, the faster the polymerization speed is. In industry, ethylbenzene is mainly used for producing styrene through gas-phase catalytic dehydrogenation, and a mixed solution obtained after ethylbenzene dehydrogenation is easy to polymerize in a rectification separation process, so that monomer loss and pipeline blockage can be caused, and the normal operation of industrial production is influenced. 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 inhibitors developed at home and abroad are mainly classified into a real polymerization inhibitor and a retarder. The real polymerization inhibitor such as nitroxide free radical compound has high polymerization inhibition efficiency, can generate a long induction period, hardly generates polymers during the induction period, but has the defects of easy consumption of free radicals and short service life. 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.

On the basis of researching single polymerization inhibitor, scholars at home and abroad combine the advantages of retarder and real polymerization inhibitor to overcome the defect of single use, and develop a compound polymerization inhibitor, namely the polymerization inhibitor is compounded by 2-3 polymerization inhibitors, and the polymerization inhibiting effect of the compound polymerization inhibitor is obviously better than that of a single component, and the compound polymerization inhibitor has the obvious characteristics of small dosage, low toxicity, low environmental pollution and the like.

For example, CN 111592440 a discloses a styrene polymerization inhibitor, which is mainly prepared by blending nitroxide free radical compound, ether compound and benzene solvent, preferably blending nitroxide free radical piperidone and ethylene glycol monobutyl ether, and using tetramethylbenzene as solvent. The compound polymerization inhibitor has excellent stability and solubility, and the synergistic effect obviously reduces the generation amount of styrene polymers.

US 20060122341 reports compounding with 4 components of aromatic sulfonic acid, organic amine, nitrophenol and nitroxide radical: namely, dodecyl benzene sulfonic acid (DDBA), N-methyl-2-pyrrolidone, DNBP and nitroxide radical piperidone TEMP are compounded, so that the effect is better.

CN 111018654A discloses that nitrogen oxygen free radical compounds, 2, 4-bis (trifluoromethyl) thiophenol halide and ethylbenzene solvent are used in a styrene rectification working section in cooperation with a polymerization inhibitor, so that the tar discharge amount of a styrene device is reduced, the production capacity of the styrene rectification device is improved, the toxicity of the polymerization inhibitor is reduced, and the method is environment-friendly.

However, the existing patents mainly study that the polymerization inhibitor can effectively reduce the amount of polymer and tar, and the relationship between the polymerization inhibitor and the viscosity of discharged tar is not clearly described, so that a novel compound polymerization inhibitor still needs to be developed, and the viscosity of discharged tar is effectively reduced while the polymerization inhibition effect is ensured, and the tar pipeline is prevented from being blocked.

Disclosure of Invention

The invention aims to provide the synergistic polymerization inhibitor which has good polymerization inhibition effect, small kinematic viscosity, low toxicity, convenient storage and transportation and good solubility in the styrene rectification process, can effectively improve the rectification yield of styrene, reduce the viscosity of discharged tar, prevent the blockage of tar pipelines and is more suitable for the industrialized production requirement.

In order to achieve the purpose, the invention provides a compound polymerization inhibitor, which comprises the following components, preferably consists of the following components based on the total mass of the polymerization inhibitor:

a) 4 to 10 percent of nitroxide free radical compound, preferably 7 to 10 percent of nitroxide free radical compound;

b) 5 to 15 percent of quinone methyl compound, preferably 5 to 10 percent of quinone methyl compound;

c) 1-5%, preferably 1-3% by mass of hydroxylamine compound;

d) 70 to 90 percent, more preferably 79 to 82 percent of ether compound, the boiling point of the ether compound is more than 200 ℃, preferably 210 to 270 ℃ and the viscosity of 20 ℃ is less than 10cp, preferably 1 to 10cp, more preferably 2 to 8 cp.

The boiling point of the ether compound is measured according to the general method for measuring the boiling point of the chemical reagent GB/T616-2006, and the viscosity is measured according to the standard method for measuring the viscosity of the liquid GB/T22235-2008.

In an embodiment, the nitroxide radical compound may be at least one selected from the group consisting of 2,2,6, 6-tetramethylpiperidine nitroxide radical, 4-hydroxy-2, 2,6, 6-tetramethylpiperidine nitroxide radical, 4-carbonyl-2, 2,6, 6-tetramethylpiperidine nitroxide radical, 4-acetamido-2, 2,6, 6-tetramethylpiperidine nitroxide radical, and 4-methoxy-2, 2,6, 6-tetramethylpiperidine nitroxide radical, and preferably 4-hydroxy-2, 2,6, 6-tetramethylpiperidine nitroxide radical. The nitroxide radical is a polymerization inhibitor, i.e., a true polymerization inhibitor. Particularly, when the nitroxide radical compound is adopted, the polymerization inhibition efficiency is high in the induction period, the chain growth of the active free radical can be stopped, and the polymerization inhibition effect is better.

In an embodiment, the quinone methyl group compound may be at least one selected from benzoquinone and 2, 6-di-tert-butyl-4-benzylidene-cyclohexa-2, 5-dienone, preferably 2, 6-di-tert-butyl-4-benzylidene-cyclohexa-2, 5-dienone. The quinone methyl compound and the nitroxide free radical compound cooperate to prevent the generation of oligomer, play the role of retarder, have lower toxicity than nitrophenol retarder and reduce the harm to the environment and human body.

In an embodiment, the hydroxylamine compound may be at least one selected from the group consisting of diethylhydroxylamine, diisopropylhydroxylamine, hydroxylamine hydrochloride, N-isopropylhydroxylamine, N-dialkylhydroxylamine, preferably diisopropylhydroxylamine. The hydroxylamine compound can be used as a metal passivator to chelate with metal ions in a styrene rectification system to generate a stable complex, and the generation of free radicals caused by the metal ions is inhibited.

In an embodiment, the ether compound may be at least one selected from the group consisting of glycerol monomethyl ether, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether, and is preferably glycerol monomethyl ether. The ether compound has good compatibility with a polymerization inhibitor main body, the compounded polymerization inhibitor product can form a uniform and stable system, the viscosity of the polymerization inhibitor solution is about 5cp at 20 ℃, the viscosity is low, and the industrial feeding is simple. Particularly, the boiling point of the glycerol monomethyl ether is about 220 ℃, the glycerol monomethyl ether is concentrated in the tower bottom of the rectifying tower and is discharged together with tar, the viscosity of the tar can be effectively reduced, and the coking and the blockage of a pipeline of the tower bottom can be prevented.

The compound polymerization inhibitor of the present invention can be obtained by uniformly mixing the components, but is not limited thereto.

The invention also provides the application of the compound polymerization inhibitor as a polymerization inhibitor in styrene rectification.

The invention also provides a styrene rectification method, which comprises the step of rectifying styrene in the presence of the compound polymerization inhibitor.

In an embodiment, the addition amount of the built-up polymerization inhibitor in styrene is 500 to 1500ppm, more preferably 800 to 1000ppm, based on the mass of styrene.

Advantageous effects

The invention relates to a compound polymerization inhibitor which can quickly and effectively capture free radicals on an active chain to generate a stable micromolecule compound, thereby further prolonging the induction period of the polymerization inhibitor under the high-temperature rectification state of styrene, improving the polymerization inhibition efficiency of the polymerization inhibitor, enabling the polymerization inhibition effect of the polymerization inhibitor to be more stable, having good wetting performance on the inner wall of metal and preventing the effective components of the polymerization inhibitor from being deposited with scale in a rectification system. Meanwhile, the solvent with high boiling point, low viscosity and good solubility is selected, so that the viscosity of discharged tar can be effectively reduced, the tar pipeline is prevented from being blocked, and the method is more suitable for industrial production requirements.

Drawings

FIG. 1 is a flow chart of the rectification of a styrene built polymerization inhibitor.

Reference numerals

T401: styrene-ethylbenzene separation tower

T402: styrene rectifying tower

P401: pump and method of operating the same

Detailed Description

The present invention is further described below with reference to examples, but the present invention is not limited thereto.

Styrene, technical grade, Asahi chemical Co., Ltd;

4-hydroxy-2, 2,6, 6-tetramethylpiperidine nitroxide free radical, chemically pure, Dalian Huarui chemical Co., Ltd;

2, 6-di-tert-butyl-4-benzylidene-cyclohexa-2, 5-dienone, chemically pure, zuelangfeng chemical company ltd;

diisopropylhydroxylamine, chemically pure, commercially available from Jiaxing, chemical industries;

glycerol monomethyl ether, analytical grade, Hangzhou chemical Co., Ltd;

ethylbenzene, technical grade, xuyang chemical ltd;

4, 6-dinitro-2-sec-butylphenol (DNBP), chemically pure, zuelang chef chemical ltd.

Phi 30 x 1800mm, equal plate height 45 plates, cigarette platform Tianyi equipment limited;

ultraviolet spectrophotometer, shanghai meida instruments ltd;

full-automatic high-temperature viscosity tester, yamao (luoyang) high-temperature technology limited.

Examples 1 to 9

A series of compound polymerization inhibitors are obtained by compounding a component A, a component B, a component C and a high-boiling-point solvent as shown in the following table 1; wherein the component A is 4-hydroxy-2, 2,6, 6-tetramethyl piperidine nitroxide free radical, the component B is 2, 6-di-tert-butyl-4-benzylidene-cyclohexane-2, 5-dienone, the component C is diisopropyl hydroxylamine, and the high boiling point solvent is glycerol monomethyl ether.

The components are uniformly stirred at the temperature of 30-35 ℃ to obtain clear red liquid, namely the compound polymerization inhibitor.

Table 1 polymerization inhibitor compound formula table

The obtained compound polymerization inhibitor is added into styrene according to the concentration of 600ppm based on the mass of the styrene and is used for the double-tower continuous rectification of the styrene. The rectification is carried out in a styrene rectification device shown in figure 1, T401 is a styrene-ethylbenzene separation tower, the rectification temperature is 100-110 ℃, the vacuum degree is 50-55 kPa, and after the continuous rectification is carried out for 8 hours in the state, the content of the styrene polymer in a tower kettle is measured. And T402 is a styrene rectifying tower, crude styrene comes from a tower kettle of T401, the rectifying temperature is 110-120 ℃, the vacuum degree is 25-30 kilopascals, and after continuous rectification is carried out for 8 hours in the state, the viscosity of the discharged tar in the tower kettle is measured. The results are shown in Table 2.

Comparative example 1

Comparative example 1 was prepared using TMHPO (2,2,6, 6-tetramethyl-4-hydroxypiperidinyloxy radical) alone (component A), ethylbenzene as a solvent, 20% by mass of TMHPO, and 80% by mass of ethylbenzene.

Comparative example 2

Comparative example 2 was DNBP alone, ethylbenzene as the solvent, 20% by mass DNBP, and 80% by mass ethylbenzene.

Comparative example 3

Comparative example 3 is a mixture of TMHPO + diisopropylhydroxylamine (component A + component C), ethylbenzene as solvent, 15% by mass of TMHPO, 5% by mass of diisopropylhydroxylamine, and 80% by mass of ethylbenzene.

Comparative example 4

Comparative example 4 is a compound of TMHPO.cndot. + diisopropylhydroxylamine (component A + component C), glycerol monomethyl ether as a solvent, 15% by mass of TMHPO.cndot., 5% by mass of diisopropylhydroxylamine, and 80% by mass of glycerol monomethyl ether.

Comparative example 5

The comparative example 5 is the compounding of the component A, the component B and the component C, the ethylbenzene is used as a solvent, the mass of the component A is 7%, the mass of the component B is 10%, the mass of the component C is 3%, and the mass of the ethylbenzene is 80%.

The polymerization inhibitors of comparative examples 1 to 5 were added to styrene in a concentration of 600ppm based on the mass of styrene, and double-column rectification was carried out completely in accordance with the rectification process of the above examples, and the effect of inhibiting polymerization was evaluated. The results are shown in Table 2

TABLE 2 Effect of different compounding ratios on the polymerization inhibiting effect

Experiment number	Polymerization inhibitor	Polymer content (%)	Viscosity of Tar (cp, 150 ℃ C.)
				Comparative example 1	Component A + ethylbenzene ·	0.4	70
Comparative example 2	DNBP + ethylbenzene	0.37	68
				Comparative example 3	Component A + component C + ethylbenzene	0.31	45
Comparative example 4	Component A, component C and glycerol monomethyl ether	0.3	38
				Comparative example 5	Component A + component B + component C + ethylbenzene	0.15	29
Example 1	Polymerization inhibitor 1	0.15	13
				Example 2	Polymerization inhibitor 2	0.13	18
Example 3	Polymerization inhibitor 3	0.12	21
				Example 4	Polymerization inhibitor 4	0.12	16
Example 5	Polymerization inhibitor 5	0.11	19
				Example 6	Polymerization inhibitor 6	0.09	22
Example 7	Polymerization inhibitor 7	0.07	17
				Example 8	Polymerization inhibitor 8	0.06	20
Example 9	Polymerization inhibitor 9	0.05	25

The experimental results show that the three-component compound polymerization inhibitor of the embodiment of the invention has obviously improved polymerization inhibition effect compared with the single-component polymerization inhibitors of comparative examples 1 and 2 and the two-component polymerization inhibitors of comparative examples 3 and 4, and the adopted glycerol monomethyl ether solvent with high boiling point has obviously reduced polymer content and tar viscosity compared with ethylbenzene solvent.

In addition, the experimental results of the examples in the above tables 1 and 2 were processed by the orthogonal analysis method with the polymer content as a result.

K1-K3, K1-K3 and R were calculated respectively as follows:

ki: the sum of the corresponding polymer contents on any column with the horizontal number i; 1,2,3

ki: ki is Ki/s, s is the number of occurrences of each level on any column; 1,2,3

R: the results of R ═ max (k1, k2, k3) -min (k1, k2, k3) are shown in table 3.

TABLE 3 Quadrature Table processing results

	Component A	B component	C component
				K1	0.4	0.34	0.3
K2	0.32	0.3	0.3
				K3	0.16	0.24	0.28
k1	0.632	0.583	0.548
				k2	0.566	0.548	0.548
k3	0.4	0.49	0.529
				R	0.232	0.093	0.019

According to orthogonal analysis, the nitroxide radical compounds have the greatest influence on the polymer content, the quinone methyl compounds have the next lowest influence, and the hydroxylamine compounds have the lowest influence. The compound polymerization inhibitor has obvious synergistic effect, and the high-boiling point solvent has better dilution effect on tar. Preferably, the addition amount of the nitroxide free radical compound is 7% -10%, the addition amount of the quinone methyl compound is 5% -10%, the addition amount of the hydroxylamine compound is 1% -3%, and the addition amount of the glycerol monomethyl ether solvent is 79% -82%.

Examples 10 to 17

The compound polymerization inhibitor is prepared according to the mixture ratio of the polymerization inhibitor 7, namely 10 percent of the component A, 5 percent of the component B, 3 percent of the component C and 82 percent of the solvent, the influence of different polymerization inhibitor dosage on the polymerization inhibition effect is examined, and the result is shown in Table 4. The amount of inhibitor used is calculated on the basis of the mass of styrene.

TABLE 4 influence of amount of polymerization inhibitor on the polymerization inhibiting effect

Experiment number	Amount of polymerization inhibitor (ppm)	Polymer content (ppm)	Viscosity of Tar (cp, 150 ℃ C.)
				Example 10	200	1450	22
Example 11	400	900	19
				Example 12	600	700	17
Example 13	800	500	15
				Example 14	1000	450	13
Example 15	1200	430	12
				Example 16	1500	420	11
Example 17	2000	400	10

And (4) conclusion: the larger the amount of the polymerization inhibitor is, the better the polymerization inhibition effect is, the process requires that the content of the polymer is not more than 500ppm, the viscosity of tar is not more than 16cp, and considering the price factor, the amount of the polymerization inhibitor is preferably 800-1000 ppm. Within this range, the cost can be minimized while the polymerization effect satisfies the industrial requirements.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.

Claims

1. A compound polymerization inhibitor comprises the following components based on the total mass of the polymerization inhibitor:

a) 4 to 10 percent of nitroxide free radical compound by mass percentage;

b) 5 to 15 mass percent of quinone methyl compound;

c) 1-5% of hydroxylamine compound;

d) 70-90% by mass of an ether compound having a boiling point of 200 ℃ or higher and a viscosity of 10cp or lower at 20 ℃.

2. The built polymerization inhibitor according to claim 1, wherein,

the mass percent of the nitrogen-oxygen free radical compound is 7-10 percent, and/or

The mass percent of the quinone methyl compound is 5-10%; and/or

The mass percentage of the hydroxylamine compound is 1-3%; and/or

The mass percentage of the ether compound is 79-82%.

3. The built polymerization inhibitor according to claim 1, wherein,

the boiling point of the ether compound is 200-300 ℃; and/or

The ether compound has a viscosity of 1cp to 10cp at 20 ℃.

4. The built polymerization inhibitor according to claim 1 or 2, wherein,

the nitroxide free radical compound is at least one selected from 2,2,6, 6-tetramethylpiperidine nitroxide radical, 4-hydroxy-2, 2,6, 6-tetramethylpiperidine nitroxide radical, 4-carbonyl-2, 2,6, 6-tetramethylpiperidine nitroxide radical, 4-acetamido-2, 2,6, 6-tetramethylpiperidine nitroxide radical and 4-methoxy-2, 2,6, 6-tetramethylpiperidine nitroxide radical; and/or

The quinone methyl compound is at least one selected from benzoquinone and 2, 6-di-tert-butyl-4-benzylidene-cyclohexane-2, 5-dienone; and/or

The hydroxylamine compound is at least one selected from diethylhydroxylamine, diisopropylhydroxylamine, hydroxylamine hydrochloride, N-isopropylhydroxylamine and N, N-dialkylhydroxylamine; and/or

The ether compound is at least one selected from glycerol monomethyl ether, ethylene glycol monomethyl ether and propylene glycol monomethyl ether.

5. The built polymerization inhibitor according to claim 1 or 2, wherein,

the nitroxide free radical compound is 4-hydroxy-2, 2,6, 6-tetramethyl piperidine nitroxide radical; and/or

The quinone methyl compound is 2, 6-di-tert-butyl-4-benzylidene-cyclohexane-2, 5-dienone; and/or

The hydroxylamine compound is diisopropylhydroxylamine; and/or

The ether compound is glycerol monomethyl ether.

6. The use of the built polymerization inhibitor according to any one of claims 1 to 5 as a polymerization inhibitor in styrene rectification.

7. A method for rectifying styrene, which comprises the step of rectifying styrene in the presence of the built polymerization inhibitor as defined in any one of claims 1 to 5.

8. The method according to claim 7, wherein the addition amount of the built polymerization inhibitor in the styrene is 500-1500 ppm based on the mass of the styrene.

9. The method according to claim 7, wherein the addition amount of the built polymerization inhibitor in the styrene is 800-1000 ppm based on the mass of the styrene.