KR101844999B1 - Method for eliminating polymerisation inhibitors of monomer mixtures including tert-butylcatechol - Google Patents

Abstract

The purpose of the present invention is to provide a method of eliminating a polymerization inhibitor containing tert-butylcatechol in high efficiency and at low costs by treating a monomer mixture in a mild condition. The method relates to the method of eliminating a polymerization inhibitor, the method comprising the steps of dissolving a mixture, including the polymerization inhibitor containing tert-butylcatechol and at least two ethylenically unsaturated monomers, into a sodium hydroxide solution to extract the tert-butylcatechol, and separating the sodium hydroxide solution including the extracted tert-butylcatechol by a specific gravity separator. The sodium hydroxide solution is injected by a sparger dispersion method, a spray dispersion method or a direct injection method, the sodium hydroxide solution has a concentration of 1 to 20 wt%, and 10 to 20 parts by weight of the sodium hydroxide solution is dissolved with respect to 100 parts by weight of the mixture.

Description

METHOD FOR ELIMINATING POLYMERISATION INHIBITORS OF MONOMER MIXTURES INCLUDING TERT-BUTYLCATECHOL [0002]

The present invention relates to a method for removing a polymerization inhibitor by removing a tert-butyl catechol polymerization inhibitor from a monomer mixture.

The monomer used as a raw material of the polymer is an unsaturated monolith which can be spontaneously polymerized by a free radical. Therefore, a polymerization inhibitor is added to prevent polymerization during storage or transportation. The polymerization inhibitor is a substance that reacts with a radical initiator or a radical of a monomer to quench the radical to stop the polymerization reaction. Representative examples of the polymerization inhibitor include tert-butyl catechol, benzonquinone, chloranil, m-dinitrobenzene, nitrobenzene, and p-phenylenediamine. When it is desired to improve the quality of the polymer or use the inhibited monomer, it is necessary to remove the polymerization inhibitor. Typical techniques for removing the polymerization inhibitor include distillation, adsorption, and extraction.

Distillation is possible only when the boiling point of the polymerization inhibitor is lower than that of the mixture or monomer and the thermal stability of the mixture or monomer is high, and the loss of the active ingredient in the oil, the investment cost and the operation cost are large.

Adsorption is a method of adsorbing a polymerization inhibitor by using an adsorbent such as alumina, ion exchange resin, silica gel, or activated carbon. If the polymerization inhibitor is no longer adsorbed, the adsorbent should be repeatedly exchanged or regenerated periodically, and adsorbed on the adsorbent depending on the components of the mixture or monomers may be lost.

The extraction is carried out using a solvent (additive) soluble in the polymerization inhibitor in the mixture to remove the polymerization inhibitor.

U.S. Patent No. 4,144,137 uses a distillation method to remove the polymerization inhibitor p-benzoquinone contained in the acrylic and methacrylic monomers. And a monoalkyl-substituted hydroquinone is added to distill only the polymerization inhibitor if the boiling points of the monomer and the polymerization inhibitor are similar.

Open Patent No. 0070329 relates to an adsorption method for removing polymerization inhibitors from an ethylenically unsaturated monomer by contacting the alumina containing at least one element of an alkali metal, an alkaline earth metal and a rare earth group, wherein the alumina has a specific surface area of 30 m ² / g or more And comprises at least one of sodium, potassium, lanthanum and cerium, and the mixture of ethylenically unsaturated monomer and polymerization inhibitor comprises 5 to 1500 ppm of polymerization inhibitor.

Japanese Patent No. 3682990 relates to a method of using an alkali metal alkoxide to remove a polymerization inhibitor p-tert-butyl catechol contained in an ethylenically unsaturated compound which is an olefin compound such as 1-pentene, It is disclosed that the unsaturated compound and the alkali metal alkoxide are brought into contact through stirring and the reaction temperature is 0 to 30 ° C and the pressure is 0.5 to 1.5 atm and the removal rate of the polymerization inhibitor is 98% have.

Japanese Patent Registration No. 1067796 discloses a method of reacting a polymerization inhibitor, which is a polar compound containing a carbonyl group, contained in? -Methylstyrene with a basic substance such as sodium hydroxide to remove it and then separating and purifying it to obtain high purity? -Methylstyrene Methylstyrene, the reaction temperature is 60 to 150 ° C, and the basic substance is added with stirring to the basic substance. The reaction is carried out at a reaction pressure of 1 to 5 kg / cm ² and a reaction temperature of 60 to 150 ° C., And a basic substance having high solubility in? -Methylstyrene has a higher removal efficiency.

U.S. Patent No. 4,162,273 discloses a method for preventing the generation of heat and explosion by injecting sodium hydroxide solution, which is an alkali solution, into liquid propane containing hydrofluoric acid, and discloses the use of a sparger in injecting an alkali solution into liquid propane have.

The present invention is intended to provide a method for removing the tert-butyl catechol containing polymerization inhibitor with high efficiency and low cost by treating the monomer mixture under mild conditions.

According to the present invention, there is provided a process for preparing a mixture comprising extracting a tert-butyl catechol by dissolving a mixture comprising a tert-butyl catechol-containing polymerization inhibitor and at least two ethylenically unsaturated monomers in a sodium hydroxide solution, A method of removing a polymerization inhibitor comprising separating a sodium hydroxide solution containing catechol by a non-separating separator,

The sodium hydroxide solution is injected by a sparger dispersion method, a spray dispersion method, or a direct injection method. The concentration of the sodium hydroxide solution is 1 wt% to 20 wt%, and the sodium hydroxide solution 10 to 20 parts by weight of the polymerization inhibitor is dissolved.

The sodium hydroxide solution is dispersed by a sparger dispersion method and is injected into a particulate form,

The average particle diameter of the dispersed sodium hydroxide solution fine particles may be from 2 탆 to 500 탆.

The sodium hydroxide solution may be injected at a temperature of 0 ° C to 40 ° C and a pressure of 1 bar to 5 bar.

The concentration of the sodium hydroxide solution may be 1 wt% to 10 wt%.

The polymerization inhibitor may further comprise at least one of benzophenone, benzotriazole, picric acid, chloranil, m-dinitrobenzene, nitrobenzene, quinone derivatives, naphthol, amine, phenylenediamine, phosphite and methoxyphenol .

The mixture may further comprise at least one of C3 to C8 aliphatic cyclic hydrocarbon, C6 to C8 saturated hydrocarbon, and C6 to C8 unsaturated hydrocarbon.

It is possible to remove the tert-butyl catechol-containing polymerization inhibitor in the monomer mixture under a mild condition at a high efficiency and low cost.

Hereinafter, a method for removing a polymerization inhibitor according to an embodiment of the present invention will be described in detail. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The invention is only defined by the scope of the claims which follow.

Unless expressly stated herein, terminology is used merely to refer to a specific embodiment and is not intended to limit the invention. Also, the singular forms as used herein include plural forms as long as the phrases do not have the obvious opposite meaning.

Means that a particular feature, region, integer, step, operation, element or component is specified, and that the addition of any other feature, region, integer, step, operation, element, It is not.

The method for removing a polymerization inhibitor according to the present invention comprises the steps of: extracting a tert-butyl catechol by dissolving a mixture containing a tert-butyl catechol-containing polymerization inhibitor and at least two ethylenically unsaturated monomers in a sodium hydroxide solution; Separating the sodium hydroxide solution containing the extracted tert-butyl catechol by a specific gravity separator,

The sodium hydroxide solution is injected by a sparger dispersion method, a spray dispersion method, or a direct injection method. The concentration of the sodium hydroxide solution is 1 wt% to 20 wt%, and the sodium hydroxide solution 10 to 20 parts by weight may be dissolved.

Butyl-catechol contained in the mixture has a relatively high boiling point of about 280 ° C, it is difficult to remove by distillation, and when the tert-butylcatechol is contained in a high content in the mixture, The extraction method can be used as a method for removing the tert-butyl catechol more efficiently.

The extraction may be carried out with a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution may be from 1 wt% to 20 wt%, and more specifically from 1 wt% to 10 wt%.

When the concentration and the weight ratio of the sodium hydroxide solution are within the above range, the removal rate of the tert-butyl catechol can be increased.

Meanwhile, the sodium hydroxide solution can be injected by a sparger dispersion method, a spray dispersion method, or a direct injection method at a temperature of 0 ° C to 40 ° C and a pressure of 1 bar to 5 bar.

According to one embodiment of the present invention, a sparse dispersion method or a spray dispersion method may be used.

According to the sparger dispersion method or the spray dispersion method, the sodium hydroxide solution as the extraction solvent can be dispersed in fine pores and can be injected in the form of fine particles. In this case, since the contact area between the polymerization inhibitor and the extraction solvent increases, Can be effectively removed.

According to a specific embodiment of the present invention, a sparse dispersion method can be used.

The term "sparse dispersion system" refers to a general method of dispersing by a sparger, which means a method of dispersing a liquid or a gas in a liquid, and the spar is also referred to as a porous dispersion tube or atomizer.

The average particle size of the fine particles dispersed by the sparse low dispersion method may be from 2 탆 to 500 탆, specifically from 5 탆 to 50 탆.

When the average particle size of the fine particles exceeds 500 μm, the contact area between the polymerization inhibitor and the extraction solvent is too small to effectively remove the polymerization inhibitor. When the average particle diameter is less than 2 μm, an emulsion of the mixture and the sodium hydroxide solution is formed, The polymerization inhibitor can not be effectively separated.

The separation step may be performed by a specific gravity separator. The specific gravity separator is to separate the specific material by specific gravity. According to one embodiment of the present invention, the mixture from which the tert-butyl catechol has been removed is discharged to the top of the separation drum and the sodium- The solution is discharged to the bottom of the separation drum to separate out the mixture from which the tert-butyl catechol has been removed.

In this case, the mixture in which the tert-butyl catechol has been removed can be quantified by using gas chromatograph equipped with an autosampler.

The polymerization inhibitor may further comprise at least one of benzophenone, benzotriazole, picric acid, chloranil, m-dinitrobenzene, nitrobenzene, quinone derivatives, naphthol, amine, phenylenediamine, phosphite and methoxyphenol .

The mixture may further comprise at least one of C3 to C8 aliphatic cyclic hydrocarbon, C6 to C8 saturated hydrocarbon, and C6 to C8 unsaturated hydrocarbon.

Hereinafter, embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

Comparative Example 1 (Adsorption method)

5 g of strong acid ion-exchange resin (product number LEWATIT K2629, LANXESS Co., China), ethert-butyl catechol (99.0%, product number B1272, SAMCHUN CHEMICAL CO., LTD.) Was quantified as 0.08 wt% The compound was fed to the HPLC pump at a constant flow rate (0.1 cc / min) to remove the tert-butyl catechol. At this time, the temperature was kept at 25 ° C and the pressure was kept at 1 bar.

The components of the model compound are as shown in Table 1 below.

ingredient Composition (% by weight) Dicyclopentadiene 28 Piperylene 26 Cyclopentane 8 C6 to C8 saturated hydrocarbons or C6 to C8 unsaturated hydrocarbons 20 Myrcene 5 t-Butylcatechol 0.08 Other 13 gun 100

Comparative Example 2 (distilled water injection)

2000 mL of model compound and distilled water were each injected with a static mixer. At this time, 100 parts by weight of distilled water was directly injected into 100 parts by weight of the model compound, and the model compound was washed with water to remove tert-butyl catechol. The washing conditions were 35 DEG C and 2 bar.

Example 1 (direct injection method)

The same conditions as those of Comparative Example 2 were used except that 1 wt% of sodium hydroxide solution (98.0%, product number S0610, SAMCHUN CHEMICAL CO., LTD.) Was used instead of the distilled water in an amount corresponding to 10 parts by weight with respect to 100 parts by weight of the model compound The tert-butyl catechol was removed.

The model compound was fed to a static mixer with a HPLC pump at a constant flow rate (33 cc / min) and an aqueous solution of sodium hydroxide was fed to a static mixer at a constant flow rate (2.67 cc / min) using an HPLC pump.

Example 2 (sparger dispersion system)

Butyl-catechol was removed under the same conditions as in Example 1 except that sodium hydroxide solution was injected using a sparger instead of the direct injection method.

Example 3 (spray dispersion method)

Butyl-catechol was removed under the same conditions as in Example 1 except that sodium hydroxide solution was injected by a spray dispersion method instead of the direct injection method.

Example  4

Butyl catechol was removed under the same conditions as in Example 1 except that sodium hydroxide solution was used in an amount corresponding to 20 parts by weight per 100 parts by weight of the model compound.

Comparative Example  3

Butyl catechol was removed under the same conditions as in Example 1, except that sodium hydroxide solution was used in an amount of 30 parts by weight based on 100 parts by weight of the model compound.

Comparative Example  4

Butyl catechol was removed under the same conditions as in Example 1 except that sodium hydroxide solution was used in an amount of 40 parts by weight per 100 parts by weight of the model compound.

Example  5

Butyl-catechol was removed under the same conditions as in Example 1 except that a 5 wt% sodium hydroxide solution was used.

Example  6

Butyl catechol was removed under the same conditions as in Example 1 except that 10 wt% sodium hydroxide solution was used.

Comparative Example  5

Butyl catechol was removed under the same conditions as in Example 1, except that 0.1 wt% sodium hydroxide solution was used.

Comparative Example  6

Butyl catechol was removed under the same conditions as in Example 1 except that 0.5 wt% sodium hydroxide solution was used.

Example  7

Butyl catechol was removed under the same conditions as in Example 1 except that the washing conditions were changed to 25 캜 and 1 bar.

Test Example  One

The mixture of the model compound and the sodium hydroxide solution is injected into the lower part of the separation drum, and the model compound in which the tert-butyl catechol is removed by the difference in specific gravity is discharged to the lower part of the separation drum and the sodium hydroxide solution in which the tert-butyl catechol is dissolved. After 30 minutes of continuous water rinsing, the mixture discharged to the upper part of the sampled drum was quantified by gas chromatography equipped with an autosampler. Plot Q was used as an analytical column, and the temperature was maintained at 150 ° C for 10 minutes and then heated to 280 ° C at 5 ° C / min for 10 minutes. FID was used as the detector.

First, Table 2 shows the results of comparing the removal rates according to the method of removing the tert-butyl catechol through Example 1 and Comparative Examples 1 and 2. In Table 2,

The results of comparison of the removal rates according to the sodium hydroxide solution injection method are shown in Table 3 through Examples 1 to 3,

The results are shown in Tables 4 and 5 through Examples 1, 4 to 7, and Comparative Examples 3 to 6 in terms of the amount and concentration of the sodium hydroxide solution and the removal rate depending on the washing condition. Wherein the initial model compound has a tert-butyl catechol content of 800 ppm.

On the other hand, the removal ratio of tert-butyl catechol was calculated according to the following formula (1).

[Equation 1]

(%) = ((Amount of reduced tert-butyl catechol (ppm)) / (content of flushing-butyl catechol (800 ppm)) * 100

Tert-butyl catechol content (ppm) Tert-butyl catechol removal rate (%) Example 1 255 68 Comparative Example 1 312 61 Comparative Example 2 512 36

As shown in Table 2, when the method of removing the tert-butyl catechol was compared, it was found that the method (Comparative Example 1) in which the sodium hydroxide solution was directly injected and removed by extraction (Example 1) And it was confirmed that it shows a high removal rate as compared with the method of extracting with distilled water (Comparative Example 2).

When the adsorption method of Comparative Example 1 is used, there is a problem in terms of the removal ability and cost of the tur-butyrichecol. This is because the adsorbent generally does not adsorb the adsorbate any more than the limit saturation state of the adsorbate, so that the exchange or regeneration process must be repeated periodically.

In addition, when sodium hydroxide solution was used as the extracting agent, higher rate of tert-butyl catechol removal was confirmed when distilled water was used as the extracting agent. This is effective for the removal of tert-butyl catechol when rinsed with a basic solution rather than distilled water, since quaternium is formed by oxidation of the tert-butyl catechol under alkaline conditions.

Tert-butyl catechol content (ppm) Tert-butyl catechol removal rate (%) Example 1 255 68 Example 2 162 80 Example 3 30 96

Referring to Table 3, it was confirmed that the removal rate of the tert-butyl catechol was varied by controlling the particle size of the sodium hydroxide solution according to the injection method of the sodium hydroxide solution.

It can be seen that as the particle size of the sodium hydroxide solution decreases from Example 1 to Example 3 and the particle size of the sodium hydroxide solution becomes smaller, the removal rate of the tert-butyl catechol improves.

In the case of Example 3, the removal rate of the tert-butyl catechol was the highest because the fine particles of the sodium hydroxide solution and the model compound effectively contacted by spraying the sodium hydroxide solution with the spray dispersion method.

However, in the case of the spray dispersion method, since the average particle size of the sodium hydroxide solution fine particles is less than 2 m, the possibility of forming the emulsion is high, and the efficiency of separation of the model compound and the sodium hydroxide solution decreases after washing, Can be difficult.

In the case of Example 2, the sparger is injected by spraying a sodium hydroxide solution in a dispersion manner. At this time, the sodium hydroxide solution fine particles dispersed in the fine pores and the model compound can efficiently contact with each other, It was confirmed that not only the removal rate but also the separation efficiency were excellent because the particle size of the sodium solution was easily controlled.

Therefore, it is most preferable to inject the sodium hydroxide solution by the sparse dispersion method in consideration of the removal rate and separation efficiency of the tert-butyl catechol.

Tert-butyl catechol content (ppm) Tert-butyl catechol removal rate (%) Example 1 255 68 Example 4 255 68 Example 7 272 66 Comparative Example 3 663 17 Comparative Example 4 699 13

Table 4 shows the results of comparing the removal rate of the tert-butyl catechol with the change of the weight ratio of the sodium hydroxide solution to the model compound.

Referring to Table 4, 30 parts by weight and 40 parts by weight of a case where 1 wt% of sodium hydroxide solution is used in an amount corresponding to 10 to 20 parts by weight of 100 parts by weight of the model compound (Examples 1 and 4) Butyl catechol removal ratio was improved as compared with the case of using the catalysts (Comparative Example 3 and Comparative Example 4). That is, the weight ratio of the most suitable sodium hydroxide solution for the removal of the tert-butyl catechol can be judged to be 10 to 20 parts by weight based on 100 parts by weight of the model compound.

On the other hand, even when the washing conditions were changed to 25 캜 and 1 bar (Example 7), the removal rate of the tert-butyl catechol did not change greatly, and it was confirmed that the influence of the washing temperature and the pressure was insignificant in a certain range.

Tert-butyl catechol content (ppm) Tert-butyl catechol removal rate (%) Example 1 255 68 Example 5 0 100 Example 6 0 100 Comparative Example 5 705 12 Comparative Example 6 444 45

Table 5 shows the results of the removal of the tert-butyl catechol according to the sodium hydroxide solution concentration when the weight ratio of the sodium hydroxide solution to the model compound was fixed at 10.

Referring to Table 5, it was confirmed that Comparative Examples 5 and 6, in which the concentration of sodium hydroxide solution was 1 wt% or less, were not effective for the removal of tert-butyl catechol. That is, it can be judged that the most suitable sodium hydroxide solution concentration for the removal of the tert-butyl catechol is 1 to 20% by weight, more preferably 1 to 10% by weight.

While the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, Such modifications and changes are to be considered as falling within the scope of the following claims.

Claims (6)

Butyl catechol by dissolving a mixture containing a tert-butyl catechol-containing polymerization inhibitor, and at least two ethylenically unsaturated monomers in a sodium hydroxide solution,
Separating the sodium hydroxide solution containing the extracted tert-butyl catechol by a specific gravity separator,
The sodium hydroxide solution is injected by a sparger dispersion method or a spray dispersion method,
The concentration of the sodium hydroxide solution is 1 wt% to 20 wt%
Wherein 10 to 20 parts by weight of the sodium hydroxide solution is dissolved in 100 parts by weight of the mixture. The method according to claim 1,
The sodium hydroxide solution is dispersed by a sparger dispersion method and is injected into a particulate form,
Wherein an average particle diameter of the dispersed sodium hydroxide solution fine particles is 2 占 퐉 to 500 占 퐉. The method according to claim 1,
Wherein the sodium hydroxide solution is injected at a temperature of 0 ° C to 40 ° C and a pressure of 1 bar to 5 bar. The method according to claim 1,
Wherein the concentration of the sodium hydroxide solution is 1 wt% to 10 wt%. The method according to claim 1,
The polymerization inhibitor may further comprise at least one of benzophenone, benzotriazole, picric acid, chloranil, m-dinitrobenzene, nitrobenzene, quinone derivatives, naphthol, amine, phenylenediamine, phosphite and methoxyphenol By weight based on the weight of the polymerization inhibitor. The method according to claim 1,
Wherein the mixture further comprises at least one of C3 to C8 aliphatic cyclic hydrocarbon, C6 to C8 saturated hydrocarbon, and C6 to C8 unsaturated hydrocarbon.