JP2008161848A - Vertical-type multi-blades reaction tank and purification method of (meth)acrylic acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical-type multi-blades reaction tank a few in adhesion of a reaction product to the wall surface of a reaction tank and to provide a purification method of (meth)acrylic acid which can efficiently produce, in commercial scale, a (meth)acrylic acid product a few in coloring and good in polymerizability. <P>SOLUTION: The vertical-type multi-blades reaction tank has a plurality of divisions in a vertical cylinder to form a plurality of division tanks and has an agitation blade in each division tank, wherein the agitation blade has a blade style that a deposit adhered to the wall surface of the tank is scraped off by the agitation blade in agitation. The purification method of (meth)acrylic acid has the step of adding the primary and/or the secondary amino group-containing compound to a raw (meth)acrylic acid and the step of treating a raw (meth)acrylic acid mixture obtained by adding the amino group-containing compound to this acid, in a reactor (A) which has the flowing characteristics of a complete-mixing tank series model and two or more tanks. Then, a method for making the above mixture contact treat with a strongly acidic cation-exchange resin, further and addition treating a formaldehyde containing substance, further, is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vertical multistage blade reactor and a method for purifying (meth) acrylic acid.

  In a reaction system containing an adhesive or a solid substance in the reaction solution or reaction product, a complete mixing type processing apparatus is preferable in that adhesion and retention in the reaction tank are suppressed.

  Moreover, the crude methacrylic acid containing impurities obtained by the synthesis of methacrylic acid can be made into a product with less impurities by purifying it by usual means such as extraction and distillation. However, in the above-mentioned method, it is difficult to remove the impurities that are a side reaction product at the time of synthesis (hereinafter referred to as “side reaction impurity”), and the methacrylic acid product is colored or polymerization is inhibited. The problem of causing

  In order to solve this problem, in Patent Document 1, after treating a crude methacrylic acid with a small amount of an amino group-containing compound and treating with a strong acid cation exchange resin, a strong acid cation exchange resin treatment is performed after adding a formaldehyde-containing material. A method has been proposed. By this method, the reaction between the amino group-containing compound and methacrylic acid can be suppressed so as not to lower the recovery rate of methacrylic acid, and purification can be performed in a state where impurities can be easily removed.

  When the crude methacrylic acid is treated with a small amount of amino group-containing compound, the reaction product of the side reaction impurity and the amino group-containing compound is often sticky or solid.

  Furthermore, as a production system on a commercial scale, in order to achieve high productivity, a complete mixed type continuous production system is usually adopted in many cases.

  However, in the various processing steps described above, in the fully mixed type continuous production method, the unprocessed liquid flows into the next step and leaks, and it is difficult to treat the impurities with as little amino group-containing compound as possible. .

Under such circumstances, there is a demand for a method capable of efficiently producing a methacrylic acid product with little coloration and good polymerizability in commercial scale production. In addition, it is desired to prevent the reaction product from adhering to the wall of the reaction tank in order to enable stable continuous production in commercial scale production.
Japanese Patent Laid-Open No. 11-60536

  An object of the present invention is to provide a vertical multistage blade reaction vessel that can prevent reaction products from adhering to the wall surface of the reaction vessel, and in a continuous production of commercial scale production, it is less colored and has a polymerizable property. The goal is to efficiently produce good (meth) acrylic acid products.

  The present invention is a vertical multistage blade reaction tank in which a plurality of partitions are provided in a vertical cylinder to form a plurality of partition tanks, and a stirring blade is installed in each partition tank, and the stirring blades are tanks during stirring. A vertical multi-stage blade reaction tank of a blade type that scrapes off deposits adhering to the wall surface of the first invention is defined as the first invention.

  In the present invention, a step of adding a primary and / or secondary amino group-containing compound to crude (meth) acrylic acid (hereinafter referred to as “amine addition step”), and then an amino group-containing compound are added. Purification of (meth) acrylic acid having a step (hereinafter referred to as “reaction step”) in which a crude (meth) acrylic acid mixture is treated with a reactor (A) having flow characteristics of two or more tanks in a complete mixing tank row model The method is the second invention.

  In the present invention, the crude (meth) acrylic acid mixture treated in the reactor (A) (hereinafter referred to as “reaction-treated crude (meth) acrylic acid mixture”) is further contacted with a strongly acidic cation exchange resin. A method for purifying (meth) acrylic acid having a step (hereinafter referred to as “ion exchange resin treatment step”) is a third invention.

  Furthermore, a crude (meth) acrylic acid mixture (hereinafter referred to as a “contact-treated crude (meth) acrylic acid mixture”) that has been contact-treated with a strong acid cation exchange resin in the presence of a strong acid cation exchange resin in the presence of formaldehyde A method for purifying (meth) acrylic acid having a step of adding (hereinafter referred to as “ion exchange resin / HCHO treatment step”) is a fourth invention.

  By using the vertical multistage blade reaction tank of the present invention, the reaction product adheres to the wall of the reaction tank even in a reaction system containing a sticky or solid substance in the reaction solution or reaction product. It is possible to suppress and operate for a long time. In addition, the purification method of the present invention enables efficient production of acrylic acid and / or methacrylic acid (hereinafter referred to as “(meth) acrylic acid”) products with little coloration and good polymerizability in commercial scale production. Is possible.

[Vertical multistage blade reactor]
The vertical multistage blade reaction tank of the present invention is a tank in which a plurality of partitions are provided in a vertical cylinder to form a plurality of partition tanks, and a stirring blade is installed in each partition tank. Sometimes it is a blade type that scrapes off deposits adhering to the wall of the tank.

  Examples of the stirring blade include an H-type blade type as shown in FIG. 1 and a flat blade-like type as shown in FIG. The size and shape of the stirring blade can be arbitrarily set according to various conditions such as the capacity of the reactor and the rotation speed of the stirring blade.

  For example, it is preferable that each stirring blade does not contact the cylindrical wall and the upper and lower partitions, and the clearance is reduced. Further, the height of the stirring blade is preferably as close to the height of the partition tank as possible.

  One or more stirring blades are used in each partition tank. For example, as shown in FIG. 1, two stirring blades (1) are symmetric with respect to the stirring shaft (3) on the stirring blade support (4). The thing installed so that it may become.

  The shape of the partition (2) constituting the partition tank does not have to be completely partitioned from the next tank. For example, a donut-shaped disk-like material is mentioned so as not to contact the stirring blade (1). It is done. The gap between the partition (2) and the stirring blade (1) can be arbitrarily set in accordance with the adhesion and mixing efficiency of the target reaction product.

  Although the number of partition tanks can be set according to the objective, 2-10 tanks are preferable from the point of discharge | emission of a reaction product.

[Rough (meth) acrylic acid]
The crude (meth) acrylic acid used in the present invention is obtained by a gas phase catalytic oxidation reaction or a liquid phase catalytic oxidation reaction.

  In the case of the gas phase catalytic oxidation reaction, crude methacrylic compound obtained from at least one compound selected from the group consisting of isobutane, isobutylene, tertiary butyl alcohol, methyl tertiary butyl ether, methacrolein, isobutyraldehyde, and isobutyric acid. Examples include acids.

  The purity of the crude methacrylic acid is preferably 50% or more, and more preferably 90% or more. More preferably, it is 99% or more.

[Amine addition process]
In the present invention, a primary and / or secondary amino group-containing compound is added to crude methacrylic acid.

[Amino group-containing compound]
The amino group-containing compound may be either an aliphatic or aromatic amine, and examples thereof include amines having a plurality of amino groups in one molecule, ammonia, hydrazine and derivatives thereof, and hydroxylamine and inorganic acid salts thereof. It is done.

  Specific examples of the amino group-containing compound include propylamine, butylamine, pentylamine, hexylamine, diethylamine, di-n-propylamine, diisopropylamine, methylethylamine, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, N, N'-diphenylethylenediamine, ethanolamine, diethanolamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, aniline, toluidine, N-ethylaniline, N-propylamine, diphenylamine, phenylenediamine, N-methylphenylenediamine, benzyl Amine, phenethylamine, anisidine and the like can be mentioned.

  The amino group-containing compounds can be used alone or in combination of two or more. Moreover, 0.001-1 mass part is preferable with respect to 100 mass parts of crude methacrylic acid, and, as for the addition amount of an amino group containing compound, 0.005-0.8 mass part is more preferable.

  The container used in the amine addition step and the method for adding the amino group-containing compound may be any container and method. For continuous production, for example, an overflow container can be used.

  In the case of continuous production in commercial scale production, if necessary, at least one mixing step can be provided between the amine addition step and the reaction step. The presence or absence of this mixing step and the number of mixing steps can be set according to the time required for mixing and stirring the crude (meth) acrylic acid and the amino group-containing compound. Moreover, the setting conditions of a mixing process can be determined as needed, and may be the same as that of an amine addition process, or may differ.

[Reaction process]
The reaction apparatus (A) used in the reaction process has a flow characteristic of two or more tanks in a complete mixing tank row model. For example, as shown in FIG. 1 or FIG. A vertical multistage reaction tank in which partitions are provided to form a plurality of partition tanks, each of which is equipped with a stirring blade, and a horizontal multistage reaction tank in which a plurality of reaction tanks are connected as shown in FIG.

  In the present invention, as the reaction apparatus (A), not only the two reaction tanks but also a plurality of reaction tanks as shown in FIG. The mixing tank row model can provide flow characteristics of two or more tanks.

  The treatment conditions in the reaction process may be set so that the complete mixing tank array model has flow characteristics of 2 or more, preferably 3 or more.

  As specific processing conditions, the temperature is preferably 50 to 150 ° C, more preferably 80 to 130 ° C.

  The time is preferably 5 minutes to 5 hours, more preferably 15 minutes to 3 hours. The treatment method may be set according to the purpose. For example, an amino group-containing compound is added to crude (meth) acrylic acid, heated to a predetermined temperature, and then the mixture is kept for a certain time while stirring. Can be mentioned.

  In this invention, as shown in FIG. 5, the container which adds the amino group containing compound used at the said amine addition process can be used as one of the reactors (A).

  The reaction-treated crude (meth) acrylic acid mixture treated in the reaction step may have a distillation step before the next ion exchange resin treatment step.

[Ion exchange resin treatment process]
When the purification of (meth) acrylic acid is insufficient only by the treatment in the reaction step, it is preferable to have an ion exchange resin treatment step after the reaction step.

  Examples of the strongly acidic cation exchange resin include those having a sulfonic acid group such as RCP-160H manufactured by Mitsubishi Chemical Corporation and Amberlyst 15wet manufactured by Rohm & Haas.

  As a method of ion exchange resin treatment, a batch method and / or a continuous method can be selected. For example, a continuous method in which a reaction-treated crude (meth) acrylic acid mixture is passed through a fixed bed filled with a strong acid cation exchange resin. preferable.

  0.1-50 mass parts is preferable with respect to 100 mass parts of reaction process rough | crude (meth) acrylic acid mixtures in a batch type, and, as for the usage-amount of a strong acidic cation exchange resin, 1-30 mass parts is more preferable.

  In the continuous method, the amount of the strongly acidic cation exchange resin in which the flow rate of the reaction-treated crude (meth) acrylic acid mixture is 0.01 to 50 L / L · hr at a space velocity with respect to the strongly acidic cation exchange resin. Is preferable, and a speed of 0.05 to 30 L / L · hr is more preferable. The strongly acidic cation exchange resin treatment temperature is preferably 20 to 150 ° C, more preferably 40 to 130 ° C, and particularly preferably 40 to 100 ° C. The strongly acidic cation exchange resin treatment time is preferably 5 minutes to 5 hours, and more preferably 15 minutes to 3 hours.

[Ion exchange resin / HCHO treatment process]
If purification of (meth) acrylic acid is insufficient even if the treatment in the ion exchange resin treatment step is performed, it is preferable to further include an ion exchange resin / HCHO treatment step after the ion exchange resin treatment step. .

  Formaldehyde-containing materials used include compounds capable of forming formaldehyde, such as formaldehyde, formaldehyde-dissolved solution, and paraformaldehyde.

  The amount of formaldehyde-containing material used is preferably such that the formaldehyde content in the contact-treated crude (meth) acrylic acid mixture is 10 to 10,000 ppm, more preferably 50 to 5,000 ppm.

  The formaldehyde-containing material can be added to the contact treated crude (meth) acrylic acid mixture before or during contact of the contact treated crude (meth) acrylic acid mixture with the strongly acidic cation exchange resin. The formaldehyde-containing material is preferably added before the contact-treated crude (meth) acrylic acid mixture comes into contact with the strongly acidic cation exchange resin in terms of the addition effect.

  For the contact treatment with the strongly acidic cation exchange resin in this step, the same treatment as in the ion exchange resin treatment step can be applied.

  The (meth) acrylic acid treated product obtained by the method of the present invention can be purified by conventional distillation. A reaction product with an amine-containing compound, an unreacted product of an amine-containing compound or a formaldehyde-containing product, and other impurities are separated and removed by this distillation.

  In the distillation step, for example, it is preferable to add a polymerization inhibitor such as phenothiazine or benzophenothiazine.

  Hereinafter, the present invention will be described in detail using examples. Moreover, below, a part and% show a mass part and mass%, respectively.

The number of tanks of the complete mixing tank array model of the reactor (A) is the color distribution (δ response curve) obtained by allowing the colored checker liquid to flow into the apparatus and measuring the color level change at the outlet of the apparatus. It was determined by comparison with the color distribution in various tank numbers of the complete mixing tank row model. (Based on the method described in Maruzen Co., Ltd., March 18, 1988, “Revised Chemical Engineering Handbook”, page 988 (iii) Complete Mixing Tank Model)
The recovery rate of methacrylic acid was determined by the following formula.

Recovery rate (%) = B / A × 100
A: Mass of methacrylic acid contained in crude methacrylic acid-containing material before purification treatment B: Mass of methacrylic acid contained in purified methacrylic acid after purification treatment The induction period was measured as follows. That is, 100 ml of purified methacrylic acid to be measured, 5 mg of hydroquinone monomethyl ether and 0.1 g of benzoyl peroxide as a polymerization accelerator were added to a test tube and dissolved. 10 ml of water was added thereto, immersed in a thermostatic bath at a temperature of 65 ° C., and the liquid temperature in the test tube was measured using a thermocouple. The time when the liquid temperature rose from 65 ° C., that is, the time when the polymerization heat began to be generated was measured, and the time required from the immersion in the thermostat until the start of the polymerization was taken as the induction period. The shorter the induction period, the better the polymerization performance.

[Example 1]
As shown in FIG. 1, a vertical multistage blade reaction tank having three partition tanks in a vertical cylinder and a stirring blade installed in each partition tank was produced. Each stirring blade is not in contact with the cylindrical wall and the upper and lower partition parts, and has two stirring blades (1) having the same length as the height of the partition tank and 1/30 the width of the cylindrical radius. The one installed so as to be symmetrical with respect to the stirring axis (3) was used in (4). Before this vertical multistage blade reaction tank, as shown in FIG. 5, a complete mixing type reaction tank (7) to which the amino group-containing compound used in the amine addition step is added is a reactor 1 (A). A reactor (A) of the type that is used together is installed.

  Methacrylic acid obtained by gas phase catalytic oxidation using isobutylene as a starting material was purified by extraction and distillation to obtain crude methacrylic acid (8) having a purity of 99.2%. The color number of this crude methacrylic acid (8) was APHA75.

  This crude methacrylic acid (8) was supplied into the reaction vessel (7) having an internal temperature of 100 ° C. at a rate of 30 minutes. Simultaneously, with respect to 100 parts of crude methacrylic acid (8), 0.05 parts of phenothiazine as a polymerization inhibitor and 0.05 parts of ethylenediamine as an amino group-containing compound were fed into the reaction vessel.

  Subsequently, the crude methacrylic acid mixture to which ethylenediamine was added was stirred in a vertical multistage blade reaction vessel under the conditions of a liquid temperature of 100 ° C. and a treatment time of 90 minutes. Under these treatment conditions, the reactor (A) had a flow characteristic of 3 tanks in a complete mixing tank row model.

  This treatment liquid (6) was simply distilled under reduced pressure of 10 mmHg to obtain purified methacrylic acid. The recovery rate of the obtained purified methacrylic acid was 94.3%, the number of colors was APHA 3.5, and the induction period was 8.2 minutes. In addition, after a continuous operation for half a year, when the presence or absence of deposits in the reactor was examined, the deposits were very small, and there was no concern about the clogging of the liquid discharge port, and good operation could be continued.

[Examples 2 and 3]
The crude methacrylic acid was purified in the same manner as in Example 1 except that the treatment was performed in the ion exchange resin treatment step under the following conditions shown in Table 1 and the ion exchange resin / HCHO treatment step under the following conditions. In addition, after a continuous operation for half a year, when the presence or absence of deposits in the reactor was examined, the deposits were very small, and there was no concern about the clogging of the liquid discharge port, and good operation could be continued. The evaluation results are shown in Table 1.

<Ion exchange resin treatment>
In a cylinder filled with strongly acidic cation exchange resin Amberlyst 15E (manufactured by Rohm & Haas), the ion exchange resin treatment was performed under the conditions of a treatment temperature of 80 ° C. and a space velocity of 1 L / L · hr.

<Ion exchange resin / HCHO treatment>
Formaldehyde was added in an amount of 0.05 parts formaldehyde to 100 parts of the contact-treated crude methacrylic acid mixture. Subsequently, in a cylinder filled with strongly acidic cation exchange resin Amberlyst 15E (manufactured by Rohm & Haas), ion exchange resin / HCHO treatment was performed under conditions of a treatment temperature of 80 ° C. and a treatment time of 30 minutes.

[Comparative Example 1]
Instead of using a vertical multistage blade reaction tank, the purification treatment of crude methacrylic acid was carried out in the same manner as in Example 1 except that the reaction apparatus (A) used a complete mixing type reaction tank as shown in FIG. Carried out. Under this processing condition, the reactor (A) had a flow characteristic corresponding to the middle of one tank and two tanks in the complete mixing tank array model. The evaluation results are shown in Table 1. Also, after six months of continuous operation, when the presence or absence of deposits in the reactor was examined, a large amount of deposits were confirmed and there was a risk of clogging the liquid outlet. It was necessary to remove.

It is explanatory drawing which shows an example of the blade type | mold vertical multistage blade reaction tank of this invention. It is explanatory drawing which shows an example of the vertical multistage blade reaction tank used for this invention. It is explanatory drawing which shows an example of the horizontal type | mold multistage blade reaction tank used for this invention. It is explanatory drawing which shows an example of the continuous multi tank type reactor (A) in this invention. It is explanatory drawing which shows an example of this invention which installed the container which adds an amino group containing compound in front of the vertical multistage blade reaction tank of this invention. In FIG. 5, it is explanatory drawing which shows an example at the time of changing a vertical multistage blade reaction tank into a complete mixing type reaction tank.

Explanation of symbols

1: Stirring blade 2: Partition 3: Stirring shaft 4: Stirring blade support 5: Liquid inlet 6: Liquid outlet 7: Container for adding amino group-containing compound 8: Crude (meth) acrylic acid 9: Amino group-containing compound

Claims (6)

  A vertical multistage reaction vessel in which a plurality of partitions are provided in a vertical cylinder to form a plurality of partition tanks, and a stirring blade is installed in each partition tank, and the stirring blades adhere to the wall surface of the tank during stirring. Vertical multistage blade reaction tank which is a blade type that scrapes off the adhered matter.   A step of adding a primary and / or secondary amino group-containing compound to the crude (meth) acrylic acid, and then a crude (meth) acrylic acid mixture to which the amino group-containing compound has been added, in a complete mixing tank model (Meth) acrylic acid refinement | purification method which has a process with a reactor (A) which has the flow characteristic of 2 or more tanks.   After the step of treating the crude (meth) acrylic acid mixture to which the amino group-containing compound has been added with the reactor (A), the crude (meth) acrylic acid mixture treated with the reactor (A) is subjected to strong acid cation exchange. The method for purifying (meth) acrylic acid according to claim 2, further comprising a step of contact treatment with a resin.   After the step of contact treatment with the strong acid cation exchange resin, the formaldehyde-containing material is added to the crude (meth) acrylic acid mixture contacted with the strong acid cation exchange resin in the presence of the strong acid cation exchange resin. The method for purifying (meth) acrylic acid according to claim 3, further comprising the step of:   Crude methacrylic acid obtained by a gas phase catalytic oxidation reaction of at least one compound selected from the group consisting of isobutane, isobutylene, tertiary butyl alcohol, methyl tertiary butyl ether, methacrolein, isobutyraldehyde, and isobutyric acid The method for purifying (meth) acrylic acid according to any one of claims 2 to 4.   The method for purifying (meth) acrylic acid according to any one of claims 2 to 5, wherein the vertical multistage reaction vessel according to claim 1 is used as the reactor (A).

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