JP2005179352A - Method of purifying (meth)acrylic acid - Google Patents

Method of purifying (meth)acrylic acid Download PDF

Info

Publication number
JP2005179352A
JP2005179352A JP2004342449A JP2004342449A JP2005179352A JP 2005179352 A JP2005179352 A JP 2005179352A JP 2004342449 A JP2004342449 A JP 2004342449A JP 2004342449 A JP2004342449 A JP 2004342449A JP 2005179352 A JP2005179352 A JP 2005179352A
Authority
JP
Japan
Prior art keywords
acrylic acid
meth
copper
method
crude
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2004342449A
Other languages
Japanese (ja)
Inventor
Yasuyuki Ogawa
Yoshiro Suzuki
Kenji Takasaki
Shuhei Yada
寧之 小川
修平 矢田
芳郎 鈴木
研二 高崎
Original Assignee
Mitsubishi Chemicals Corp
三菱化学株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to JP2003399124 priority Critical
Application filed by Mitsubishi Chemicals Corp, 三菱化学株式会社 filed Critical Mitsubishi Chemicals Corp
Priority to JP2004342449A priority patent/JP2005179352A/en
Publication of JP2005179352A publication Critical patent/JP2005179352A/en
Application status is Pending legal-status Critical

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently produce high purity (meth)acrylic acid by preventing the formation of polymerized products of (meth)acrylic acid in the obtained condensate in producing the high purity (meth)acrylic acid by distillation. <P>SOLUTION: A crude acrylic acid-containing solution containing acrylic acid is distilled in a distillation column to obtain an acrylic acid condensate having a purity of acrylic acid of ≥90%, and an oxygen-containing gas (air) containing oxygen is supplied into the acrylic acid condensate housed in a reflux tank for containing this acrylic acid condensate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for purifying (meth) acrylic acid. Specifically, the present invention relates to a method for purifying (meth) acrylic acid obtained by a vapor phase catalytic oxidation method by distillation.

  As a method for producing (meth) acrylic acid, there is a method of hydrolyzing a corresponding nitrile compound, but at present, a gas phase catalytic oxidation method of a corresponding hydrocarbon, that is, propylene or isobutylene is mainly performed. Recently, a gas phase catalytic oxidation method using a corresponding alkane, which is cheaper instead of olefin, as a raw material has been studied.

  In the production of (meth) acrylic acid by the gas phase catalytic oxidation method, the reaction product gas containing the generated (meth) acrylic acid is brought into contact with an absorbing solvent, for example, water, and (meth) acrylic acid in the gas is converted to (meth) Collect as an acrylic acid solution. In this solution, in addition to (meth) acrylic acid, various impurities by-produced during vapor phase catalytic oxidation, for example, acrylic acid, carboxylic acid such as formic acid, acetic acid, maleic acid and maleic anhydride, acrolein Aldehydes such as furfural and benzaldehyde, acetone and the like are also included.

  A number of methods for recovering purified (meth) acrylic acid from this (meth) acrylic acid solution have been proposed, but the mainstream is absorption from the (meth) acrylic acid solution in the pre-purification process. Solvent and some of the impurities are removed to form crude (meth) acrylic acid consisting essentially of (meth) acrylic acid and its dimer and other heavy components, which are then purified in a purification step to provide the desired It is a method to make a product of quality.

  In recent years, for example, acrylic acid has been increasing in demand as a raw material for superabsorbent resins used in paper diapers and the like, food additives, and the like. In such applications, high-purity acrylic acid is required. If crude acrylic acid is used as a raw material for an acrylic polymer such as the superabsorbent resin without removing impurities, problems such as a delay in the reaction, a decrease in the degree of polymerization, and coloring of the polymer may occur. There is.

  Therefore, industrially, purification of (meth) acrylic acid by distillation is performed. As a purification method of crude (meth) acrylic acid obtained by gas phase catalytic oxidation, a distillation method is generally used, but (meth) acrylic acid is very easily polymerized, and its handling has been a problem.

For example, conventionally, when trying to obtain high-purity acrylic acid by distillation, the occurrence of polymerization in the tower of a distillation tower having a high temperature has been a problem. For this reason, various developments have been made,
1) Types of polymerization inhibitors 2) Polymerization inhibitor concentrations and charging methods 3) Distillation tower operating conditions have been improved.

  As such a conventional technique, for example, as a method for producing high-purity acrylic acid by separating and removing impurities from crude acrylic acid obtained by gas phase catalytic oxidation, there is a method of performing distillation in the presence of hydrazines. (For example, refer to Patent Document 1 and Patent Document 2.) Further, a method of distillation in the presence of hydrazine and ammonia is known (see, for example, Patent Document 3). This method is said to be effective in removing maleic acids.

Further, as a method for continuously producing high-purity acrylic acid by preventing sludge formation in the distillation column, it is possible to use crude acrylic acid having a maleic acid concentration of 2,000 ppm or less as a raw material for high-purity acrylic acid. It is known (for example, refer to Patent Document 4).

  Moreover, when distilling high-purity acrylic acid with these techniques, the higher the purity, the easier it is to polymerize, and there is a need for a technique that can be obtained industrially and stably. As such a technique, for example, as a technique for preventing polymerization inside the distillation column, a technique is known in which copper dithiocarbamate is added to try to suppress polymerization of an easily polymerizable compound (see, for example, Patent Document 5).

  In addition, a technique is known in which air (oxygen) is supplied into a distillation column in order to prevent polymerization of a vinyl group-containing compound such as acrylic acid in the distillation step (see, for example, Patent Document 6).

As a result, the polymerization of (meth) acrylic acid in the distillation column has tended to be suppressed, but other polymerization problems have occurred in the operation of the distillation column. In the purification of (meth) acrylic acid, the (meth) acrylic acid having higher purity was contained in the reflux tank containing the condensate of (meth) acrylic acid, In spite of the environment, a polymer of (meth) acrylic acid is generated, and the pump attached to the reflux tank causes the pump to stop due to the polymer. Stopping the pump necessitates stopping the operation of the distillation column, and a method for suppressing the formation of such a polymer is desired.
JP-A-49-30312 Japanese Patent Publication No.58-37290 JP-A-7-330659 JP 2001-316326 A JP-A-7-228548 JP 2001-122909 A

  In the present invention, when high-purity (meth) acrylic acid is produced by distillation, high-purity (meth) acrylic acid is prevented by preventing generation of a polymer of (meth) acrylic acid in the resulting condensate. The present invention intends to provide a method for efficiently producing the above.

That is, the present inventors have conducted extensive studies in order to solve the conventional problems in continuously producing high-purity acrylic acid industrially,
(1) Oxygen (usually air) supplied to the acrylic acid distillation column for the purpose of inhibiting polymerization is consumed in the column, and the acrylic acid solution in the reflux tank has not been given a polymerization inhibiting effect.
(2) For this reason, a method of increasing the oxygen (usually air) supplied to the distillation column is conceivable. However, since the distillation column is hot, if a large amount of air is supplied, squeal is generated in the distillation column. It cannot be increased because it may form.
(3) The acrylic acid distillation column is usually a vacuum distillation column to lower the temperature in the distillation column for the purpose of preventing polymerization, so a simple increase in air increases the gas flow rate in the distillation column. The existing distillation column exceeds the tray capacity limit, or the efficiency decreases due to the increase of inert gas (ie, air) in the gas supplied to the top condenser. The new distillation column increases the column diameter of the distillation column. It becomes uneconomical due to an increase in the heat transfer area of the top condenser.
Thus, as an industrially simple and effective method, (4) it was found that the formation of a polymer can be avoided by newly supplying oxygen (usually air) into the acrylic acid liquid in the reflux tank, Long-term stable operation of the pump attached to the reflux tank has been obtained.

  That is, the present invention includes a step of distilling a crude (meth) acrylic acid-containing liquid containing acrylic acid or methacrylic acid to obtain a (meth) acrylic acid condensate having a purity of (meth) acrylic acid of 90% or more. Supplying an oxygen-containing gas containing oxygen to the (meth) acrylic acid condensate in a reflux tank in which the (meth) acrylic acid condensate is accommodated. It is a purification method.

  In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid.

  According to the method for purifying (meth) acrylic acid of the present invention, generation of a polymer from the resulting high-purity (meth) acrylic acid condensate is prevented, and the production line is blocked or produced and purified by this polymer. Abnormal operation of the apparatus is prevented, and high-purity (meth) acrylic acid can be stably produced for a long period of time.

  Further, in the present invention, when 90% or more (meth) acrylic acid is obtained by distillation from crude (meth) acrylic acid obtained by gas phase catalytic oxidation, it is overloaded by the polymer in the pump attached to the reflux tank of the distillation column. It is possible to produce high-purity (meth) acrylic acid stably for a long period of time, even when high-purity products are required in the future. Its industrial value is extremely large.

Hereinafter, the present invention will be described in more detail.
The method for purifying (meth) acrylic acid according to the present invention comprises distilling a crude (meth) acrylic acid-containing liquid containing acrylic acid or methacrylic acid, and (meth) acrylic acid having a purity of 90% or more. A process for obtaining a condensate (hereinafter, this process is also referred to as a “distillation process”), and the (meth) acrylic acid condensate in the reflux tank containing the (meth) acrylic acid condensate contains oxygen. And a step of supplying an oxygen-containing gas (hereinafter, this step is also referred to as “oxygen supply step”).

  The distillation step is not particularly limited as long as it can obtain a condensate of (meth) acrylic acid having a purity of 90% or more, preferably 95% or more. For such a distillation process, for example, a known technique described in the background art can be used.

  The crude (meth) acrylic acid-containing liquid is not particularly limited as long as it is a liquid containing acrylic acid or methacrylic acid. Examples of such a (meth) acrylic acid-containing liquid include (meth) acrylic acid itself or a solution of these with an appropriate solvent such as water or an organic solvent. The crude (meth) acrylic acid-containing liquid is preferably obtained by a vapor phase catalytic oxidation method from the viewpoint of productivity and the like. The crude (meth) acrylic acid-containing liquid can be obtained by, for example, a known technique described in the background art.

  The distillation in the distillation step may be any distillation method that can obtain a condensate of (meth) acrylic acid with the above-described purity from the crude (meth) acrylic acid-containing liquid, and the distillation method is particularly limited. It is not a thing. For such a distillation method, various distillation methods such as simple distillation and precision distillation can be applied. The distillation can be applied to either a continuous type or a batch type. As usual, it is preferable from the viewpoint of industrial production and the like to distill the crude (meth) acrylic acid-containing liquid using a distillation column. The purity of the condensate is adjusted according to various conditions such as the distillation column to be used, the type of packing, the reflux ratio, the distillation temperature, the type and amount of additives added to the crude (meth) acrylic acid-containing liquid. Is possible.

  In the distillation step, the crude (meth) acrylic acid-containing liquid is distilled in the presence of a known polymerization inhibitor or polymerization inhibitor (hereinafter, also simply referred to as “polymerization inhibitor”) such as a phenol compound or a phenothiazine compound. It is preferable to prevent generation of a polymer of (meth) acrylic acid and stably obtain high-purity (meth) acrylic acid over a long period of time.

  A method for obtaining high-purity crude (meth) acrylic acid from the production of crude (meth) acrylic acid will be described using acrylic acid as an example. Examples of a method for obtaining high-purity crude (meth) acrylic acid from the production of crude (meth) acrylic acid include the following (1) to (3).

  (1) Oxidation process for producing acrylic acid by contact gas phase oxidation of propane, propylene and / or acrolein, and bringing acrylic acid-containing gas produced in the oxidation process into contact with water to collect acrylic acid as an aqueous acrylic acid solution Collection step, extraction step of extracting acrylic acid from the aqueous acrylic acid solution obtained in this step using an appropriate extraction solvent, separation step of separating acrylic acid and solvent from the obtained extract, separated acrylic Low boiling point component removal step for removing low boiling point component from acid, purification step for purifying acrylic acid-containing liquid from which low boiling point component has been removed by distillation, Michael Michael adduct recovered from these steps, and each step A recovery process for recovering valuable materials by supplying a high-boiling liquid (liquid high-boiler) containing a polymerization inhibitor used in the above process to the decomposition reaction tower as a raw material, and Method comprising the recycling step of supplying objects to one of the steps subsequent absorption step.

  (2) An oxidation process for producing acrylic acid by catalytic gas phase oxidation of propane, propylene and / or acrolein, and bringing acrylic acid-containing gas produced in the oxidation process into contact with water to collect acrylic acid as an aqueous acrylic acid solution Collection step, an azeotropic separation step in which the aqueous acrylic acid solution obtained in this step is distilled in the presence of an azeotropic solvent in the azeotropic separation tower, and the crude acrylic acid is taken out from the bottom of the tower, from the extracted acrylic acid Acetic acid separation step for removing acetic acid, purification step for removing high boiling point impurities, Michael acid adduct recovered from these steps, and a high boiling liquid containing a polymerization inhibitor used in each step. A method comprising a recovery step of recovering valuable materials by supplying them to the decomposition reaction tower as raw materials, and a recycling step of supplying the recovered valuable resources to any step after the collection step.

  (3) Oxidation process for producing acrylic acid by contact gas phase oxidation of propane, propylene and / or acrolein, contacting acrylic acid-containing gas produced in the oxidation process with an organic solvent to make acrylic acid as an acrylic acid organic solvent solution Collection / separation step for collecting and removing water, acetic acid and the like at the same time, separation step for removing acrylic acid from the acrylic acid organic solvent solution, polymerization inhibitor used in these steps, organic solvent, and these steps The recovery process for recovering valuable resources by supplying the high boiling liquid containing the Michael adduct adsorbed from the raw material to the decomposition reaction tower as a raw material, and supplying the recovered valuable resources to any process after the collection process A method comprising a use step and a solvent purification step for purifying part or all of the recovered organic solvent.

  Usually, crude acrylic acid used as a raw material for obtaining high-purity acrylic acid in an industrial acrylic acid plant is a liquid after removing this low-boiling component, and as impurities, water remaining in a trace amount, Low boiling impurities such as furfural, benzaldehyde, acetic acid, or high boiling impurities such as dimer, trimer, maleic anhydride, β-hydroxypropionic acid, β-alkoxypropionic acid of (meth) acrylic acid, When this liquid is distilled using a distillation column, acrylic acid having a purity of 90% or more from the top of the column is obtained. It is also possible to obtain a condensate of (meth) acrylic acid directly by recovering valuable materials in the recovery step.

The present invention can be applied to methacrylic acid in the same manner as acrylic acid. When the present invention is applied to the production of methacrylic acid, for example, crude methacrylic acid is obtained by gas-phase catalytic oxidation of isobutylene and / or t-butyl alcohol. Citraconic acids are included as impurities in addition to benzene, ketones and maleic acids.

  The tower top liquid obtained by distillation of the crude (meth) acrylic acid-containing liquid usually contains trace amounts of impurities such as carboxylic acids such as maleic acid and acetic acid, aldehydes such as furfural and benzaldehyde, and water. Therefore, in order to obtain higher-purity acrylic acid, it is preferable to perform a further step (removal of impurities by addition of hydrazines or mercaptans (described later)).

  For example, when a purified product is used as high-purity acrylic acid, it reacts with such impurities to produce compounds that can be separated by distillation in order to remove impurities that are difficult to remove economically by distillation separation. After the reactant is added to the crude acrylic acid-containing liquid, the crude acrylic acid-containing liquid is supplied to the distillation column. The treatment of (meth) acrylic acid containing an aldehyde component with an aldehyde remover to remove the aldehyde component is also described in JP-A-2001-58970 and JP-A-2001-213839. Can be applied to the present invention.

  In separating the impurities by distillation, the crude (meth) acrylic acid-containing liquid preferably further contains a hydrazine compound. Examples of the hydrazine compound include hydrazine, hydrazine hydrate, phenyl hydrazine, hydrazine sulfate, and hydrazine hydrochloride. These are used alone or in combination of two or more. The amount of hydrazine compound added is appropriately selected depending on, for example, the amount of impurities to be removed and the concentration of impurities allowed to be contained in high-purity acrylic acid obtained after distillation.

  The hydrazine compound is preferably added to the crude (meth) acrylic acid-containing liquid as it is, and the amount of the hydrazine compound is usually the total amount of aldehydes and maleic acids such as furfural and benzaldehyde in the crude acrylic acid-containing liquid. It is 0.1-2 times mole with respect to this, Preferably it is 0.5-2 times mole, More preferably, it is 0.5-1 times mole.

  The method for adding the hydrazine compound to the crude (meth) acrylic acid-containing liquid is not particularly limited as long as the hydrazine compound and the impurities to be removed can react with each other.

  In the present invention, a hydrazine compound is added to the crude (meth) acrylic acid-containing liquid before being supplied to the distillation column, and impurities such as maleic acids in the crude (meth) acrylic acid-containing liquid are reacted in advance with the hydrazine compound. It is preferable to carry out distillation purification. The reaction between the hydrazine compound and the impurities is preferably performed using a reaction apparatus capable of ensuring the necessary temperature and residence time. For example, a reaction tank with a stirrer or a tubular reaction tank may be used. The reaction temperature is preferably as low as possible. Specifically, the reaction temperature is selected from the range of the melting point of acrylic acid to 50 ° C. The reaction time is 10 minutes or longer, and it is usually preferred to retain for about 30 minutes to 3 hours.

  The reaction between the hydrazine compound and the impurities can be performed in the distillation column. In this case, after adding the hydrazine compound to the crude (meth) acrylic acid compound, preferably from the top of the distillation column until purified (meth) acrylic acid is obtained as a distillate, preferably 10 minutes to 5 hours, More preferably, there is a residence time of 20 minutes to 3 hours. When the residence time is short, the hydrazine compound and impurities may not sufficiently react. If the residence time is too long, impurities may increase due to the decomposition reaction of the reactant. For this reason, the residence time is selected from the above range.

  The crude (meth) acrylic acid to which the hydrazine compound has been added is subjected to a distillation treatment to remove impurities such as maleic acid to be removed.

  In separating the impurities by distillation, the crude (meth) acrylic acid-containing liquid preferably further contains mercaptans. Examples of mercaptans include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, and the like. In the present invention, one of these can be used alone, or two or more can be mixed and used.

In the case of using the mercaptans, a crude (meth) acrylic acid-containing liquid obtained by adding mercaptans to a resin tower packed with a sulfonic acid type cation exchange resin is 20 to 90 ° C., LHSV (liquid space velocity) = 0. The aldehyde component in the crude (meth) acrylic acid-containing liquid can be removed by passing at .1 to 10 hr −1 . This liquid is used as a supply liquid to the distillation column. The liquid flow may be a down flow system or an up flow system. The mercaptans as aldehyde removing agents are usually used in an amount of 1 to 8 moles relative to the aldehyde component.

  The oxygen supply step is particularly limited as long as the oxygen-containing gas can be supplied to the (meth) acrylic acid condensate in the reflux tank in which the (meth) acrylic acid condensate is accommodated. Not. For such an oxygen supply step, a known technique for supplying gas into the liquid and bringing it into gas-liquid contact can be used.

The oxygen-containing gas is not particularly limited as long as it contains oxygen. As such an oxygen-containing gas, for example, a single gas consisting only of oxygen or air, or the single gas and any one or more gases selected from the following (1) to (4) are mixed. Or a mixed gas.
(1) Nitrogen (2) Process exhaust gas (3) Air (except when the single gas is air)
(4) Carbon dioxide

  Here, the process exhaust gas is a process exhaust gas discharged from the above-mentioned acrylic acid process or an acrylic ester plant adjacent to the acrylic acid plant, etc., and affects the use destination of the high purity acrylic acid obtained in the present invention. It is a gas component that does not give The process exhaust gas contains a gas component composed of a substance or a compound that does not affect the quality of the high purity (meth) acrylic acid obtained in the present invention, or a component that does not affect the quality. Specifically, “water”, “acetic acid” and the like can be mentioned.

  The oxygen content ratio of the oxygen-containing gas is not particularly limited as long as it does not form squeal gas from the operating conditions of the reflux tank, but is preferably 5 to 30% by volume. As the oxygen supply gas, air is particularly preferable.

The supply amount of the oxygen-containing gas is affected by the size of the reflux tank and the residence time of the condensate of (meth) acrylic acid in the reflux tank, but the condensate in the standard state (0 ° C., 1 atm). It is preferable that the ratio (Nm 3 / t) of the supply amount of oxygen in the oxygen-containing gas to the inflow amount into the reflux tank satisfies the relationship represented by the following formula.

[Equation 1]
0.004 ≦ A / B ≦ 1.0
(In the formula, A represents the O 2 supply amount (Nm 3 / h), and B represents the inflow amount (t / h) of the condensate to the reflux tank. Note that N in the “Nm 3 / h” represents , Indicating a numerical value in a standard state (0 ° C., 1 atm: Normal).

  In the present invention, as described above, a polymerization inhibitor (a polymerization inhibitor and / or a polymerization inhibitor) can be used to suppress the generation of a polymer during production or purification. As the polymerization inhibitor, known polymerization inhibitors and / or polymerization inhibitors can be used. Specifically, copper-based compounds such as copper (meth) acrylate and copper dithiocarbamate, phenol compounds, phenothiazine compounds, and the like. Can be mentioned. These polymerization inhibitors may be used alone or in combination of two or more. The polymerization inhibitor can be added to a crude (meth) acrylic acid-containing liquid, or can be added to a condensed liquid of (meth) acrylic acid. In any case, it is preferable for preventing generation of a polymer in purification of (meth) acrylic acid.

  Examples of the phenol compound used in the present invention include hydroquinone, methoquinone (methoxyhydroquinone), pyrogallol, catechol, resorcin, phenol, and cresol. The said phenol compound can be used individually by 1 type or in mixture of 2 or more types. The amount of the phenol compound added is 0 to 800 ppm by weight, preferably 50 to 600 ppm by weight, based on the crude (meth) acrylic acid-containing liquid supplied to the distillation column. Moreover, the addition amount of a phenol compound is 0-500 weight ppm with respect to the condensate of (meth) acrylic acid supplied to a reflux tank, Preferably it is 1-300 weight ppm. If the amount added is small, the polymerization inhibitory effect may be insufficient. If the amount added is too large, the polymerization inhibiting effect is not adversely affected, but it is not economically preferable.

  Examples of the phenothiazine compound used in the present invention include phenothiazine, bis- (α-methylbenzyl) phenothiazine, 3,7-dioctylphenothiazine, bis- (α-dimethylbenzyl) phenothiazine and the like. The said phenothiazine compound can be used individually by 1 type or in mixture of 2 or more types. The addition amount of the phenothiazine compound is 0 to 400 ppm by weight, preferably 50 to 300 ppm by weight, based on (meth) acrylic acid supplied to the distillation column. Moreover, the addition amount of a phenothiazine compound is 0-200 weight ppm with respect to the condensate of (meth) acrylic acid supplied to a reflux tank, Preferably it is 1-100 weight ppm. If the amount added is small, the polymerization inhibitory effect may be insufficient. If the amount added is too large, the polymerization inhibiting effect is not adversely affected, but it is not economically preferable.

  Examples of the copper compound include copper compounds such as cupric chloride, copper acetate, copper carbonate, copper (meth) acrylate, copper dimethyldithiocarbamate, copper diethyldithiocarbamate, and copper dibutyldithiocarbamate. These polymerization inhibitors may be used individually by 1 type, and may be used in combination of 2 or more type. The addition amount of these polymerization inhibitors is not particularly limited, but is preferably about 1 to 1000 ppm.

  Examples of the copper dithiocarbamate include copper dimethyldithiocarbamate, copper diethyldithiocarbamate, copper dipropyldithiocarbamate, copper dibutyldithiocarbamate, and the like; copper ethylenedithiocarbamate, copper tetramethylenedithiocarbamate, copper pentamethylenedithiocarbamate And cyclic alkylene dithiocarbamate copper such as copper hexamethylenedithiocarbamate; cyclic oxydialkylene dithiocarbamate copper such as copper oxydiethylenedithiocarbamate; and the like. These may be used alone or in combination.

The amount of copper dithiocarbamate added is 1 to 100 ppm by weight, preferably 10 to 80 ppm by weight, based on the (meth) acrylic acid-containing liquid supplied to the distillation column. Moreover, the addition amount of copper dithiocarbamate is 0-50 weight ppm with respect to the condensate of (meth) acrylic acid supplied to a reflux tank, Preferably it is 1-20 weight ppm. When the addition amount is small, the polymerization inhibitory effect becomes insufficient. A large addition amount is not preferable because corrosion of the apparatus occurs at the bottom of the distillation column. In the distillation system of the present invention, copper dithiocarbamate is presumed to have a greater effect on the polymerization inhibition of the bottom liquid than the polymerization inhibition on the liquid flowing down the distillation column. Therefore, it is preferable to add copper dithiocarbamate to a crude (meth) acrylic acid-containing liquid as a raw material or a bottom liquid of a distillation column.

  (Meth) acrylic acid copper used in the present invention acts as a polymerization inhibitor for (meth) acrylic acid, like copper dithiocarbamate. By using both in combination, a remarkable effect in preventing polymerization is obtained. Play.

  The copper (meth) acrylate can be prepared by dissolving copper carbonate, chloride, organic acid salt, hydroxide, or copper powder in (meth) acrylic acid. Copper carbonate is particularly preferable. Chloride is not preferable because a distillation column for handling (meth) acrylic acid is generally constructed of a stainless steel material, which may cause stress corrosion cracking. Specific materials dissolved in (meth) acrylic acid to obtain copper (meth) acrylate used in the present invention include cupric carbonate as a carbonate; copper formate and copper acetate as an organic acid salt. , Copper salicylate; examples of the hydroxide include cuprous hydroxide and cupric hydroxide. Further, copper powder may be directly dissolved in (meth) acrylic acid. These can be used individually by 1 type or in mixture of 2 or more types.

  The copper (meth) acrylate can also be obtained by dissolving in a solvent containing (meth) acrylic acid. As the solvent in this case, it is preferable to use a solvent having a boiling point higher than that of (meth) acrylic acid so that the solvent is not mixed into high purity (meth) acrylic acid obtained from the top of the distillation column. Specific examples include diphenyl ether, o-phthalic acid esters, oleic acid esters, adipic acid esters, hydrocarbons in the middle oil fraction, heat transfer oil having a boiling point of 170 ° C. or higher. As the solvent, one kind may be used alone, or two or more kinds of mixed solvents may be used.

  When the crude (meth) acrylic acid-containing liquid that is a raw material to be distilled contains water, water can also be used as a solvent having a lower boiling point than (meth) acrylic acid. The concentration of water may be determined in consideration of the value allowed for the high-purity (meth) acrylic acid obtained and the required addition amount of copper (meth) acrylate. If the crude (meth) acrylic acid-containing liquid does not contain water, an appropriate amount of water may be added. However, depending on the product specifications of the refined product, re-dehydration is required, so care must be taken.

  The addition amount of the (meth) acrylic acid copper is 1 with respect to the crude (meth) acrylic acid-containing liquid supplied to the distillation tower when it is assumed that all of the dissolved copper has changed to (meth) acrylic acid copper. -100 ppm by weight, preferably 5-80 ppm by weight. Moreover, the addition amount of (meth) acrylic acid copper is 0-50 weight ppm with respect to the condensate of (meth) acrylic acid supplied to a reflux tank, Preferably it is 1-20 weight ppm. When the addition amount is small, the polymerization inhibitory effect becomes insufficient. If the amount added is too large, corrosion of the apparatus occurs at the bottom of the distillation column, which is not preferable.

  Unlike copper dithiocarbamate, copper (meth) acrylate has a great effect on the liquid flowing down the distillation column. Therefore, it is preferable to add (meth) acrylic acid copper to the crude (meth) acrylic acid containing liquid used as a raw material or the top liquid (condensate) of the distillation column.

  In the present invention, one or more kinds of polymerization inhibitors having different actions as described above are used. In addition to these hydrazine compounds, copper dithiocarbamate, copper (meth) acrylate, phenolic compounds, and / or phenothiazine compounds, other polymerization inhibitors can be used as necessary.

Examples of such other polymerization inhibitors include tert-butyl nitroxide, 2,2,6,6-tetramethyl-4-hydroxypiperidyl-1-oxyl, 2,2,6,6-tetramethylpiperidyl- 1-oxyl, 2,2,6,6-tetramethylpiperidinooxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl, 4,4 ′, 4 ″ -tris-1- N-oxyl compounds such as (2,2,6,6-tetramethylpiperidinooxyl) phosphite; phenylenediamines such as p-phenylenediamine; nitroso compounds such as N-nitrosodiphenylamine; ureas such as urea; Examples thereof include thioureas such as thiourea, etc. These other polymerization inhibitors can be used alone or in combination of two or more.

  There are no particular restrictions on the method of adding copper (meth) acrylate, copper dithiocarbamate, phenolic compound, or phenothiazine compound that exerts an effect on polymerization inhibition. For example, a method of adding each directly to a crude (meth) acrylic acid-containing liquid supplied to a distillation column or a condensate of (meth) acrylic acid liquid refluxed as a distillate, and dissolving using an appropriate solvent And a method of adding to the crude (meth) acrylic acid-containing liquid or distillation column. The addition temperature can also be determined as appropriate.

  In the present invention, substances other than the above may be included depending on the process, but the type is higher than the boiling point of (meth) acrylic acid of the condensate as defined in the present invention as described above. If it has a boiling point, it will not specifically limit.

  In the present invention, the crude (meth) acrylic acid-containing liquid to which the hydrazine compound, copper (meth) acrylate and copper dithiocarbamate are added is subjected to distillation treatment to remove impurities to be removed. The obtained (meth) acrylic acid is not particularly limited in its use, and is a raw material for (meth) acrylic acid esters, a raw material for high-purity (meth) acrylic acid for highly absorbent resins, a general product (meta ) It can be used for various applications such as acrylic acid.

  In the present invention, it is specified that the oxygen supply step is performed when the concentration of (meth) acrylic acid in the condensate is 90% or more, but (meth) acrylic acid in the condensate is defined. Even if the concentration of is less than 90%, it may be better to apply the oxygen supply step depending on the situation. For example, when the temperature of the condensate in the reflux tank is relatively high (for example, 40 ° C. or higher), or a substance that easily causes an exothermic reaction with (meth) acrylic acid, or a substance that is easily polymerized in the condensate in the reflux tank (For example, acrolein or the like) is present in the condensate. As described above, when the oxygen-containing gas is supplied to the condensate under a condition where polymerization of (meth) acrylic acid is likely to occur, high-purity (meth) acrylic acid can be stably produced over a long period of time. Can do.

  The method for purifying (meth) acrylic acid of the present invention can be carried out by using a normal apparatus or means used for the production or purification of (meth) acrylic acid as it is or with some improvements.

  The distillation column is generally used in a chemical plant. That is, as the distillation tower, there are a perforated plate tower, a bubble bell tower, a packed tower, or a combination of these (for example, a combination of a perforated plate tower and a packed tower), and the presence or absence of overflow weirs and downcomers is distinguished. Neither can be used in the present invention.

  Specific examples of the tray include a bubble bell tray with a downcomer, a perforated plate tray, a bubble tray, a super flash tray, a max flux tray, and a dual flow tray without a downcomer.

As the filler, in addition to those conventionally used such as columnar, cylindrical, saddle-shaped, spherical, cubic, pyramidal, etc., in recent years regular or irregular having a special shape as a high-performance filler Fillers are commercially available and are preferably used in the present invention.

  Examples of such commercially available products include gauze type rules such as, for example, Sulzer Packing (manufactured by Sulzer Brothers), Sumitomo Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.), Techno Pack (Mitsui & Co.). Sheet type rule packing such as packing, Merapack (Sumitomo Heavy Industries, Ltd.), Techno pack (Mitsui & Co.), MC pack (Mitsubishi Chemical Engineering), and grid type rules such as flexi grid (Coke) A filling material etc. are mentioned. Other examples include Gem Pack (Glitch), Monz Pack (Montz), Good Roll Packing (Tokyo Special Wire Mesh), Honeycomb Pack (Nippon NGK), Impulse Packing (Nagaoka).

  For irregular packing, Raschig ring, polling (manufactured by BASF), cascade mini ring (manufactured by Mass Transfer), IMTP (manufactured by Norton), interlock saddle (manufactured by Norton), terralet (Nippon Chemical Industries) And Flexiring (manufactured by JGC Corporation).

  Any of these fillers may be used, or two or more kinds may be used in combination. Further, the present invention can be applied to a combination with a conventionally used tray.

  Specifically, the operating conditions of the distillation tower can be selected usually in the range of 60 to 100 ° C. as the tower bottom temperature and 1.33 to 26.7 kPa as the tower top pressure.

  In the present invention, an overhead gas cooling heat exchanger attached to the distillation column can be used as a condenser for condensing the vapor of (meth) acrylic acid obtained by distillation. The heat exchanger is generally classified into a case where it is installed inside a tower and a case where it is installed outside the tower, but is not particularly limited in the present invention. The heat exchanger may be used as a vent gas condenser or a reboiler for heating the tower bottom liquid in addition to the condenser, and the number of installed units is not particularly limited. The type of the heat exchanger is not particularly limited. Specific examples include a vertical fixed tube plate type, a horizontal fixed tube plate type, a U-shaped tube type, a double tube type, a spiral type, a square block type, and a plate type.

  The reflux tank is not particularly limited as long as a part or substantially all of the condensate flows into the reflux tank. From the temperature of the cooling water for condensers used industrially, the temperature of the liquid in the reflux tank is usually 15 to 40 ° C. The temperature of the liquid in the reflux tank is preferably lower because it deals with (meth) acrylic acid which is an easily polymerizable compound. Moreover, although the liquid average residence time (liquid outflow amount / liquid residence amount) of a reflux tank is 2 minutes-30 minutes normally, there is no restriction | limiting in this invention.

  In the present invention, the type and amount of the above-described polymerization inhibitor or polymerization inhibitor in the condensate in the reflux tank may be limited depending on the use of (meth) acrylic acid obtained in the present invention. . For example, when the use of (meth) acrylic acid obtained in the present invention is a raw material for acrylic ester or a raw material for high-purity acrylic acid for a highly water-absorbent resin, there is no particular limitation.

  For example, when the use of (meth) acrylic acid obtained in the present invention is general product acrylic acid or product high-purity acrylic acid, methoxyhydroquinone is used as the polymerization inhibitor, and the polymerization inhibitor is conventionally used. Since the concentration is 180 to 220 ppm (standard 200 ppm), it is usually performed to match this practice. Moreover, in the case where the use of (meth) acrylic acid obtained in the present invention is an intermediate product, it usually depends on conditions such as the influence on the subsequent reaction, but usually, for example, 10 to 10 for the phenol compound. If it is the said phenothiazine compound, it is 5-100 ppm.

  The means used for supplying the oxygen-containing gas to the condensate is not particularly limited, but it is preferable that the oxygen-containing gas is well dispersed in the condensate of (meth) acrylic acid. For example, a sparger having holes for ejecting fluid on the surface of the pipe into which the oxygen-containing gas is introduced, a fluid ejecting means for ejecting a small fluid, such as a spray nozzle, or a porous body such as a sintered metal And an introduction pipe for introducing the oxygen-containing gas into the fluid jetting means, and the like, so that the oxygen-containing gas supplied into the liquid is preferably refined.

  The materials of various equipment used in the practice of the present invention, such as various nozzles of each tower, tower body, reboiler, condenser, vent gas condenser, reflux tank, piping, and pumps as auxiliary equipment, are easily polymerizable compounds and their temperatures. It can be selected according to conditions. For example, stainless steel is often used as the material, but the present invention is not limited to this. For example, SUS304, SUS304L, SUS316, SUS316L, SUS317, SUS317L, SUS327, or hastelloys may be used as the material.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 5 shows an example of an acrylic acid distillation apparatus in which the present invention can be implemented.

  As shown in FIG. 5, the acrylic acid distillation apparatus includes a column main body (distillation column) 1 for distilling crude acrylic acid, a condenser 20 that cools and condenses vapor containing acrylic acid, and a condenser 20. A reflux tank 21 for storing the condensed condensate, a vent gas condenser 25 for further recovering valuable materials by further cooling the gas cooled by the condenser 20, and a vacuum facility 26 for depressurizing these distillation systems. .

  At the bottom of the column main body 1, an extraction nozzle 2 for extracting the column bottom liquid is provided. The extraction nozzle 2 is connected to an introduction nozzle 3 to which a part of the extracted column bottom liquid is supplied and a pipe 11.

  A pipe 4 for sending the column bottom liquid from the introduction nozzle 3 is connected to the introduction nozzle 3, and a reboiler 5 for heating the column bottom liquid from the pipe 4 is connected to the line 4. A pipe 6 for sending the heated tower bottom liquid is connected to the pipe 6, and a nozzle 7 for supplying the tower bottom liquid from the pipe 6 to the tower main body 1 is connected.

  A pump 12 for sending the column bottom liquid from the pipe 11 is connected to the pipe 11, and a pipe 13 is connected to the pump 12.

  On the other hand, a pipe 19 for sending a gas containing acrylic acid is connected to the top of the tower body 1, a condenser 20 is connected to the pipe 19, and a reflux tank 21 is connected to the condenser 20. The reflux tank 21 is connected to a vent gas condenser 25 and a pump 22 for sending the condensate contained in the reflux tank 21. A vacuum facility 26 is connected to the vent gas condenser 25.

  A pipe 23 for returning a part of the condensate to the tower body 1 is connected to the pump 22. A pipe 24 for sending a part of the condensate as purified acrylic acid and a pipe 27 for sending a part of the condensate toward the condenser 20 and the vent gas condenser 25 are branched from the pipe 23.

The piping 27 is connected to a polymerization inhibitor supply piping 30 for supplying a polymerization inhibitor to a part of the condensate. Further, the pipe 27 supplies a first polymerization inhibitor supply pipe 28 for supplying the condensate supplied with the polymerization inhibitor to the capacitor 20 and a condensate supplied with the polymerization inhibitor to the vent gas condenser 25. The second polymerization inhibitor supply pipe 29 is branched. The condenser 20 and the vent gas condenser 25 are each provided with a sprayer for spraying the polymerization inhibitor supplied from the first and second polymerization inhibitor supply pipes 28 and 29 into the condenser.

  As shown in FIG. 1, the reflux tank 21 has a tank body 41, an inflow nozzle 42 that allows the condensate from the condenser 20 to flow into the tank body 41, and the condensate contained in the tank body 41 toward the pump 22. It has an outlet nozzle 43 that discharges, a gas outlet nozzle 44 that discharges gas components in the tank body 41 toward the vent gas condenser 25, and a sparger (porous pipe) 46 provided in the lower part inside the tank body 41. .

  The sparger 46 is a substantially horizontal tubular member, and has a plurality of small-diameter holes 47 opened on the upper surface of the sparger 46 and a liquid drain hole opened on the lower surface of the sparger 46. 48. An oxygen-containing gas introduction nozzle 45 for introducing an oxygen-containing gas into the sparger 46 from the outside of the tank body 1 is connected to the lower portion of the sparger 46.

  The crude acrylic acid-containing liquid is introduced into the tower body 1 and distilled. A part of the tower bottom liquid circulates in the order of the extraction nozzle 2, the introduction nozzle 3, the pipe 4, the reboiler 5, the pipe 6, and the nozzle 7. The other part of the tower bottom liquid is the extraction nozzle 2, the pipe 11, and the pump 12. And taken out as a residue through the pipe 13.

  The distillate from the top of the column is sent to the condenser 20 via the pipe 19 and condensed in the condenser 20 to become a condensate of acrylic acid. On the other hand, a mixed liquid of a condensate of acrylic acid accommodated in the reflux tank 21 and a polymerization inhibitor supplied from the polymerization inhibitor supply pipe 30 is sprayed into the condenser 20 from the sprayer. The acrylic acid condensate condensed in the condenser 20 is introduced from the condenser 20 into the tank body 41 of the reflux tank 21 through the inflow nozzle 42 in a state containing a polymerization inhibitor.

  A part of the condensate of acrylic acid in the tank body 41 is returned to the tower top via the pump 22 and the pipe 23. The other part of the condensate of acrylic acid is connected to the polymerization inhibitor supply pipe 30 via the pipe 27, and the first polymerization inhibitor supply pipe 28 and the second polymerization inhibitor supply pipe 29 are connected. Through the condenser 20 and the vent gas condenser 25. The remaining portion of the acrylic acid condensate is taken out as purified acrylic acid through the pipe 24.

  In the tank body 41, an oxygen-containing gas (for example, air) is supplied from the oxygen-containing gas introduction nozzle 45 to the sparger 46, and the oxygen-containing gas is ejected from the holes 47 and the drain holes 48 as bubbles having a small particle diameter. . The acrylic acid condensate contained in the tank body 41 is in gas-liquid contact with the oxygen-containing gas, and polymerization of the acrylic acid condensate is prevented. Therefore, polymerization of acrylic acid in the condensate in the reflux tank 21 and downstream thereof is prevented, and generation of a polymer in the reflux tank 21 and piping and pumps downstream of the reflux tank 21 is prevented.

  The gas in the tank body 41 is cooled by the vent gas condenser 25 via the gas outlet nozzle 44. The acrylic acid condensed here returns to the reflux tank 21 as a condensate, and the gas component is taken out as a vent gas through the vacuum facility 26.

  In the purification of acrylic acid by the distillation apparatus shown in FIG. 5, for example, the column bottom temperature is preferably 60 to 120 ° C., particularly preferably 70 to 100 ° C., and the column top pressure is preferably 1 to 50 kPa, particularly 2 to 20 kPa.

  In the present invention, the supply form of the oxygen-containing gas to the condensate accommodated in the reflux tank 21 is not limited to the form shown in FIG.

  For example, in the present invention, as shown in FIG. 2, instead of the sparger 46, an introduction pipe 56 that is a tubular member provided substantially horizontally at the lower part inside the tank body 41 and an upper part of the introduction pipe 56 are provided. In addition, a plurality of sprays 57 for ejecting the gas in the introduction pipe 56 as bubbles having a small particle diameter may be provided. Further, for example, in the present invention, as shown in FIG. 3, instead of the spray 57, a plurality of sintered metals 67, which are porous bodies that discharge the gas in the introduction pipe 56 as bubbles having a small particle diameter, are provided. Also good.

  2 and FIG. 3 also prevents the polymerization of acrylic acid in the condensate in the reflux tank 21 and downstream thereof, as in the embodiment shown in FIG. It is possible to prevent the generation of a polymer in a downstream pipe or pump.

  Further, in the present invention, in order to make the contact between the condensed liquid of acrylic acid and the supplied oxygen-containing gas more effective in the reflux tank 21, as shown in FIG. It is also possible to provide a baffle plate 50 that is provided above the jar 46 and prevents the bubbles ejected from the holes 47 from rising. According to such a form, the contact time between the acrylic acid condensate contained in the tank body 41 and the oxygen-containing gas can be increased, and the effect of preventing the polymerization of acrylic acid by the oxygen-containing gas can be increased. Even more effective.

  Further, in the present invention, in order to make the contact between the condensate of acrylic acid and the supplied oxygen-containing gas more effective, it is further branched from the pipe 23 and connected to the reflux tank 21 as shown in FIG. It is also a part of a preferable form that a circulation pipe 31 is further provided to force the acrylic acid condensate to flow (circulate) with the pump 22. According to such a configuration, the concentration of the oxygen-containing gas in the condensate of acrylic acid is increased, and the effect of preventing the polymerization of acrylic acid by the oxygen-containing gas is further effective.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to the following Example, unless the summary is exceeded. The raw material acrylic acid and impurities were analyzed by a gas chromatography apparatus (GC14A manufactured by Shimadzu Corporation). Since maleic acid becomes maleic anhydride in the gas chromatographic analysis process and the contents of both cannot be specified, the total content of maleic acid and maleic anhydride is referred to as the content of maleic acids below. To do.

<Example 1>
In the distillation apparatus shown in FIG. 5, using a stainless steel SUS316 distillation tower having an inner diameter of 1,100 mm, a length of 20,000 mm, and 21 perforated plates (dual flow trays) inside as a column main body 1, crude acrylic acid is used. The contained liquid was distilled. A pump was provided in the middle of the pipe 4 to supply the bottom liquid to the reboiler 5. The reboiler 5 was a vertical fixed tube plate type heat exchanger, and the tower bottom liquid was circulated to the tube side of the reboiler 5.

  As the crude acrylic acid-containing liquid, a mixture (feed liquid) containing 98.5% by weight of acrylic acid, 0.3% by weight of maleic acid and 0.3% by weight of acrylic acid dimer was added to the tower body 1 at 90 ° C. It was supplied at 300 kg / h. Further, from a liquid tank containing a polymerization inhibitor (not shown), a solution prepared by dissolving 8% by weight of methoquinone and 1% by weight of phenothiazine in acrylic acid was supplied to the supply liquid at 60 kg / h.

  By carrying out the operation at a tower top pressure of 2.8 kPa, a tower bottom temperature of 75 ° C., a reflux ratio of 1 and a temperature of the condensate in the reflux tank of 27 ° C., the purity from the tower top is 99.8% by weight or more. High purity acrylic acid was obtained. The amount extracted from the top of the column is 97% by weight of the supply amount of the supply liquid to the column main body 1.

  From another polymerization inhibitor-containing liquid tank (not shown), a solution obtained by dissolving 8% by weight of methoquinone in acrylic acid was supplied from the polymerization inhibitor supply pipe 30 at 3.08 kg / h.

The reflux tank 21 has an inner diameter of 820 mm and a length of 3,200 mm, and a sparger 46 (length: 2500 mm, hole diameter: 2 mm, number of 25 pieces) shown in FIG. Air was supplied to the sparger 46 at 1.5 Nm 3 / h as an oxygen-containing gas.

  During 6 months of continuous operation, the pump 22 attached to the reflux tank 21 achieved continuous operation.

<Example 2>
In Example 1, instead of the sparger 46, the operation was performed under the same conditions except that an introduction pipe as shown in FIG. 2 in which five sprays (1 / 8MJJRP015PTFE, manufactured by Ikeuchi Co., Ltd.) were installed was installed. Carried out. Six months of continuous operation was carried out, during which time the pump 22 achieved continuous operation.

<Example 3>
In Example 2, instead of spraying, operation was performed under the same conditions except that a sintered metal having a pore size of 5 microns (Fuji Plate, manufactured by Fuji Filter Industry Co., Ltd.) was installed as shown in FIG. . Six months of continuous operation was carried out, during which time the pump 22 achieved continuous operation.

<Comparative Examples 1-3>
In Examples 1 to 3, the supply of the oxygen-containing gas to the reflux tank 21 was stopped. On the third day after the stop, the pump 22 stopped due to overload. When the pump 22 was checked, a polymer was found between the shaft and the mechanical seal.

<Example 4>
Column body 1 is a distillation column made of stainless steel (SUS316) having an inner diameter of 1,100 mm, a length of 20,000 mm, filled with 8 m of Norton's irregular packing (IMTP) inside, and 9 perforated plates below it. The raw material for distillation was supplied at 1,300 kg / h. The crude acrylic acid monomer as a raw material for distillation includes 98.5% by weight of acrylic acid, 0.3% by weight of maleic acid, 0.276% by weight of acrylic acid dimer, 0.02% by weight of furfural, 0.004% by weight of benzaldehyde. A mixture containing was used.

  Prior to supplying the mixture to the distillation column, hydrazine monohydrate 1,650 ppm by weight, copper dibutyldithiocarbamate 40 ppm by weight, copper acrylate 40 ppm by weight, and hydroquinone 300 ppm by weight are added to the mixture. Mixed. The copper acrylate was prepared by dissolving cupric carbonate in acrylic acid, and mixing was performed at 20 ° C. for 30 minutes.

  The purity of acrylic acid is 99.5 wt. From the top of the tower when the top pressure is 10.1 kPa, the bottom temperature is 95.degree. % Or more of furfural and benzaldehyde, respectively, high purity acrylic acid of 1 ppm by weight or less was obtained. The amount extracted from the top of the column is 95% by weight of the amount of the mixture supplied to the column main body 1.

The reflux tank 21 and the sparger 46 were the same as those in Example 1, and air was supplied to the sparger 46 as an oxygen-containing gas at 2 Nm 3 / h. Further, methoquinone was continuously added from the polymerization inhibitor supply pipe 30 so that the methoquinone concentration of the acrylic acid solution in the reflux tank 21 was 180 to 220 ppm by weight.

  Six months of continuous operation was carried out, during which time the pump 22 achieved continuous operation.

<Example 5>
In Example 4, the operation was carried out under the same conditions except that instead of the sparger, an introduction pipe having 5 sprays was installed as shown in FIG. Six months of continuous operation was performed, during which time the pump 22 achieved continuous operation.

<Example 6>
In Example 5, operation was carried out under the same conditions except that a sintered metal having 3 micron pores was installed as shown in FIG. 3 instead of spraying. Six months of continuous operation was carried out, during which time the pump 22 achieved continuous operation.

<Comparative Examples 4-6>
In Examples 4 to 6, the supply of the oxygen-containing gas to the reflux tank 21 was stopped. Several days after the stop, the pump 22 stopped due to overload. When the pump 22 was checked, a polymer was found between the shaft and the mechanical seal.

<Example 7>
Instead of the hydrazine monohydrate of Example 4, n-dodecyl mercaptan as an aldehyde removing agent was mixed with the mixed solution at 2,200 ppm by weight with respect to the mixed solution, and the resulting mixed solution was mixed with sulfonic acid. Example 4 except that the crude acrylic acid-containing liquid passed through a packed column of a type cation exchange resin (Diaion PK-216H, Diaion is a registered trademark of Mitsubishi Chemical Corporation) was supplied to the distillation column of Example 4. The same operation was performed.

  Six months of continuous operation was carried out, during which time the pump 22 achieved continuous operation.

It is a longitudinal cross-sectional view which shows an example of the reflux tank used for implementation of this invention. It is a longitudinal cross-sectional view which shows another example of the reflux tank used for implementation of this invention. It is a longitudinal cross-sectional view which shows another example of the reflux tank used for implementation of this invention. It is a longitudinal cross-sectional view which shows another example of the reflux tank used for implementation of this invention. It is a systematic diagram which shows an example of the distillation apparatus of acrylic acid which can implement this invention. It is a systematic diagram which shows another example of the distillation apparatus of acrylic acid which can implement this invention.

Explanation of symbols

1 tower body (distillation tower)
2 Extraction nozzle 3 Introduction nozzle 4, 6, 11, 13, 19, 23, 24, 27 Piping 5 Reboiler 7 Nozzle 12, 22 Pump 20 Capacitor 21 Reflux tank 25 Vent gas condenser 26 Vacuum equipment 28 First polymerization inhibitor supply pipe 29 Second Polymerization Inhibitor Supply Pipe 30 Polymerization Inhibitor Supply Pipe 31 Circulation Pipe 41 Tank Body 42 Inflow Nozzle 43 Outlet Nozzle 44 Gas Outlet Nozzle 45 Oxygen-Containing Gas Introducing Nozzle 46 Sparger 47 Hole 48 Liquid Drain Hole 50 Baffle Plate 56 Introduction pipe 57 Spray 67 Sintered metal

Claims (17)

  1. A step of distilling a crude (meth) acrylic acid-containing liquid containing acrylic acid or methacrylic acid to obtain a condensate of (meth) acrylic acid having a purity of (meth) acrylic acid of 90% or more;
    Supplying an oxygen-containing gas containing oxygen to the (meth) acrylic acid condensate in the reflux tank in which the (meth) acrylic acid condensate is accommodated, and purifying (meth) acrylic acid Method.
  2.   The method for purifying (meth) acrylic acid according to claim 1, wherein the crude (meth) acrylic acid-containing liquid is obtained by a gas phase catalytic oxidation method.
  3.   3. The method for purifying (meth) acrylic acid according to claim 1, wherein in the step of distilling, the crude (meth) acrylic acid-containing liquid is distilled using a distillation tower.
  4.   The method for purifying (meth) acrylic acid according to any one of claims 1 to 3, wherein the condensate obtained in the distillation step has a (meth) acrylic acid purity of 95% or more. .
  5. The oxygen-containing gas is a single gas of oxygen or air, or a mixed gas of the single gas and any one or more kinds of gases selected from the gases described in (1) to (4) below: The purification method of (meth) acrylic acid as described in any one of 1-4.
    (1) Nitrogen (2) Process exhaust gas (3) Air (except when the single gas is air)
    (4) Carbon dioxide
  6.   The method for purifying (meth) acrylic acid according to any one of claims 1 to 5, further comprising a step of adding a polymerization inhibitor to the condensate of (meth) acrylic acid.
  7.   The purification of (meth) acrylic acid according to claim 6, wherein the polymerization inhibitor is at least one selected from copper (meth) acrylate, copper dithiocarbamate, a phenol compound, and a phenothiazine compound. Method.
  8.   The copper dithiocarbamate is copper dimethyldithiocarbamate, copper diethyldithiocarbamate, copper dipropyldithiocarbamate, copper dibutyldithiocarbamate, copper copper ethylenedithiocarbamate, copper tetramethylenedithiocarbamate, copper pentamethylenedithiocarbamate, copper hexamethylenedithiocarbamate and The method for purifying (meth) acrylic acid according to claim 7, wherein the method is any one selected from copper oxydiethylenedithiocarbamate.
  9.   The (meth) acrylic acid copper salt is obtained by dissolving one or more compounds selected from copper powder, cupric carbonate, cuprous hydroxide, cupric hydroxide and copper acetate in acrylic acid. The method for purifying (meth) acrylic acid according to claim 7 or 8, wherein:
  10.   The method for purifying (meth) acrylic acid according to any one of claims 1 to 9, wherein the crude (meth) acrylic acid-containing liquid further contains a hydrazine compound.
  11.   The method for purifying (meth) acrylic acid according to claim 10, wherein the hydrazine compound is any one selected from hydrazine, hydrazine hydrate, phenyl hydrazine, hydrazine sulfate and hydrazine hydrochloride.
  12.   The method for purifying (meth) acrylic acid according to any one of claims 1 to 9, wherein the crude (meth) acrylic acid-containing liquid further contains mercaptans.
  13.   The method for purifying (meth) acrylic acid according to claim 12, wherein the mercaptans are any one selected from n-butyl mercaptan, n-octyl mercaptan and n-dodecyl mercaptan.
  14.   The method for purifying (meth) acrylic acid according to any one of claims 1 to 13, wherein in the step of distillation, the crude (meth) acrylic acid-containing liquid is distilled in the presence of a phenol compound. .
  15.   The method for purifying (meth) acrylic acid according to any one of claims 1 to 14, wherein in the step of distillation, the crude (meth) acrylic acid-containing liquid is distilled in the presence of a phenothiazine compound. .
  16.   The (meth) acryl according to any one of claims 1 to 15, wherein in the step of distillation, the crude (meth) acrylic acid-containing liquid is distilled in the presence of copper (meth) acrylate. Acid purification method.
  17.   The purification of (meth) acrylic acid according to any one of claims 1 to 16, wherein in the step of distilling, the crude (meth) acrylic acid-containing liquid is distilled in the presence of copper dithiocarbamate. Method.
JP2004342449A 2003-11-28 2004-11-26 Method of purifying (meth)acrylic acid Pending JP2005179352A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2003399124 2003-11-28
JP2004342449A JP2005179352A (en) 2003-11-28 2004-11-26 Method of purifying (meth)acrylic acid

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2004342449A JP2005179352A (en) 2003-11-28 2004-11-26 Method of purifying (meth)acrylic acid

Publications (1)

Publication Number Publication Date
JP2005179352A true JP2005179352A (en) 2005-07-07

Family

ID=34797368

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2004342449A Pending JP2005179352A (en) 2003-11-28 2004-11-26 Method of purifying (meth)acrylic acid

Country Status (1)

Country Link
JP (1) JP2005179352A (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007291041A (en) * 2006-04-27 2007-11-08 Osaka Organic Chem Ind Ltd Method for producing adamantyl (meth)acrylate compound
JP2011011986A (en) * 2009-06-30 2011-01-20 Mitsubishi Rayon Co Ltd Method for purifying (meth)acrylic acid
JP2013513638A (en) * 2009-12-14 2013-04-22 ビーエーエスエフ ソシエタス・ヨーロピアBasf Se Method for preventing polymerization of (meth) acrylic acid and / or (meth) acrylic ester
JP2015515963A (en) * 2012-05-03 2015-06-04 エボニック インダストリーズ アクチエンゲゼルシャフトEvonik Industries AG Method for producing high purity, non-yellowing (meth) acrylic acid
JP2016520096A (en) * 2013-05-20 2016-07-11 サウディ ベーシック インダストリーズ コーポレイション Method for purifying acetic acid and acrylic acid
JP2017509613A (en) * 2014-02-20 2017-04-06 アーケマ・インコーポレイテッド Method and system for producing acrylic acid
WO2017090948A1 (en) * 2015-11-27 2017-06-01 주식회사 엘지화학 Method for preparing (meth)acrylic acid
US10414711B2 (en) 2015-11-27 2019-09-17 Lg Chem, Ltd. Method of preparing (meth)acrylic acid

Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2241175A (en) * 1939-01-30 1941-05-06 Norton Co Method of distilling monomeric polymerizable substances
US3627820A (en) * 1967-01-25 1971-12-14 Daicel Ltd Polymerization process
JPS4918820A (en) * 1971-12-24 1974-02-19
JPS4985016A (en) * 1972-12-22 1974-08-15
JPS5498718A (en) * 1978-01-19 1979-08-03 Nippon Shokubai Kagaku Kogyo Co Ltd Recovery of acrylic acid
JPS55127340A (en) * 1979-03-15 1980-10-02 Halcon International Inc Recovery of methacrylic acid
JPS56108735A (en) * 1980-02-01 1981-08-28 Sumitomo Chem Co Ltd Treating method of waste water in preparation of methacrylic acid
JPH07228548A (en) * 1993-12-24 1995-08-29 Sumitomo Chem Co Ltd Method for purifying acrylic acid
JPH1017524A (en) * 1996-06-26 1998-01-20 Mitsubishi Chem Corp Purification of (meth)acrylic acid
JPH1087551A (en) * 1996-09-13 1998-04-07 Mitsubishi Rayon Co Ltd Purification of methacrylic acid
JPH11269121A (en) * 1998-03-23 1999-10-05 Sumitomo Chem Co Ltd Polymerization inhibition of acrylic acid
JP2000256258A (en) * 1999-03-09 2000-09-19 Nippon Shokubai Co Ltd Production of (meth)acrylic acid and/or its ester
JP2000290221A (en) * 1999-03-31 2000-10-17 Nippon Shokubai Co Ltd Purification of (meth)acrylic acid
JP2003073328A (en) * 1993-12-24 2003-03-12 Sumitomo Chem Co Ltd Method for purifying acrylic acid
WO2003043969A1 (en) * 2001-11-21 2003-05-30 Mitsubishi Chemical Corporation Method for supplying atmosphere gas
JP2003342231A (en) * 2002-05-23 2003-12-03 Mitsubishi Rayon Co Ltd Method for storing (meth)acrylic acid or its ester

Patent Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2241175A (en) * 1939-01-30 1941-05-06 Norton Co Method of distilling monomeric polymerizable substances
US3627820A (en) * 1967-01-25 1971-12-14 Daicel Ltd Polymerization process
JPS4918820A (en) * 1971-12-24 1974-02-19
JPS4985016A (en) * 1972-12-22 1974-08-15
JPS5498718A (en) * 1978-01-19 1979-08-03 Nippon Shokubai Kagaku Kogyo Co Ltd Recovery of acrylic acid
JPS55127340A (en) * 1979-03-15 1980-10-02 Halcon International Inc Recovery of methacrylic acid
JPS56108735A (en) * 1980-02-01 1981-08-28 Sumitomo Chem Co Ltd Treating method of waste water in preparation of methacrylic acid
JP2003073328A (en) * 1993-12-24 2003-03-12 Sumitomo Chem Co Ltd Method for purifying acrylic acid
JPH07228548A (en) * 1993-12-24 1995-08-29 Sumitomo Chem Co Ltd Method for purifying acrylic acid
JPH1017524A (en) * 1996-06-26 1998-01-20 Mitsubishi Chem Corp Purification of (meth)acrylic acid
JPH1087551A (en) * 1996-09-13 1998-04-07 Mitsubishi Rayon Co Ltd Purification of methacrylic acid
JPH11269121A (en) * 1998-03-23 1999-10-05 Sumitomo Chem Co Ltd Polymerization inhibition of acrylic acid
JP2000256258A (en) * 1999-03-09 2000-09-19 Nippon Shokubai Co Ltd Production of (meth)acrylic acid and/or its ester
JP2000290221A (en) * 1999-03-31 2000-10-17 Nippon Shokubai Co Ltd Purification of (meth)acrylic acid
WO2003043969A1 (en) * 2001-11-21 2003-05-30 Mitsubishi Chemical Corporation Method for supplying atmosphere gas
JP2003342231A (en) * 2002-05-23 2003-12-03 Mitsubishi Rayon Co Ltd Method for storing (meth)acrylic acid or its ester

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007291041A (en) * 2006-04-27 2007-11-08 Osaka Organic Chem Ind Ltd Method for producing adamantyl (meth)acrylate compound
JP2011011986A (en) * 2009-06-30 2011-01-20 Mitsubishi Rayon Co Ltd Method for purifying (meth)acrylic acid
JP2013513638A (en) * 2009-12-14 2013-04-22 ビーエーエスエフ ソシエタス・ヨーロピアBasf Se Method for preventing polymerization of (meth) acrylic acid and / or (meth) acrylic ester
JP2016028108A (en) * 2009-12-14 2016-02-25 ビーエーエスエフ ソシエタス・ヨーロピアBasf Se Process for inhibiting polymerization of (meth)acrylic acid and/or (meth)acrylic ester
JP2015515963A (en) * 2012-05-03 2015-06-04 エボニック インダストリーズ アクチエンゲゼルシャフトEvonik Industries AG Method for producing high purity, non-yellowing (meth) acrylic acid
JP2016520096A (en) * 2013-05-20 2016-07-11 サウディ ベーシック インダストリーズ コーポレイション Method for purifying acetic acid and acrylic acid
US9944582B2 (en) 2013-05-20 2018-04-17 Saudi Basic Industries Corporation Method for the purification of acetic acid and acrylic acid
JP2017509613A (en) * 2014-02-20 2017-04-06 アーケマ・インコーポレイテッド Method and system for producing acrylic acid
WO2017090948A1 (en) * 2015-11-27 2017-06-01 주식회사 엘지화학 Method for preparing (meth)acrylic acid
US10414711B2 (en) 2015-11-27 2019-09-17 Lg Chem, Ltd. Method of preparing (meth)acrylic acid

Similar Documents

Publication Publication Date Title
EP1159249B1 (en) Fractional condensation of a product gas mixture containing acrylic acid
EP1163201B1 (en) Method for producing acrylic acid
US6482981B2 (en) Method for producing acrylic acid
CN102887820B (en) Process for producing acrylic acid
US7118098B2 (en) Hydraulically sealed crossflow mass transfer tray
EP1041062A2 (en) Method for refining (meth)acrylic acid
US5780679A (en) Separation of (meth)acrylic acid from the reaction gas mixture formed in the catalytic gas phase oxidation of C3 /C4 compounds
JP2007091759A (en) Method for purifying mixture obtained through catalytic vapor-phase oxidation of propene and/or acrolein, by separation treatment inducing phase formation
US7566804B2 (en) Process for preparing acrylic acid
US7183428B2 (en) Method for production of acrylic acid
US5897749A (en) Continuous distillative separation of liquid mixtures which contain (meth) acrylic acid as the main component
JP3957298B2 (en) Acrylic acid production method
CN1313429C (en) Preparation of acrylic acid
KR101096420B1 (en) Thermal separating method for separating at least one mass flux containing enriched methacrylic monomers
US7319168B2 (en) Process for producing aliphatic carboxylic acid
US7326323B2 (en) High capacity purification of thermally unstable compounds
CZ2000885A3 (en) Process for preparing acrylic acid and methacrylic acid
EP1097741B2 (en) Column treating process and apparatus therefor
JP5892729B2 (en) Method for producing high purity methacrylic acid
JP3999160B2 (en) Method for producing easily polymerizable substance
DE10138150A1 (en) Process for preparation of a water absorbing resin superabsorbers from acrylic acid useful for the production hygiene articles
EP1382592A1 (en) Method for production of acrylic acid
US20010016668A1 (en) Method for production of (meth) acrylic acid
US5637222A (en) Process for the fractional separation of (meth)acrylic acid from a mixture containing (meth)acrylic acid
CN1107046C (en) Method for producing acrylic acid and acrylic acid esters

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20070724

A131 Notification of reasons for refusal

Effective date: 20100810

Free format text: JAPANESE INTERMEDIATE CODE: A131

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20100916

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20110125

A02 Decision of refusal

Effective date: 20110726

Free format text: JAPANESE INTERMEDIATE CODE: A02