JP2007015957A - Method and apparatus for producing (meth)acrylate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for producing a (meth)acrylate, capable of efficiently performing a filtration treatment within a short time. <P>SOLUTION: The (meth)acrylate is produced by subjecting (meth)acrylic acid to esterification reaction with an alcohol in the presence of an acid catalyst and an organic solvent, neutralizing the reaction product with an aqueous alkali solution, removing the organic solvent from the product in a desolvation vessel 20, and subjecting the product to a filtration treatment. The filtration treatment is carried out by supplying a filtration assistant from a hopper 31 to the desolvation vessel 20 and depositing the filtration assistant onto a filter 35 of a vertical-type horizontal filter plate type connected to the desolvation vessel 20. Diatomaceous earth is desirable as a filtering aid, and the filtration pressure of 1 MPa or lower is preferable. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for producing (meth) acrylates such as (meth) acrylate obtained by esterification reaction of acrylic acid and alcohol under reduced pressure.

  In general, (meth) acrylates are esterified with (meth) acrylic acid and alcohol in the presence of an acid catalyst and an organic solvent in a reactor, and the reaction product is neutralized with an aqueous alkaline solution in a neutralization tank. It is produced by removing the organic solvent from the reaction product in a solvent removal tank. At this time, since the fine solid foreign matter remains in the (meth) acrylate extracted from the solvent removal tank and is turbid, filtration is performed. As such a filtration treatment, a method using a filter paper, a filter cloth, a strainer or the like, a precoat method method in which a filter aid is coated on the filter paper, and the like are known.

Specifically, in the distillation of acrylic acid or acrylic acid ester, a method is known in which crude acrylic acid or acrylic acid ester taken out from the bottom of the distillation column is passed through a strainer for filtration (for example, (See Patent Document 1). Furthermore, a method of filtering a sulfur-containing acrylic compound with a microfilter is also known (see, for example, Patent Document 2).
JP 2001-129388 A (2nd page, 5th page and 6th page) JP 2001-181257 (page 2, page 3 and page 5)

  However, the methods described in Patent Documents 1 and 2 are those in which a liquid to be filtered such as (meth) acrylate is filtered with a filter medium, and filtration is performed when the filter medium has a fineness of micron order. Pressure increases and clogging is likely to occur. Therefore, there has been a problem that the filtration time becomes long and the efficiency of the filtration treatment is poor.

  In addition, in the pre-coating method in which the filter aid is coated on the filter paper, a suspension obtained by suspending the filter aid in a solvent is used, and this is passed through the filter paper to deposit the filter aid on the filter paper. Since the solvent cannot be completely dried, there is a problem that the solvent in the suspension is mixed into the final product and the purity of the final product is lowered.

  The present invention has been made by paying attention to such problems existing in the prior art, and the object of the present invention is to maintain the purity of the final product at a high level and to perform the filtration process in a short time. The object is to provide a method and an apparatus for producing (meth) acrylate that can be carried out efficiently.

  In order to achieve the above object, the method for producing a (meth) acrylate according to the first aspect of the present invention includes (meth) acrylic acid and an alcohol esterified in the presence of an acid catalyst and an organic solvent. The product is neutralized with an aqueous alkaline solution, and the organic solvent is removed from the reaction product in a solvent removal tank. A filter aid is supplied to the solvent removal tank, and a vertical horizontal filter plate connected to the solvent removal tank. The filtration product of the reaction product is deposited by depositing a filter aid on the filter.

The method for producing a (meth) acrylate according to claim 2 is characterized in that, in the invention according to claim 1, the filter aid is diatomaceous earth.
The method for producing (meth) acrylate according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the filtration pressure in the vertical horizontal filter type filter is set to 1 MPa or less. It is what.

  The apparatus for producing (meth) acrylate according to claim 4 comprises a reactor for esterifying the (meth) acrylic acid and alcohol in the presence of an acid catalyst and an organic solvent, and a lower part of the reactor. And a neutralization tank for neutralizing the reaction product with an alkaline aqueous solution, and a desolvation tank connected to the neutralization tank for removing the organic solvent from the reaction product ( In the meth) acrylate production apparatus, a vertical horizontal filter plate type filter is connected to the lower part of the solvent removal tank, and a filter aid supply unit is provided at the upper part of the solvent removal tank. A filter aid is supplied to the solvent tank, and the filter aid is deposited on the filter to filter the reaction product.

  In the present invention, acrylate or methacrylate is represented as (meth) acrylate, and acrylic acid or methacrylic acid is represented as (meth) acrylic acid.

According to the present invention, the following effects can be exhibited.
In the method for producing a (meth) acrylate according to the first aspect of the invention, the organic solvent is removed from the product of the esterification reaction in a desolvation tank, and a filter aid is supplied to the desolvation tank. The reaction product is filtered by depositing a filter aid on a filter type filter. In this filtration treatment, a filter aid is mixed with the reaction product, and when the reaction product reaches the filter, the filter aid is deposited on the filter paper of the filter to gradually increase the filtration area. . Therefore, it is possible to prevent the solvent from being mixed into the final product as in the case of filtration by the precoat method, to maintain the purity of the final product high, and to efficiently perform the filtration process in a short time. It can be carried out.

  In the method for producing a (meth) acrylate according to the second aspect of the present invention, the filter aid is diatomaceous earth and a large capillary diameter is obtained. Therefore, in addition to the effect of the first aspect, the high viscosity The reaction product can be filtered well.

  In the method for producing a (meth) acrylate according to the third aspect of the invention, by setting the filtration pressure in the vertical horizontal filter type filter to 1 MPa or less, the filter from the filter caused by an increase in the filtration pressure is used. The passage of foreign matter can be suppressed. For this reason, in addition to the effect of the invention according to claim 1 or claim 2, foreign substances contained in the reaction product can be reliably removed.

  In the (meth) acrylate production apparatus according to claim 4, a vertical horizontal filter plate type filter is connected to the lower part of the solvent removal tank, and a filter aid is supplied to the upper part of the solvent removal tank. And a filter aid is supplied from the supply portion to the solvent removal tank, and the filter aid is deposited on the filter to filter the reaction product. For this reason, the effect of the invention which concerns on Claim 1 can be exhibited by the simple structure change of providing the supply part of a filter aid in the upper part of a solvent removal tank, and mixing a filter aid with a reaction product. .

Hereinafter, embodiments of the present invention will be described in detail.
(Esterification reaction)
In the present invention, (meth) acrylic acid and alcohol are esterified (dehydration condensation reaction) in the presence of an acid catalyst and an organic solvent. The esterification reaction may be performed according to a conventional method in the production of (meth) acrylate.

  As (meth) acrylate, (meth) acrylate of alkylalkylene oxide adduct such as (meth) acrylate of alkylene oxide adduct of 2-ethylhexyl alcohol; (meth) acrylate, phenol of p-cumylphenol alkylene oxide adduct (Meth) acrylates of phenol alkylene oxide adducts such as (meth) acrylates of alkylene oxide adducts and (meth) acrylates of nonylphenol alkylene oxide adducts; polycyclic alkyldi (such as tricyclodecane dimethylol di (meth) acrylate) (Meth) acrylate; ethylene glycol mono- or di (meth) acrylate, propylene glycol mono- or di (meth) acrylate, pentanediol mono- or di (meth) a Mono- or di (meth) acrylates of dihydric alcohols such as mono- or di (meth) acrylates of relate and hexanediol; mono- or di (meth) acrylates of diethylene glycol, mono- or di (meth) acrylates of triethylene glycol, tetraethylene Mono or di (meth) acrylate of glycol, mono or di (meth) acrylate of polyethylene glycol, mono or di (meth) acrylate of dipropylene glycol, mono or di (meth) acrylate of tripropylene glycol and mono or di of polypropylene glycol Mono- or di (meth) acrylates of polyalkylene glycols such as di (meth) acrylate; di- or tri (meth) acrylates of glycerin and di- or tri (meth) acrylates of diglycerin, etc. Di- or tri (meth) acrylates of lysines; di- or tri (meth) acrylates of alkylene oxide adducts of glycerols; di (meth) acrylates of bisphenol A alkylene oxide adducts and di (meth) of bisphenol F alkylene oxide adducts ) Di (meth) acrylates of bisphenol alkylene oxide adducts such as acrylate; trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate , Pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate Poly (meth) acrylates such as poly (meth) acrylates; poly (meth) acrylates of alkylene oxide adducts of these polyols; di- or tri (meth) acrylates of isocyanuric acid alkylene oxide adducts; and polyester (meth) acrylates.

  The present invention can be preferably applied to the production of (meth) acrylate having a high viscosity of 500 to 30000 mPa · s at room temperature (25 ° C.) among the above (meth) acrylates. Such (meth) acrylates include (meth) acrylates of alkyl alkylene oxide adducts such as (meth) acrylates of alkylene oxide adducts of 2-ethylhexyl alcohol; (meth) of p-cumylphenol alkylene oxide adducts. (Meth) acrylates of phenol alkylene oxide adducts such as (meth) acrylates of acrylates, (meth) acrylates of phenol alkylene oxide adducts and (meth) acrylates of nonylphenol alkylene oxide adducts; polycyclic such as tricyclodecane dimethylol di (meth) acrylate Polyalkylene glycols such as mono- or di (meth) acrylate of polyethylene glycol and mono- or di (meth) acrylate of polypropylene glycol Cole mono- or di (meth) acrylate; di- or tri- (meth) acrylate of alkylene oxide adduct of glycerins; di (meth) acrylate of bisphenol A alkylene oxide adduct and di (meth) of bisphenol F alkylene oxide adduct Di (meth) acrylates of bisphenol alkylene oxide adducts such as acrylates; trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, Pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate ; Poly alkylene oxide adducts of these polyols (meth) acrylate; and polyester (meth) acrylate.

  Particularly preferably applicable (meth) acrylates have high viscosity, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri Tri (meth) acrylate of methylolpropane alkylene oxide adduct, tri (meth) acrylate of ditrimethylolpropane alkylene oxide adduct, tetra (meth) acrylate of ditrimethylolpropane alkylene oxide adduct, hexa of ditrimethylolpropane alkylene oxide adduct (Meth) acrylate.

  Examples of the alcohol include alkylene oxide adducts and alkyl alkylene oxide adducts of 2-ethylhexyl alcohol; phenol alkylene oxide adducts such as p-cumylphenol alkylene oxide adduct, phenol alkylene oxide adduct and nonylphenol alkylene oxide adduct; Polycyclic alkyl di (meth) acrylates such as tricyclodecane dimethylol; dihydric alcohols of ethylene glycol, propylene glycol, pentanediol and hexanediol; diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tri Polyalkylene glycols such as propylene glycol and polypropylene glycol; And glycerins such as diglycerin; alkylene oxide adducts of glycerins; bisphenol alkylene oxide adducts such as bisphenol A alkylene oxide adduct and bisphenol F alkylene oxide adduct; trimethylolpropane, ditrimethylolpropane, pentaerythritol and dipenta Polyols such as erythritol; alkylene oxide adducts of these polyols; isocyanuric acid alkylene oxide adducts; and polyester diols are used. Examples of the alkylene oxide in the alkylene oxide adduct include ethylene oxide and propylene oxide. Further, the addition number of alkylene oxide is preferably 1 to 20.

  (Meth) acrylic acid is acrylic acid or methacrylic acid, and is selected depending on whether the target ester is an acrylate or a methacrylate. The amount of (meth) acrylic acid used is adjusted with respect to 1 mol of all hydroxyl groups of the alcohol so that the resulting (meth) acrylate has the desired hydroxyl value.

  Examples of the acidic catalyst include sulfuric acid and paratoluenesulfonic acid. Moreover, what is necessary is just to set reaction temperature suitably according to the raw material to be used and the objective, However, 65-140 degreeC is preferable from a viewpoint of shortening of reaction time and superposition | polymerization prevention, and 75-120 degreeC is more preferable. When the reaction temperature is less than 65 ° C., the esterification reaction is slowed or the yield is reduced. On the other hand, when the reaction temperature exceeds 140 ° C., (meth) acrylic acid or the produced (meth) acrylate There is a risk of thermal polymerization of.

  In the esterification reaction, it is preferable to promote dehydration while azeotropically water generated by the esterification reaction with an organic solvent. Preferred organic solvents include aromatic hydrocarbons such as toluene, benzene and xylene, aliphatic hydrocarbons such as hexane and heptane, and ketones such as methyl ethyl ketone. The amount of the organic solvent used is preferably 0.1 to 10 times, more preferably 1 to 5 times the mass of the total amount of the alcohol and (meth) acrylic acid.

The esterification reaction is preferably performed at a low temperature in a reduced pressure state for the purpose of preventing thermal polymerization of (meth) acrylic acid or the generated (meth) acrylate. Moreover, it is preferable to perform esterification reaction in presence of oxygen. For the same purpose, it is preferable to add a polymerization inhibitor to the reaction solution. Examples of such a polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, 2,4-dimethyl-6-t-butylphenol, and the like. The degree of progress of the esterification reaction is performed by monitoring the amount of water produced by the esterification reaction, that is, the amount of dehydration.
(Neutralization treatment)
After the esterification reaction, the reaction product is neutralized with an aqueous alkaline solution for the purpose of removing unreacted (meth) acrylic acid and acid catalyst. This neutralization treatment may be carried out according to a conventional method, and examples thereof include a method of adding an aqueous alkali solution such as aqueous sodium hydroxide and potassium hydroxide to the reaction solution as an alkali component, stirring and mixing.

  In this case, the amount of the alkali component is usually 1 time or more, preferably 1.1 to 2.0 times in molar ratio to the acid content of the reaction solution. If this addition amount is less than 1 time in molar ratio with respect to the acid content of the reaction solution, neutralization of the acid content becomes insufficient, such being undesirable. Moreover, it is preferable that the density | concentration of aqueous alkali solution is 1-25 mass%, More preferably, it is 10-25 mass%. If this concentration is less than 1% by mass, the amount of waste water after neutralization will increase, which is not preferred. If it exceeds 25% by mass, (meth) acrylate may be polymerized. Further, the stirring and mixing time is preferably about 5 to 120 minutes.

In the present invention, the above-described reaction solution or neutralization treatment solution is preferably washed with water. The water washing treatment can be performed on the reaction solution obtained by the esterification reaction and the organic layer after neutralization. The point at which the water washing treatment is performed may be appropriately selected according to the components to be used and the purpose. This washing treatment may be performed according to a conventional method. Specific examples include a method of adding water to the reaction solution obtained by the esterification reaction and the neutralized organic layer, and stirring and mixing.
(Solvent removal)
After the neutralization treatment, the organic layer is separated from the aqueous layer by removing the organic solvent in a solvent removal tank.

  The solvent removal treatment may be carried out in accordance with a conventional method, for example, a method in which the solvent removal tank is decompressed and the organic solvent is removed. What is necessary is just to set suitably as a vacuum degree of a solvent removal tank according to the raw material to be used and the objective, Preferably it is 0.5-50 kPa, and the method of increasing a pressure reduction degree gradually by the removal degree of a solvent is preferable.

In order to suppress thermal polymerization of (meth) acrylate, this solvent removal treatment is performed under reduced pressure by supplying oxygen or adding a polymerization inhibitor and maintaining the temperature at 80 ° C. or lower, for example. Is preferred.
(Filtration method)
In the present invention, the organic solvent is removed from the reaction product in the solvent removal treatment in the solvent removal tank, and a filter aid is supplied to the solvent removal tank and connected to the solvent removal tank. The reaction product is filtered by depositing a filter aid.

  As a vertical horizontal filter plate type filter, a commonly used one can be used. As the filter aid, diatomaceous earth, activated carbon, cellulose, pearlite, and the like are used, and diatomaceous earth is preferred from the viewpoint that a capillary having a large diameter can be obtained and a high-viscosity reaction product can be filtered well. From such a viewpoint, in the case of diatomaceous earth, those having an average capillary diameter of about 3 to 10 μm are preferable.

  The filtration pressure during filtration is preferably 1 MPa or less, and more preferably 0.1 to 0.3 MPa. When the filtration pressure exceeds 1 MPa, the passage of foreign matter from the filter 35 due to the increase in the filtration pressure cannot be sufficiently suppressed. The amount of filter aid used and the amount of liquid to be filtered are preferably set so large that the filtration pressure does not exceed 1 MPa. The usage-amount of a filter aid is set, for example in the range of about 0.04-0.1 mass% with respect to the (meth) acrylate which is a reaction product after a solvent removal process.

Next, a preferred embodiment of the present invention will be described with reference to FIG.
FIG. 1 is an example in which a vertical horizontal filter plate type filter is connected to a solvent removal tank. As shown in FIG. 1, a hopper 31 as a supply unit in which a filter aid is stored is connected to the upper portion of the solvent removal tank 20, and the filter aid is supplied into the solvent removal tank 20. The other end of the extraction pipe 29 connected to the bottom of the solvent removal tank 20 is connected to the supply pump 33, one end of the filtrate supply pipe 34 is connected to the discharge side of the supply pump 33, and the other end is a vertical horizontal shape. A filter plate type filter (sparkler filter) 35 is connected to the upper part. And the to-be-filtered liquid with which the filter aid was mixed with the process liquid which carried out the solvent removal arrives in the filter 35 from the piping 29, and a filter aid settles and deposits by gravity there, and is according to a filter aid. An increase in the filtration area is achieved (body feed method). One end of the first circulation pipe 36 is connected to the bottom of the filter 35 and the other end is connected to the upper portion of the solvent removal tank 20 so that the filtrate after filtration is circulated to the solvent removal tank 20. Yes. A bypass pipe 37 is connected between the filtrate supply pipe 34 and the first circulation pipe 36. The first circulation pipe 36 is provided with a sampling section 42, from which sampling can be performed and the turbidity of the filtrate can be measured.

  The saddle type horizontal filter plate type filter will be described with reference to FIG. In the vertical horizontal filter plate type filter 35, a disk-shaped filter plate 45 having a large number of holes is arranged in multiple stages in a tank 44 in which the upper part of a bottomed cylindrical body is fitted with a lid 43. Has been. The filter plate 45 is of a cartridge type and can be easily taken out of the tank 44, and can be disassembled and cleaned. An inlet pipe 46 for introducing the filtrate to be filtrated is provided on the side wall of the tank 44, and the filtrate to be filtrated supply pipe 34 is connected thereto. A filtrate outlet pipe 47 is provided at the center of the bottom of the filter 35 and is connected to the first circulation pipe 36. A scavenger plate 48 is provided at the bottom of the tank 44 so as to receive the liquid to be filtered flowing downward from the filter plate 45 and lead it to a dedicated scavenger pipe 49. The lid 43 is provided with an air introduction pipe 50 and a pressure gauge 51. A drain pipe 52 is provided at the bottom of the tank 44.

Then, the reaction product as the liquid to be filtered mixed with the filter aid is introduced into the tank from the introduction pipe 46 and moves between the filter plates 45, and the filter aid is placed on the filter paper installed on the filter plate 45. The filtrate is filtered while being settled in the filtrate, and the filtrate is discharged from the filtrate outlet pipe 47.
((Meth) acrylate production equipment)
Next, the preferable embodiment of the manufacturing apparatus used by the (meth) acrylate manufacture of this invention is demonstrated based on FIG.

  As shown in FIG. 3, a rectifying column 12 is disposed above a cylindrical reactor 11 whose top and bottom are sealed, and is connected to the reactor 11 by a distillation pipe 13 and a reflux pipe 14. ing. A rectifying column condenser 15 is provided in the upper part of the rectifying column 12, and the reaction gas distilled from the distilling pipe 13 is condensed in the rectifying column condenser 15 and is refluxed to the reactor 11 from the refluxing pipe 14. The An exhaust gas condenser 16 is connected to the rectification column 12, and the exhaust gas discharged from the rectification column 12 is condensed. In the reactor 11, (meth) acrylic acid and alcohol are esterified in the presence of an acid catalyst and an organic solvent.

  One end of the first connection pipe 17 is connected to the bottom of the reactor 11, and the other end is connected to the upper part of the neutralization tank 18. The reaction solution esterified in the reactor 11 is transferred to the neutralization tank 18. . In the neutralization tank 18, the reaction product is neutralized with an alkaline aqueous solution. If necessary, in the neutralization tank 18, the reaction solution or the neutralized organic layer can be washed with water.

  One end of the second connection pipe 19 is connected to the bottom of the neutralization tank 18, the other end is connected to the top of the solvent removal tank 20, and the neutralization treatment liquid is transferred to the solvent removal tank 20. A solvent removal capacitor 23 is connected to an upper portion of the solvent removal tank 20 through a solvent distillation pipe 21 and a solvent reflux pipe 22. An exhaust gas condenser 24 is connected to the desolvation condenser 23, and a high-boiling fraction is condensed from the exhaust gas discharged from the desolvation condenser 23 and circulated to the desolvation tank 20.

  An extraction pipe 29 is connected to the bottom of the solvent removal tank 20 and is connected to the filtration device shown in FIG. One end of a third connection pipe 25 is connected to the exhaust gas condenser 24, and two roots type vacuum pumps (rotary vacuum pumps) 26 are connected in series to the other end, and a fourth connection is provided downstream thereof. A water ring vacuum pump (Nash type vacuum pump) 28 is connected via a pipe 27. By these vacuum pumps, the solvent removal tank 20 is maintained at a high vacuum of about 0.5 kPa through the solvent removal condenser 23 and the exhaust gas condenser 24, and the organic solvent is removed from the reaction product. One end of a fifth connection pipe 30 is connected to the upper part of the exhaust gas condenser 16 and the other end is connected to the fourth connection pipe 27, and the exhaust gas condenser 16 and the rectification tower 12 are connected by a water ring vacuum pump 28. The inside of the reactor 11 is maintained at a low vacuum of about 40 to 100 kPa.

  Now, the operation of the present embodiment will be described. (Meth) acrylic acid and alcohol undergo an esterification reaction in the presence of an acid catalyst and an organic solvent, and the reaction product is neutralized with an aqueous alkali solution to remove the solvent. At 20, the organic solvent is removed from the reaction product to produce (meth) acrylate. In this manufacturing process, the filter aid is supplied from the hopper 31 to the solvent removal tank 20, and the filter aid is deposited on the vertical horizontal filter plate type filter 35 to filter the reaction product. In this filtration process, when the filtrate to be filtered in which the reaction product is mixed with the filter aid reaches the filter 35, the filter aid is proportional to the flow rate of the filtrate on the filter plate 45 of the filter 35. On the filter paper placed in the bottom of the ground by gravity. For this reason, the filtration function is expressed by the deposited filter aid. Therefore, during filtration, the filter aid deposited on the filter paper placed on the filter plate 45 can be gradually increased compared to the conventional pre-coating filtration method, and the filtration can be performed efficiently. Can do.

The effects exhibited by the above embodiment will be described collectively below.
-In the manufacturing method of (meth) acrylate of this embodiment, while removing the organic solvent from the product of esterification reaction in the desolvation tank 20, a filter aid is supplied to the desolvation tank 20, and the vertical horizontal filtration is performed. A filter aid is deposited on the plate-type filter 35 to filter the reaction product. In this filtration process, a filter aid is mixed with the reaction product, and when the reaction product reaches the filter 35, the filter aid is deposited on the filter paper placed on the filter plate 45 of the filter 35. Thus, the filtration area can be gradually increased. Therefore, the filtration process can be performed efficiently in a short time. As described above, since a sufficient filtration area can be secured, the size of the filtration device can be reduced. Moreover, it can prevent that a solvent mixes in the final product like the case where it filters by the precoat method, and can maintain the purity of a final product high.

-By using diatomaceous earth as the filter aid, a product having a large capillary diameter can be obtained, so that a highly viscous reaction product can be filtered well.
-By setting the filtration pressure in the vertical horizontal filter plate type filter 35 to 1 MPa or less, it is possible to suppress the passage of foreign matter from the filter 35 due to an increase in the filtration pressure. The contained foreign matter can be reliably removed.

  In the (meth) acrylate production apparatus, a vertical horizontal filter plate type filter 35 is connected to the lower part of the solvent removal tank 20, and a filter aid hopper 31 is provided to the upper part of the solvent removal tank 20, A filter aid is supplied from the hopper 31 to the solvent removal tank 20, and the filter aid is deposited on the filter 35 to filter the reaction product. For this reason, the above effect can be exhibited by a simple configuration change in which a filter aid hopper 31 is provided in the upper part of the solvent removal tank 20 and the filter aid is mixed with the reaction product.

Examples and Comparative Examples will be given below to describe the above embodiments more specifically. However, the present invention is not limited to these Examples.
Example 1
Acrylate was produced using the (meth) acrylate production apparatus shown in FIG. 1 and FIG. That is, 3600 kg of dipentaerythritol, 7347 kg of acrylic acid, 173 kg of sulfuric acid, 17.3 kg of cupric chloride and 6011 kg of toluene were charged into the reactor 11, and the esterification reaction was started under the conditions of a temperature of 84 ° C. and a pressure of 53.2 kPa. The condensed water of the esterification reaction azeotroped with toluene was distilled off in the rectifying column 12 to advance the esterification reaction, and the esterification reaction was stopped after 17 hours.

  The reaction solution is guided to the neutralization tank 18 through the first connection pipe 17, washed with 4% ammonium sulfate aqueous solution in the neutralization tank 18, and then neutralized with sodium hydroxide aqueous solution. Washing with water was performed. Subsequently, the reaction solution after the water washing treatment is transferred to the solvent removal tank 20 through the second connection pipe 19, and degassed under reduced pressure while blowing 5% oxygen-containing nitrogen gas in a state where the temperature is set to 50 ° C. Solvent treatment was performed. In this solvent removal treatment, the temperature was changed to 75 ° C. and the pressure was changed to 0.6 kPa. As a result, 5000 kg of dipentaerythritol hexaacrylate having a viscosity of 6000 mPa · s (25 ° C.) was obtained.

  A filter aid diatomaceous earth (made by Showa Chemical Industry Co., Ltd., trade name Radiolite # 800, average capillary diameter 6.5 μm) is removed from the hopper 31 installed at the top of the solvent removal tank 20 at the start of the solvent removal treatment. 20 was supplied. Then, the reaction solution containing the filter aid after the solvent removal treatment is supplied to a vertical horizontal filter plate type filter [manufactured by Nissen Co., Ltd., trade name: Sparkler filter, 33 stages of filter paper] 35 and filtered. It was. The filtration pressure was set to a maximum filtration pressure of 0.4 to 0.5 MPa and an average filtration pressure of 0.3 MPa. The amount of filter aid used was 5 kg with respect to 5000 kg of dipentaerythritol hexaacrylate. The filtrate that passed through the filter 35 was returned to the solvent-removing tank 20 and circulated. Further, the filtration could be completed smoothly in 1 hour without causing the filtration surface to be blocked. And the target dipentaerythritol hexaacrylate was able to be obtained.

In this way, it was possible to increase the filtration area with a compact filtration device, and to minimize equipment (only one filtration device). The concentration of toluene in the final product dipentaerythritol hexaacrylate was 200 ppm, and high-purity dipentaerythritol hexaacrylate was obtained.
(Example 2)
In Example 1, 2800 kg of pentaerythritol, 6819 kg of acrylic acid, 280 kg of paratoluenesulfonic acid, 6.8 g of cupric chloride and 4120 kg of toluene were charged into the reactor 11 and esterified under the conditions of a temperature of 83 ° C. and a pressure of 60.0 kPa. The reaction was started. Others were carried out in the same manner as in Example 1 for the esterification reaction, neutralization treatment, water washing treatment and solvent removal treatment. As a result, 7000 kg of pentaerythritol tetraacrylate having a viscosity of 500 mPa · s (25 ° C.) was obtained.

The pentaerythritol tetraacrylate was filtered. That is, 3 kg of diatomaceous earth (manufactured by Showa Chemical Industry Co., Ltd., trade name Radiolite # 500, average capillary diameter 3.9 μm) was used as a filter aid, the maximum filtration pressure was 0.25 to 0.3 MPa, and the average filtration pressure was 0.00. Set to 2 MPa. As a result, a liquid without turbidity could be obtained by circulation for 1 hour. The toluene concentration in the final product, pentaerythritol tetraacrylate, was 200 ppm, and high-purity pentaerythritol tetraacrylate was obtained.
(Comparative Example 1)
In Example 1, when a cartridge filter was used in place of the vertical horizontal filter plate type filter 35, it was necessary to install about 20 cartridges themselves in order to secure the same filtration area. This installation area was about three times that of the vertical horizontal filter plate type filter 35. Further, it is necessary to replace the cartridge every time the cartridge is clogged, and 40 or more cartridges are generated as waste to filter the same amount of liquid to be filtered.
(Comparative Example 2)
In Example 1, filtration was performed only with filter paper without using a filter aid in the filtration treatment. As a result, the filter surface was blocked and the flow rate became 0 immediately after circulation, and filtration could not be performed smoothly. Even if the filtration was continued as it was, only the labor for replacing the filter paper increased, so the filtration was interrupted.
(Comparative Example 3)
In Example 1, the filtration treatment was performed by a precoat method. That is, in Example 1, the filter aid was not supplied to the solvent removal tank 20, and the filter aid diatomaceous earth (radiolite # used in Example 1 was used in the vertical horizontal filter plate type filter 35 before the solvent removal treatment. 800) was added to toluene and the mixed turbid liquid was supplied to the filter 35, and the filter plate 45 was coated with a filter aid.

  As an apparatus, it changed into the filtration process shown in FIG. 4 from the filtration process shown in FIG. FIG. 4 is different from FIG. 1 in that one end of a branch pipe 38 is connected to the first circulation pipe 36 and the other end is connected to a precoat suspension tank 39. In the precoat suspension tank 39, a toluene suspension of filter aid is stored. One end of a second circulation pipe 40 is connected to the bottom of the precoat suspension tank 39, and the other end is connected to the filtrate supply pipe 34 via a circulation pump 41. The turbid liquid of the filter aid in the precoat suspension tank 39 is supplied to the filter 35 through the pipe 40, and the filter aid is precoated on the filter paper.

The concentration of toluene in the obtained dipentaerythritol hexaacrylate was as high as 1000 ppm or more, and the filtration treatment was inappropriate.
In addition, the said embodiment can also be changed and actualized as follows.

-It is also possible to perform filtration by connecting a plurality of vertical horizontal filter plate type filters 35 in series.
In the vertical horizontal filter plate type filter 35, the number of filter plates 45 in the tank 44, the diameter, the interval between the filter plates 45, and the like can be changed according to the purpose.

Further, the technical idea that can be grasped from the embodiment will be described below.
-The average capillary diameter of the said diatomaceous earth is 3-10 micrometers, The manufacturing method of the (meth) acrylate of Claim 2 or Claim 3 characterized by the above-mentioned. According to this production method, in addition to the effect of the invention according to claim 2 or claim 3, it is possible to satisfactorily filter the reaction product having a high viscosity.

Explanatory drawing which shows the filtration process process for manufacturing the (meth) acrylate in embodiment. A schematic sectional view showing a vertical horizontal filter type filter. Explanatory drawing which shows the manufacturing process of (meth) acrylate. Explanatory drawing which shows the filtration process process used by the comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Reactor, 18 ... Neutralization tank, 20 ... Desolvation tank, 31 ... Hopper as supply part of filter aid, 35 ... Vertical type horizontal filter type filter.

Claims (4)

(Meth) acrylic acid and alcohol are esterified in the presence of an acid catalyst and an organic solvent, the reaction product is neutralized with an aqueous alkali solution, and the organic solvent is removed from the reaction product in a solvent removal tank. , Supplying a filter aid to the solvent removal tank, and depositing the filter aid on a vertical horizontal filter plate type filter connected to the solvent removal tank to filter the reaction product (meta ) A process for producing acrylates. The method for producing (meth) acrylate according to claim 1, wherein the filter aid is diatomaceous earth. The method for producing (meth) acrylate according to claim 1 or 2, wherein a filtration pressure in the vertical horizontal filter type filter is set to 1 MPa or less. A reactor for esterifying (meth) acrylic acid and alcohol in the presence of an acid catalyst and an organic solvent, and connected to the lower part of the reactor, for neutralizing the reaction product with an alkaline aqueous solution An apparatus for producing (meth) acrylate, comprising a neutralization tank and a desolvation tank connected to the neutralization tank for removing the organic solvent from the reaction product,
A vertical horizontal filter plate type filter is connected to the lower part of the solvent removal tank, and a filter aid supply part is provided at the upper part of the solvent removal tank, and the filter aid is supplied from the supply part to the solvent removal tank. And a (meth) acrylate production apparatus, wherein a filtration aid is deposited on the filter and the reaction product is filtered.

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