JP2006169220A - Method for producing (meth)acrylic acid ester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a (meth)acrylic acid ester in a good efficiency while preventing not only the raw material for the production of the (meth)acrylic acid ester but also the produced (meth)acrylic acid ester from polymerization. <P>SOLUTION: This method for producing the (meth)acrylic acid ester in a reaction container is characterized by supplying a raw material containing the raw material compounds for producing the (meth)acrylic acid ester and a polymerization inhibitor into the reaction container and then spraying the content of the reaction container to an internal space of the reaction container by using an oxygen-containing gas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a (meth) acrylic acid ester. More specifically, when the (meth) acrylic acid ester is produced, for example, the raw material compound of the (meth) acrylic acid ester is present at the pipe connection portion, the upper inner wall of the reaction vessel, near the internal inspection window, near the raw material inlet, etc. The present invention relates to a method for producing a (meth) acrylic acid ester that can efficiently produce a (meth) acrylic acid ester while preventing polymerization.

  In general, (meth) acrylic acid esters are produced in a reaction vessel (for example, see Patent Document 1). Since the (meth) acrylic acid ester is a compound having a very high polymerizability, when producing the (meth) acrylic acid ester, a polymerization initiator is added to the raw material compound in advance, and the resulting raw material for production is obtained. Is introduced into the reaction vessel. However, in this method, the vapor of the (meth) acrylic acid ester produced may aggregate on the inner wall surface of the gas phase portion of the reaction vessel and polymerize.

  Therefore, as a method for solving this problem, a method is known in which a reaction is carried out while bringing a raw material for producing (meth) acrylic acid ester, in which a polymerization inhibitor is dissolved, into contact with a member existing in the gas phase part of the reaction vessel. (For example, refer to Patent Document 2).

  This method is certainly an effective method for preventing the production raw material (reaction solution) itself adhering to the member from being polymerized. However, since the droplets formed by agglomeration of the generated (meth) acrylic acid ester vapor contain almost no polymerization inhibitor, the generated (meth) acrylic acid ester droplets are contained in the reaction vessel. It adheres to the upper inner wall, the vicinity of the internal inspection window, the vicinity of the raw material inlet, and the like, resulting in polymerization.

Therefore, in recent years, development of a method capable of efficiently producing (meth) acrylic acid esters while preventing polymerization of not only (meth) acrylic acid ester production raw materials but also produced (meth) acrylic acid esters is awaited. ing.
JP 2000-355570 A JP 2003-292472 A

  The present invention has been made in view of the above prior art, and efficiently (meth) acrylic while preventing polymerization of the (meth) acrylic acid ester produced as well as the raw material for producing (meth) acrylic acid ester. It is an object to provide a method capable of producing an acid ester.

  The present invention relates to a method for producing a (meth) acrylic acid ester in a reaction vessel, wherein a raw material compound for producing (meth) acrylic acid ester and a production raw material containing a polymerization inhibitor are used in the reaction vessel. The present invention relates to a method for producing a (meth) acrylic acid ester, wherein the contents in the reaction vessel are sprayed into the internal space of the reaction vessel using an oxygen-containing gas after being supplied.

  In the present specification, “(meth) acryl” means both “acryl” and / or “methacryl”. Further, the content in the reaction vessel is a production raw material containing a raw material compound and a polymerization inhibitor in the initial stage of the reaction, and becomes a mixture of the production raw material and the produced (meth) acrylic ester as the reaction proceeds, After completion of the reaction, the reaction mixture is mainly composed of the produced (meth) acrylic acid ester.

  According to the production method of the present invention, it is possible to efficiently produce a (meth) acrylic acid ester while preventing polymerization of the produced (meth) acrylic acid ester as well as a raw material for producing the (meth) acrylic acid ester. The effect that it can be produced.

  The raw material for producing (meth) acrylic acid ester contains a raw material compound for producing (meth) acrylic acid ester as a target compound and a polymerization inhibitor.

  For example, when the target (meth) acrylic acid ester is produced by a dehydration condensation reaction between (meth) acrylic acid and alcohol, the raw material compound corresponds to (meth) acrylic acid and its ester moiety. When the target (meth) acrylic acid ester is produced from another (meth) acrylic acid lower alkyl ester by transesterification, the other (meth) acrylic acid lower alkyl ester and its ( Examples thereof include alcohols corresponding to the ester portion of the (meth) acrylic acid ester. As a typical example of the raw material compound, the number of carbon atoms of the ester moiety such as (meth) acrylic acid, (meth) acrylic acid lower alkyl ester such as methyl (meth) acrylate and ethyl (meth) acrylate is 1 to 4 carbon atoms. A certain (meth) acrylic-acid lower alkyl ester etc. are mentioned.

  Any polymerization inhibitor may be used as long as it is generally used in the production of (meth) acrylic acid esters, and the present invention is not limited by the type of the polymerization inhibitor.

  Representative examples of polymerization inhibitors include phenolic compounds such as p-benzoquinone, methoxyhydroquinone, hydroquinone, pt-butylcatechol, 2,6-di-t-butylphenol; 4-hydroxy-2,2,6,6- N-oxyl compounds such as tetramethylpiperidine-N-oxyl, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl; copper chloride, copper sulfate, copper acetate, manganese acetate, iron chloride, Metal salts such as iron acetate, nickel chloride, nickel acetate, zinc chloride, zinc acetate, manganese chloride, manganese acetate, cobalt chloride, cobalt acetate; alkylated diphenylamine, phenothiazine, N, N'-diphenyl-p-phenylenediamine, N , N'-di-2-naphthyl-p-phenylenediamine, N-phenyl-1,3-dimethylbutyl-p-phenylenediamine and other amino compounds; 4-hydroxy-2,2,6,6-tetramethylpi Peridine-N-oxyl, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 1-hydroxy-4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N- Oxyl, 1,4-dihydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-acetylamino-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-benzoylamino- And piperidine compounds such as 2,2,6,6-tetramethylpiperidine-N-oxyl and 4-propionylamino-2,2,6,6-tetramethylpiperidine-N-oxyl.

  The polymerization inhibitor can be used by dissolving it in a solvent such as hexane if necessary. However, since its solubility is low, it is used by mixing with raw material (meth) acrylic acid, (meth) acrylic acid lower alkyl ester, etc. It is preferable. Moreover, in this invention, the reaction mixture after completion | finish of reaction can be filtered, and the obtained filtrate can also be utilized as a solution of a polymerization inhibitor.

  The amount of the polymerization inhibitor may be an amount generally employed when producing a (meth) acrylic acid ester, and the present invention is not limited by such an amount. Usually, the amount of the polymerization inhibitor is preferably adjusted so that the content in the production raw material is 0.01 to 1.5% by weight.

  In the present invention, first, by using a raw material for producing a (meth) acrylic acid ester and a production raw material containing a polymerization inhibitor, polymerization in the raw material stage can be prevented. Thus, by blending the polymerization inhibitor with the production raw material, it is natural that polymerization of the production raw material itself can be prevented.

  The present invention has one feature in that the contents in the reaction vessel are sprayed into the internal space of the reaction vessel using an oxygen-containing gas.

  Thus, when the content in the reaction vessel is sprayed on the internal space of the reaction vessel using the oxygen-containing gas, the production raw material contained in the content and the produced (meth) acrylate ester are As it becomes a fine mist inside and dries quickly, it becomes a liquid when adhering to the upper inner wall of the reaction vessel, near the internal inspection window, near the raw material inlet, the inner wall of the reaction vessel, etc. Since it does not stay, the polymerization can be effectively suppressed.

  Furthermore, since the oxygen-containing gas quickly removes the heat of vaporization from the production raw materials contained in the sprayed contents and the generated (meth) acrylic acid ester, the (meth) acrylic acid ester is promptly absorbed in the gas phase. Since it dries, polymerization of the produced (meth) acrylic acid ester can be effectively suppressed. Further, in the present invention, by spraying the contents, the produced (meth) acrylic acid ester can be diffused over a wide range, so that drying of the produced (meth) acrylic acid ester can be promoted, and consequently Polymerization of (meth) acrylic acid ester can be effectively suppressed.

  Therefore, according to the present invention, not only the raw material compound but also the produced (meth) acrylic acid ester can be efficiently dried in the gas phase while promoting the reaction of the unreacted raw material compound. Therefore, (meth) acrylic acid ester can be produced efficiently.

  Examples of the oxygen-containing gas include oxygen gas, air, and a mixed gas of oxygen and an inert gas such as nitrogen gas and argon gas. However, the present invention is not limited to such examples. The oxygen-containing gas is preferably dried so as not to adversely affect the catalyst in the reaction system. Among the oxygen-containing gases, air and oxygen gas, more preferably air, are preferable from the viewpoint of cost, and dry air is more preferable from the viewpoint of not reducing the catalytic activity.

  When the amount of the oxygen-containing gas is small, the polymerization prevention effect tends to decrease. When the amount of the oxygen-containing gas is large, the polymerization inhibitor and the raw material alcohol are oxidized, resulting in the loss of the polymerization inhibitor or alcohol. There is a tendency that the generated (meth) acrylic acid ester is denatured by the oxide of the raw material compound or by the oxidizing action of the oxygen-containing gas. Accordingly, the amount of the oxygen-containing gas varies depending on the production conditions of the (meth) acrylic acid ester and cannot be determined unconditionally, but is usually 1 to 100% by volume, preferably 2 to 50% by volume of the evaporated vapor. It is desirable to adjust to be%.

  The evaporated vapor is a solvent vapor for efficiently removing water generated by the reaction or alcohol generated from the lower alkyl ester of (meth) acrylic acid.

  As a method for supplying the contents in the reaction container to the internal space of the reaction container, for example, the contents inside the reaction container are taken out from the lower part of the reaction container, and the contents are sprayed in the internal space of the reaction container. The method of spraying from a nozzle is mentioned. The contents taken out from the lower part of the reaction vessel can be conveyed to the spray nozzle, for example, via a pipe arranged outside or inside the reaction vessel.

  As the spray nozzle, a two-fluid nozzle can be suitably used. When this two-fluid nozzle is used, a mist of fine contents can be formed without applying high pressure to the contents, and the mixing ratio of the contents and the oxygen-containing gas can be easily adjusted. There is an advantage that you can.

  The two-fluid nozzle has a liquid inlet and a gas inlet, and has an opening of a spray nozzle for mixing the liquid and gas flowing into the inside and spraying the gas-liquid mixture. . A typical example of a two-fluid nozzle is an internal air type two-fluid nozzle in which a gas passes through the central part inside the nozzle and a liquid flows outside thereof, and an outside air through which a liquid passes through the central part inside the nozzle and gas flows outside. Externally mixed two-fluid nozzles such as type two-fluid nozzles, and internal mixed two-fluid nozzles that spray liquid from spray nozzles by blowing pressured gas into the liquid flowing into the nozzle. Can be mentioned.

  The spray form (spray cross-sectional shape) of the contents sprayed from the spray nozzle is not particularly limited, and examples thereof include a conical shape such as a full cone and an empty cone, and a fan shape. In addition, the mist sprayed from the spray nozzle has a small particle size so that the mist is spread throughout the reaction vessel, and the mist is placed on the vaporized vapor and sent to the bottom of the vapor pipe 12 connected to the reaction vessel. However, if it is too small, the amount of the content to be sprayed is reduced, the amount of oxygen-containing gas used is relatively increased, and the production efficiency is increased. Tends to decrease. Therefore, it is desirable that the average particle diameter of the mist is 0.1 to 1000 μm, preferably 1 to 200 μm.

  In addition, when spraying the contents in the reaction vessel, from the viewpoint of avoiding polymerization of the (meth) acrylic acid ester produced, the reaction vessel is not attached as much as possible to the inner wall surface of the reaction vessel. It is preferable to spray only in the interior space.

  Thus, the raw material for the production of (meth) acrylic acid ester can be reacted by spraying the contents into the internal space of the reaction vessel using the oxygen-containing gas. In addition, since reaction temperature changes with kinds etc. of the manufacturing raw material of (meth) acrylic acid ester, it cannot be determined unconditionally, However, Usually, it can select from the temperature range of 20-140 degreeC. Moreover, it is preferable that the pressure in reaction container is 1-200 kPa normally.

  The time required for the reaction varies depending on the type of raw material compound, reaction conditions, and the like, and therefore cannot be determined generally, but is usually about 2 to 48 hours.

  Below, the manufacturing method of this invention is demonstrated based on drawing. FIG. 1 is one embodiment of the reaction apparatus used in the present invention, and is a schematic explanatory view in the vicinity of the upper part thereof.

  In FIG. 1, a stirrer 2 is disposed at the center of the reaction vessel 1, and a seal portion 3 is provided between the reaction vessel 1 and the stirrer 2. In addition, a spray nozzle 5 is disposed on the upper portion of the reaction vessel 1 via a pipe 4 so as to communicate with the internal space of the reaction vessel 1, and a vapor pipe 12 for discharging steam is disposed. For example, the pipe 4 can be constituted by a double pipe, and the contents can be supplied to the inner pipe of the double pipe and the oxygen-containing gas can be supplied to the outer pipe. The other end of the pipe 4 is connected to a connection part 6 for supplying the contents and oxygen-containing gas into the pipe 4, and the contents for introducing the contents of the reaction vessel 1 into the connection part 6. An oxygen-containing gas introduction pipe 8 for introducing oxygen-containing gas into the introduction pipe 7 and the pipe 4 is connected.

  First, at the start of production of (meth) acrylic acid ester, for example, production raw material supplied from a storage tank (not shown) or the like can be supplied into the reaction vessel 1 from the raw material introduction pipe 11.

  Next, after supplying the production raw material into the reaction vessel 1, the content 9 in the reaction vessel 1 is supplied to the connection portion 6 through the content introduction pipe 7 connected to the bottom of the vessel 1. The contents 9 supplied to the connection unit 6 are sprayed from the spray nozzle 5 through the pipe 4. Thus, the content 9 can be circulated by spraying from the spray nozzle 5 from the reaction vessel 1 through the content introduction pipe 7, the connecting portion 6 and the pipe 4.

  When the contents 9 are sprayed from the spray nozzle 5, the oxygen-containing gas is supplied from the oxygen-containing gas introduction pipe 8 to the spray nozzle 5 through the connection portion 6 and the pipe 4, and the supplied oxygen-containing gas is The content 9 is mixed with the content 9 in the spray nozzle 5, and the content 9 is sprayed from the spray nozzle 5 into the internal space of the reaction vessel 1 as a gas-liquid mixture with the oxygen-containing gas. The other end of the oxygen-containing gas introduction pipe 8 can be connected to, for example, an air cylinder, an oxygen cylinder, an air compressor, or the like.

  By the way, in the conventional manufacturing method, the method of making the reaction mixture produced | generated in reaction container contact the member which exists in the gaseous-phase part of reaction container is taken. However, in this method, for example, using the reaction vessel 1 shown in FIG. 1, (meth) acrylic acid or (( The (meth) acrylic acid ester evaporates, and the vapor passes through the inner wall surface at the top of the reaction vessel 1, the seal portion 3 provided between the reaction vessel 1 and the stirrer 2, and the internal inspection provided on the upper surface of the reaction vessel 1. Because it is cooled and condensed near the eye glass of the window 10 and near the flange 11a of the raw material introduction tube 11, the resulting condensate contains almost no polymerization inhibitor, so (meth) acrylic acid or (meth) There is a drawback that acrylic esters are polymerized.

  On the other hand, in the production method of the present invention, the content 9 is sprayed from the spray nozzle 5 together with the oxygen-containing gas, and the formed mist is quickly dried in the internal space of the reaction vessel 1 to condense the reaction mixture. Since it does not occur, polymerization of the raw material compound and the produced (meth) acrylic acid ester can be effectively prevented, and as a result, the intended (meth) acrylic acid ester can be produced efficiently.

  In addition, after completion | finish of reaction, the obtained reaction mixture can be taken out from the reaction container 1, and can be used by refine | purifying as needed.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to such examples.

Example 1
The reaction vessel 1 shown in FIG. 1 (made of stainless steel, capacity: 20 kL, provided with six external mixing type two-fluid nozzles) was used. In this reaction vessel 1, a raw material introducing tube 11 is used to produce 9300 kg of methyl acrylate and 4400 kg of tetrahydrofurfuryl alcohol, and 4-acetylamino-2,2,6,6-tetramethylpiperidine- is used as a polymerization inhibitor. 6 kg of N-oxyl and 3 kg of methoxyhydroquinone were added, and 200 kg of n-hexane was also added to extract methanol.

  Next, the contents of the reaction vessel 1 are sequentially introduced into the connection portion 6 and the pipe 4 through the content introduction pipe 7 connected to the lower part of the reaction vessel 1 so as to communicate with the inside thereof (volume). The flow rate is 30 L / min), dry air (volume flow rate 10 L / min) is introduced from the oxygen gas introduction pipe 8, and the mist composed of the gas-liquid mixture of the contents and the dry air is sprayed from the spray nozzle 5 to the inner wall surface of the reaction vessel 1. Further, spraying was performed until the residual amount of alcohol was 0.5% or less while adjusting the internal temperature to 110 ° C. so as not to adhere to the stirrer 2.

  After completion of the reaction, the obtained reaction mixture was taken out from the lower part of the reaction vessel 1 to obtain a reaction mixture containing 6700 kg of the produced tetrahydrofurfuryl acrylate (yield 99.5%).

  After 5 cycles of the above operation as one cycle, the vicinity of the eyeglass of the internal inspection window 10 of the reaction vessel 1 and the vicinity of the flange 11a of the raw material introducing tube 11 were observed, but adhesion of a polymer was not recognized.

  From the above results, it can be seen that according to Example 1, tetrahydrofurfuryl acrylate can be efficiently produced without generating a polymer.

  In each Example and each Comparative Example, the residual amount of raw material alcohol and the yield of (meth) acrylic acid ester were determined by gas chromatography (GC) analyzer [manufactured by Shimadzu Corporation] after distillation and separation. , GC-14B gas chromatograph, detector FID, column capillary DB-1701: 25 m], and was analyzed by the following conditions.

  The remaining amount is a value obtained from the ratio of the raw alcohol to the (meth) acrylic acid ester produced using the GC area percentage obtained by the above method. The yield is a value obtained from the ratio of the actual production amount to the theoretical production amount of the target product based on the raw material alcohol used in the reaction.

(Gas chromatography analysis conditions)
Injection temperature: 280 ° C., detection temperature: 280 ° C., initial temperature: 100 ° C., initial temperature holding time: 3 minutes, temperature rising rate: 10 ° C./min, temperature rising final temperature: 250 ° C., temperature rising final temperature holding time: 20 minutes

Comparative Example 1
In Example 1, the reaction was performed in the same manner as in Example 1 except that the two-fluid nozzle was removed from the reaction vessel 1 and the reaction was carried out while the contents in the reaction vessel 1 were in liquid contact with the upper inner wall of the reaction vessel 1. Went. The obtained reaction mixture was taken out from the lower part of the reaction vessel 1 to obtain a reaction mixture containing 6700 kg of the produced tetrahydrofurfuryl acrylate acrylate (yield 99.5%).

  The above operation was taken as one cycle, and five cycles of operation were performed. Observation of the vicinity of the eye glass of the internal inspection window 10 of the reaction vessel 1 and the vicinity of the flange 11a of the raw material introduction pipe 11 for each cycle showed adhesion of a polymer. Furthermore, only air was blown onto the wall surface, but polymer adhesion was observed on the body part of the liquid interface, near the eye glass of the internal inspection window 10 and near the flange 11a of the raw material introduction pipe 11, and cleaning operation was performed for each cycle. Needed.

Example 2
Instead of the production raw material and polymerization inhibitor used in Example 1, a production raw material consisting of 8000 kg of methyl acrylate and 5000 kg of ethoxyethanol, and 4-acetylamino-2,2,6,6-tetramethylpiperidine- as a polymerization inhibitor 6 kg of N-oxyl and 3 kg of methoxyhydroquinone were added, and 2000 kg of n-hexane was added to extract methanol.

  Next, the contents of the reaction vessel 1 are introduced from the content introduction pipe 7 into the pipe 4 through the connection portion 6 via a pipe (not shown) arranged at the lower part of the reaction vessel 1 (volume). In order to prevent the contents from adhering to the inner wall surface of the reaction vessel 1 and the stirrer 2 from the spray nozzle 5 by introducing dry air (volume flow rate 10 L / min) from the oxygen gas introduction pipe 8 at a flow rate of 30 L / min). While adjusting the internal temperature to 110 ° C., spraying was performed while heating until the residual amount of alcohol was 0.5% or less.

  The obtained reaction mixture was taken out from the lower part of the reaction vessel 1 to obtain a reaction mixture containing 6420 kg of produced ethoxyethoxyethyl acrylate (yield 99.5%).

  After 5 cycles of the above operation as one cycle, the vicinity of the eyeglass of the internal inspection window 10 of the reaction vessel 1 and the vicinity of the flange 11a of the raw material introducing tube 11 were observed, but adhesion of a polymer was not recognized.

Comparative Example 2
In Example 2, the two-fluid nozzle was removed from the reaction vessel 1, and spraying was carried out in the same manner as in Example 1 except that the reaction was conducted while the contents in the reaction vessel 1 were in liquid contact with the upper inner wall of the reaction vessel 1. Went. The obtained reaction mixture was taken out from the lower part of the reaction vessel 1 to obtain a reaction mixture containing 6420 kg of the produced ethoxyethyl acrylate (yield 99.5%).

  The above operation is defined as 1 cycle, and the operation is performed for 5 cycles. When each cycle is observed in the vicinity of the eye glass of the internal inspection window 10 and in the vicinity of the flange 11a of the raw material introduction pipe 11, adhesion of the polymer is observed. Recognized and required a wash operation for each cycle.

  From the above results, it can be seen that according to the method of each example, the formation of a polymer is not recognized as in each comparative example, and (meth) acrylic acid ester can be produced efficiently.

  The (meth) acrylic acid ester obtained by the production method of the present invention is a useful compound for various resins, paints, adhesives and the like.

It is one embodiment of the reaction apparatus used for this invention, and is a schematic explanatory drawing in the upper part vicinity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction container 2 Stirrer 3 Sealing part 4 Piping 5 Spray nozzle 6 Connection part 7 Content introduction pipe 8 Oxygen-containing gas introduction pipe 9 Contents
10 Internal inspection window
11 Raw material introduction pipe
11a Flange
12 Vapor tube

Claims (3)

  A method for producing a (meth) acrylic acid ester in a reaction vessel, wherein a raw material compound for producing a (meth) acrylic acid ester and a production raw material containing a polymerization inhibitor are supplied to the reaction vessel, A method for producing a (meth) acrylic acid ester, wherein the contents in the reaction vessel are sprayed into the internal space of the reaction vessel using an oxygen-containing gas.   The process according to claim 1, wherein the oxygen-containing gas is air or oxygen gas.   The production method according to claim 1 or 2, wherein the contents are sprayed into the internal space of the reaction vessel using a two-fluid nozzle as a spray nozzle.

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