JP5089964B2 - Method and system for producing hydroxyalkyl (meth) acrylate - Google Patents

Description

  The present invention relates to a production method and production system of hydroxyalkyl (meth) acrylate.

  Conventionally, in the reaction of alkylene oxide and (meth) acrylic acid in the presence of a catalyst, alkylene glycol di (meth) acrylate which is a diester as an impurity or dialkylene glycol mono (meth) acrylate which is a diadduct as an impurity. There was a problem that it was easy to by-produce. These by-products are known to increase rapidly when the raw material (meth) acrylic acid disappears after the end of the reaction. Therefore, in order to suppress the production of by-products, it is necessary to stop the reaction accurately at the end point of the reaction.

  On the other hand, as a means for suppressing the by-product of the diester or the diadduct, it is conceivable to stop the reaction at an early stage when there is a large amount of unreacted (meth) acrylic acid remaining. However, it is difficult to remove the remaining acid component by distillation or the like, and even if by-product formation of the diester or the diadduct can be suppressed, the product quality is deteriorated as a result.

Conventionally, determination of when to stop the reaction is performed by determining the amount of unreacted (meth) acrylic acid by, for example, the absorbance of the reaction solution during the reaction or after a certain period of time predicted empirically. (For example, refer to Patent Document 1).
JP 2004-182634 A (published July 2, 2004)

  However, in the above conventional configuration, since the reaction stop time is determined by measuring the amount of unreacted (meth) acrylic acid during the reaction or after a lapse of time that is empirically predicted, the reaction stop time is determined. This causes a problem that the error of the error increases. Specifically, since the reaction is stopped after measuring the amount of unreacted (meth) acrylic acid, it is necessarily between the time of measuring the amount of (meth) acrylic acid and the time of stopping the reaction. A time difference occurs, and when the reaction is stopped, the reaction end point may have already passed. For this reason, it was difficult to stably produce a hydroxyalkyl (meth) acrylate with a small amount of by-products of the diester or diadduct.

  Furthermore, when recycling the catalyst to reduce the amount of catalyst used, if the amount of the acid component at the end of the reaction is too low, the catalyst is deactivated and cannot be used for the next reaction. Arise.

  The present invention has been made in view of the above-mentioned problems, and it is possible to stably produce a hydroxyalkyl (meth) acrylate with few by-products, and to suppress the deactivation of a catalyst. The object is to realize a method and a system for producing a (meth) acrylate.

  This inventor examined in order to manufacture stably the hydroxyalkyl (meth) acrylate with few by-products, and to manufacture the hydroxyalkyl (meth) acrylate in which the deactivation of the catalyst was suppressed. As a result, it was found that the reaction was accurately stopped at the end point of the reaction by predicting the reaction stop time from the transition of the amount of the acid component in the reaction solution, and the present invention was completed.

  Furthermore, this inventor examined in order to suppress the measurement error at the time of automating the measurement of the amount of unreacted (meth) acrylic acid. As a result, since the reaction liquid contains gaseous unreacted alkylene oxide, bubbles are likely to be generated in the sampling liquid at the time of sampling. Discovered that it will grow. Specifically, when the amount of unreacted (meth) acrylic acid is measured due to the generation of bubbles in the sampling solution, an error is likely to occur in the volume of the sampling solution. Since the light is scattered due to the above, the obtained measurement value has a large error.

  And this inventor discovered the sampling method which suppressed generation | occurrence | production of the bubble of the alkylene oxide containing reaction liquid at the time of sampling. In addition, by using the sampling method, a production method capable of stably producing hydroxyalkyl (meth) acrylate even when the measurement of the amount of unreacted (meth) acrylic acid is automated. Established.

  That is, in order to solve the above problems, the method for producing a hydroxyalkyl (meth) acrylate according to the present invention produces a hydroxyalkyl (meth) acrylate in which an alkylene oxide and (meth) acrylic acid are reacted in the presence of a catalyst. By sampling a reaction solution in a state where the sampling line is pressurized by a manufacturing system including a reaction vessel equipped with a sampling line, and measuring the amount of acid components in the sampled reaction solution, It is characterized by predicting the reaction stop time from the transition of the amount of acid component in the reaction solution and stopping the reaction.

  According to the above method, the sampling of the reaction liquid is performed with the sampling line pressurized, and the transition of the amount of the acid component in the reaction liquid is measured. It's hard to make it. For this reason, generation | occurrence | production of the bubble of the alkylene oxide containing reaction liquid at the time of sampling is suppressed. Thereby, the measurement error of analysis caused by the generation of bubbles can be suppressed.

  Therefore, according to the above method, since the reaction can be stopped accurately at the end point of the reaction, hydroxyalkyl (meth) acrylate with less by-products can be stably produced, and the deactivation of the catalyst is suppressed. There is an effect that can be.

  In the method for producing hydroxyalkyl (meth) acrylate according to the present invention, the production system further includes an automatic analyzer and an automatic reaction stop device, and performs sampling of the reaction liquid in a state where the sampling line is pressurized, It is preferable to automatically measure the amount of the acid component in the sampled reaction solution, thereby predicting the reaction stop timing from the change in the amount of the acid component in the reaction solution and automatically stopping the reaction.

  According to the above method, the reaction stop time is predicted from the transition of the amount of the acid component in the reaction solution, and the reaction is automatically stopped. Therefore, compared with the case where the end point of the reaction is judged after the analysis is performed. It is possible to shorten the period from when the end point reaches to the end of the reaction. Therefore, according to the above method, it is not necessary to calculate the end point of the reaction by performing sampling and analysis by human power (manual operation) as in the prior art. Therefore, the further effect that a hydroxyalkyl (meth) acrylate can be manufactured at lower cost is produced.

  Moreover, in the manufacturing method of the hydroxyalkyl (meth) acrylate which concerns on this invention, it is preferable to maintain the state from which the amount of acid components with respect to the catalyst amount in a reaction liquid will be 0.01 or more by calculation.

  According to the said method, since the deactivation of a catalyst can be suppressed more, there exists the further effect that a hydroxyalkyl (meth) acrylate can be manufactured at lower cost.

  Moreover, in the manufacturing method of the hydroxyalkyl (meth) acrylate which concerns on this invention, the process of distilling the reaction liquid of alkylene oxide and (meth) acrylic acid, and the process of using the distillation residue of the said reaction liquid for the following reaction. It is preferable to include.

  According to the said method, since the process of using the distillation residue of a reaction liquid for the next reaction is included, the quantity of the catalyst used by the next reaction can be reduced. Therefore, the further effect that a hydroxyalkyl (meth) acrylate can be manufactured at lower cost is produced.

  In the method for producing hydroxyalkyl (meth) acrylate according to the present invention, the automatic analyzer is preferably a potentiometric automatic titrator.

  According to the above method, since the analysis time is short and it is not difficult to use in a plant or the like like a spectrophotometer, it is possible to more stably produce a hydroxyalkyl (meth) acrylate with fewer by-products. There is a further effect.

  In the method for producing a hydroxyalkyl (meth) acrylate according to the present invention, the reaction is performed in a reaction vessel equipped with a sampling line, and the automatic analyzer comprises an alkylene oxide-containing reaction solution in the reaction vessel. Automatic sampling means that automatically samples and analyzes the sampled alkylene oxide-containing reaction solution, inert gas introduction means that introduces an inert gas into the sampling line, and sampling by the inert gas introduction means It is preferable that the automatic analysis means includes a sampling control means for controlling so that the alkylene oxide-containing reaction liquid is sampled while the inside of the service line is pressurized.

  According to the above method, in the automatic analyzer, the sampling control means controls the automatic analysis means so that the alkylene oxide-containing reaction liquid is sampled in a state where the inside of the sampling line is pressurized. Alkylene oxide hardly vaporizes during liquid sampling. For this reason, generation | occurrence | production of the bubble of the alkylene oxide containing reaction liquid at the time of sampling is suppressed. Thereby, the measurement error of analysis caused by the generation of bubbles can be suppressed. Therefore, the further effect that the hydroxyalkyl (meth) acrylate with fewer by-products can be manufactured stably is produced.

  In order to solve the above problems, the production system for hydroxyalkyl (meth) acrylate according to the present invention is used for production of hydroxyalkyl (meth) acrylate in which alkylene oxide and (meth) acrylic acid are reacted in the presence of a catalyst. A hydroxyalkyl (meth) acrylate production system comprising a reaction vessel equipped with a sampling line, an automatic analyzer, and an automatic reaction stop device. The automatic reaction stop device was analyzed by the automatic analyzer. It is characterized by predicting the reaction stop time from the transition of the amount of acid component and automatically stopping the reaction.

  According to the above configuration, since the reaction stop time can be predicted from the transition of the acid component amount analyzed by the automatic analyzer and the reaction can be automatically stopped, sampling and analysis by human power (manual operation) as in the past. It is not necessary to calculate the end point of the reaction. Therefore, it is possible to stably produce a hydroxyalkyl (meth) acrylate with less by-products at a lower cost, and the deactivation of the catalyst can be suppressed.

  In the hydroxyalkyl (meth) acrylate production system according to the present invention, the automatic analyzer automatically samples the alkylene oxide-containing reaction solution in the reaction vessel, and automatically analyzes the sampled alkylene oxide-containing reaction solution. Automatic analysis means for automatic analysis sent to the apparatus, inert gas introduction means for introducing an inert gas into the sampling line, and automatically in a state where the sampling line is pressurized by the inert gas introduction means It is preferable that the analysis means includes a sampling control means for controlling the sampling of the alkylene oxide-containing reaction solution.

  According to the above configuration, the reaction solution is sampled in a state where the sampling line is pressurized, and the transition of the amount of the acid component in the reaction solution is automatically measured. Oxide hardly vaporizes. For this reason, generation | occurrence | production of the bubble of the alkylene oxide containing reaction liquid at the time of sampling is suppressed. Thereby, the measurement error of analysis caused by the generation of bubbles can be suppressed. Therefore, the hydroxyalkyl (meth) acrylate with few by-products can be produced more stably, and the further effect that the deactivation of a catalyst can be suppressed more is produced.

  As described above, the method for producing a hydroxyalkyl (meth) acrylate according to the present invention is a method for producing a hydroxyalkyl (meth) acrylate in which an alkylene oxide and (meth) acrylic acid are reacted in the presence of a catalyst. By sampling the reaction solution with the sampling line pressurized with a production system including a reaction vessel equipped with a reaction line, and measuring the amount of acid component in the sampled reaction solution, the acid in the reaction solution is measured. It is characterized by predicting the reaction stop time from the transition of the component amount and stopping the reaction.

  For this reason, the hydroxyalkyl (meth) acrylate with few by-products can be manufactured stably, and there exists an effect that the deactivation of a catalyst can be suppressed.

  As described above, the production system for hydroxyalkyl (meth) acrylate according to the present invention is used for production of hydroxyalkyl (meth) acrylate in which alkylene oxide and (meth) acrylic acid are reacted in the presence of a catalyst. A hydroxyalkyl (meth) acrylate production system comprising a reaction vessel equipped with a working line, an automatic analyzer, and an automatic reaction stop device, wherein the automatic reaction stop device is an acid component amount analyzed by the automatic analyzer It is characterized by predicting the reaction stop time from the transition of the system and automatically stopping the reaction.

  For this reason, it is possible to stably produce a hydroxyalkyl (meth) acrylate with less by-products at a lower cost, and the deactivation of the catalyst can be suppressed.

  Hereinafter, the present invention will be described in detail. However, the scope of the present invention is not limited to these descriptions, and modifications other than the following examples can be made as appropriate without departing from the spirit of the present invention. In the present specification, “(meth) acrylic acid” means acrylic acid or methacrylic acid, “hydroxyalkyl (meth) acrylate” means hydroxyalkyl acrylate or hydroxyalkyl methacrylate, and “alkylene glycol di ( “Meth) acrylate” means alkylene glycol diacrylate or alkylene glycol dimethacrylate.

  Further, “weight” is treated as a synonym for “mass”, and “weight%” is treated as a synonym for “mass%”. In addition, “A to B” indicating a range indicates that the range is A or more and B or less.

  The method for producing a hydroxyalkyl (meth) acrylate according to the present invention is a method for producing a hydroxyalkyl (meth) acrylate in which an alkylene oxide and (meth) acrylic acid are reacted in the presence of a catalyst, and the acid component in the reaction solution Predict when the reaction will stop based on the change in quantity, and stop the reaction.

  The method for predicting the reaction stop timing is not particularly limited. For example, the acid component amount in the reaction solution is measured at 3 or more points, and the reaction end point is determined from the acid component amount by the least square method or exponential approximation curve. A method of obtaining by extrapolation can be used.

  The value of the amount of acid component used as the end point (when the reaction is stopped) can be appropriately set according to various conditions of the reaction, cooling efficiency, and the like. The target final acid component amount is appropriately set according to the use of the hydroxyalkyl (meth) acrylate, and is usually preferably 1% by weight or less in the reaction solution, preferably 0.1% by weight. More preferably, it is as follows.

  The reaction can be stopped by various means such as cooling of the reaction solution or the reaction vessel (reactor) or removing the raw material from the reaction system.

  Hereinafter, measurement of the acid component amount in the reaction solution and the like will be described in more detail.

(I) Hydroxyalkyl (meth) acrylate production system The hydroxyalkyl (meth) acrylate production system according to the present invention is based on an automatic analyzer described later and the transition of the amount of acid components analyzed by the automatic analyzer. An automatic reaction stop device that predicts the timing and automatically stops the reaction.

  The automatic reaction stop device is configured to automatically stop the reaction by determining a reaction stop time based on a change in the amount of acid components analyzed by the automatic analyzer using, for example, a computer.

  Specifically, the reaction stop timing is determined, for example, by automatically obtaining the reaction end point by the least square method, exponential approximation curve, or the like from the acid component amount analyzed by the automatic analyzer using a computer or the like. be able to.

  The value of the amount of acid component used as the timing for stopping the reaction can be appropriately set according to various conditions of the reaction, cooling efficiency, etc., as in the production method of hydroxyalkyl (meth) acrylate described later, and the final target The value of the acid component amount is appropriately set according to the use of the hydroxyalkyl (meth) acrylate, and is usually preferably 1% by weight or less, more preferably 0.1% by weight or less in the reaction solution. preferable.

  The method for automatically stopping the reaction is not particularly limited as long as the reaction can be performed by various means such as cooling of the reaction liquid or the reaction vessel or removal of the raw material from the reaction system by the automatic reaction stopping device. For example, the method of extracting all or part of the reaction solution from the reactor, cooling it by passing the reaction solution through an automatic reaction stop device composed of an external heat exchanger, and circulating it again to the reactor is a reaction. The cooling efficiency of the liquid is increased, which is preferable in that the reaction liquid can be cooled to a predetermined temperature in a short time. The cooling temperature for stopping the reaction is preferably 50 ° C. or lower, more preferably 45 ° C. or lower, and further preferably 40 ° C. or lower.

  The production system according to the present invention can also be applied to the production of (meth) acrylic acid esters by reaction of aliphatic alcohols, aromatic alcohols or polyhydric alcohols with (meth) acrylic acid in the presence of a catalyst. it can.

(II) Automatic Analyzer FIG. 1 is a schematic diagram showing a schematic configuration of an automatic analyzer according to the present embodiment. FIG. 2 is a schematic diagram showing a schematic configuration of an automatic analyzer according to another embodiment of the present invention.

  The automatic analyzer according to the present embodiment is an automatic analyzer used in the production of hydroxyalkyl (meth) acrylate in which an alkylene oxide and (meth) acrylic acid are reacted in the presence of a catalyst, and is shown in FIG. As described above, the automatic analysis means for automatically sampling the alkylene oxide-containing reaction liquid (hereinafter sometimes simply referred to as “reaction liquid”) 9 in the reaction vessel 1 and automatically analyzing the sampled reaction liquid 9. 2, the inert gas introduction means 3 for introducing an inert gas into the circulation line (sampling line) 10, and the automatic analysis means 2 in a state where the inside of the circulation line 10 is pressurized by the inert gas introduction means 3. And sampling control means (not shown) for controlling the reaction solution 9 to be sampled. In other words, the automatic analyzer according to the present embodiment is an apparatus that automatically performs a method of sampling an alkylene oxide-containing reaction liquid described later and automatically performs analysis.

  The above-mentioned “production of hydroxyalkyl (meth) acrylate” means production by the production method described in “(IV) Production method of hydroxyalkyl (meth) acrylate” described later.

  In the present embodiment, the reaction vessel 1 is provided with a circulation line 10 for taking out a part of the reaction solution 9 from the reaction vessel 1 and returning the reaction solution 9 back to the reaction vessel 1. Is connected to the circulation line 10. Further, a first valve 4 and a second valve 5 for adjusting the flow rate of the reaction solution 9 are provided on the upstream side and the downstream side of the connection position with the automatic analysis means 2 in the circulation line 10, respectively. Furthermore, on the upstream side of the reaction vessel 1 in the circulation line 10, a pump 6 for allowing the reaction liquid 9 to flow into the circulation line 10 and a strainer 7 for preventing foreign matter from entering the automatic analysis means 2. And. In other words, the pump 6, the strainer 7, the first valve 4, the automatic analysis means 2, the inert gas introduction means 3, and the second valve 5 are connected to the circulation line 10 in this order from the upstream side to the downstream side. Yes.

  The automatic analysis means 2 is not particularly limited as long as the reaction solution 9 can be automatically sampled and the sampled reaction solution 9 can be automatically analyzed. For example, a gas chromatograph analyzer, a potentiometric automatic titrator, a spectrophotometer, a moisture meter, a pH meter and the like are configured to automatically sample and analyze. A gas chromatograph analyzer has a long analysis time, and a spectrophotometer is difficult to use in a plant or the like because the cell intensity is low. Therefore, an automatic potentiometric titrator is more preferable. In addition, the physical properties measured by the potentiometric automatic titrator are not particularly limited, and examples thereof include an acid component amount, an alkali component amount, and a hydroxyl value. Among these, it is more preferable that the automatic analysis means is a means for measuring the acid component amount by a potentiometric automatic titrator.

  The inert gas introduction means 3 is not particularly limited as long as the inert gas can be introduced into the circulation line (sampling line) 10, and any configuration may be used. In the present embodiment, the inert gas introduction means 3 uses a gas tank filled with an inert gas. The inert gas introduction means 3 is provided between the first valve 4 and the second valve 5 and can pressurize the circulation line 10 by adjusting the flow rate of the inert gas by the valve 3a. It has become.

  Examples of the inert gas used in the inert gas introduction means 3 are the same as those exemplified in “(III) Sampling method of alkylene oxide-containing reaction liquid” described later.

  In the present embodiment, the sampling control means closes the first valve 4 and the second valve 5 and circulates between the first valve 4 and the second valve 5 by the inert gas introduction means 3. Control is performed so that the automatic analysis means 2 samples the reaction liquid 9 in a state where the inside of the line 10 is pressurized. As a result, bubbles are not easily generated in the sampled reaction solution 9, so that there is little error in the value measured by the automatic analysis means 2. Furthermore, most of the reaction can be automated by further providing a control means (automatic reaction stop device) for predicting the reaction stop time from the transition of the value measured by the automatic analysis means 2 and automatically stopping the reaction. Therefore, the manufacturing cost can be greatly reduced.

  The sampling control means is not particularly limited as long as the automatic analysis means 2 can be controlled to sample the reaction liquid 9 in a state where the inside of the circulation line (sampling line) 10 is pressurized. For example, A configuration in which each device or the like is automatically controlled by a computer or the like can be mentioned.

  In the above description, the case where the sampling line is the circulation line 10 has been described. However, the present invention is not limited to this. For example, as shown in FIG. 2, the automatic analyzer 2 may be directly connected to the reaction vessel 1. If the sampling line containing the sampled reaction liquid 9 can be pressurized, the same effect as in the present embodiment can be obtained.

  However, when the sampling line is the circulation line 10 as in this embodiment, a more uniform reaction solution can be sampled, so that the analysis can be performed more accurately, and the effect is particularly great.

  In the case of the above configuration shown in FIG. 2, after the reaction liquid 9 has flowed into the sampling line, the first valve 4 is closed, and the inside of the sampling line is pressurized by the inert gas introduction means 3. What is necessary is just to set so that the sampling control means may be controlled so that the automatic analysis means 2 samples the reaction solution 9.

(III) Sampling Method for Alkylene Oxide-Containing Reaction Liquid As a sampling method for the alkylene oxide-containing reaction liquid according to the present invention (hereinafter sometimes simply referred to as “reaction liquid”), an alkylene oxide and (meta ) Sampling method of reaction liquid containing alkylene oxide in production of hydroxyalkyl (meth) acrylate to react with acrylic acid, sampling reaction liquid containing alkylene oxide in sampling line under pressure with inert gas Preferred is the method.

  Thereby, since the alkylene oxide in a reaction liquid is hard to evaporate, it can suppress that a bubble generate | occur | produces in the sampled reaction liquid.

  In the sampling method of the alkylene oxide-containing reaction solution, the sampling line is a circulation line for taking out a part of the reaction solution from the reaction vessel and returning the reaction solution to the reaction vessel again. The sampling may be performed in a state where the inside of the sampling line is pressurized with an inert gas.

  Examples of the method for pressurizing the sampling line include a method in which a valve is provided in the sampling line, a region including a sampling point is sealed by operating the valve, and the region is pressurized by introducing an inert gas. .

  The pressure reached by the pressurization is not particularly limited as long as it is higher than the standard atmospheric pressure (1 atm), and may be appropriately set depending on the pressure resistance strength of the equipment. For example, the gauge pressure can be set within a range of 0.03 to 0.1 MPa.

  Although it does not specifically limit as said inert gas, Nitrogen, helium, argon etc. are mentioned.

  Although it does not specifically limit as alkylene oxide, For example, C2-C6 alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide, are mentioned.

  The above-mentioned “production of hydroxyalkyl (meth) acrylate” means production by the production method described in “(IV) Production method of hydroxyalkyl (meth) acrylate” described later.

(IV) Method for Producing Hydroxyalkyl (meth) acrylate The method for producing hydroxyalkyl (meth) acrylate according to the present invention (hereinafter sometimes simply referred to as “production method according to the present invention”) is used in the presence of a catalyst. , A method for producing a hydroxyalkyl (meth) acrylate in which an alkylene oxide and (meth) acrylic acid are reacted, and preferably includes a step of automatically stopping the reaction by the production system according to the present invention.

  Further, in the production method according to the present invention, when the distillation residue described later is reused in the next reaction, the amount of the acid component relative to the amount of the catalyst in the reaction solution is further calculated as a molar ratio of 0.01. It is preferable to maintain the above state.

  The method for producing hydroxyalkyl (meth) acrylate according to the present invention is not particularly limited except that the reaction stop timing is predicted from the transition of the acid component amount in the reaction solution described above, and the reaction is stopped. For example, it can carry out by the method similar to the conventionally well-known method described in the international publication 2006/013971 pamphlet and Unexamined-Japanese-Patent No. 2004-182634. This will be specifically described below.

  Examples of the alkylene oxide used in the production method according to the present invention include the same compounds as those exemplified in “(III) Sampling method of alkylene oxide-containing reaction solution”.

  In the production method according to the present invention, the relationship between the total supply amount of (meth) acrylic acid and the total supply amount of alkylene oxide is that 1.0 to 10 mol of alkylene oxide is present per 1 mol of (meth) acrylic acid. It is preferably within the range, more preferably within the range of 1.0 to 5.0 mol, even more preferably within the range of 1.0 to 3.0 mol, particularly preferably 1.0 to 2.0 mol. Within range. When the alkylene oxide is less than 1.0 mol with respect to 1 mol of (meth) acrylic acid, the reaction tends to be difficult to proceed. On the other hand, when the alkylene oxide exceeds 10 mol, the process of recovering the alkylene oxide, etc. Tends to be necessary and the manufacturing cost tends to increase.

  In the production method according to the present invention, with regard to the charging method (order) of the raw materials (meth) acrylic acid and alkylene oxide, usually, a part or all of (meth) acrylic acid is initially charged in a reaction vessel. A method of supplying alkylene oxide or alkylene oxide and the remainder of (meth) acrylic acid thereto is generally used, but is not limited thereto. For example, a part or all of the alkylene oxide may be initially charged.

  Further, the supply of the (meth) acrylic acid and the alkylene oxide may be either batch charging or sequential charging (continuous charging and / or intermittent charging), but preferably the initial charge is batch. It is more preferable that the portions to be charged and then supplied are sequentially charged. The continuous charging means a mode of continuously charging little by little, and the intermittent charging means a mode of charging in an arbitrary number of times in a pulsed manner or intermittently. When continuously charging, the charging speed may be constant until the end of charging, or the charging speed may be changed at least once in the middle, or the charging speed itself may be arbitrarily changed continuously. Also good.

  In addition, when (meth) acrylic acid and alkylene oxide are charged, they may be charged at room temperature or after preheating to a desired temperature so as not to change the temperature in the system at that time. You may throw it in.

  In addition, when both (meth) acrylic acid and alkylene oxide are charged at the same time, they may be charged from separate charging lines, or before being charged into the reaction vessel, piping, line mixer, mixing tank, etc. It may be added after mixing in advance. When added from separate charging lines, the molar ratio of alkylene oxide and (meth) acrylic acid in the system may be biased. It is more preferable. In addition, in the case of charging from separate charging lines, the charging mode (batch charging, sequential charging), the temperature of the raw material to be charged, the charging speed, etc. are not necessarily the same for each raw material.

  In the production method according to the present invention, the time required to finish the total supply of (meth) acrylic acid and alkylene oxide is not particularly limited, considering the progress of the reaction, productivity, etc. Can be set as appropriate.

  The catalyst used for the reaction is not particularly limited, and a conventionally known catalyst generally used for this kind of reaction can be used. Specific examples of the catalyst used in the reaction include all homogeneous catalysts soluble in a reaction solution containing (meth) acrylic acid and alkylene oxide. More specifically, chromium (Cr) compound, iron (Fe) compound, yttrium (Y) compound, lanthanum (La) compound, cerium (Ce) compound, tungsten (W) compound, zirconium (Zr) compound, titanium ( A homogeneous catalyst soluble in the reaction solution, comprising at least one selected from the group consisting of (Ti) compound, vanadium (V) compound, phosphorus (P) compound, aluminum (Al) compound and molybdenum (Mo) compound. Can be mentioned. Among these, a homogeneous catalyst soluble in the reaction solution containing a chromium (Cr) compound and / or an iron (Fe) compound is more preferable, and a homogeneous catalyst soluble in the reaction solution containing a chromium (Cr) compound is more preferable. More preferred is a homogeneous catalyst that is soluble in the reaction solution and comprises a chromium (Cr) compound. In particular, in the embodiment in which the amount of acid component relative to the amount of catalyst in the reaction solution described later is adjusted and the distillation residue is used in the next reaction solution, the reaction solution containing a chromium (Cr) compound as a catalyst is acceptable. It is preferable to use a homogeneous homogeneous catalyst because a more remarkable effect can be obtained, and it is more preferred to use a homogeneous catalyst made of a chromium (Cr) compound and soluble in the reaction solution.

  The chromium (Cr) compound is not particularly limited, and examples thereof include a compound having a chromium (Cr) atom in the molecule and soluble in the reaction solution. Specific examples include chromium chloride, acetylacetone chromium, chromium formate, chromium acetate, chromium octanoate, chromium isooctanoate, chromium acrylate, chromium methacrylate, sodium dichromate, chromium dibutyldithiocarbamate and the like.

  The iron (Fe) compound is not particularly limited, and examples thereof include compounds having an iron (Fe) atom in the molecule and soluble in the reaction solution. Specific examples include iron powder, iron chloride, iron formate, iron acetate, iron acrylate, and iron methacrylate.

  The yttrium (Y) compound is not particularly limited, and examples thereof include a compound having an yttrium (Y) atom in the molecule and soluble in the reaction solution. Specific examples include yttrium acetylacetone, yttrium chloride, yttrium acetate, yttrium nitrate, yttrium sulfate, yttrium acrylate, and yttrium methacrylate.

  The lanthanum (La) compound is not particularly limited, and examples thereof include a compound having a lanthanum (La) atom in the molecule and soluble in the reaction solution. Specific examples include lanthanum acetylacetone, lanthanum chloride, lanthanum acetate, lanthanum nitrate, lanthanum sulfate, lanthanum acrylate, and lanthanum methacrylate.

  The cerium (Ce) compound is not particularly limited, and examples thereof include compounds having a cerium (Ce) atom in the molecule and soluble in the reaction solution. Specific examples include acetylacetone cerium, cerium chloride, cerium acetate, cerium nitrate, cerium sulfate, cerium acrylate, and cerium methacrylate.

  The tungsten (W) compound is not particularly limited, and includes a compound having a tungsten (W) atom in the molecule and soluble in the reaction solution. Specific examples include tungsten chloride, tungsten acrylate, tungsten methacrylate, and the like.

  The zirconium (Zr) compound is not particularly limited, and examples thereof include a compound having a zirconium (Zr) atom in the molecule and soluble in the reaction solution. Specifically, zirconium acetylacetone, zirconium chloride, zirconium acetate, zirconium nitrate, zirconium sulfate, zirconium acrylate, zirconium methacrylate, zirconium butoxide, zirconium propoxide, zirconyl chloride, zirconyl acetate, zirconyl nitrate, zirconyl acrylate, methacrylic acid Zirconyl etc. are mentioned.

  The titanium (Ti) compound is not particularly limited, and includes a compound having a titanium (Ti) atom in the molecule and soluble in the reaction solution. Specific examples include titanium chloride, titanium nitrate, titanium sulfate, titanium methoxide, titanium ethoxide, titanium propoxide, titanium isopropoxide, titanium acrylate, and titanium methacrylate.

  The vanadium (V) compound is not particularly limited, and examples thereof include a compound having a vanadium (V) atom in the molecule and soluble in the reaction solution. Specific examples include vanadium acetylacetone, vanadium chloride, vanadium naphthenate, vanadium acrylate, and vanadium methacrylate.

  The phosphorus (P) compound is not particularly limited, and examples thereof include compounds having a phosphorus (P) atom in the molecule and soluble in the reaction solution. Specifically, alkyl phosphines such as trimethylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphine, tritoluylphosphine, 1,2-bis (diphenylphosphine) ethane, and quaternary phosphonium such as (meth) acrylic acid. Examples include salts.

  The aluminum (Al) compound is not particularly limited, and examples thereof include a compound having an aluminum (Al) atom in the molecule and soluble in the reaction solution. Specific examples include aluminum acetylacetone, aluminum chloride, aluminum acetate, aluminum nitrate, aluminum sulfate, aluminum ethoxide, aluminum isopropoxide, aluminum acrylate, and aluminum methacrylate.

  The molybdenum (Mo) compound is not particularly limited, and examples include compounds having a molybdenum (Mo) atom in the molecule and soluble in the reaction solution. Specific examples include molybdenum chloride, molybdenum acetate, molybdenum acrylate, molybdenum methacrylate, and the like.

  Further, as a catalyst that can be used in the manufacturing method according to this embodiment, the chromium (Cr) compound, the iron (Fe) compound, the yttrium (Y) compound, the lanthanum (La) compound, the cerium (Ce) compound, tungsten ( W) at least one selected from the group consisting of a compound, a zirconium (Zr) compound, a titanium (Ti) compound, a vanadium (V) compound, a phosphorus (P) compound, an aluminum (Al) compound, and a molybdenum (Mo) compound, Preferred is a catalyst (amine compound combined type) containing a homogeneous catalyst soluble in the reaction solution and an amine compound.

  The amine compound is not particularly limited as long as it is a compound having an amine functional group in the molecule. Specifically, the amine compound is uniform such as trialkylamines, cyclic amines such as pyridine, and quaternary salts thereof. Based amine compounds. By using the amine compound in combination, the catalytic activity can be synergistically improved, and both the reaction conversion rate and the reaction selectivity can be increased.

  The amount of the catalyst used in the production method according to the present embodiment is not particularly limited, but includes, for example, at least one selected from the group consisting of the chromium (Cr) compounds described above and is soluble in the reaction solution. When using a homogeneous catalyst (a type that does not use an amine compound in combination), it is preferably in the range of 0.01 to 10 mol%, preferably in the range of 0.02 to 5 mol% with respect to (meth) acrylic acid. It is more preferable that it is in the range of 0.04 to 3 mol%. If the amount used is less than 0.01 mol%, the reaction rate becomes slow, so the reaction time becomes longer and the production cost tends to increase. If the amount used exceeds 10 mol%, the reaction selectivity of by-products tends to increase.

  Moreover, when using the amine compound combined type catalyst mentioned above, it is preferable that the usage-amount of an amine compound exists in the range of 0.01-10 mol% with respect to (meth) acrylic acid, and 0.02-5 mol % Is more preferable, and 0.04 to 3 mol% is still more preferable. The use amount of the homogeneous catalyst that contains at least one selected from the group consisting of chromium (Cr) compounds and the like and is soluble in the reaction solution is preferably in the range of 0.01 to 5 mol%. The content is more preferably in the range of 02 to 5 mol%, and still more preferably in the range of 0.04 to 3 mol%. If the amount used is less than 0.01 mol%, the synergistic effect of the amine compound and the catalyst may not be obtained, and if it exceeds 5 mol%, the production cost tends to increase.

  In the production method according to the present invention, the catalyst is generally charged in advance in the reaction vessel with the total amount used, but the present invention is not limited to this. For example, a part of the total amount used is a reaction vessel. It is also possible to initially charge and then supply the remainder in the course of the reaction. In the case where the catalyst is a homogeneous catalyst, it may be preliminarily dissolved in either of the raw materials and then charged into the reaction vessel or supplied. For example, when initially charged, it may be dissolved in the raw material to be initially charged in a dissolution tank different from the reaction vessel and charged into the reaction vessel.

  In the production method according to the present invention, if necessary, a polymerization inhibitor may be added to the system during the reaction. The polymerization inhibitor is not particularly limited and can be used as long as it is generally industrially used. Specifically, for example, hydroquinone, methylhydroquinone, tert-butylhydroquinone, 2,6-di- Phenol compounds such as -tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,4-dimethyl-6-tert-butylphenol, hydroquinone monomethyl ether; N-isopropyl-N'-phenyl-para-phenylenediamine N- (1,3-dimethylbutyl) -N′-phenyl-para-phenylenediamine, N- (1-methylheptyl) -N′-phenyl-para-phenylenediamine, N, N′-diphenyl-para- Phenylenediamine, N, N'-di-2-naphthyl-para-pheny Paraphenylenediamines such as diamines; amine compounds such as thiodiphenylamine and phenothiazine; dialkyldithiocarbamate copper salts such as copper dibutyldithiocarbamate, copper diethyldithiocarbamate and copper dimethyldithiocarbamate; Din-1-oxyl, 2,2-dimethyl-4,4-dipropylazetidine-1-oxyl, 2,2,5,5-tetramethylpyrrolidine-1-oxyl, 2,2,5,5-tetra Methyl-3-oxopyrrolidine-1-oxyl, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 6-aza -7,7-dimethyl-spiro (4,5) decan-6-oxyl, 2,2,6,6- Tramethyl-4-acetoxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-benzoyloxypiperidine-1-oxyl, 4,4 ′, 4 ″ -tris- (2,2,6,6) N-oxyl compounds such as 6-tetramethylpiperidine-1-oxyl) phosphite and 4,4′-bis- (2,2,6,6-tetramethylpiperidine-1-oxyl) sebacate; These polymerization inhibitors may be used alone or in combination of two or more.

  When using the said polymerization inhibitor, it is preferable that the addition amount exists in the range of 0.0001 to 1 weight% with respect to the total supply amount of (meth) acrylic acid, More preferably, it is 0.001-0. Within the range of 5% by weight. Further, the timing of adding the polymerization inhibitor is not particularly limited, but it is preferable to add it to the reaction system first together with the components initially charged.

  In the production method according to the present invention, the reaction may be carried out in the presence of a solvent in the reaction system within the range not impairing the effects of the present invention for the purpose of allowing the reaction to proceed mildly. Specific examples of the solvent include common solvents such as toluene, xylene, heptane, and octane, and one or more of these can be used in combination.

  In the production method according to the present invention, the reaction temperature of (meth) acrylic acid and alkylene oxide is usually preferably in the range of 40 to 130 ° C, more preferably in the range of 50 to 120 ° C, and 50 to 110 ° C. It is more preferable to be within the range. When the reaction temperature is less than 40 ° C., the reaction rate is remarkably lowered, the reaction time is prolonged, and the productivity tends to be lowered. On the other hand, when reaction temperature exceeds 130 degreeC, there exists a tendency for a diester body and a diadduct to become easy to byproduce.

  In the production method of the present invention, the internal pressure during the reaction is preferably higher than the standard pressure (1 atm), although it depends on the type of raw material used and the proportion of the raw material used. It is performed in a liquid state under reduction.

  In the production method according to the present invention, it is preferable to add a diester inhibitor. Thereby, the by-product of the diester body which progresses after reaction stop can be suppressed effectively, and a diester body can be reduced.

  Examples of diester inhibitors include oxalic acid, oxalic anhydride, malonic acid, succinic acid, succinic anhydride, fumaric acid, maleic acid, maleic anhydride, salicylic acid, octanoic acid, adipic acid, sebacic acid, tetradecanedicarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,3,6-hexanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 1,6, 7,12-dodecanetetracarboxylic acid, benzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, pyromellitic acid, pyromellitic anhydride , Trimellitic acid, trimellitic anhydride, 1,2,4-benzenetricarboxylic acid, 1,4,5,8 Carboxylic acids such as naphthalenetetracarboxylic acid, 1,3,5,7-naphthalenetetracarboxylic acid and polyacrylic acid and their anhydrides; glycerin, diethylene glycol, trimethylolpropane, cresol, 1,2,6-hexanetriol, penta Erythritol, dipentaerythritol, 2,3,4,5-tetrahydroxyhexane, xylitol, mannitol, catechol, resorcin, 2,6-dihydroxytoluene, tert-butylcatechol, pyrogallol, 2,4-bis (hydroxymethyl) phenol , 1,2,4-trihydroxybenzene, 1,3,5-trihydroxybenzene, 2,4,6-tris (hydroxymethyl) phenol, 1,2,4,5-tetrahydroxybenzene and other polyhydric alcohols ;ethylene Tetraacetic acid, ethylenediaminetetraacetic propionic acid, nitrilotriacetic acid, iminodiacetic acid, 1,2-diaminocyclohexane tetraacetic acid, acetylacetone, cupferron, oxine, benzidine, metal chelating agents such as diethyldithiocarbamate; and the like. These diester inhibitors may be used alone or in combination of two or more.

  When using the said diester inhibitor, the addition amount is preferably in the range of 0.1 to 10 mol, and more preferably in the range of 0.5 to 5 mol, per mol of the catalyst. If the amount is less than 0.1 mole per mole of the catalyst, the effect of suppressing diester by-product may not be sufficiently exerted. On the other hand, if the amount exceeds 10 moles, the added diester inhibitor may lower the product purity. In particular, when carboxylic acids are used, the content of the acid component contained in the resulting product may increase. Further, the timing of adding the diester inhibitor is not particularly limited. For example, before starting the reaction (at the initial raw material charging), immediately after stopping the reaction (starting cooling), at the start of distillation, during distillation, etc., Or what is necessary is just to divide and add in multiple times. It is preferably added immediately after the reaction is stopped.

  The production method according to the present invention preferably further includes a step (distillation step) of distilling the reaction solution of alkylene oxide and (meth) acrylic acid.

  The said distillation process can be performed on the conditions generally used for distillation of hydroxyalkyl (meth) acrylate. Specifically, distillation is performed at a temperature within a range of 50 to 120 ° C., more preferably within a range of 60 to 100 ° C. under a pressure within a range of 1 to 15 hPa, more preferably within a range of 2 to 10 hPa. Usually, it is more preferable to carry out distillation after removing the remaining unreacted alkylene oxide under reduced pressure.

  Diester suppression in such an amount that the total amount with the diester inhibitor used in the reaction during the distillation step is within the range of 0.1 to 10 mol, more preferably within the range of 0.5 to 5 mol, per mol of catalyst. An additional agent may be added. In this case, the diester inhibitor may be the same as that used in the reaction step, or may be different.

  In this Embodiment, it is preferable to include the process of using the distillation residue in the said distillation process for next reaction.

  The distillation residue is not particularly limited. For example, the distillation residue obtained by completely reacting the raw material compound (meth) acrylic acid with alkylene oxide and distilling off the hydroxyalkyl (meth) acrylate is used. Alternatively, the reaction may be terminated at any stage during the reaction between (meth) acrylic acid and alkylene oxide, and the distillation residue after distillation of hydroxyalkyl (meth) acrylate may be used. What is necessary is just to prepare suitably so that recycling efficiency, the yield of a target product, etc. may improve more.

  In the distillation residue, the target product, hydroxyalkyl (meth) acrylate, may be completely distilled off, or it may remain without being partially distilled off. Moreover, other components, such as various by-products and raw material compounds, may remain in the distillation residue, or may be distilled off together with the target product.

  Further, if the distillation residue is used in the next reaction in a state where the by-product alkylene oxide diadduct (dialkylene glycol mono (meth) acrylate) remains, the diadduct of the diadduct in the next reaction is used. It is more preferable because by-products can be effectively suppressed.

  The total amount of the distillation residue is preferably used for the next reaction, but is not particularly limited, and only a part of the distillation residue may be used or divided into a plurality of reactions.

  In the present embodiment, as described above, when the distillation residue is used for the next reaction, the amount of the acid component in the reaction solution relative to the amount of the catalyst in the reaction solution is less than the amount of the catalyst in the reaction solution. In terms of calculation, it is preferable to maintain a state where the molar ratio is 0.01 or more. The molar ratio is more preferably 0.03 or more, and still more preferably 0.05 or more. When the molar ratio is less than 0.01, the catalyst in the reaction solution is inactivated, and even if the distillation residue is used in the next reaction, the activity of the catalyst contained in the distillation residue may not be sufficiently exhibited. . The above molar ratio value is the molar concentration (mol%) ratio, that is, the ratio of the molar concentration (mol%) of the acid component in the reaction liquid to the molar concentration (mol%) of the catalyst in the reaction liquid. Is the same.

  The above-mentioned “amount of acid component in the reaction solution” means the amount of all acid components in the reaction solution. Specifically, it is contained in the reaction solution in addition to (meth) acrylic acid which is a raw material compound. Other acids obtained are also included.

  In order to maintain the above molar ratio in the reaction solution, specifically, at least when the catalyst is supplied into the reaction solution, the distillation residue obtained from the reaction solution is used for the next reaction, It means that the above molar ratio is always maintained during the entire period until the next reaction is actually started (hereinafter, sometimes referred to as a maintenance period). Therefore, not only at the time of reaction but also at the time of cooling to end the reaction, at the time of waiting until the target product is distilled off, and at all steps of the target product at the time of distilling and after the distillation, always, It is preferable to maintain the molar ratio.

  Here, the “calculation” means that the “amount of catalyst in the reaction solution” is the amount of the catalyst present in the reaction solution at an arbitrary time point within the maintenance period. More specifically, in the case of batch reaction, it means the total amount of catalyst supplied into the reaction solution up to a predetermined point in time.

  The calculation of the amount of catalyst in the reaction solution is performed without considering whether or not the catalyst performance originally possessed by use in the reaction has deteriorated or disappeared. On the other hand, the “amount of acid component in the reaction solution” means the amount of acid component such as (meth) acrylic acid present in the reaction solution in the reaction vessel at any given time.

  The means for maintaining the molar ratio in the reaction solution is not particularly limited. For example, (i) (meth) acrylic acid as a raw material compound is supplied into the reaction solution to such an extent that the molar ratio is maintained. (Ii) means for supplying an acid having a lower reactivity than the raw material compound (meth) acrylic acid into the reaction liquid, and (iii) means for removing unreacted alkylene oxide from the reaction liquid at the end of the reaction. (For example, gas purge or diffusion), (iv) means for reducing the reaction temperature just before the end of the reaction by 5 ° C. or more from the set temperature, or shortening the cooling time at the end of the reaction. The supply in the means (i) and (ii) may be performed sequentially while managing the amount of the acid component in the reaction solution as needed as the reaction proceeds.

  Examples of the acid having low reactivity include carboxylic acids such as saturated carboxylic acids having 6 or more carbon atoms such as octanoic acid, isooctanoic acid, decanoic acid, and dodecanoic acid.

  In the present embodiment, since the amount of acid component in the reaction solution is analyzed by the automatic analyzer according to the present invention, the amount of acid component in the reaction solution can be easily managed. That is, based on the value of the amount of acid components obtained by the automatic analyzer according to the present invention, the means (i) to (iv) for maintaining the molar ratio in the reaction solution, the hydroxyalkyl (meth) acrylate production apparatus. If it is configured to be performed automatically, the molar ratio in the reaction solution can be automatically maintained.

  The method for adjusting the amount of the acid component relative to the amount of catalyst in the reaction solution described above can be applied to all conventionally known methods for producing hydroxyalkyl (meth) acrylates by the reaction of (meth) acrylic acid and alkylene oxide. it can. For example, the present invention can be preferably applied to a production method carried out under the condition that the molar ratio of alkylene oxide to (meth) acrylic acid initially charged is 1 or more. In this production method, when the molar ratio of alkylene oxide to (meth) acrylic acid at the time of initial charging is 1.4 or more, for example, there has been a problem that catalyst deactivation becomes significant. However, if the molar ratio of the acid component to the catalyst in the reaction solution is maintained within the above-described range, the problem can be easily solved. This is considered to be because when the molar ratio of alkylene oxide to (meth) acrylic acid at the initial charge is large, the molar ratio of the acid component to the catalyst in the reaction solution may be lower than the above-described range during the reaction. It is done.

  In the above description, the case where the change in the amount of the acid component in the reaction solution is measured by the automatic analyzer has been described, but the present invention is not limited to this. For example, if sampling is performed while maintaining the sampling line in a pressurized state, the analysis may be performed manually (manually), that is, manually (manually operated). If the reaction stop timing is predicted from the transition of the amount of the acid component in the reaction solution and the reaction can be stopped, the same effect as in the present embodiment can be obtained. However, the effect is particularly great when measurement is performed by an automatic analyzer as in this embodiment.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

〔Example〕
Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples.

[Method for measuring acid content]
The acid component amount in the examples is measured by neutralizing and titrating the acid component amount in the reaction solution by an automatic potentiometric titrator (Examples 1 and 2) or by manual analysis with a burette (Example 3). I did it. The molar ratio of the amount of acid component (% by weight) and the amount of acid component to the amount of catalyst in the reaction solution after cooling depends on the acid component used as the raw material acid (acrylic acid (Example 1) or methacrylic acid in this example). It calculated | required in conversion to the acid (Example 2, Example 3).

[Production Example 1]
A reactor (made of SUS316) equipped with a stirring device having a capacity of 2000 L was charged with 466 kg of acrylic acid, 2.81 kg of chromium acetate as a catalyst, and 0.26 kg of phenothiazine as a polymerization inhibitor. After the temperature in the reactor was raised to 60 ° C., the inside thereof was replaced with nitrogen gas, so that the oxygen concentration was 3% by volume and the internal pressure was 0.05 MPa (G).

  Thereafter, 309 kg of ethylene oxide was fed into the reactor at a constant speed over 3 hours. During this time, the reaction temperature was maintained at 60 ° C. After supplying ethylene oxide, the reaction temperature was raised to 80 ° C. to continue the reaction. By continuing the reaction for 3 hours, the acrylic acid concentration in the reaction solution became 0.1% by weight. Therefore, the reaction solution was cooled to 50 ° C. or less to complete the reaction.

  Subsequently, 750 kg of the reaction solution obtained in the above reaction was charged into a pilot scale distillation kettle (manufactured by SUS316) equipped with a 1000 L capacity heating device, and 0.14 kg of hydroquinone monomethyl ether was added as a polymerization inhibitor. The distillation kettle was heated with steam to perform batch distillation. The distillation was carried out with the internal pressure of the distillation kettle 3-5 hPa and the internal temperature of the distillation kettle within the range of 65-80 ° C. while introducing air into the distillation kettle at 280 L / hour. By distillation, 650 kg of a purified product of hydroxyethyl acrylate, which was a target purified product, and 96 kg of a distillation residue (residual reaction solution) (A-1) were obtained. In addition, the acid component amount of the distillation residue (residual reaction solution) (A-1) was 0.04% by weight (molar ratio of the acid component amount to the catalyst amount: 0.05).

  The above reaction and distillation operation were repeated twice to obtain 192 kg as a distillation residue (residual reaction solution) (A-1).

[Example 1]
In the apparatus shown in FIG. 1, a reactor (made of SUS316) provided with a stirring device having a capacity of 2000 L as a reaction vessel, a potentiometric automatic titration apparatus as an automatic analyzer, and a nitrogen cylinder as an inert gas introduction apparatus are used as follows. Used for operation.

  In the reactor, 27.7 kg of the total supply amount of acrylic acid of 396.6 kg, 1.3 kg of chromium acetate as a catalyst, 126.4 kg of distillation residue (A-1) obtained in Production Example 1, and phenothiazine as a polymerization inhibitor 0.60 kg was charged. After the temperature in the reactor was raised to 85 ° C., the inside thereof was replaced with nitrogen gas, so that the oxygen concentration was 3% by volume and the internal pressure was 0.05 MPa (G).

  Ethylene oxide was fed into the reactor at 126.7 kg / hour for 0.15 hours (18.7 kg), then acrylic acid (368.9 kg) at 199.2 kg / hour, ethylene oxide at 126.7 kg / hour. (234.6 kg) was fed for 1.85 hours. During this time, the reaction temperature was maintained at 85 ° C. Even after the end of the supply of the raw acrylic acid and raw ethylene oxide, the reaction was continued with the reaction temperature maintained at 85 ° C.

  In order to start the automatic measurement of the amount of the acid component in the reaction solution after 30 minutes from the time when the raw material supply was completed, the extraction of the reaction solution was started.

  The acid component amount was measured as follows.

  The reaction solution was extracted from the bottom of the reactor using a pump, and the circulation line was filled with the reaction solution. Thereafter, the valve 4 and the valve 5 were closed, and the valve 3a was opened, whereby nitrogen was blown into the circulation line from the nitrogen cylinder, and the pressure in the circulation line was increased to 0.07 MPa. Thereafter, the valve 2a was opened, and the ethylene oxide-containing reaction liquid was introduced into the potentiometric automatic titrator. Simultaneously with the start of measurement of the acid component amount, the valves 2a and 3a were closed, the valves 4 and 5 were opened, and the reaction solution was circulated (see FIG. 1).

  The automatic sampling operation and the automatic analysis operation were performed at intervals of 4 to 10 minutes from the start of extraction of the reaction liquid (30 minutes after the end of the raw material supply), and the amount of acid components in the reaction liquid was measured three times. After measuring the acid component amount in the reaction solution, an exponential approximation curve is obtained from the transition of the acid component amount, and extrapolated to predict when the acid component amount in the reaction solution is 0.1% by weight, Cooling of the reaction solution was started and the reaction was stopped.

  The cooling of the reaction liquid was performed by extracting the reaction liquid from the reactor, passing the reaction liquid through an external heat exchanger, and returning the cooled reaction liquid to the reactor again. This operation was performed until the reaction liquid temperature became 50 ° C. or lower.

  The reaction solution cooled to 50 ° C. or lower was distilled by the same distillation method as described in Production Example 1 to obtain a purified product of hydroxyethyl acrylate and a distillation residue.

  The distillation residue obtained here was further charged into the next reaction, whereby the above reaction and distillation operation were further repeated 4 times, and the reaction and distillation operation were performed 5 times in total. About the reaction liquid (B-1 to B-5) obtained in each round, the concentration of unreacted acrylic acid (AA) in the reaction liquid after the reaction was stopped and ethylene glycol diacrylate (Diester) (by gas chromatography) EGDA) concentration and diethylene glycol monoacrylate (DEGMA) concentration, which is a diadduct, were measured. The results are shown as follows: transition of measurement results of potentiometric auto titration, cooling start time (cooling timing determined from transition of acid component amount), and molar ratio of acid component amount to catalyst amount in reaction solution after cooling (in reaction solution) Table 1 shows the calculated molar ratio of the amount of acid component to the amount of catalyst. Moreover, about each measured value, it shows together about the average value of 5 times, and the amplitude (the difference of the maximum value of 5 times and the minimum value).

  “Sampling start (min)” in Table 1 indicates the time until the start of each sampling, starting from the point in time when the raw material supply is completed. In addition, “cooling start (min)” is also expressed as a time starting from the time when the raw material supply is completed.

[Comparative Example 1]
Instead of starting the operation of introducing the reaction liquid into the potentiometric automatic titration apparatus 30 minutes after the end of the raw material supply, the potentiometric titration apparatus indicates that the amount of the acid component in the reaction liquid is 0.1% by weight or less. After confirming the above, the reaction and the distillation operation were performed in the same manner as in Example 1 except that the cooling was started.

  In the first reaction, the reaction solution was sampled after the elapse of 67 minutes, which was the same as in Example 1, from the time when the supply of the raw materials was completed. Therefore, cooling was started. Since the cooling was started after confirming that the measured value of the acid component amount was 0.1% by weight or less, a time lag of about 20 minutes occurred, and the actual cooling start time was 85 minutes from the end of the raw material supply. It was later.

  The composition of the reaction solution after cooling was AA concentration 0.001% by weight, EGDA concentration 0.50% by weight, and DEGMA concentration 9.8% by weight. The molar ratio of the acid component amount to the catalyst amount in the reaction solution was 0.006.

  Subsequent to the above reaction, distillation was carried out in the same manner as in the method described in Production Example 1 to obtain a purified product of hydroxyethyl acrylate and a distillation residue.

  The distillation residue obtained here was further charged to the next reaction (second time) to carry out the reaction. As in the first reaction, the reaction solution was sampled 67 minutes after the starting of the supply of the raw materials, and the amount of the acid component measured was 0.97% by weight. Therefore, the reaction was further continued. After 85 minutes, the reaction solution was sampled and the acid component amount was measured again, but it was 0.75% by weight. Eventually, the amount of the acid component in the reaction solution did not decrease to 0.1% by weight, and the deactivation of the catalyst was observed.

[Example 2]
In the apparatus shown in FIG. 1, a reactor (made of SUS316) provided with a stirring device having a capacity of 2000 L as a reaction vessel, a potentiometric automatic titration apparatus as an automatic analyzer, and a nitrogen cylinder as an inert gas introduction apparatus are used as follows. Used for operation.

  The reactor was charged with 112 kg of the total methacrylic acid feed rate of 448 kg, 0.45 kg of chromium acetate as the catalyst, and 0.45 kg of phenothiazine as the polymerization inhibitor. After the temperature in the reactor was raised to 80 ° C., the inside thereof was replaced with nitrogen gas, so that the oxygen concentration was 1 vol% and the internal pressure was 0.1 MPa (G).

  In the reactor, ethylene oxide was supplied at 120.4 kg / hour for 0.5 hours (60.2 kg), then methacrylic acid (336 kg) was supplied at 224 kg / hour, and ethylene oxide (180.5 kg at 120.4 kg / hour). ) For 1.5 hours. During this time, the reaction temperature was maintained at 80 ° C. After the supply of raw material methacrylic acid and raw material ethylene oxide was completed, the reaction temperature was raised to 90 ° C. and the reaction was continued.

  Forty minutes after starting the supply of the raw material, extraction of the reaction solution was started to start automatic measurement of the amount of acid components in the reaction solution.

  The acid component amount was measured as follows.

  The reaction solution was extracted from the bottom of the reactor using a pump, and the circulation line was filled with the reaction solution. Thereafter, the valve 4 and the valve 5 were closed, and the valve 3a was opened, whereby nitrogen was blown into the circulation line from the nitrogen cylinder, and the pressure in the circulation line was increased to 0.07 MPa. Thereafter, the valve 2a was opened, and the ethylene oxide-containing reaction liquid was introduced into the potentiometric automatic titrator. Simultaneously with the start of measurement of the acid component amount, the valves 2a and 3a were closed, the valves 4 and 5 were opened, and the reaction solution was circulated (see FIG. 1).

  The automatic sampling operation and the automatic analysis operation were performed at intervals of 4 to 11 minutes from the start of extraction of the reaction solution (40 minutes after the completion of the raw material supply), and the amount of acid component in the reaction solution was measured three times. After measuring the acid component amount in the reaction solution, an exponential approximation curve is obtained from the transition of the acid component amount, and extrapolated to predict when the acid component amount in the reaction solution is 0.1% by weight, Cooling of the reaction solution was started and the reaction was stopped.

  The cooling of the reaction liquid was performed by extracting the reaction liquid from the reactor, passing the reaction liquid through an external heat exchanger, and returning the cooled reaction liquid to the reactor again. This operation was performed until the reaction liquid temperature became 50 ° C. or lower.

  The above reaction operation was performed 5 times in total. About the reaction liquid obtained each time, by gas chromatography, the unreacted methacrylic acid (MAA) density | concentration in the reaction liquid after reaction stop, the ethylene glycol dimethacrylate (EGDMA) density | concentration which is a diester body, the diethylene glycol which is a diadduct Monomethacrylate (DEGMMA) concentration was measured respectively. The result is shown in Table 2 together with the transition of the measurement result of potentiometric automatic titration and the cooling start time (cooling time determined from the transition of the amount of acid component). Moreover, about each measured value, it shows together about the average value of 5 times, and the amplitude (the difference of the maximum value of 5 times and the minimum value).

[Comparative Example 2]
When the reaction solution was introduced into the potentiometric automatic titrator, the reaction operation was repeated 5 times in the same manner as in Example 2 except that no pressure was applied with nitrogen. About the reaction liquid obtained in each time, MAA density | concentration, EGDMA density | concentration, and DEGGMA density | concentration of the reaction liquid after reaction stop were measured, respectively. The results are shown in Table 3 together with the transition of the measurement result of the potentiometric automatic titration and the cooling start time. Moreover, about each measured value, it shows together about the average value of 5 times, and the amplitude (the difference of the maximum value of 5 times and the minimum value).

Example 3
A reactor (made of SUS316) having a capacity of 2000 L as a reaction vessel, a burette as a manual analyzer, and a nitrogen cylinder as an inert gas introduction device were used for the following operations.

  The reactor was charged with 112 kg of the total methacrylic acid feed rate of 448 kg, 0.45 kg of chromium acetate as the catalyst, and 0.45 kg of phenothiazine as the polymerization inhibitor. After the temperature in the reactor was raised to 80 ° C., the inside thereof was replaced with nitrogen gas, so that the oxygen concentration was 1 vol% and the internal pressure was 0.1 MPa (G).

  In the reactor, ethylene oxide was supplied at 120.4 kg / hour for 0.5 hours (60.2 kg), then methacrylic acid (336 kg) was supplied at 224 kg / hour, and ethylene oxide (180.5 kg at 120.4 kg / hour). ) For 1.5 hours. During this time, the reaction temperature was maintained at 80 ° C. After the supply of raw material methacrylic acid and raw material ethylene oxide was completed, the reaction temperature was raised to 90 ° C. and the reaction was continued.

  Measurement of the amount of the acid component in the reaction solution was started 40 minutes after the start of the raw material supply.

  The acid component amount was measured as follows.

  The reaction solution was extracted from the bottom of the reactor using a pump, and the circulation line was filled with the reaction solution. Thereafter, nitrogen was blown into the circulation line from the nitrogen cylinder, and the pressure in the circulation line was increased to 0.07 MPa. Thereafter, the ethylene oxide-containing reaction liquid in the circulation line was sampled, and the amount of acid component was measured using a burette.

  This operation was performed at intervals of 4 to 11 minutes from the start of extraction of the reaction solution (40 minutes after the end of the raw material supply), and the amount of acid component in the reaction solution was measured three times. After measuring the acid component amount in the reaction solution, an exponential approximation curve is obtained from the transition of the acid component amount, and extrapolated to predict when the acid component amount in the reaction solution is 0.1% by weight, Cooling of the reaction solution was started and the reaction was stopped.

  The cooling of the reaction liquid was performed by extracting the reaction liquid from the reactor, passing the reaction liquid through an external heat exchanger, and returning the cooled reaction liquid to the reactor again. This operation was performed until the reaction liquid temperature became 50 ° C. or lower.

  The above reaction operation was performed 5 times in total. About the reaction liquid obtained each time, by gas chromatography, the unreacted methacrylic acid (MAA) density | concentration in the reaction liquid after reaction stop, the ethylene glycol dimethacrylate (EGDMA) density | concentration which is a diester body, the diethylene glycol which is a diadduct Monomethacrylate (DEGMMA) concentration was measured respectively. The results are shown in Table 4 together with the transition of the titration measurement result by the burette and the cooling start time (cooling time determined from the transition of the acid component amount). Moreover, about each measured value, it shows together about the average value of 5 times, and the amplitude (the difference of the maximum value of 5 times and the minimum value).

[Comparative Example 3]
Instead of starting the measurement of the amount of acid components in the reaction solution 40 minutes after the end of the raw material supply, it was confirmed by manual analysis that the amount of acid components in the reaction solution was 0.1% by weight or less. The reaction operation was repeated 5 times in the same manner as in Example 3 except that cooling was started after confirmation.

  After the raw material supply was completed, the reaction solution was sampled after the elapse of 68 minutes as in Example 3. Similarly, the amount of the acid component was measured by manual analysis using a burette. As a result, it was 0.07% by weight. Started. Since cooling was started after confirming that the measured value of the acid component amount was 0.1% by weight or less, a time lag of about 20 minutes occurred, and the actual cooling start time was 90 minutes from the time when the raw material supply was completed. It was later.

  About the reaction liquid obtained each time, by gas chromatography, the unreacted methacrylic acid (MAA) density | concentration in the reaction liquid after reaction stop, the ethylene glycol dimethacrylate (EGDMA) density | concentration which is a diester body, the diethylene glycol which is a diadduct Monomethacrylate (DEGMMA) concentration was measured respectively. The result is shown in Table 5 together with the transition of the measurement result in the manual analysis by the burette and the cooling start time. Moreover, about each measured value, it shows together about the average value of 5 times, and the amplitude (the difference of the maximum value of 5 times and the minimum value).

  In the results of Example 1 shown in Table 1, the results of Example 2 shown in Table 2, and the results of Example 3 shown in Table 4, acrylic acid contained in the obtained hydroxyethyl acrylate and hydroxyethyl methacrylate (Example The amount of 1) or methacrylic acid (Examples 2 and 3), diesters and diadducts was constant from the first to the fifth, and stable quality products were obtained.

  On the other hand, in the result of Comparative Example 1, the catalyst was deactivated in the first reaction, and the product could not be obtained in the second and subsequent reactions. Moreover, in the result of the comparative example 2 shown in Table 3, the quantity of the methacrylic acid, the diester body, and the diadduct which are contained in the obtained hydroxyethyl methacrylate has a big variation from the 1st time to the 5th time, and product quality is unstable. Met. Furthermore, in the result of Comparative Example 3 shown in Table 5, since the cooling of the reaction solution is started after the measurement of the amount of the acid component in the reaction solution, the amount of by-products such as diesters and diadducts increases. The product quality was reduced.

  Specifically, in the result of Comparative Example 1, since the cooling of the reaction solution is started after the measurement of the acid component amount in the reaction solution, the acid component amount with respect to the catalyst amount in the reaction solution is calculated by a molar ratio. It became 0.01 or less, and the catalyst in the distillation residue used for the next reaction was deactivated. As a result, the reaction rate of the second reaction slowed down, and when the cooling was started at the same timing, the concentration of the acid component in the reaction solution increased.

  Further, as shown in the results of Comparative Example 1 and Comparative Example 3 above, since the cooling of the reaction liquid is started after the measurement of the amount of the acid component in the reaction liquid, the cooling of the reaction liquid is started from the sampling of the reaction liquid. A time lag of about 1 to 20 minutes may occur. In such a case, the analysis value of the acid component amount finally obtained is often different from the acid component amount of the reaction solution at the start of cooling of the reaction solution, and the analysis of the finally obtained acid component amount Even if the value is within the range of the reaction end point, the amount of the acid component of the reaction solution at the start of cooling of the reaction solution may deviate from the range of the reaction end point. For this reason, it is easy to produce the problem of manufacture, such as the amount of impurities in the product obtained increasing, or the composition of the product obtained being unstable.

  However, as shown in the examples, by predicting the reaction end point from the transition of the amount of the acid component in the reaction solution, the reaction can be stopped at the optimum point, and the above problem can be solved.

  In addition, the automatic stop method employed in the above embodiment is a form in which heat exchange is performed by changing the heat medium introduced into the heat exchanger to a cold water medium when the reaction is cooled by the heat exchanger. is there. In this case, the reaction can be stopped quickly without installing an extra heat exchanger for cooling, and the object of the present invention can be achieved.

  In the automatic stop, for example, a stop signal from an automatic acid component amount measuring device is received by sequence control, and operations such as switching the heat medium and cooling medium pipes installed in the heat exchanger by valve operation are automatically controlled. This can be done.

  Further, in the result of Comparative Example 2 shown in Table 3, since no pressurization was performed at the time of sampling, an error was likely to occur in the sampling amount as compared with the result of Example 2 in which pressurization was performed at the time of sampling. The amount error increased, and the error at the start of cooling based on the transition of the analysis value tended to increase.

  In this example, although not specifically described, the reaction is performed by cooling using a heat exchanger described in JP-A No. 2002-226427 which switches between a heat medium and a cooling medium. Stopped. By using this heat exchanger, it is possible to automatically control the timing for starting the cooling by the signal from the acid component automatic analysis means, and to cool the reaction liquid quickly. Accordingly, the reaction can be stopped at an appropriate time. Therefore, the method described in the above publication, in which the heat medium of the heat exchanger used as a heater is switched and used as a cooler, is a preferred specific example of reaction stopping means that can be adopted by the present invention.

  The sampling method of the present invention can sample an alkylene oxide-containing reaction solution while suppressing the generation of bubbles. Therefore, it can be suitably used for an automatic analyzer for a reaction system using an alkylene oxide-containing reaction solution, such as a reaction between alkylene oxide and (meth) acrylic acid.

It is a schematic diagram which shows schematic structure of the automatic analyzer which concerns on this Embodiment. It is a schematic diagram which shows schematic structure of the automatic analyzer which concerns on the other form of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction container 2 Automatic analysis means 3 Inert gas introduction means 4 1st valve 5 2nd valve 9 Alkylene oxide containing reaction liquid 10 Circulation line (sampling line)

Claims (6)

A process for producing a hydroxyalkyl (meth) acrylate in which an alkylene oxide and (meth) acrylic acid are reacted in the presence of a catalyst,
By sampling the reaction solution with the sampling line pressurized with a production system including a reaction vessel equipped with a sampling line, and measuring the amount of acid component in the sampled reaction solution, A method for producing a hydroxyalkyl (meth) acrylate, characterized by predicting a reaction stop timing from a transition of an acid component amount and stopping the reaction. The manufacturing system further includes an automatic analyzer and an automatic reaction stop device,
Sampling of the reaction solution while the sampling line is pressurized, and automatically measuring the amount of acid component in the sampled reaction solution to predict when the reaction will stop based on changes in the amount of acid component in the reaction solution The method for producing hydroxyalkyl (meth) acrylate according to claim 1, wherein the reaction is automatically stopped. The method for producing a hydroxyalkyl (meth) acrylate according to claim 2 , wherein the automatic analyzer is a potentiometric automatic titrator. The above reaction is performed in a reaction vessel equipped with a sampling line,
The automatic analyzer is
Automatic analysis means for automatically sampling the alkylene oxide-containing reaction liquid in the reaction vessel and automatically analyzing the sampled alkylene oxide-containing reaction liquid;
An inert gas introduction means for introducing an inert gas into the sampling line;
3. The sampling control means for controlling the automatic analysis means to perform sampling of the reaction liquid containing alkylene oxide in a state where the inside of the sampling line is pressurized by the inert gas introduction means. Or 3. A method for producing a hydroxyalkyl (meth) acrylate according to 3 . A reaction vessel equipped with a sampling line, an automatic analyzer, and an automatic reaction stop device are used for the production of a hydroxyalkyl (meth) acrylate that reacts an alkylene oxide with (meth) acrylic acid in the presence of a catalyst. A system for producing a hydroxyalkyl (meth) acrylate,
The automatic reaction stop device predicts the reaction stop timing from the transition of the amount of acid component analyzed by the automatic analyzer, and automatically stops the reaction, thereby producing a hydroxyalkyl (meth) acrylate production system. The automatic analyzer is
Automatic analysis means for automatically sampling the alkylene oxide-containing reaction liquid in the reaction vessel, sending the sampled alkylene oxide-containing reaction liquid to an automatic analyzer, and automatically analyzing it;
An inert gas introduction means for introducing an inert gas into the sampling line;
The sampling in line with pressurized state by inert gas introduction means, according to claim 5, automatic analysis means, characterized in that it comprises a sampling control means for controlling to perform sampling of the alkylene oxide-containing reaction mixture The production system of hydroxyalkyl (meth) acrylate.

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