JP2002265424A - N-alkoxymethylacrylamide, method for producing the same and method for producing crystal and aqueous solution of n-methylolacrylamide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing high-purity N- alkoxymethylacrylamide(NAMA) and N-methylolacrylamide(NMAA), with which one of reaction raw materials is not used in an excessive amount and a complex purification process is not introduced. SOLUTION: In this method for producing NAMA comprising acrylamide, formaldehyde and an alcohol as main raw materials, the method has a process for subjecting acrylamide and formaldehyde to a methylolation reaction in the presence of an alkali catalyst and a process for etherifying the product of the methylolation reaction with an alcohol. In the methylolation reaction, the aging reaction of methylolation is carried out in the presence of N- methylolacrylamide crystal. In this method for producing crystal or an aqueous solution of NMAA by methylolating acrylamide with formaldehyde in the presence of an alkali catalyst, the aging of methylolation is carried out in the presence of NMAA crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION N-Alkoxymethyl acrylamide and N-methylol acrylamide are known as cross-linking functional groups of polymers and are mainly used for the production of coating resins and adhesives. The present invention relates to an improved method for producing N-alkoxymethyl acrylamide and N-methylol acrylamide. The method according to the present invention uses high-purity N-alkoxymethyl acrylamide by using one of the raw materials in the reaction in a large excess amount or is complicated. It can be manufactured without introducing a refining process. Further, N-methylolacrylamide crystals can be efficiently obtained by the method of the present invention, and an N-methylolacrylamide aqueous solution having a small content of formaldehyde and by-products can be easily produced.

[0002]

2. Description of the Related Art Generally, N-alkoxymethylacrylamide is obtained by reacting acrylamide and formaldehyde in an alcohol in the presence of an alkali catalyst to obtain a reaction solution containing N-methylolacrylamide, and subsequently adding an alcohol to the reaction solution. It is produced by conducting an etherification reaction after adding an acid catalyst (Japanese Patent Publication No. 38-2).
3607), however, various proposals have been made for the production method of N-alkoxymethylacrylamide even after JP-B-38-23607. For example, Tokuho 7
In JP-A-33362, an alcohol and an acid catalyst are added to an N-methylolation reaction product solution to perform an etherification reaction, and then the solvent is distilled off at a pH of the reaction product solution in the range of 2 to 5,
A method of concentration is proposed. Also, JP-A-8-176
In JP-A-81-81, an alcohol and an acid catalyst are added to the N-methylolation reaction product solution to perform an etherification reaction while blowing air, and then adjusting the pH of the reaction solution to 5 to 8 and then blowing air. A method of concentrating under reduced pressure is proposed. In Japanese Patent Application Laid-Open No. 8-176082, the obtained reaction solution of N-butoxymethylacrylamide is washed with warm water at 40 to 80 ° C., and the pH of the reaction solution is adjusted to 5 to 8. It proposes a method of concentrating under reduced pressure while blowing air after adjusting.

[0003] The patent methods proposed in the past regarding the production of N-alkoxymethylacrylamide are directed to an etherification reaction method or a purification method of N-alkoxymethylacrylamide produced by the etherification reaction from the viewpoint of improving the production method. , N-methylolation reaction, as described in JP-B-7-33362, (meth)
Acrylamide crystals and paraformaldehyde crystals are easily dissolved, ensuring a predetermined reaction rate and (meth)
In order to prevent hydrolysis of acrylamide and furthermore, in consideration of economy, butyl alcohol is used in an amount of 0.4 to 1.0 mol, preferably 0.5 to 0.7 mol, per 1 mol of (meth) acrylamide.
A method of using a mole and conducting the reaction at 40 to 60 ° C. and a pH of 8.0 to 11.0, more preferably 9.5 to 10.5 for 1 to 4 hours is general and has not been studied in detail. For this reason,
In order to improve the production rate of N-alkoxymethyl acrylamide, in the method of Japanese Patent Publication No. 7-33362, 1.5 (Example 1) or 1.2 equivalents (Example 2) of formaldehyde is used relative to acrylamide. The excess amount of formaldehyde is removed from the distillate in the step of distilling off the solvent after completion of the etherification reaction, the pressure reduction line, or the N-alkoxymethylacrylamide after washing with water. The waste liquor is further distributed to the product N-alkoxymethylacrylamide. Further, in Japanese Patent Application Laid-Open No. 8-176082, in order to purify the obtained N-butoxymethylacrylamide, the reaction solution is neutralized, washed with warm water 5 to 8 times, and then concentrated. Not only does the yield increase, but the N-butoxymethylacrylamide partially dissolves in the wash water, resulting in a lower yield. As described above, the N-alkoxymethyl acrylamide produced by the conventionally proposed method for producing N-alkoxymethyl acrylamide is disadvantageous in that the N-methylolation reaction is an equilibrium reaction, resulting in the use of a large excess amount of one raw material of the reaction. By doing so, the reaction rate of N-methylolation and, consequently, the production rate of N-alkoxymethylacrylamide can be increased, or if water can be washed like N-butoxymethylacrylamide, the purity can be increased by washing with water or warm water. I was

On the other hand, as a conventional method for producing crystalline N-methylolacrylamide, acrylamide diluted with water to a concentration of 60 to 97% by mass is reacted with formaldehyde at a predetermined temperature for a predetermined time using an alkali catalyst, and then the reaction solution Is cooled to crystallize and obtain N-methylolacrylamide crystals (Japanese Patent Publication No. 38-15358). In recent years, N-methylol (meth) acrylamide obtained by reacting (meth) acrylamide with formaldehyde has been developed. A method has been proposed in which a solution is concentrated by blowing a low-humidity gas (Japanese Patent Laid-Open No. 9-309867). However, Japanese Patent Application Laid-Open No. 9-309867 proposes that the viewpoint of the proposal is to efficiently remove N-methylol (meth) acrylamide from the N-methylol (meth) acrylamide reaction solution after neutralizing with an acid to terminate the reaction.
It is directed to a method for obtaining methylol (meth) acrylamide crystals, and the separation mother liquor of the previous batch, an aqueous solution of acrylamide having a concentration of 70% by mass, an alkali catalyst, and paraformaldehyde described in Example 1 are charged at 50 ° C. for 2 hours. After the reaction, neutralize and terminate the reaction after the reaction is completed.
The method of filtering the wet crystals by gradually cooling the mixture is as described in Example 1 of Japanese Patent Publication No. 38-15358, except that the separated mother liquor of the previous batch is charged, the polymerization inhibitor, water, acrylamide, paraformaldehyde. , Charge with alkaline catalyst, 5
The reaction is continued for 2 hours at 0 ° C. until the reaction is substantially completed, and then cooled to obtain crystals, which is basically the same as that of the N-methylolacrylamide separation used in Examples. Acrylamide concentration of mother liquor (18.
3% by mass) and the concentration of formaldehyde (5.4% by mass)
Is 99% by mass /% by mass.

[0005] As a method for producing an aqueous solution of N-methylolacrylamide, formaldehyde containing substantially no formic acid and acrylamide are reacted in the presence of a basic catalyst to produce by-products of N, N'-methylenebisacrylamide. (Japanese Patent Application Laid-Open No. 62-142146), or the reaction of a polymerizable amide (for example, acrylamide) with an aldehyde (for example, formaldehyde) to obtain p-type N-alkylolamide monomer.
The H is adjusted to 10-11 and then at -10-25 ° C an alkali or alkaline earth metal borohydride is added to convert the free aldehyde remaining in the equilibrium mixture to the corresponding alcohol, resulting in an aldehyde. N with low content
-Method for producing aqueous alkyl amide (Japanese Patent Laid-Open No.
279382).

However, in the method described in Japanese Patent Application Laid-Open No. 62-142146, only an excess amount of acrylamide is used as a method for increasing the conversion of formaldehyde, and a specific reaction method has not been deeply pursued. That is, in the method for producing an aqueous solution of N-methylolacrylamide described in Japanese Patent Application Laid-Open No. 62-142146, as described in
The use of acrylamide in excess of 7 to 18 mol% enhances the reaction rate of formaldehyde, but still, 4.7 mol% of formaldehyde remains in the reaction solution with respect to the charged acrylamide, and unreacted formaldehyde is present. Measures are needed. For example, a large amount of formaldehyde remaining in an aqueous solution of N-methylolacrylamide changes to formic acid during storage, lowering the pH of the solution during storage, and reducing the pH of N, N'-methylenebisacrylamide in the aqueous solution of N-methylolacrylamide with time. Promote the increase. Therefore, a salt having a buffering action is added to the aqueous solution of N-methylolacrylamide to minimize the pH decrease of the solution due to the change of formaldehyde to formic acid,
As a result, N,
A method for preventing an increase in N'-methylenebisacrylamide with the passage of time has been proposed (JP-A-62-175449).
No.). In the method described in JP-A-6-279382, acrylamide and formaldehyde are reacted using equimolar amounts, and unreacted remaining formaldehyde is reduced to an alcohol with an alkali borohydride or an alkaline earth metal. The formaldehyde concentration in the N-methylolacrylamide aqueous solution is reduced.

Furthermore, in the production of an aqueous solution of N-methylolacrylamide by a conventionally proposed method, not only the conversion of formaldehyde is low, but also the selectivity of formaldehyde to N-methylolacrylamide is low.
The yield of methylolacrylamide is lower than the value calculated from the amount of formaldehyde consumed in the reaction.

[0008]

SUMMARY OF THE INVENTION N-
In the N-methylolation reaction method in the production of alkoxymethylacrylamide, the production rate of N-methylolacrylamide or the quality of the N-methylolation reaction product is unsatisfactory, and as a result, the production of N-alkoxymethylacrylamide based on acrylamide In order to increase the rate, a large excess of formaldehyde must be used, and excess formaldehyde remains in the product or is released out of the reaction system, or impurities in the obtained N-alkoxymethylacrylamide. A complicated purification step has to be introduced in order to remove this.

Further, in the conventional N-methylol acrylamide production method for producing N-methylol acrylamide crystals, the yield of N-methylol acrylamide has not reached a satisfactory value, and the separation at the time of obtaining the N-methylol acrylamide crystals has not been achieved. As a result, the amounts of filtrate and crystal washing waste liquid increase. For this reason, in the conventionally proposed method for producing N-methylolacrylamide crystals, the separated filtrate or the crystal washing waste liquid at the time of obtaining N-methylolacrylamide crystals containing a large amount of reaction raw materials such as acrylamide and formaldehyde in addition to N-methylolacrylamide. Or N
-The point of view of the proposal was directed to a method for concentrating the methylol acrylamidation reaction solution itself.

Furthermore, in the method of producing an aqueous solution of N-methylolacrylamide proposed in the prior art, a large excess of acrylamide was used or obtained during the N-methylolation reaction in order to reduce the formaldehyde concentration in the aqueous solution of N-methylolacrylamide. At present, an N-methylolacrylamide aqueous solution must be carefully treated with a strong reducing agent such as sodium borohydride or an alkaline earth metal, which requires attention to fire. Also,
In the conventionally proposed method for producing an aqueous solution of N-methylolacrylamide, not only the conversion of formaldehyde is low, but also the selectivity of formaldehyde to N-methylolacrylamide is low. At present, a considerable amount of acrylamide remains in the obtained N-methylolacrylamide aqueous solution even if the reaction is performed using an equimolar amount of acrylamide and formaldehyde, which is lower than the value calculated from the amount. .

In the production of N-alkoxymethylacrylamide, the present invention focuses on the N-methylolation reaction, which can be said to be the basis of the production of the substance, and greatly improves the yield of N-methylolacrylamide in the N-methylolation reaction. The present invention proposes a method for easily producing high-quality N-alkoxymethylacrylamide.

The present invention also proposes a method for efficiently producing N-methylolacrylamide crystals without using a large excess of one of the raw materials in the reaction in producing N-methylolacrylamide crystals.

Furthermore, in the present invention, in the production of an aqueous solution of N-methylolacrylamide, a large excess of acrylamide is used to greatly increase the production rate of N-methylolacrylamide, and sodium borohydride or alkaline earth metal is used. The amount of free formaldehyde is low without using a strong reducing agent that requires care in handling, and the pH of aqueous solution of N-methylolacrylamide by the conversion of free formaldehyde to formic acid during storage is reduced.
The present invention proposes a method for easily and safely producing an aqueous solution of N-methylolacrylamide in which an increase in N, N'-methylenebisacrylamide caused by a decrease in H with time is suppressed.

[0014]

Means for Solving the Problems The present inventors have conducted intensive studies on the production method of N-alkoxymethylacrylamide and N-methylolacrylamide. As a result, the N-methylolation reaction is an equilibrium reaction and the N-methylolacrylamide crystal is The aging reaction in the precipitated state shifts the equilibrium to the N-methylolacrylamide generation side, so that the reaction rate of the N-methylolation reaction is greatly improved, and the aging reaction can be performed under mild conditions. It has been found that the formation of undesired side reaction products is suppressed, and high-quality N-alkoxymethylacrylamide and N-methylolacrylamide can be easily produced in high yield, and the present invention has been achieved.

That is, the present invention relates to a compound of the formula (1) containing acrylamide, formaldehyde and alcohol as main raw materials.

[0016]

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Wherein R represents an alkyl group having 1 to 4 carbon atoms, wherein the alcohol, water, or a mixed solvent of the alcohol and water is used in the method for producing N-alkoxymethylacrylamide represented by the formula: Is used as a main reaction solvent to carry out an N-methylolation reaction of acrylamide and formaldehyde in the presence of an alkali catalyst, followed by reacting the N-methylolation product with the alcohol in the presence of an acid catalyst to produce the N-methylol. Producing an alkoxymethylacrylamide, wherein the N-methylolation reaction is carried out according to the formula (2)

[0018]

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A method for producing N-alkoxymethylacrylamide, which comprises performing an aging reaction for N-methylolation in the presence of crystals of N-methylolacrylamide represented by the formula:
The N-alkoxymethylacrylamide is characterized in that the product of the acrylamide content and the formaldehyde content is 10% by mass or less by mass.

The present invention also relates to a method of reacting acrylamide and formaldehyde with N-methylol using an alcohol, water, or a mixed solvent of alcohol and water as a main reaction solvent in the presence of an alkali catalyst.

[0021]

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A method for producing N-methylol acrylamide crystals represented by the formula: wherein the N-methylol acrylamide crystals are subjected to a ripening reaction for N-methylol acrylamide in the presence of the crystals. It is.

Further, according to the present invention, acrylamide and formaldehyde are subjected to N-methylolation reaction in the presence of an alkali catalyst using water as a main reaction solvent to obtain a compound represented by the formula (2):

[0024]

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A method for producing an aqueous solution of N-methylolacrylamide represented by the formula: wherein the aging reaction of N-methylol acrylamide is carried out in the presence of N-methylolacrylamide crystals. Is manufactured by this method,
Further, an aqueous N-methylolacrylamide solution is characterized in that the product of the mass concentration ratio of each of acrylamide and formaldehyde to N-methylolacrylamide is 20 × 10 ⁻⁴ or less.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.

[Production of N-alkoxymethylacrylamide] In the N-methylolation reaction for producing N-alkoxymethylacrylamide, a reaction solvent, acrylamide, an alkali catalyst, formaldehyde, and, if necessary, a polymerization inhibitor and the like are charged.

As the reaction solvent, water, methyl alcohol,
Examples thereof include ethyl alcohol, propyl alcohol, butyl alcohol, and a mixture of water and alcohol. The alcohol must be the same as the alcohol forming the alkoxy group of N-alkoxymethylacrylamide. Also, an N-methylolacrylamide solution prepared in advance can be used as a reaction solvent. Further, in order to increase the reaction rate of the N-methylolation reaction during the aging reaction, a solvent that is inert to the reaction such as xylene and promotes the crystallization of N-methylolacrylamide is added at the time of charging the reaction solvent or during the reaction. You can do it.

The amount of the reaction solvent used for acrylamide depends on the aging reaction temperature, the type of alcohol, the amount of water used, and the amount of a solvent inert to the reaction such as xylene, but is preferably 0.04 to 1.0. Times by mass, more preferably 0.0
It is 7 to 0.5 times by mass.

As formaldehyde, a formaldehyde polymer is generally used.

As the formaldehyde polymer, lower polyoxymethylene glycol, paraformaldehyde, α
-Polyoxymethylene, β-polyoxymethylene and the like can be used, but usually paraformaldehyde is used. Further, instead of the formaldehyde polymer, an aqueous formaldehyde solution, in particular, an aqueous formaldehyde solution having a high formaldehyde concentration can be used. When an aqueous formaldehyde solution is used, the formaldehyde concentration is preferably at least 40%, more preferably at least 50%.

The use amount of formaldehyde to acrylamide is preferably 0.8 to 1.5, more preferably 1.0 to 1.1 in a molar ratio (here, when using a formaldehyde polymer, The above molar ratio is considered based on the number of moles of formaldehyde when all are depolymerized).

The N-methylolation reaction in the method of the present invention is preferably carried out at a high concentration. In order to carry out the N-methylolation reaction at a high concentration, the raw materials for acrylamide and formaldehyde are charged with the reaction solvent being as small as possible. Will be For this reason, the preparation of acrylamide and formaldehyde in the practice of the method of the present invention is as if it could not be carried out industrially unless a special reactor equipped with a powerful stirring device is used in the usual random preparation method. appear. The present inventors have carefully observed the N-methylolation reaction. As a result, the method of the present invention can be easily carried out on an industrial scale by devising such that a good fluidity of the slurry liquid is secured at the time of charging the reaction raw materials. I found that I can do it. That is, the dissolution of acrylamide in the reaction solvent is endothermic,
In order to promote the dissolution of acrylamide in the charged liquid, it is preferable to divide the acrylamide into small portions while heating the charged liquid or the charged slurry liquid and charge the acrylamide in small portions. Also, even during the preparation of the formaldehyde polymer, it is preferable to add the formaldehyde polymer in small portions at a time in order to ensure good fluidity of the slurry liquid. Further, a method of alternately adding the acrylamide and the formaldehyde polymer little by little is also a preferable method for securing a good fluidity of the slurry liquid. The charged formaldehyde polymer undergoes depolymerization and gradually dissolves in the charged slurry liquid.
-The depolymerization rate of the formaldehyde polymer under the methylolation reaction condition, that is, the alkali condition, is remarkably faster than that without addition of the alkali, and the formaldehyde polymer dissolves at a rate that can be recognized by careful observation.
For this reason, even if the amount of the reaction solvent used is small, good fluidity of the slurry during addition of the formaldehyde polymer can be ensured by adding the formaldehyde polymer little by little. Furthermore, since formaldehyde polymers such as lower polyoxymethylene glycol and paraformaldehyde contain water, the formaldehyde polymer is divided into small portions and charged. It promotes the dissolution of the polymer and acrylamide, and as a result, gives a better fluidity to the slurry liquid when the formaldehyde polymer is charged.

As the alkali catalyst, conventionally known alkaline substances are used, for example, alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, and alkaline earths such as magnesium hydroxide and calcium hydroxide. Metal hydroxide, sodium carbonate, potassium carbonate,
Salts of weak acids and strong alkalis such as trisodium phosphate, disodium phosphate, sodium pyrophosphate, tripotassium phosphate, dipotassium phosphate, etc., tertiary amines such as triethylamine, metal alkoxides, etc. alone or two or more kinds Can be mixed and used. The amount of the alkali catalyst used depends on the strength of the alkali catalyst as an alkali and the type of the reaction solvent, but is preferably such that the pH of the reaction solution is 8 or more, more preferably 9 to 13. The alkali catalyst may be added in portions, and may be additionally added during the N-methylolation reaction.

In the method of the present invention, unlike the conventional method, it is not necessary to reach the equilibrium during the reaction at a high temperature, and the reaction temperature can be changed to a mild condition after a certain amount of the reaction has progressed, or in the first place. Since the high-temperature reaction can be avoided, the N-methylolation reaction can be carried out under reaction conditions in which troubles such as polymerization do not easily occur as compared with the conventionally proposed method. However, in order to prevent unexpected polymerization, hydroquinone (hereinafter referred to as H
Q) and hydroquinone monomethyl ether (hereinafter abbreviated as MEHQ) are preferably used. The polymerization inhibitors can be used alone or as a mixture.

The order of preparation is not particularly limited. Considering production in a factory, it is preferable to prepare a reaction solvent, a polymerization inhibitor, an acrylamide, an alkali catalyst, and a formaldehyde polymer in this order. In the preparation of the product, a method in which acrylamide and formaldehyde polymer are alternately added in small amounts, respectively, is also a preferable method. When a high-concentration aqueous solution of formaldehyde is used instead of the formaldehyde polymer, it is preferable to first charge the aqueous solution of formaldehyde.

After charging the N-methylolation reaction raw material, the mixture is heated to a predetermined temperature to perform an N-methylolation reaction, thereby dissolving the formaldehyde polymer almost or completely.
Thereafter, if necessary, cooling is performed, and a ripening reaction is carried out in a state in which N-methylolacrylamide crystals are precipitated, and a high-concentration aqueous solution of formaldehyde is used as formaldehyde. If the N-methylolation reaction raw material is charged, the N-methylolation reaction raw material is charged and then heated to a predetermined temperature to perform the N-methylolation reaction. In a typical embodiment, the ripening reaction is performed in a state in which N-methylolacrylamide crystals are precipitated. However, after the N-methylolation reaction raw materials are charged, the N-methylolation reaction is performed without heating. Is carried out, and then the aging reaction is carried out in a state where N-methylolacrylamide crystals are precipitated. It is possible to manufacture a highly-methylolacrylamide formation rate N- methylol reaction.

The temperature and time for dissolving the formaldehyde polymer almost or completely are greatly affected by the pH of the reaction solution and the type and amount of the reaction solvent, but are preferably 10-8.
0 ° C., 0.1 to 10 hours, more preferably 20 to 60 hours
° C, 0.2 to 6 hours.

The aging reaction temperature is closely related to the pH of the reaction solution, the type and amount of the reaction solvent, and the aging reaction time. From the viewpoint of performing the aging reaction in a state where N-methylolacrylamide crystals are precipitated. Preferably it is 0-50 degreeC, More preferably, it is 15-35 degreeC. The aging reaction time is N-
It is preferably within 48 hours, more preferably 2 to 20 hours after the methylol acrylamide crystal starts to crystallize. When the aging reaction is performed in a short time, it is recommended to set the pH of the reaction solution to be higher from the viewpoint of the reaction rate.

The alkaline catalyst for raising the pH can be charged in its entirety at the time of charging the raw materials for the reaction. However, when the initial reaction (methylolation reaction before aging) is carried out at a high temperature, the pH is suppressed to a low value during the high temperature reaction. Thus, it is reasonable to suppress the hydrolysis of acrylamide and increase the reaction rate during the aging reaction by adding an alkali catalyst during the aging reaction performed under mild temperature conditions.

Since N-methylolacrylamide does not easily crystallize even when it reaches solubility, it is preferable to crystallize N-methylolacrylamide crystals by adding separately prepared N-methylolacrylamide crystals as seed crystals.
The device for securing the fluidity of the slurry liquid during the preparation of the N-methylolation reaction raw material and the use of seed crystals in the precipitation of N-methylolacrylamide crystals enable the present invention to be easily and industrially implemented with excellent reproducibility. Preferred for tightening. By adding a separately prepared N-methylol acrylamide crystal as a seed crystal, the ripening reaction in a state where the N-methylol acrylamide crystal is crystallized can be surely performed for a predetermined time, and the N-methylol acrylamide crystal After the N-methylolacrylamide crystals are precipitated to promote crystallization, the reaction is carried out at such a high concentration that it becomes difficult to stir with a stirrer generally used in industry, or once the temperature has reached a predetermined aging reaction temperature. After cooling to precipitate crystals, it is no longer necessary to heat the mixture to a predetermined aging reaction temperature and then perform the aging reaction. In a preferred embodiment of the present invention, the seed crystals are added in a state where the N-methylolacrylamide concentration of the reaction solution is higher than the solubility of N-methylolacrylamide.

After the N-methylolation reaction, a conventional method is used.
An etherification reaction is performed by adding an acid catalyst and, if necessary, an alcohol. In the method of the present invention, the addition is preferably performed in the order of an acid catalyst and an alcohol. Since the equilibrium reaction of N-methylolation is stopped by adding the acid catalyst first, even if the N-methylolacrylamide crystals are dissolved when alcohol is added, N-methylolacrylamide does not decompose to the starting material side. In addition, at the time of addition, a small amount of an acid catalyst is first added to stop the equilibrium reaction, then alcohol is added to dissolve N-methylolacrylamide, and then the remaining acid catalyst is added to obtain an accurate pH in the etherification reaction. Adjustment becomes easy.

Examples of the acid catalyst include inorganic acids such as sulfuric acid and phosphoric acid;
Alternatively, organic acids such as oxalic acid, malonic acid, phthalic acid and paratoluenesulfonic acid are used.

After the etherification reaction, the product is usually concentrated to remove excess alcohol and water, and the product is concentrated. From the viewpoint of preventing an increase in vinyl monomer impurities during the concentration, the concentration is performed with an alkali such as NaOH. It is preferable to carry out after neutralization.

By the above method, the content of acrylamide and formaldehyde is small, specifically, the product of the acrylamide content and the formaldehyde content is 10%.
It is possible to obtain N-alkoxymethylacrylamide of not more than% by mass. Such N-alkoxymethylacrylamide is not only less burdensome for removing acrylamide and formaldehyde, but also industrially extremely useful in terms of safety and health or environmental measures because acrylamide and formaldehyde are harmful substances.

[Production of N-methylol acrylamide crystals] In the case of producing N-methylol acrylamide crystals, a reaction solvent, acrylamide, an alkali catalyst, formaldehyde, and a polymerization inhibitor, if necessary, are charged.

As the reaction solvent, alcohol, water, or a mixture of alcohol and water is used. In order to increase the reaction rate of the N-methylolation reaction during the aging reaction, the reaction solvent is inert to xylene and the like. A solvent that promotes crystallization of N-methylolacrylamide can be added at the time of charging the reaction solvent or during the reaction. When N-methylolacrylamide crystals are continuously produced in batches, it is preferable to use, as a reaction solvent, a separated filtrate and a crystal washing waste liquid discharged during the production in the previous batch from the viewpoint of improving the yield. When the separated filtrate and the crystal washing waste liquid discharged during the production in the previous batch are used as the reaction solvent, and when the crystals are separated without neutralizing the slurry liquid with acid at the time of obtaining the crystals in the previous batch, In addition, the amount of the alkali catalyst used can be reduced.

As the alcohol, methyl alcohol, ethyl alcohol, propyl alcohol and butyl alcohol can be used. When an alcohol is used as the reaction solvent, it is preferable to select the type of alcohol in consideration of the operability at the time of producing N-methylolacrylamide, the method of drying wet crystals, and the like. From the viewpoint of easy drying of the obtained N-methylolacrylamide wet crystals, it is recommended to use methyl alcohol having a low boiling point, but from the viewpoint of easy adjustment of the slurry concentration during the aging reaction, propyl alcohol or butyl alcohol is used. It is recommended to use an alcohol which is more difficult to dissolve N-methylolacrylamide than methyl alcohol.

When water is used as a reaction solvent, the solubility of N-methylolacrylamide in water is high, so that N-methylolacrylamide is not contained in the separated filtrate at the time of crystal acquisition or in the crystal washing waste liquid.
Due to the large amount of methylolacrylamide effluent, it is preferable that the production be performed continuously for a plurality of batches, and the separated filtrate and the crystal washing waste liquid be used as the reaction solvent in the next batch.

The amount of the reaction solvent used for acrylamide depends on the aging reaction temperature and the type of the reaction solvent, but is preferably 0.04 to 1.0, more preferably 0.07 to 0.5.
It is mass times. When the filtrate discharged in the previous batch and the crystal washing waste liquid are used as the reaction solvent, the content ratio of the reaction solvent to N-methylolacrylamide in the slurry liquid after the completion of the aging reaction is the filtrate discharged in the previous batch. ,
The filtrate, the crystal washing waste liquid, and the reaction raw materials are charged so that the crystal washing waste liquid is in the same range as when not recycled.

As formaldehyde, a formaldehyde polymer is generally used. As the formaldehyde polymer, lower polyoxymethylene glycol, paraformaldehyde, α-polyoxymethylene, β-polyoxymethylene and the like can be used, but usually paraformaldehyde is used. In place of the formaldehyde polymer, an aqueous formaldehyde solution, in particular, a high-concentration aqueous formaldehyde solution can be used. When an aqueous formaldehyde solution is used, the formaldehyde concentration is preferably at least 40%, more preferably at least 50%. The amount of formaldehyde to be used relative to acrylamide is preferably 0.7 to 1.3, more preferably 0.9 to 1.1 in a molar ratio.

Also in the case of producing N-methylolacrylamide crystals, it is preferable to carry out the N-methylolation reaction at a high concentration, as in the case of producing N-alkoxymethylacrylamide. By taking measures to ensure the fluidity, the method of the present invention can be carried out industrially smoothly. That is,
Even in the case of producing N-methylolacrylamide crystals, industrial practice of the present invention is facilitated by dividing and charging both acrylamide and formaldehyde polymer in small amounts. It should be noted that the preparation of acrylamide is carried out while heating because the dissolution is endothermic, and the better the flowability of the preparation of formaldehyde polymer, the longer the required time, the better the fluidity.

In the method of the present invention, unlike the conventional method, it is not necessary to reach the equilibrium during the reaction at a high temperature, and the reaction temperature can be changed to a mild condition after a certain amount of the reaction has progressed, or in the first place. Since the high-temperature reaction can be avoided, the N-methylolation reaction can be performed under reaction conditions in which troubles such as polymerization are unlikely to occur as compared with the conventionally proposed method. However, in order to prevent unexpected polymerization, HQ, MEHQ, etc. The reaction is preferably carried out in the presence of a polymerization inhibitor commonly used industrially. The polymerization inhibitors can be used alone or as a mixture.

As the alkali catalyst, lithium hydroxide,
Alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide, sodium carbonate, potassium carbonate, trisodium phosphate, disodium phosphate, pyrophosphoric acid Salts of weak acids and strong alkalis such as sodium, tripotassium phosphate, dipotassium phosphate, etc., tertiary amines such as triethylamine, alkali metal alkoxides such as sodium methoxide and potassium ethoxide, etc. alone or in combination of two or more Can be used. The amount of the alkali catalyst used depends on the strength of the alkali catalyst as an alkali and the type of the reaction solvent, but the pH of the reaction solution is preferably 8 or more,
More preferably, the amount is 9 to 13.

The order of charging is not particularly limited, but considering the production in a factory, a reaction solvent, a polymerization inhibitor if necessary,
Generally, acrylamide, an alkali catalyst, and a formaldehyde polymer are charged in this order, but in the case of charging acrylamide and a formaldehyde polymer, a method in which acrylamide and a formaldehyde polymer are alternately added in small amounts, respectively, is also a preferable method. A solvent which is inert to the reaction such as xylene and promotes crystallization of N-methylolacrylamide can be added at the time of charging the reaction solvent or during the reaction. When a high-concentration aqueous formaldehyde solution is used instead of the formaldehyde polymer, it is preferable to first charge the aqueous formaldehyde solution. In the method of the present invention, after charging the N-methylolation reaction raw material, the N-methylolation reaction is carried out by heating to a predetermined temperature, and after the formaldehyde polymer is almost or completely dissolved, cooling is performed as necessary. A typical embodiment of the present invention is to carry out an aging reaction in a state where N-methylolacrylamide crystals are precipitated. However, after charging N-methylolation reaction raw materials, N-methylolation is carried out without heating. The reaction is performed, and the aging reaction is performed in a state where the N-methylolacrylamide crystals are precipitated, thereby suppressing the generation of by-products and preparing an N-methylolated slurry liquid having a high production rate of N-methylolacrylamide. be able to.

In the case of producing N-methylolacrylamide crystals, the control of the reaction is facilitated by adding separately prepared N-methylolacrylamide crystals as seed crystals.

The temperature and time required for the formaldehyde polymer to be substantially or completely dissolved are greatly affected by the pH of the reaction solution and the type and amount of the reaction solvent.
-80 ° C, 0.1-10 hours, more preferably 20-6
0 ° C., 0.2 to 6 hours. The aging reaction temperature is also closely related to the pH of the reaction solution, the type and amount of the reaction solvent, and the aging reaction time. However, from the viewpoint that the aging reaction is carried out in a state where N-methylolacrylamide crystals are precipitated, it is preferably 0. To 50 ° C, more preferably 15 to 35 ° C. The aging reaction time is preferably from 2 to 48 hours, and more preferably from 4 to 20 hours. When the aging reaction time at 15 ° C. or more is 3 hours or less, the pH of the reaction solution during the aging reaction is 1 pH.
It is preferable to increase the reaction rate during the aging reaction to 0.5 or more. The alkali catalyst for increasing the pH can be charged in its entirety at the time of charging the raw materials for the methylolation reaction, or can be added in portions and added during the reaction.

After the completion of the aging reaction, the N-methylol acrylamide wet crystals are separated and obtained according to a conventional method, either as it is or after further cooling the slurry to lower the solubility of N-methylol acrylamide.

[Production of an aqueous solution of N-methylolacrylamide] When an aqueous solution is produced in the production of N-methylolacrylamide, water, acrylamide, an alkali catalyst, formaldehyde, and a polymerization inhibitor, if necessary, are charged. In the preparation, an aqueous acrylamide solution may be used instead of water and acrylamide, or an aqueous formaldehyde solution, particularly a high-concentration aqueous formaldehyde solution, may be used instead of water and the formaldehyde polymer. When an aqueous formaldehyde solution is used, the formaldehyde concentration is preferably at least 40%, more preferably at least 50%. Moreover, it can also be charged using an N-methylolacrylamide aqueous solution as a reaction solvent.

The amount of water used for acrylamide depends on the aging reaction temperature, but is preferably 0.04 to 0.6 times by mass, and more preferably 0.07 to 0.4 times by mass. N
-When an aqueous methylolacrylamide solution is used as the reaction solvent, the content ratio of water to N-methylolacrylamide in the reaction solution after the reaction is within the same range as when the aqueous N-methylolacrylamide solution is not used as the reaction solvent. , An N-methylolacrylamide aqueous solution and a reaction raw material are charged.

As the alkaline catalyst, lithium hydroxide,
Alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide, sodium carbonate, potassium carbonate, trisodium phosphate, disodium phosphate, pyrophosphoric acid Salts of weak acids and strong alkalis such as sodium, tripotassium phosphate, dipotassium phosphate, etc., tertiary amines such as triethylamine, alkali metal alkoxides such as sodium methoxide and potassium ethoxide, etc. alone or in combination of two or more Can be used. The amount of the alkali catalyst used depends on the strength of the alkali catalyst as an alkali, but is preferably an amount that makes the pH of the reaction mixture 8 or more, more preferably 9 to 13.

As formaldehyde, a formaldehyde polymer is generally used. As the formaldehyde polymer, lower polyoxymethylene glycol, paraformaldehyde, α-polyoxymethylene, β-polyoxymethylene and the like can be used, but usually paraformaldehyde is used. Instead of the formaldehyde polymer, an aqueous formaldehyde solution having a high formaldehyde concentration can be used.

The preferred amount of formaldehyde to acrylamide is 0.7 to 1.1, more preferably 0.8 to 1.05, in a molar ratio. In the production of an aqueous solution of N-methylolacrylamide, it is preferable to carry out the reaction in the presence of an industrially commonly used polymerization inhibitor such as HQ and MEHQ in order to prevent unexpected polymerization. The polymerization inhibitors can be used alone or as a mixture.

The order of preparation is not particularly limited, but generally, water, a polymerization inhibitor, if necessary, an acrylamide, an alkali catalyst, and a formaldehyde polymer are charged in this order. A method of alternately adding a small amount each time is also preferable. In addition, acrylamide aqueous solution, high concentration formaldehyde aqueous solution, or N-
When an aqueous solution of methylolacrylamide is used, it is preferable to charge these aqueous solutions first.

In the case of producing an aqueous solution of N-methylolacrylamide, it is preferable that the solubility of N-methylolacrylamide in water is higher than that in alcohol and that the amount of the solvent used is smaller than in the case of reacting with an alcohol solvent. In addition, consideration for ensuring good fluidity of the slurry liquid at the time of charging the reaction raw materials becomes even more important. That is, even in the case of producing an aqueous solution of N-methylolacrylamide, if the acrylamide and the formaldehyde polymer are separately charged little by little, the practice of the present invention on an industrial scale becomes easy. It should be noted that the preparation of acrylamide is carried out while heating because the dissolution is endothermic, and the longer the time required for preparation of the formaldehyde polymer, the better the fluidity.

In one embodiment of the method of the present invention, the N-methylolation reaction raw material is charged and then heated to carry out the N-methylolation reaction, and if necessary, after the formaldehyde polymer is substantially or completely dissolved. After cooling, the ripening reaction is carried out in a state where N-methylol acrylamide crystals are precipitated. After charging the N-methylol acrylamide raw materials, the N-methylol acrylamide crystals are reacted without heating, and then the N-methylol acrylamide crystals Even when the aging reaction is carried out in a state in which N- is precipitated, N-
An aqueous methylolacrylamide solution can be produced.

In the case of producing an aqueous solution of N-methylolacrylamide, the addition of separately prepared N-methylolacrylamide crystals is recommended.

The temperature and time required for the formaldehyde polymer to be substantially or completely dissolved are greatly affected by the pH of the reaction solution and the type and amount of the reaction solvent.
80 ° C., 0.1 to 10 hours, more preferably 20 to 60
° C, 0.2 to 6 hours. The aging reaction temperature is p
H, the type and amount of the reaction solvent, there is a close relationship with the aging reaction time, from the viewpoint of performing the aging reaction in the state where N-methylolacrylamide crystals are precipitated, preferably 0 ~ 50 ℃, more preferably 15-35 ° C. The aging reaction time is preferably within 48 hours after N-methylol acrylamide crystals started to crystallize, more preferably 2 hours.
~ 20 hours. When performing the aging reaction in a short time,
From the viewpoint of the reaction rate, it is recommended to set the pH of the reaction solution during the aging reaction to a higher value.

After completion of the aging reaction, the mixture is neutralized and stabilized by adding an acid such as oxalic acid or sulfuric acid.
An aqueous methylol acrylamide solution is obtained.

According to the above method, the product of the acrylamide and formaldehyde content is small, specifically, the product of the mass concentration ratio of acrylamide and formaldehyde to N-methylolacrylamide is 20 × 10
^An aqueous solution of N-methylolacrylamide of not more than ^-4 can be obtained. Such an aqueous solution not only has a small burden of removing acrylamide and formaldehyde, but also is industrially extremely useful in terms of safety and health or environmental measures since acrylamide and formaldehyde are harmful substances.

[0071]

EXAMPLES Hereinafter, typical examples of the present invention will be described more specifically with reference to examples. Unless otherwise specified below,
[%] Means [% by mass], and the pH of the reaction solution is a value measured without dilution. In the table that summarizes the experimental results, AA is acrylamide, HCHO is formaldehyde, NMAA
Represents N-methylolacrylamide, NMMA represents N-methoxymethylacrylamide, NEMA represents N-ethoxymethylacrylamide, NIPMA represents N-isopropoxymethylacrylamide, and NBMA represents Nn-butoxymethylacrylamide. Further, acrylamide and N
-Methylol acrylamide is HPLC method, formaldehyde is replaced with 1N sodium hydroxide and 1N acid,
A titration method using ammonium chloride (Imoto, Kakiuchi, Huang et al., Edited by "Formaldehyde-Its Chemistry and Applications-"), 415, Asakura Shoten (1965), except that 1 / 10N sodium hydroxide and 1 / 10N hydrochloric acid were used. )). The HPLC analysis was performed using Inertsil C4.
5 μm, 4.6 × 250 mm (GL Sciences
Inc. By using the external standard method.

Example 1 A device equipped with a stirrer, a thermometer, a condenser and an air inlet tube was prepared.
L at room temperature in a separable flask of L, methanol 58g,
0.5 g of MEHQ was charged, and 215.4 g of 99% acrylamide was added little by little over 20 minutes while heating so that the liquid temperature became 30 to 35 ° C. Then, after adding 1.2 g of triethylamine, 102.8 g of 92% paraformaldehyde was added little by little over 20 minutes while maintaining the internal temperature at 30 to 33 ° C. This is heated to 51-
Hold at 53 ° C. for 0.8 hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 30 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution before adding the seed crystal was 10.8.
Met. It took 1 hour from the addition of the seed crystal to carry out an aging reaction while cooling to 20 ° C, and then an aging reaction at 18 to 20 ° C for 12 hours.

After the aging reaction, 1 g of oxalic acid and 4 g of methanol
After adding 23 g and oxalic acid (2.1 g) to adjust the pH to 3.0, the mixture was reacted at 70 to 71 ° C. for 6 hours under normal pressure while introducing air to obtain 794.2 g of a reaction solution. 30 of the reaction solution
0 g with 10% aqueous sodium hydroxide solution 3.8 g
After the mixture was adjusted to 7.0, it was divided and charged in a 300 cc eggplant type flask, and concentrated under reduced pressure to 0.5% of water while introducing air, whereby the liquid amount became 127.6 g. Table 1 shows the yield of N-methoxymethylacrylamide based on acrylamide after concentration under reduced pressure, the concentration of acrylamide and formaldehyde HCHO, the concentration product, the loss of formaldehyde, and the residual ratio of acrylamide.

The solid yield was determined from the following equation. ALM in the formula
A represents alkoxymethylacrylamide.

[0076]

(Equation 1)

Example 2 1 provided with a stirrer, a thermometer, a condenser, and an air inlet tube
L at room temperature in a separable flask of L, methanol 58g,
0.5 g of MEHQ was charged, and 215.4 g of 99% acrylamide was added little by little over 20 minutes while heating so that the liquid temperature became 30 to 35 ° C. Then, after adding 1.2 g of triethylamine, 102.8 g of 92% paraformaldehyde was added little by little over 20 minutes while maintaining the internal temperature at 30 to 33 ° C. This is heated to 51-
It was kept at 53 ° C. for 1 hour. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 30 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution before adding the seed crystal was 10.8.
Met. An aging reaction was performed while cooling to 25 ° C., which took 1 hour from the addition of the seed crystal, and then an aging reaction was performed at 25 ° C. for 1.5 hours. After aging reaction for a total of 2.5 hours, 1 g of oxalic acid, 423 g of methanol, and 2.1 g of oxalic acid were added to the solution, and the pH was adjusted.
2.9 and then 70 to 7 under normal pressure while introducing air
The reaction was carried out at 1 ° C. for 6 hours to obtain 795.0 g of a reaction solution. 300 g of the reaction solution was placed in a 10% aqueous sodium hydroxide solution 4.4.
After adjusting the pH to 7.6 with g, the liquid was divided and charged in a 300 cc eggplant-shaped flask, and the water content was adjusted to 0.1 while introducing air.
After concentration under reduced pressure to 6%, the liquid amount was 128.2 g. Table 1 shows the yield of N-methoxymethylacrylamide based on acrylamide after concentration under reduced pressure, the concentration of acrylamide and formaldehyde, the concentration product, the loss of formaldehyde, and the residual ratio of acrylamide.

Comparative Example 1 A stirrer, a thermometer, a condenser, and an air inlet tube were provided.
In a separable flask of L, methanol at room temperature, 77 g,
MEHQ 0.5 g, 99% acrylamide 215.4
g, 1.2 g of triethylamine and 102.8 g of 92% paraformaldehyde, and then heated while stirring with almost no liquid components. Dissolution of raw materials during heating,
Liquefaction progressed, and the mixture was kept at 51 to 53 ° C. for 1.5 hours to confirm that paraformaldehyde was completely dissolved and no crystals were precipitated.

Next, 403 g of methanol and 3.2 of oxalic acid were used.
g was added to adjust the pH to 3.0, and the mixture was reacted at 70 to 71 ° C. for 6 hours under normal pressure while introducing air to obtain 795 g of a reaction solution.

After adjusting 300 g of the reaction solution to pH 7.2 with 4.2 g of 10% aqueous sodium hydroxide solution, 300 cc
And the mixture was concentrated under reduced pressure while introducing air until the water content became 0.6%. As a result, the mass of the liquid became 126.0 g. N-methoxymethylacrylamide based acrylamide yield after concentration under reduced pressure, acrylamide and formaldehyde concentration, concentration product,
Table 1 shows the loss of formaldehyde and the residual ratio of acrylamide.
It writes in.

As shown in Table 1, during the production of N-methoxymethylacrylamide (including N-methylolation reaction), the loss of formaldehyde to the outside of the reaction system with respect to the charge was increased by 4.6% as compared with Example 1. Not only A
A residual rate is 8.1% higher, and the remaining acrylamide is N-
The result is an increase in the apparent (apparent) yield of methoxymethylacrylamide.

Example 3 1 provided with a stirrer, a thermometer, a condenser, and an air inlet tube
L in a separable flask at room temperature, ethanol 69g,
0.5 g of MEHQ was charged, and 179.4 g of 99% acrylamide was gradually added thereto over 20 minutes while heating so that the liquid temperature became 30 to 35 ° C. Next, after adding 0.8 g of triethylamine, 85.7 g of 92% paraformaldehyde was added while maintaining the internal temperature at 30 to 33 ° C.
It took 0 minutes and added little by little. The temperature was raised and kept at 54-56 ° C for 0.5 hour. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 33 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution before adding the seed crystal was 10.6.
Met. The aging reaction was performed while cooling to 26 ° C. for 2 hours after the addition of the seed crystal, and then the aging reaction was performed at 24 to 26 ° C. for 12 hours.

The reaction mixture contained 1 g of oxalic acid, 507 g of ethanol,
Further, 2.5 g of oxalic acid was added to adjust the pH to 3.1, and the mixture was reacted at 79 to 81 ° C. for 7 hours under normal pressure while introducing air to obtain 839.4 g of a reaction solution. The reaction solution (300 g) was adjusted to pH 7.5 with a 10% aqueous sodium hydroxide solution (5.3 g), and the pH was adjusted to 30
The mixture was charged in a 0 cc eggplant-shaped flask and concentrated under reduced pressure while introducing air to reduce the water content to 0.3% by mass. As a result, the mass of the liquid became 113.8 g. The yield of N-ethoxymethylacrylamide based on acrylamide,
Table 1 shows the concentration of acrylamide and formaldehyde, the concentration product, the loss of formaldehyde, and the residual ratio of acrylamide.

Example 4 1 provided with a stirrer, a thermometer, a condenser, and an air inlet tube
In a separable flask of L, 66 g of isopropyl alcohol and 0.5 g of MEHQ were charged at room temperature.
143.6 g of 9% acrylamide with a liquid temperature of 30 to 35 ° C
The mixture was added little by little over 20 minutes while heating so that Next, after adding 0.6 g of triethylamine, 68.5 g of 92% paraformaldehyde was added little by little over 20 minutes while maintaining the internal temperature at 30 to 33 ° C. This was heated and kept at 53-55 ° C for 1 hour. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 30 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution before adding the seed crystal was 10.4.
Met. The aging reaction was performed while cooling to 26 ° C. for 2 hours after the addition of the seed crystal, and then the aging reaction was performed at 24 to 26 ° C. for 12 hours.

1 g of oxalic acid, 500 g of isopropyl alcohol, and 4.3 g of oxalic acid were added to the reaction solution, and the mixture was reacted at 84 to 85 ° C. for 8 hours under normal pressure while introducing air to obtain 777.7 g of a reaction solution. After 360 g of the reaction solution was adjusted to pH 7.1 with 13.7 g of a 10% aqueous sodium hydroxide solution,
The mixture was separately charged into a 300 cc eggplant-shaped flask, and concentrated under reduced pressure while introducing air to reduce the water content to 0.1%. The mass of the liquid became 125.4 g. Table 1 shows the yield of N-isopropoxymethylacrylamide based on acrylamide, the concentration of acrylamide and formaldehyde, the concentration product, the loss of formaldehyde, and the residual acrylamide ratio.

Example 5 In a 1 L separable flask used in Example 1 in which a condenser with a stationary liquid separating device was set instead of the condenser, 67 g of n-butyl alcohol, MEHQ
0.5g was charged and 99% acrylamide 14
3.6 g was added little by little over 20 minutes while heating so that the liquid temperature became 30 to 35 ° C. Then, after adding 0.5 g of a 10% aqueous sodium hydroxide solution, the internal temperature was raised to 30 to 3%.
92% paraformaldehyde 68.5 while keeping at 3 ° C.
g was added in small portions over 20 minutes. This is heated and 5
Hold at 6-58 ° C for 0.4 hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 30 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution was 10.7 before adding the seed crystal. It took 1 hour from the addition of the seed crystal to carry out the aging reaction while cooling to 23 ° C, and then the aging reaction at 21 to 23 ° C for 15 hours.

After adding 1 g of oxalic acid, 527 g of n-butyl alcohol and 1 g of oxalic acid to the reaction mixture, air is introduced, and water is extracted from the stationary liquid separating apparatus at 90 to 95 ° C. while 6.5.
The mixture was refluxed under reduced pressure for an hour to obtain 735.7 g of a reaction solution. 420 g of the reaction solution was treated with a 10% by mass aqueous solution of sodium hydroxide 6.2.
g to pH 7.0, divided into 300 cc eggplant-shaped flasks and charged, and while introducing air, the water content is 0.1%.
The solution was concentrated under reduced pressure until the mass became 191.4.
g. Table 1 shows the appearance yield of Nn-butoxymethylacrylamide based on acrylamide, the concentration of acrylamide and formaldehyde, the concentration product, the loss of formaldehyde, and the residual acrylamide ratio.

Comparative Example 2 111 g of n-butyl alcohol and MEHQ were added at room temperature to the 1 L separable flask used in Example 1 in which a condenser with a stationary liquid separating device was set instead of the condenser.
0.5 g, 99% acrylamide 143.6 g, 10%
After charging 0.5 g of an aqueous sodium hydroxide solution and 68.5 g of 92% paraformaldehyde, the temperature was raised while stirring, and the mixture was kept at 56 to 58 ° C. for 1.8 hours to confirm that paraformaldehyde was completely dissolved. It was confirmed that there was no precipitation.

Next, 482 g of n-butyl alcohol and 2 g of oxalic acid were added to adjust the pH to 1.9, air was introduced, and water was removed from the stationary liquid separating apparatus at 90 to 95 ° C.
The mixture was refluxed under reduced pressure for 6.5 hours to obtain 736.3 g of a reaction solution.

420 g of the reaction solution was adjusted to pH 6.8 with 6.1 g of a 10% aqueous sodium hydroxide solution, and then 300 cc.
And the mixture was concentrated under reduced pressure while introducing air to reduce the water content to 0.1%. As a result, the mass of the liquid was 184.9 g. Acrylamide standard N
Table 1 shows the appearance yield of -n-butoxymethylacrylamide, the concentration of acrylamide and formaldehyde, the concentration product, the loss of formaldehyde, and the residual ratio of acrylamide.

As shown in Table 1, when N-butoxymethylacrylamide was produced (containing N-methylolation reaction), the loss of formaldehyde to the outside of the reaction system with respect to the charge was increased by 4.0% as compared with Example 2. Not only A
A residual ratio was 4.6% higher and the remaining acrylamide was N-
The result is an increase in the apparent (apparent) yield of butoxymethylacrylamide.

[0096]

[Table 1]

In the table, HCHO loss (%) is the amount of HCHO loss during the production of N-alkoxymethylacrylamide (containing N-methylolation reaction), and was calculated by the following equation. In calculating the HCHO loss (%), a) no side reaction of the charged AA occurs, b) AA and HC
It is assumed that HO reacts on a one-to-one basis, and when AA side reaction occurs, AA may have a negative HCHO loss (%). The calculation method of the AA residual rate is also shown below.

[0098]

(Equation 2)

Example 6 A 1 L separable flask equipped with a stirrer, a thermometer and a condenser was charged with 72 g of water and 0.7 g of MEHQ, and 301.6 g of 99% acrylamide was added at a liquid temperature of 30 to 30%.
The mixture was added little by little over 20 minutes while warming to 35 ° C. Next, after 0.5 g of triethylamine was added, 130.6 g of 92% paraformaldehyde was added little by little over 20 minutes while maintaining the internal temperature at 30 to 33 ° C. The temperature was raised and kept at 51 to 53 ° C for 0.5 hour.
At this point, the heat generated by the heat of reaction had subsided.

After cooling to 31 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. In addition, pH before adding a seed crystal is 10.4,
No crystals were precipitated. 2 hours from seeding to 21
C., and then aged at 19-21.degree. C. for 12 hours. Next, the mixture was cooled to 5 ° C. for 2 hours, and kept at 5 ° C. for 1 hour. After a total of 17 hours of aging reaction, N-methylolacrylamide crystals were suction-filtered. MEHQ
After washing with 75 g of water cooled to 5 ° C. containing 0.2 g, 213.3 g of wet crystals, a mixed solution of a filtrate and a crystal washing waste liquid 357.
2 g, and the entire amount of wet crystals was dried under reduced pressure to obtain N.
-193.9 g of methylolacrylamide crystals were obtained. Table 2 shows the acquisition yield of N-methylolacrylamide crystals, the concentration of acrylamide and formaldehyde in the filtrate and the waste liquid for washing the crystal, and the concentration product.

Example 7 49.5 N-methylolacrylamide was placed in a 1 L separable flask equipped with a stirrer, a thermometer and a condenser.
% Of acrylamide, 5.5% of acrylamide, 0.65% of formaldehyde, and 39.5% of water.
% Acrylamide was added little by little over 15 minutes while heating so that the liquid temperature became 25 to 30 ° C.
Then, while maintaining the internal temperature at 25 to 28 ° C, 131.9 g of 92% paraformaldehyde was added little by little over 15 minutes, the temperature was raised, and the temperature was maintained at 51 to 53 ° C for 0.7 hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 28 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. In addition, pH before adding a seed crystal is 10.0,
No crystals were precipitated. 2 hours from seeding to 21
C., and then aged at 19-21.degree. C. for 12 hours. Next, the mixture was cooled to 3 ° C. for 2 hours, and kept at 3 ° C. for 1 hour. After a total of 17 hours of aging reaction, N-methylolacrylamide crystals were filtered by suction. MEHQ
Washed with 90 g of water cooled to 5 ° C. containing 0.2 g, 293.1 g of wet crystals, and a mixed liquid of a filtrate and a crystal washing waste liquid 520.
2 g were obtained. The whole amount of the wet crystals was dried under reduced pressure to obtain 263.1 g of N-methylolacrylamide crystals. Acquisition yield of N-methylolacrylamide crystals,
Table 2 shows the concentrations and concentration products of acrylamide and formaldehyde in the mixed solution of the filtrate and the crystal washing waste liquid.

Incidentally, 17.3 g (315 × 0.055) of acrylamide and 109.6 g (315 × 0.495 × 7) were contained in the mixture of the filtrate of Example 6 and the crystal washing waste liquid.
N-methylol acrylamide corresponding to acrylamide of 1.08 / 101.11) is contained, and 284.4 g of pure acrylamide (287.3 × 0.
99), the composition of the slurry after the aging reaction becomes 41
This is the same as the N-methylolation reaction using 1.3 g of acrylamide. Similarly, 124.4 g (315 × 0.3) was contained in the mixture of the filtrate of Example 6 and the crystal washing waste liquid.
This means that the water of 95) has been charged.

Example 8 72 g of water and 0.7 g of MEHQ were charged into a 1 L separable flask equipped with a stirrer, a thermometer, and a condenser, and 301.6 g of 99% acrylamide was added thereto.
The mixture was added little by little over 20 minutes while warming to 35 ° C. Next, after 0.5 g of triethylamine was added, 130.6 g of 92% paraformaldehyde was added little by little over 20 minutes while maintaining the internal temperature at 30 to 33 ° C. The temperature was raised and maintained at 51 to 53 ° C for 0.6 hours. At this point, the heat generated by the heat of reaction had subsided.

This was cooled to 28 ° C., and 0.5 g of triethylamine was additionally added to adjust the pH of the reaction solution to 10.8.
At this point, it was confirmed that no crystals had precipitated, and then 0.2 g of N-methylolacrylamide crystals were added as seed crystals. It takes 1 hour from seeding to cool to 26 ° C, then cools to 25-26 ° C for 1 hour, further cools to 4 ° C for 1 hour, keeps it at 4 ° C for 1.5 hours, a total of .5
After the aging reaction, the N-methylolacrylamide crystals were suction-filtered. It was washed with 62 g of water cooled to 5 ° C. containing 0.4 g of MEHQ to obtain 216.3 g of wet crystals and 343.5 g of a mixed solution of a filtrate and a crystal washing waste liquid. The whole amount of the wet crystals was dried under reduced pressure to obtain 199.5 g of N-methylolacrylamide crystals. Table 2 shows the acquisition yield of N-methylolacrylamide crystals, the concentration of acrylamide and formaldehyde in the mixture of the filtrate and the waste liquid for washing the crystals, and the concentration product.

Example 9 A 1 L separable flask equipped with a stirrer, a thermometer and a condenser was charged with 10 g of water and 90 g of isopropyl alcohol.
g and 0.7 g of MEHQ, and 301.6 g of 99% acrylamide was gradually added thereto over 20 minutes while heating so that the liquid temperature became 30 to 35 ° C. Then, after adding 1.5 g of triethylamine, the internal temperature was raised to 30 to 3 g.
While maintaining at 3 ° C., 92% of paraformaldehyde 13
0.6 g was added little by little over 20 minutes. This was heated and kept at 52-54 ° C for 1.2 hours. At this point, the heat generated by the heat of reaction had subsided.

This was cooled to 32 ° C., and 1.5 g of triethylamine was added to adjust the pH of the reaction solution to 10.8.
At this point, it was confirmed that no crystals had precipitated, and then 0.2 g of N-methylolacrylamide crystals were added as seed crystals. After 1.5 hours from the seed crystal addition, the mixture was cooled to 21 ° C., and then aged at 19 to 21 ° C. for 10 hours.
After cooling for 3 hours, the mixture was kept at 3 ° C. for 2 hours, and after aging for a total of 16.5 hours, N-methylolacrylamide crystals were suction-filtered. It was washed with 85 g of isopropyl alcohol cooled to 0 ° C. containing 0.3 g of MEHQ to obtain 309.8 g of wet crystals and 291.8 g of a mixture of a filtrate and a crystal washing waste liquid. The entire amount of the wet crystals was dried under reduced pressure to obtain N-methylolacrylamide crystals 283.1.
g was obtained. Table 2 shows the acquisition yield of N-methylolacrylamide crystals, the concentration of acrylamide and formaldehyde in the mixture of the filtrate and the waste liquid for washing the crystals, and the concentration product.

Comparative Example 3 296 g of water, 0.7 g of MEHQ, 301.6 g of 99% acrylamide, 301.6 g of triethylamine, 0.5 g of triethylamine, and 9 g of water were placed in a 1 L separable flask equipped with a stirrer, a thermometer, and a distillation apparatus.
After charging 130.6 g of 2% paraformaldehyde, the temperature was raised, and the mixture was reacted at 51 to 53 ° C. for 1 hour to confirm that paraformaldehyde was completely dissolved.

After cooling to 40 ° C. and confirming that no crystals were precipitated at this time, 0.3 g of oxalic acid was added to the pH 10.3 reaction solution to adjust the pH to 7.0, and then the internal temperature was lowered to 4 ° C.
While maintaining the temperature at 5 to 50 ° C, the solution was concentrated under reduced pressure until the liquid amount reached 498 g. Then it takes 3 hours to cool down to 3 ° C,
After holding for 1 hour, the N-methylolacrylamide crystals were subjected to suction filtration. It was washed with 70 g of water cooled to 5 ° C. containing 0.3 g of MEHQ to obtain 141.7 g of wet crystals and 421.4 g of a mixed solution of filtrate and crystal washing waste liquid, and the entire amount of wet crystals was dried under reduced pressure to obtain N-. 122.4 g of methylol acrylamide crystals were obtained. Table 2 shows the acquisition yield of N-methylolacrylamide crystals, the concentration of acrylamide and formaldehyde in the mixture of the filtrate and the waste liquid for washing the crystals, and the concentration product.

In the present example, N-methylolacrylamide crystals were crystallized during cooling after concentration, but neutralization was performed before concentration, and the N-methylolation reaction was stopped at this point. No ripening reaction was performed in the presence of crystals.

[0111]

[Table 2]

In the table, Example 7 is based on AA, and the others are HCH.
The O-based NMAA crystal acquisition yield is indicated.

Example 10 A 1 L separable flask equipped with a stirrer, a thermometer and a condenser was charged with 50 g of water and 0.5 g of MEHQ.
To this, 247.7 g of 99% acrylamide was added at a liquid temperature of 30.
It was added little by little over 20 minutes while warming to ~ 35 ° C. Then, a 10% aqueous solution of sodium hydroxide 0.5
g, add 92 g while maintaining the internal temperature at 30 to 33 ° C.
98.0 g of paraformaldehyde was added little by little over 20 minutes. This was heated and kept at 52-54 ° C for 0.3 hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 25 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution before adding the seed crystal was 10.3.
Met. It takes 2 hours from the seed crystal addition to carry out the aging reaction while cooling to 21 ° C., and after the aging reaction at 19-21 ° C. for 15 hours, 0.1 g of oxalic acid and 178 g of water are added, and a 50% aqueous solution of N-methylolacrylamide is added. 572.3 g were obtained. Table 3 shows the results of the analysis of the obtained aqueous solution of N-methylolacrylamide and the products of the concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide.

Example 11 A 1 L separable flask equipped with a stirrer, a thermometer and a condenser was charged with 54 g of water and 0.5 g of MEHQ.
229.8 g of 99% acrylamide was added thereto at a liquid temperature of 30.
It was added little by little over 20 minutes while warming to ~ 35 ° C. Then, 10% aqueous solution of sodium hydroxide 0.4
g, add 92 g while maintaining the internal temperature at 30 to 33 ° C.
98.0 g of paraformaldehyde was added little by little over 20 minutes. This was heated and kept at 52-54 ° C for 0.4 hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 30 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution before adding the seed crystal was 10.0.
Met. The aging reaction was carried out while cooling to 20 ° C. in 2 hours from the seed crystal addition, and after the aging reaction at 18-20 ° C. for 14 hours, 0.1 g of oxalic acid and 175 g of water were added and the concentration was 50%.
555.1 g of an aqueous solution of N-methylolacrylamide was obtained. Table 3 shows the results of the analysis of the obtained aqueous solution of N-methylolacrylamide and the products of the concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide.

Example 12 A 1 L separable flask equipped with a stirrer, a thermometer and a condenser was charged with 72 g of water and 0.5 g of MEHQ.
301.6 g of 99% acrylamide was added thereto at a liquid temperature of 30.
It was added little by little over 20 minutes while warming to ~ 35 ° C. Then, after adding 0.4 g of triethylamine, 130.6 g of 92% paraformaldehyde was added little by little over 20 minutes while maintaining the internal temperature at 30 to 33 ° C. This was heated and kept at 52-54 ° C for 0.6 hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 30 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH before the addition of the seed crystal was 10.4. After 1.5 hours from the addition of the seed crystal, the ripening reaction was carried out while cooling to 26 ° C., and the aging reaction was further performed at 24 to 26 ° C. for 2 hours. Then, 0.3 g of oxalic acid and 215 g of water were added, and a 50% N- 718.4 g of an aqueous methylolacrylamide solution was obtained. Table 3 shows the results of the analysis of the obtained aqueous solution of N-methylolacrylamide and the products of the concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide.

Example 13 A 1 L separable flask equipped with a stirrer, a thermometer and a condenser was charged with 68 g of water and 0.7 g of MEHQ.
295.8 g of 99% acrylamide was added thereto at a liquid temperature of 30.
It was added little by little over 20 minutes while warming to ~ 35 ° C. Next, after 0.5 g of triethylamine was added, 130.6 g of 92% paraformaldehyde was added little by little over 20 minutes while maintaining the internal temperature at 30 to 33 ° C. This was heated and kept at 52-54 ° C for 0.6 hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 28 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH before the addition of the seed crystal was 10.3. After 2 hours from the addition of the seed crystal, an aging reaction was performed while cooling to 21 ° C., and an aging reaction was performed at 19 to 21 ° C. for 11 hours.
0.3 g of oxalic acid and 245 g of water were added to obtain 738.4 g of a 50% aqueous solution of N-methylolacrylamide. The analysis results of the obtained aqueous solution of N-methylolacrylamide and the respective N-methylacrylacrylamide and formaldehyde N-
Table 3 shows the product of the concentration ratio to methylol acrylamide.

Example 14 46 g of water and 0.7 g of MEHQ were placed in a 1 L separable flask equipped with a stirrer, a thermometer, and a condenser.
295.8 g of 99% acrylamide was added thereto at a liquid temperature of 35.
It was added little by little over 20 minutes while heating to ４０40 ° C. Then, after 0.5 g of triethylamine was added, 130.6 g of 92% paraformaldehyde was added little by little over 25 minutes while maintaining the internal temperature at 30 to 33 ° C. This was heated and kept at 54-56 ° C for 0.3 hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 28 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH before the addition of the seed crystal was 10.3. After 2 hours from the seed crystal addition, the ripening reaction was performed while cooling to 21 ° C., and the aging reaction was performed at 19 to 21 ° C. for 12 hours.
0.3 g of oxalic acid and 291 g of water were added to obtain 761.3 g of a 50% aqueous solution of N-methylolacrylamide. The analysis results of the obtained aqueous solution of N-methylolacrylamide and the respective N-methylacrylacrylamide and formaldehyde N-
Table 3 shows the product of the concentration ratio to methylol acrylamide.

Example 15 60 g of water and 0.7 g of MEHQ were placed in a 1 L separable flask equipped with a stirrer, a thermometer, and a condenser.
295.8 g of 99% acrylamide was added thereto at a liquid temperature of 30.
It was added little by little over 20 minutes while warming to ~ 35 ° C. Next, after adding 0.5 g of triethylamine, 130.6 g of 92% paraformaldehyde was added little by little over 30 minutes while maintaining the internal temperature at 25 to 28 ° C. Hold at 25-27 ° C for 5 hours. At this point, the heat generated by the heat of reaction had subsided.

To this, 0.2 g of N-methylolacrylamide crystals were added as seed crystals. It takes 2 hours from the addition of the seed crystal to the aging reaction while cooling to 22 ° C.
After 4 hours of aging reaction, 0.3 g of oxalic acid and 255 g of water were added to obtain 740.3 g of a 50% aqueous solution of N-methylolacrylamide. Table 3 shows the results of the analysis of the obtained aqueous solution of N-methylolacrylamide and the products of the concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide.

Example 16 A 1 L separable flask equipped with a stirrer, a thermometer and a condenser was charged with 67 g of water and 0.7 g of MEHQ.
To this, 287.2 g of 99% acrylamide was added at a liquid temperature of 30.
It was added little by little over 20 minutes while heating to ~ 35 ° C. Then a 10% aqueous solution of sodium hydroxide 0.6
g was added, and the internal temperature was maintained at 30 to 33 ° C.
130.6 g of paraformaldehyde was added little by little over 20 minutes. This was heated to a temperature of
Hold for hours. At this point, the heat generated by the heat of reaction had subsided.

After cooling to 30 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution before adding the seed crystal was 10.2.
Met. The aging reaction was carried out while cooling to 21 ° C. in 2 hours from the addition of the seed crystal, and the aging reaction was carried out at 19 to 21 ° C. for 13 hours. Then, 0.1 g of oxalic acid and 242 g of water were added, and a 50% N-methylolacrylamide aqueous solution was added. 725.8 g were obtained. Table 3 shows the results of the analysis of the obtained aqueous solution of N-methylolacrylamide and the products of the concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide.

Comparative Example 4 200 g of water, 0.5 g of MEHQ, 247.7 g of 99% acrylamide, 0.5 g of 10% aqueous sodium hydroxide solution, 0.5 g of 92% paraformaldehyde 98 were placed in a 1 L separable flask equipped with a stirrer, thermometer and condenser. 0.0g
After heating, the mixture was heated and reacted at 52 to 54 ° C. for 5 hours to confirm that paraformaldehyde was completely dissolved.

After cooling to 30 ° C. and confirming that no crystals were precipitated at this time, 0.1 g of oxalic acid and 1 g of water were added.
Was added to obtain 545.2 g of a 45% aqueous solution of N-methylolacrylamide. Table 3 shows the results of the analysis of the obtained aqueous solution of N-methylolacrylamide and the products of the concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide.

Comparative Example 5 300 g of water, 0.7 g of MEHQ, 295.8 g of 99% acrylamide and 0.58 g of triethylamine were placed in a 1 L separable flask equipped with a stirrer, a thermometer and a condenser.
g, 130.6 g of 92% paraformaldehyde, and then heated, and reacted at 52 to 54 ° C. for 2 hours to confirm that paraformaldehyde was completely dissolved.

After cooling to 30 ° C. and confirming that no crystals were precipitated at this time, 0.3 g of oxalic acid and 18 g of water were added.
g was added to obtain 742.7 g of an aqueous solution of N-methylolacrylamide having a concentration of 45%. Table 3 shows the results of the analysis of the obtained aqueous solution of N-methylolacrylamide and the products of the concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide.

Example 17 26 g of water, 0.5 g of MEHQ and 0.3 g of triethylamine were charged into a 1 L separable flask equipped with a stirrer, a thermometer and a condenser, and 287.2 g of 99% acrylamide and 92% of 92% paraffin were added thereto. Formaldehyde 13
3.2 g were alternately added little by little over 40 minutes while heating so that the liquid temperature became 25 to 30 ° C. This is heated,
It was kept at 50-52 ° C for 0.6 hours. At this point, the heat generated by the heat of reaction had subsided. Next, after cooling to 35 ° C., 0.2 g of N-methylolacrylamide crystals were added as seed crystals. The pH of the reaction solution before the addition of the seed crystal was 9.9. 23 hours after 2 hours from seeding
After aging reaction while cooling to ℃, then aging reaction at 21-23 ℃ for 12 hours, 0.2 g of oxalic acid and 321 g of water were added to obtain 766.5 g of a 50% aqueous solution of N-methylolacrylamide. Table 3 shows the results of the analysis of the obtained aqueous solution of N-methylolacrylamide and the products of the concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide.

[0132]

[Table 3]

In the table, the NMAA generation rate in Example 17 is based on the charged AA, and the others are based on the charged HCHO. The HCHO conversion rate and the HCHO selectivity were determined from the following equations.

[0134]

(Equation 3)

[0135]

According to the method of the present invention, high-purity N-alkoxymethylacrylamide can be produced without using a large excess of formaldehyde or introducing a complicated purification step. Further, N-methylolacrylamide crystals can be efficiently obtained by the method of the present invention. Further, by the method of the present invention, an N-methylolacrylamide aqueous solution having a small content of formaldehyde and by-products can be easily produced.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4H006 AA02 AC41 AC43 AD15 BA02 BA29 BA51 BA66 BB14 BB31 BE10 BN10 BP10 BV30 4H039 CA60 CA61 CD30 CF30

Claims (5)

[Claims] 1. A compound of the formula (1) containing acrylamide, formaldehyde and alcohol as main raw materials. (Wherein, R represents an alkyl group having 1 to 4 carbon atoms) in a method for producing N-alkoxymethylacrylamide represented by the following formula: Acrylamide and formaldehyde are used as solvents in the presence of
A step of reacting the alcohol with the product of the N-methylolation reaction in the presence of an acid catalyst to produce the N-alkoxymethylacrylamide. In carrying out the reaction, the formula (2) A method for producing N-alkoxymethylacrylamide, comprising performing an aging reaction for N-methylolation in the presence of N-methylolacrylamide crystals represented by the formula: 2. An acrylamide and formaldehyde are reacted with N-methylol in the presence of an alkali catalyst using alcohol, water or a mixed solvent of alcohol and water as a main reaction solvent to obtain a compound of the formula (2). A method for producing a crystal of N-methylol acrylamide represented by the formula: wherein the ripening reaction for N-methylol acrylamide is carried out in the presence of the crystal of N-methylol acrylamide. 3. An acrylamide and formaldehyde are reacted with N-methylol in the presence of an alkali catalyst using water as a main reaction solvent to obtain a compound of the formula (2). A method for producing an aqueous solution of N-methylolacrylamide represented by the formula: wherein an aging reaction of N-methylol acrylamide is carried out in the presence of N-methylolacrylamide crystals. 4. Manufactured by the method of claim 1,
N-alkoxymethylacrylamide, wherein the product of the acrylamide content and the formaldehyde content is 10% by mass or less by mass. 5. Manufactured by the method of claim 3,
An aqueous solution of N-methylolacrylamide, wherein the product of the mass concentration ratios of acrylamide and formaldehyde to N-methylolacrylamide is 20 × 10 ⁻⁴ or less.