JP4782606B2 - Method for storing N-alkenylcarboxylic acid tertiary amide - Google Patents

Description

  The present invention relates to a method for stably storing an N-alkenylcarboxylic acid tertiary amide for a long period of time.

  N-vinyl-2-pyrrolidone, an N-alkenylcarboxylic acid tertiary amide, is useful as a reactive diluent, and the polymer has advantages and advantages such as biocompatibility, safety, and hydrophilicity. Therefore, it has been widely used in various fields such as pharmaceuticals, cosmetics, adhesives, paints, dispersants, inks, electronic parts, and photoresist materials.

  By the way, N-vinyl-2-pyrrolidone is known to have properties such as polymerization reactivity, pH, contained polymer concentration, and color value that change with time during storage. N-vinyl-2-pyrrolidone has difficulty in handling such as the need to use it immediately after synthesis. Therefore, N-vinyl-2-pyrrolidone has been strongly required to be stable during storage.

  A polymer of N-vinyl-2-pyrrolidone is generally a radical polymerization method using a hydrogen peroxide, an organic peroxide, or an azo organic compound as a polymerization initiator in a polar solvent such as water or alcohol. Is produced industrially.

  As is known in the case of acrylic acid and the like, such a method for handling a radical polymerizable compound needs to be handled while avoiding radical polymerization caused by radicals generated during storage. Therefore, it is known to add a compound having radical scavenging ability represented by quinones as a stabilizer. In addition, for long-term storage, it is common to store in a dark place.

  On the other hand, it is common to add a basic substance to stabilize pH and the like. For this reason, a method of adding ammonia, N, N′-di-sec-butyl-p-phenylenediamine, sodium hydroxide or the like has been proposed for the purpose of suppressing the quality change (see, for example, Patent Document 1). .)

  Patent Document 2 describes that an amine such as triethylamine is added. However, it is an object to prevent polymerization in the purification process, and it is difficult to say that the stability of storage that is the object of the present invention is solved.

  The presence of alkali metal is effective in stabilizing the pH, and the presence of N, N′-di-sec-butyl-p-phenylenediamine is stable in terms of polymerization reactivity, pH, contained polymer concentration, color value, and the like. It is thought that it is effective for conversion.

For storage of N-vinyl-2-pyrrolidone, it is common to use a sealed tank, drum, or the like. However, even when the stabilizer is used, the quality such as polymerization reactivity, pH, polymer concentration contained, and color value may change when stored for a long period of time.
Japanese National Patent Publication No. 8-506580 Japanese Patent Laid-Open No. 7-252221

  Therefore, the problem to be solved by the present invention is that it has extremely good storage stability regardless of the presence or absence of the addition of a stabilizer, that is, even when stored for a long period of time, the polymerization reactivity, pH, polymer concentration contained Another object of the present invention is to provide a method for storing an N-alkenylcarboxylic acid tertiary amide with little change in quality such as color value.

  The present inventors have intensively studied to solve the above problems. As a result, the present inventors have found that the inner wall of the storage container may be wetted with the N-alkenylcarboxylic acid tertiary amide during storage of the N-alkenylcarboxylic acid tertiary amide.

According to the present invention, when the N-alkenylcarboxylic acid tertiary amide is stored, the inner wall surface in contact with the gas phase part of the container for storing the N-alkenylcarboxylic acid tertiary amide is replaced with the N-alkenylcarboxylic acid tertiary amide. continuing wet method continues wetting the inner wall surface in the N- alkenyl carboxylic acid tertiary amide is either performed by showering, or performed by rotating or shaking in the vertical direction of the container as an axis in the vertical direction or the horizontal plane The N-alkenylcarboxylic acid tertiary amide is N-vinyl-2-pyrrolidone, and can provide a method for storing an N-alkenylcarboxylic acid tertiary amide.

  N with little or no change in quality such as polymerization reactivity, pH, polymer concentration, color value, etc. -A method for storing an alkenylcarboxylic acid tertiary amide can be provided.

    The present invention will be described in detail below.

  The N-alkenylcarboxylic acid tertiary amide used in the present invention is not particularly limited, but is a cyclic N-alkenylcarboxylic acid tertiary amide, particularly N-vinyl-2-pyrrolidone (hereinafter referred to as “NVP”). Is sometimes abbreviated as “.”).

  Hereinafter, NVP will be described as a representative example of an N-alkenylcarboxylic acid tertiary amide.

  The method for producing NVP used in the present invention is not particularly limited, and examples thereof include a method for vapor-phase dehydration reaction of N-hydroxyethyl-2-pyrrolidone, a Reppe method and the like.

  Further, the manufactured NVP may or may not be subjected to a purification treatment. However, it is preferable to perform a purification process such as a distillation process, a crystallization process, or both, and in particular, from the point of purity of NVP, a crystallization process is performed after the distillation process.

  A stabilizer may or may not be added to the NVP used in the present invention. Although it does not specifically limit as a stabilizer, Metal hydroxides, such as sodium hydroxide and potassium hydroxide, N, N'-di-sec-butyl-p-phenylenediamine, etc. are preferable, Especially, N N'-di-sec-butyl-p-phenylenediamine is more preferred. The amount of stabilizer added is not particularly limited. For example, in the case of N, N′-di-sec-butyl-p-phenylenediamine, it is preferably 1 ppm to 5%, more preferably 3 to 3000 ppm, and most preferably 5 to 100 ppm based on the total mass of NVP. When the added amount of the stabilizer is less than 1 ppm, the effect of suppressing the polymerization and the effect of suppressing the increase in the concentration of the contained polymer may be low. On the other hand, when it exceeds 5%, the NVP may be colored. is there.

  On the other hand, in the case of a metal hydroxide such as sodium hydroxide, 1 ppm to 5% is preferable and 100 to 5000 ppm is more preferable with respect to the total mass of NVP. When the added amount of the stabilizer is less than 1 ppm, the effect of suppressing the polymerization and the effect of suppressing the increase in the concentration of the contained polymer may be low. On the other hand, when it exceeds 5%, the NVP may be colored. is there.

  There is no particular limitation as long as at least part of the inner wall surface in contact with the gas phase portion of the container storing NVP is wetted with the amide. It is preferable that almost the entire inner wall surface in contact with the gas phase portion is wet.

  Specifically, when the storage container is a fixed tank or the like, a container that is in contact with the gas phase part including a top plate by shower ring or the like, in which a rotary nozzle or a sprinkler is installed on the upper part of the storage container It is preferable to always supply the NVP solution to the entire inner wall surface. It may be effective for storage stability that the liquid temperature of NVP at the time of showering is the same as the liquid temperature of NVP in the storage container. In the case of showering, it is preferable to perform the showering by pumping up the NVP present at the bottom of the storage container so that the NVP in the container is replaced or mixed sufficiently. Since the added amount of the stabilizer is small, the stability of the NVP during storage can be improved by uniformly dispersing the stabilizer in the container by such a method.

  On the other hand, in the case of a drum can or the like in which the storage container is not fixed, an operation such as rotating or shaking the container at regular intervals is effective. At that time, it is preferable to use a drum overturning machine, a drum shaker or the like. In this way, the NVP contained in the container is mixed by rotating the drum can or the like continuously or intermittently in the vertical direction about the vertical or horizontal plane, and the inner wall surface of the gas phase portion of the container is mixed. Wetting can be continued and polymerization of NVP can be prevented.

  The material of the NVP storage container used in the present invention is not particularly limited, but polyolefins such as polyethylene and polypropylene, PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin), fluororesins such as PTFE, stainless steel, etc. Aluminum is preferable, and stainless steel is particularly preferable.

  Further, it is preferable to use the storage container with the surface roughness lowered. As the method, when the material of the inner surface of the container is a metal such as SUS304 or SUS316, buffing or electrolytic polishing can be used. Of course, the same applies to the case where the above material is coated or lined on the inner surface of another material.

  The storage temperature of NVP is not particularly limited as long as NVP can maintain a liquid state, but is preferably 80 ° C. or lower, more preferably 60 ° C. or lower, and most preferably 40 ° C. or lower. Especially, if it is a temperature range below 35 degreeC and 15 degreeC or more, the effect of this invention will be drawn out to the maximum. When it exceeds 80 ° C., even if a stabilizer is present, it may cause an increase in the concentration of contained polymer, coloring, and the like.

  The atmosphere of the gas phase portion of the NVP solution storage container used in the present invention is not particularly limited, but is preferably handled without contact with an acid gas such as carbon dioxide, and specifically, inert such as nitrogen. Gas is preferred.

  The storage of the present invention is usually storage in a container or the like. Storage and the like are also included in the scope of the present invention. This includes not only simple storage but also transportation and transportation.

  The NVP used in the present invention is preferably stored as it is or with only the stabilizer added. Moreover, you may mix and store with water or another solvent. Furthermore, you may add additives, such as pH adjusters other than the said stabilizer, a buffering agent, a coloring inhibitor, a deodorizer, and a coloring agent.

  According to the method of the present invention, even when stored for a long period of time, there is very little change in the quality of the amide, such as polymerization reactivity, pH, contained polymer concentration, and color value.

  Examples of the present invention will be described below, but the present invention is not limited to the examples.

(NVP production example 1)
N- (2-hydroxyethyl) -2-pyrrolidone derived from maleic anhydride as a raw material was subjected to vapor phase dehydration to obtain crude NVP.

  This crude NVP was purified by distillation so that the initial distillate rejection was 20% by mass relative to that before distillation, and the yield was 60% by mass relative to the undistilled stock solution, and NVP (“NVP-A1”) was obtained. Obtained). The pH, polymer concentration, and color value of the obtained NVP were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(NVP production example 2)
After performing the same operation as in Production Example 1, the obtained NVP was placed in a 500 mL standard bottle and cooled in a 4 ° C. incubator for 24 hours. A portion of the solidified NVP thus obtained was used as a seed crystal and charged into 300 g of NVP obtained in Production Example 1 held in a 500 mL beaker at 13 ° C., and then stirred to obtain an NVP microcrystal mixed solution. It was. This was filtered with a suction filter (filter paper: No. 2 (manufactured by ADVANTEC)) maintained at 13 ° C., and the crystals on the filter paper were melted to obtain NVP (referred to as “NVP-A2”). The pH, polymer concentration, and color value of the obtained NVP were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Example of production of NVP polymer)
In a 500 mL flask equipped with a stirrer, a monomer supply tank, a thermometer, a cooling pipe, and a nitrogen introduction pipe, 320 g of water is introduced, nitrogen gas is introduced, and the internal temperature is heated to 70 ° C. while stirring. In this flask, 80 g of NVP and 0.08 g of 2,2′-azobis (2-methylbutyronitrile) obtained in the production examples of NVP or the examples described later are added, and the temperature is raised to 95 ° C. over 90 minutes. To do. The polymerization is completed by heating at the same temperature for 2 hours to obtain an aqueous solution of NVP polymer. The K value of the obtained NVP polymer is measured.

  NVP and the polymer of NVP obtained using the same are analyzed by the following method.

(Polymerization reactivity of NVP)
Comparison is made using the K value of the polymer obtained from NVP. The K value was determined by measuring the viscosity of the obtained NVP polymer at a concentration of 1% by mass in water using a method shown in the production example from NVP, and measuring the viscosity of the solution at 25 ° C. with a capillary viscometer. Use the value to calculate from the following fixture formula. It can be said that the higher the K value, the higher the molecular weight.

(Log ηrel) / C = {(75K ₀ ² ) / (1 + 1.5K ₀ C)} + K ₀
K = 1000K ₀
(Where C represents the number of grams in 100 mL of the solution, and ηrel represents the viscosity of the solution relative to the solvent).

(PH of NVP)
NVP is adjusted to 10% by mass with pure water having a pH of 7.0 and measured using a pH meter (manufactured by HORIBA: pH METER F-12, electrode type # 6366-10D).

(NVP polymer concentration)
NVP analysis (solvent: water, temperature: 40 ° C., flow rate: 1.5 mL / min) was performed using liquid chromatography (column: Showa Denko: shodex Asahipak GF-310 HQ), and commercially available polyvinylpyrrolidone (Japan) A calibration curve is prepared using a catalyst manufactured by K-30) to obtain the polymer concentration in NVP.

(NVP color value)
NVP is used as it is without dilution, and measured by the APHA method.

Example 1
In a sealable container (inner diameter: 3 cm, height: 20 cm) made of SUS304, 100 g of NVP obtained in Production Example 2 and 0.001 g of N, N′-di-sec-butyl-p-phenylenediamine are placed. The interior was purged with nitrogen, and the gas phase was sealed at an oxygen concentration of 1% by volume or less.

  Thereafter, as shown in FIG. 1, the container was mounted on a rotator that was rotated in the height direction by a three-one motor. In a constant temperature bath at 40 ° C. and 60 ° C., the rotator was rotated at 1 rpm and held for 45 days and 90 days. There is a gas phase part (B2) in the container, and the NVP liquid (B1) moves as the container rotates, so that the inner wall surface of the gas phase part (B2) of the container is always NVP liquid (B1). Can continue to wet.

  The sample was taken out after 45 days and 90 days, and the pH, polymer concentration, and color value of the obtained NVP (NVP-B1) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Example 2)
The same operation as in Example 1 was performed except that the NVP obtained in Production Example 1 was used, and the pH, polymer concentration, and color value of the obtained NVP (NVP-B2) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Comparative Example 1)
In a SUS304 sealable container (inner diameter 3 cm, height 20 cm), 100 g of NVP obtained in Production Example 2 and 0.001 g of N, N′-di-sec-butyl-p-phenylenediamine were put in the container. Was replaced with nitrogen, and the gas phase was sealed with an oxygen concentration of 1 vol% or less.

  Thereafter, the container was kept still in a constant temperature bath at 40 ° C. and 60 ° C. for 45 days and 90 days.

  The sample was taken out after 45 days and 90 days, and the pH, polymer concentration and color value of the obtained NVP (NVP-C1) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Comparative Example 2)
The same operation as in Comparative Example 1 was performed except that NVP obtained in Production Example 1 was used, and the pH, polymer concentration, and color value of the obtained NVP (NVP-C2) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Example 3)
It implemented like Example 2 except not using "N, N'-di-sec-butyl-p-phenylenediamine 0.001g."

  The sample was taken out after 45 days and 90 days, and the pH, polymer concentration and color value of the obtained NVP (NVP-B3) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Comparative Example 3)
“As shown in FIG. 1, the container was attached to a rotator rotating in the height direction by a three-one motor. In a constant temperature bath at 40 ° C. and 60 ° C., the rotator was rotated at 1 rpm for 45 days. And was held for 90 days. ”Was carried out in the same manner as in Example 3 except that“ the container was kept still in a constant temperature bath at 40 ° C. and 60 ° C. for 45 days and 90 days ”.

  The sample was taken out after 45 days and 90 days, and the pH, polymer concentration, and color value of the obtained NVP (NVP-C3) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

Example 4
It implemented like Example 1 except using "the container made from PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin)" instead of "the container made from SUS304".

  The sample was taken out after 45 days and 90 days, and the pH, polymer concentration and color value of the obtained NVP (NVP-B4) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Comparative Example 4)
“As shown in FIG. 1, the container was attached to a rotator rotating in the height direction by a three-one motor. In a constant temperature bath at 40 ° C. and 60 ° C., the rotator was rotated at 1 rpm for 45 days. And was held for 90 days. ”Was carried out in the same manner as in Example 4 except that“ the container was kept still in a constant temperature bath at 40 ° C. and 60 ° C. for 45 days and 90 days ”.

  The sample was taken out after 45 days and 90 days, and the pH, polymer concentration, and color value of the obtained NVP (NVP-C4) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Example 5)
The same operation as in Example 1 was performed except that “0.01 g of sodium hydroxide” was used instead of “0.001 g of“ N, N′-di-sec-butyl-p-phenylenediamine ”.

  The sample was taken out after 45 days and 90 days, and the pH, polymer concentration and color value of the obtained NVP (NVP-B5) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

(Comparative Example 5)
“As shown in FIG. 1, the container was attached to a rotator rotating in the height direction by a three-one motor. In a constant temperature bath at 40 ° C. and 60 ° C., the rotator was rotated at 1 rpm for 45 days. And was held for 90 days. ”Was carried out in the same manner as in Example 5 except that“ the vessel was kept still in a constant temperature bath at 40 ° C. and 60 ° C. for 45 days and 90 days ”.

  The sample was taken out after 45 days and 90 days, and the pH, polymer concentration and color value of the obtained NVP (NVP-C5) were measured. Furthermore, the K value of the polymer polymerized according to (Production Example of NVP Polymer) was measured. The results are shown in Table 1.

Table 1: CM: Container material
ST: Storage temperature
SP: retention period
PC: Polymer concentration.

  According to the storage method of the present invention, the N-alkenylcarboxylic acid has little change in quality such as polymerization reactivity, pH, contained polymer concentration and color value even when stored for a long period of time regardless of the addition of a stabilizer. Acid tertiary amides can be provided.

It is drawing which shows the evaluation apparatus used in the Example.

Explanation of symbols

A: Motor B: Container B1: NVP liquid B2: Gas phase part C: Shaft D: Bearing

Claims (5)

When storing the N-alkenylcarboxylic acid tertiary amide, the inner wall surface in contact with the gas phase part of the container for storing the N-alkenylcarboxylic acid tertiary amide is kept wet with the N-alkenylcarboxylic acid tertiary amide,
How to keep wetting the inner wall surface in the N- alkenyl carboxylic acid tertiary amide is either performed by showering, or performed by rotating or shaking in the vertical direction of the container as an axis in the vertical direction or the horizontal plane,
The method for storing an N-alkenylcarboxylic acid tertiary amide, wherein the N-alkenylcarboxylic acid tertiary amide is N-vinyl-2-pyrrolidone.   The storage method according to claim 1, wherein the N-alkenylcarboxylic acid tertiary amide contains 1 ppm to 5 mass% of a stabilizer.   The storage method according to claim 1 or 2, wherein a material of the storage container is stainless steel, polyolefin, or fluororesin.   The storage method according to claim 3, wherein the material of the storage container is a metal whose surface roughness is lowered by buffing or electrolytic polishing.   The storage according to any one of claims 1 to 4, wherein the showering is performed by pumping up the amide present at the bottom of the container and replacing the N-alkenylcarboxylic acid tertiary amide in the container. Method.

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