JP2004059577A - N- (1,1-dimethyl-3-oxobutyl) acrylamide - Google Patents

Abstract

The present invention has sufficient quality as a polymerizable monomer, and is particularly useful for producing a hair spray resin, a photosensitive resin, a coating resin, an adhesive resin, a crosslinking agent for unsaturated polyester, and the like. Certain N- (1,1-dimethyl-3-oxobutyl) acrylamides are provided.
SOLUTION: A crude N- (1,1-dimethyl-3-oxobutyl) acrylamide obtained by reacting acetone or diacetone alcohol with acrylonitrile and sulfuric acid, followed by hydrolysis and neutralization is heated in the presence of an alkaline aqueous solution. Thus, the coexisting acrylamide is hydrolyzed, the hydrolysis reaction solution is separated into an aqueous phase and an organic phase, and the organic phase is distilled under reduced pressure, whereby a high-quality target product can be obtained.
[Selection diagram] None

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to N- (1,1-dimethyl-3-oxobutyl) acrylamide (hereinafter abbreviated as DAAM). Specifically, the present invention is obtained by reacting acetone or diacetone alcohol with acrylonitrile and sulfuric acid, then hydrolyzing and neutralizing to obtain a crude DAAM, and then purifying the crude DAAM to obtain a polymerizable monomer. As to the quality of DAAM. The DAAM of the present invention is useful for producing a resin for hair spray, a photosensitive resin, a resin for paint, a resin for adhesive, a crosslinking agent for unsaturated polyester, and the like.
[0002]
[Prior art]
The crude DAAM obtained by reacting acetone or diacetone alcohol with acrylonitrile and sulfuric acid, and then hydrolyzing and neutralizing it, is mostly DAAM, but also other thermally unstable polymerizable components such as acrylamide. And coloring components such as phorone, isophorone and mesityl oxide, as well as heavy components such as DAAM reacted with acetone, acrylonitrile and other by-products.
[0003]
Although DAAM is expected to be used in various fields as described above, an industrially applicable purification technique for removing the above-mentioned impurities has not yet been established. Conventionally, it has been known that crude DAAM is purified by distillation under reduced pressure (for example, see Patent Document 1). However, since crude DAAM contains acrylamide which is polymerizable and has a boiling point close to that of DAAM, distillation purification is very difficult.
[0004]
A method of purifying crude DAAM by crystallization from an organic solvent is also known (for example, see Patent Documents 2 and 3). This method requires a large amount of an organic solvent, requires considerable cost for recovering the organic solvent and ensuring the safety of the working environment, and has a low DAAM yield. Further, the crude DAAM was subjected to an operation of removing impurities having poor water solubility by water extraction and an operation of removing acrylamide by hydrolysis in the presence of an alkaline aqueous solution, and then distilled under reduced pressure to obtain purified DAAM. Has also been proposed (for example, see Patent Document 4). This method gives high quality DAAM, but the yield is quite low, on the order of 43%.
[0005]
[Problems to be solved by the invention]
The present inventors have studied the cause of the low yield of DAAM in the above proposed method and found that a considerable amount of DAAM was lost in the water extraction step. That is, a large amount of water must be used to increase the extraction rate of DAAM, but this lowers the concentration of the resulting DAAM aqueous solution and makes it difficult to recover DAAM from this aqueous solution. Therefore, the amount of water used for extraction must be limited, and it is unavoidable that DAAM remains in the organic phase. Furthermore, DAAM loss occurs when DAAM is recovered from the DAAM aqueous solution by salting out. In addition to the loss of DAAM, this water extraction-recovery process of DAAM from the aqueous solution is cumbersome as an operation and requires considerable cost. Therefore, it would be extremely advantageous if high quality DAAM could be obtained without performing this water extraction.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 41-17968 [Patent Document 2]
US Patent No. 3,542,867 [Patent Document 3]
No. 3,542,875 [Patent Document 4]
Japanese Patent Publication No. 61-26986
[Means for Solving the Problems]
The present inventors have surprisingly found that DAAM having sufficient quality as a polymerizable monomer can be obtained only by hydrolysis and distillation under reduced pressure without water extraction. That is, according to the present invention, a crude DAAM obtained by reacting acetone or diacetone alcohol with acrylonitrile and sulfuric acid, and subsequently hydrolyzing and neutralizing, is heated in the presence of an alkaline aqueous solution to remove coexisting acrylamide. Hydrolysis, the hydrolysis reaction solution is separated into an aqueous phase and an organic phase, and the organic phase is distilled under reduced pressure, whereby a high-quality DAAM can be produced in a high yield. As a result, according to the present invention, there is provided DAAM having an acrylamide content of 0.1% by weight or less as DAAM of sufficient quality as a polymerizable monomer.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in detail. In the present invention, first, acetone or diacetone alcohol is reacted with acrylonitrile and sulfuric acid, followed by hydrolysis and neutralization to produce a crude DAAM. Just do it. Usually, acrylonitrile is mixed with a stoichiometric amount or a slightly excessive amount of acetone or diacetone alcohol with respect to the mixture, and about 2 moles of concentrated sulfuric acid is added to the acrylonitrile at 40 to 50 ° C for several hours. After the reaction, the reaction product is added to water, hydrolyzed, and then neutralized with an alkali. During this time, the temperature is preferably maintained at 40 ° C. or lower.
[0009]
Since the neutralization reaction solution separates into an aqueous phase and an organic phase when left to stand, the organic phase is obtained and subjected to the next alkaline hydrolysis without performing water extraction. Although alkali hydrolysis can be carried out by adding an alkali to the neutralization reaction solution, a large amount of water is present, so that a large amount of alkali is required to obtain a desired alkali concentration, which is disadvantageous. Alkaline hydrolysis is a process in which acrylamide coexisting in crude DAAM is decomposed into acrylic acid, and only acrylamide is selectively decomposed without decomposing DAAM. The hydrolysis is usually carried out using a 5 to 50% by weight aqueous solution of sodium hydroxide or potassium hydroxide, preferably a 10 to 30% by weight aqueous solution. If the concentration of the alkaline aqueous solution is too low, the hydrolysis takes a long time, and if the concentration is too high, there is a risk that the target substance, DAAM, is hydrolyzed and the yield decreases.
[0010]
The alkali is used in an amount of usually 1 to 10 equivalents, preferably 1.2 to 6 equivalents, to acrylamide coexisting in the crude DAAM. If the amount of alkali is too small, the progress of the reaction is slow, and it is difficult to complete the reaction. Conversely, if the amount of alkali is too large, hydrolysis of DAAM occurs and the yield decreases. The optimal equivalent ratio of alkali to acrylamide is 1.5-4. The hydrolysis is preferably carried out at 60 to 100 ° C, especially 70 to 90 ° C. If the temperature is too low, the reaction takes a long time, and if it is too high, there is a risk of DAAM being hydrolyzed.
[0011]
The time required for the hydrolysis is usually 10 minutes to 1 hour. Prolonged hydrolysis risks decomposing DAAM. When the hydrolysis is completed, the mixture is allowed to stand and separated into an aqueous phase and an organic phase, and the organic phase is subjected to the next step of distillation under reduced pressure. Since the organic phase contains alkali, it is preferable to neutralize the organic phase in advance. It is not impossible to subject the hydrolyzed solution to vacuum distillation only by neutralizing it without phase separation. However, since the amount of the residue increases and a large amount of salt is contained, the treatment becomes a problem. It is also preferable to wash the organic phase in advance with an organic solvent that does not dissolve DAAM. This washing can remove a considerable amount of heavy components in the organic phase. Examples of the organic solvent used for washing include pentane, hexane, heptane, cyclohexane, methylcyclohexane, petroleum ether, saturated hydrocarbons such as naphtha, ethyl ether, ethers such as diisopropyl ether, and halogenated hydrocarbons such as perchloroethylene. Can be Washing with an organic solvent is performed by adding 10 to 200% by volume, preferably 50 to 100% by volume of the above organic solvent with respect to the organic phase, stirring and bringing the two well into contact with each other, and then allowing them to stand for layer separation. Just fine.
[0012]
The organic phase subjected to vacuum distillation contains almost no acrylamide, which has a boiling point close to that of DAAM, and has only low-boiling components and heavy components as impurities, making distillation purification easy. It is. Normally, low-boiling components are first removed by evaporation or simple distillation, and then simple distillation or distillation under reduced pressure is carried out in a distillation column having several stages. The top pressure is usually 20 mmHg or less, preferably 5 mmHg or less. It is preferable to add a polymerization inhibitor such as hydroquinone or phenothiazine during the distillation.
[0013]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. In the following examples, analysis was performed by high performance liquid chromatography and gas chromatography.
[0014]
Example 1
(Synthesis of crude DAAM)
1.47 mol of acetone and 0.7 mol of acrylonitrile were charged into a 500 ml three-necked flask equipped with a mechanical stirrer, a thermometer, and a dropping funnel. While stirring, 1.47 mol of sulfuric acid was added dropwise thereto. During this time, the temperature was kept below 40 ° C. After completion of the dropwise addition, the reaction was carried out at 45 ° C. for 2 hours. The reaction solution was dropped into 140 g of water, and 200 g of 25% aqueous ammonia was further added for neutralization. During this time, the temperature was kept below 40 ° C. After the neutralization, the mixture was allowed to stand at room temperature to separate into a water phase and an organic phase, thereby obtaining 110 g of an organic phase (containing 68 g of DAAM and 4.6 g of acrylamide).
[0015]
(Purification of crude DAAM)
To 110 g of the organic phase obtained above, 34 g of a 15% by weight aqueous sodium hydroxide solution (twice the mol of acrylamide) was added, and the mixture was stirred at 80 ° C. for 1 hour. After cooling, the reaction solution was allowed to stand at room temperature, and separated into a water phase and an organic phase. The organic phase was neutralized by adding a 10% by weight aqueous sulfuric acid solution, and then allowed to stand to remove the aqueous phase to obtain an organic phase. After 100 g of cyclohexane was added to the organic phase and stirred vigorously, the mixture was allowed to stand and separated into two layers. The upper cyclohexane layer was distilled to recover cyclohexane. To the lower organic phase, 70 mg of phenothiazine and 35 mg of hydroquinone were added, and the mixture was easily distilled at 60 ° C. to remove low-boiling components, followed by simple distillation under reduced pressure of 2.0 mmHg to obtain DAAM. Yield: 60 g, purity: 98.6% by weight (purification step recovery: 86%), impurities (1.3% by weight of high boiling component, 0.1% by weight of acrylamide).
[0016]
Example 2
DAAM was purified in exactly the same manner as in Example 1 except that washing with cyclohexane was not performed. Yield 62 g, purity 96.6% by weight (purification step recovery rate 88%), impurities (high-boiling component 3.3% by weight, acrylamide 0.1% by weight).
[0017]
Example 3
Exactly the same as in Example 1 except that 48 g of a 15% by weight aqueous solution of potassium hydroxide was used instead of the 15% by weight aqueous solution of sodium hydroxide (twice the mol of acrylamide) and 100 g of petroleum ether was used instead of cyclohexane. To purify DAAM. Yield: 59 g, purity: 98.4% by weight (purification process recovery rate: 85%), impurities (high-boiling component: 1.6% by weight, acrylamide: 0.1% by weight).
[0018]
Example 4
To 110 g of the organic phase, 34 g of a 15% by weight aqueous sodium hydroxide solution (twice the mol of acrylamide) was added, and the mixture was stirred at 80 ° C. for 1 hour. After cooling, the reaction solution was allowed to stand at room temperature, and separated into a water phase and an organic phase. The organic phase was neutralized by adding a 10% by weight aqueous sulfuric acid solution, and then allowed to stand to remove the aqueous phase to obtain an organic phase. The organic layer was extracted with 150 g of water. This extraction was performed twice more. The obtained aqueous phases were combined, and 20 g of cyclohexane was added thereto. After vigorous stirring, the mixture was allowed to stand and separated into a water phase and a cyclohexane phase. 180 g of ammonium sulfate was dissolved in the aqueous phase, allowed to stand, and separated into a water phase and an organic phase. 70 mg of phenothiazine and 35 mg of hydroquinone were added to the organic phase, and the mixture was distilled at 60 ° C. in the same manner as in Example 1 to remove low-boiling components, and then distilled under reduced pressure of 2.0 mmHg to obtain DAAM. . Yield: 48 g, purity: 98.2% by weight (purification step recovery: 69%), impurities (1.7% by weight of high boiling component, 0.1% by weight of acrylamide).
[0019]
Comparative Example 1
To 110 g of the organic phase, 70 mg of phenothiazine and 35 mg of hydroquinone were added without hydrolysis, and the mixture was distilled at 60 ° C. in the same manner as in Example 1 to remove low-boiling components, and then reduced under 2.0 mmHg under reduced pressure. Distilled briefly to give DAAM. Yield: 49 g, purity: 96.0% by weight (purification step recovery: 69%), impurities (high-boiling component: 2.0% by weight, acrylamide: 2.0% by weight).
[0020]
【The invention's effect】
According to the present invention described above, it has a sufficient quality as a polymerizable monomer, and particularly, a hair spray resin, a photosensitive resin, a paint resin, an adhesive resin, an unsaturated polyester crosslinking agent, and the like. N- (1,1-dimethyl-3-oxobutyl) acrylamide is provided, which is useful for the production of the present invention, and the industrial value of the present invention is remarkable.

Claims (2)

N- (1,1-dimethyl-3-oxobutyl) acrylamide having an acrylamide content of 0.1% by weight or less. The N- (1,1-dimethyl-3-oxobutyl) acrylamide according to claim 1, which is obtained from acetone or diacetone alcohol and acrylonitrile.