JPH08208576A - Production of n-(1-alkoxyethyl)carboxylic acid amide - Google Patents

Abstract

PURPOSE: To obtain an N-(1-alkoxyethyl)carboxylic acid amide useful as an intermediate for synthesizing an N-vinylcarboxylic acid amide suitable as a synthetic raw material for an adsorbent, a thickening agent and a chemical simply and in high final yield. CONSTITUTION: A first carboxylic acid amide (acetamide), acetaldehyde, a 1-5C alcohol (methanol), ethylidene bisamide and an acetaldehyde dialkyl acetal in the most preferable molar ratio of 1:(2-20):(1-20):(0-5):(0-1) are simultaneously subjected to reaction and extraction and separation in the presence of an acidic catalyst such as sulfuric acid or nitric acid in an amount of preferably 0.5-2% the feed weight in an aqueous solution and an organic solvent such as dichloromethane or chloroform which forms two phases with the aqueous solution to give the objective amide. The reaction temperature is most preferably 20-80 deg.C, the reaction time is 1-5 hours, the ratio of the organic solvent to form the two phases based on the aqueous solution is (2-5wt.%):(95-98wt.%).

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is extremely useful as a monomer for N-vinylcarboxylic acid amide type polymers that can be used as water absorbing agents, thickeners, etc., or as a raw material for synthesizing chemicals such as taurine and cysteamine. -A method for producing N- (1-alkoxyethyl) carboxylic acid amide which is a synthetic intermediate of vinylcarboxylic acid amide. More specifically, it relates to a method for producing N- (1-alkoxyethyl) carboxylic acid amide by reacting a predetermined reaction substrate with water and an organic solvent in the presence of an acidic catalyst in a solution forming two phases.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed as a method for synthesizing N- (1-alkoxyethyl) carboxylic acid amides. Focusing on the starting materials in these methods, they are classified into a method using acetaldehyde, a method using acetal, a method using ethylidene bisacetamide, and the like. As a method using acetaldehyde as a starting material, West German Patent No. 1,273,533 discloses carboxylic acid amides, aldehydes and alcohols, or carboxylic acid amides and acetals produced from acetaldehyde and alcohols with hydrochloric acid, thionyl chloride, Although a method of reacting with sulfuryl chloride or the like as a catalyst is disclosed, in this method, the carboxylic acid amide as the raw material is secondarily
In addition to being limited to amides, the yields of linear carboxylic acid amides are extremely low. For example, N- (1 from N-methylacetamide and acetaldehyde diethyl acetal
The yield of -ethoxyethyl) -N-methylacetamide is only 26%.

JP-A-62-289549 and JP-A-63-96160 are improved methods of this method.
The target N- (1-alkoxyethyl) carboxylic acid amide is obtained in a relatively high yield, but acetal and ethylidene bisacetamide are by-produced. JP-A-2-
No. 003641 describes the possibility of using the acetal by-produced in this reaction by recycling it to the reaction system, but there is no specific disclosure about the influence on the reaction results. Also, the reaction results were not at a sufficient level. As described above, the method using acetaldehyde as a starting material is relatively easy to obtain in a single step in the presence of a strong acid catalyst from three kinds of compounds, which are carboxylic acid amide, acetaldehyde, and alcohol, which are relatively inexpensive. Since the target N- (1-alkoxyethyl) carboxylic acid amide can be synthesized, it is industrially advantageous to use N- (1-alkoxyethyl) carboxylic acid amide.
Although it is expected as a method for producing (1-alkoxyethyl) carboxylic acid amide, the production of N- (1-alkoxyethyl) carboxylic acid amide is accompanied by the production of by-products, particularly ethylidene bisacetamide and unreacted carboxylic acid amide. Processing is a problem.

As a method using dimethyl acetal as a starting material, US Pat. No. 4,554,377 discloses that dimethyl acetal and a carboxylic acid amide are reacted in the presence of a strong acid such as methanesulfonic acid or sulfuric acid, or a strong acidic cation exchange resin. A method of causing is disclosed. However, in this method, it is necessary to separately synthesize dimethyl acetal, and further isolate and use this, and in order to obtain a high yield, the raw material composition is 20 mol of dimethyl acetal to 1 mol of acetamide. Therefore, it has to be extremely diluted and has a drawback that the productivity is extremely low. Further, Japanese Unexamined Patent Publication (Kokai) No. 2-009851 reports that N- (1-alkoxyethyl) formamide is similarly synthesized from formamide and acetal, but has the same problem.

Further, as a method of using ethylidene bisacetamide as a starting material, there are Japanese Patent Laid-Open Nos. 1-100153 and 2-304053. This method is simple and easy to obtain the desired N- by reacting ethylidene biscarboxylic acid amide easily produced from acetaldehyde and carboxylic acid amide or vinyl ether and carboxylic acid amide which are easily available and inexpensive with alkanol.
A (1-alkoxyethyl) carboxylic acid amide is obtained. However, the problem with this method is that N
In order to isolate the-(1-alkoxyethyl) carboxylic acid amide, a complicated operation including extraction is required, and the synthesis of the ethylidene biscarboxylic acid amide and the synthesis of the N- (1-alkoxyethyl) carboxylic acid amide are required. It may require steps. As described above, the conventional N- (1-
The method for synthesizing alkoxyethyl) carboxylic acid amide cannot be said to be a satisfactory method in terms of yield, production of by-products, difficulty in obtaining raw materials, complexity of reaction step and purification step, and the like.

[0006]

The problem of the present invention is N-
An object of the present invention is to develop a method for industrially producing (1-alkoxyethyl) carboxylic acid amide. Therefore, N- (1-alkoxy) can be simply and efficiently carried out by simultaneously performing reaction and extraction separation in a reaction vessel. It is to develop a method for producing ethyl) carboxylic acid amide.

[0007]

In view of the above situation, the inventors of the present invention have comprehensively studied over the entire manufacturing process including reaction raw materials, catalysts, reaction conditions, reaction operations, and separation steps, and as a result, N- (1 -Alkoxyethyl) carboxylic acid amide is selectively distributed to an organic solvent, and the carboxylic acid amide as a reaction raw material and ethylidene biscarboxylic acid amide as a by-product are selectively distributed to an aqueous solution. completed.

That is, the present invention provides (1) at least a primary carboxylic acid amide, acetaldehyde, and 1 to 5 carbon atoms.
N is characterized by reacting the alcohol in the presence of an acidic catalyst with water and an organic solvent in a solution forming two phases.
-(1-alkoxyethyl) carboxylic acid amide production method, (2) at least ethylidene biscarboxylic acid amide and an alcohol having 1 to 5 carbon atoms in the presence of an acidic catalyst,
A method for producing N- (1-alkoxyethyl) carboxylic acid amide, which comprises reacting in a solution forming two phases with water and an organic solvent, (3) the first carboxylic acid amide is acetamide, and the carbon number is 1 to 1 The production method according to 1 above, wherein the alcohol of 5 is methanol, and (4) the production method of 1 to 3 above, wherein the organic solvent is dichloromethane and / or chloroform.

The method of the present invention will be described in more detail below. The acidic catalyst used in the present invention is not particularly limited in principle, for example, sulfuric acid, nitric acid, hydrochloric acid, mineral acids such as phosphoric acid, heteropolyacids such as phosphotungstic acid,
Organic acids such as methanesulfonic acid and p-toluenesulfonic acid, sulfonic acid type strongly acidic ion exchange resins such as Amberlyst (registered trademark), Amberlite (registered trademark) and Dowex (registered trademark), sulfonated tetrafluoroethylene Various conventionally known resins such as sulfonic acid type fluorinated alkylene resins such as resins can be used. In the present invention, a non-volatile liquid strong acid such as sulfuric acid having a large distribution in an aqueous solution is particularly preferable in the process.

There is no strict limitation on the amount of the acidic catalyst used, but when a homogeneous catalyst is used, it is selected from the range of 0.01 to 5% by weight based on the charged weight. ~ 2% is particularly preferred. Even if it is used in an amount of 5% or more, the reaction rate does not significantly increase, which is economically undesirable. On the other hand, if it is 0.1% or less, the reaction rate is low, which is not preferable in terms of productivity.

The aqueous solution used in the present invention is a primary carboxylic acid amide used as a reaction substrate, acetaldehyde,
An alcohol having 1 to 5 carbon atoms, an acetal of acetaldehyde, and an ethylidene biscarboxylic acid amide (these are also reaction by-products) are dissolved. further,
This aqueous solution can also dissolve the inorganic salts that are added as appropriate. As such an inorganic salt, one that does not react with an acidic catalyst is preferable, and a salt of the same acid as the acidic catalyst is more preferable. Examples of inorganic salts include sulfates such as sodium sulfate and potassium sulfate, nitrates such as sodium nitrate and potassium nitrate, hydrochlorides such as sodium chloride and potassium chloride, sodium phosphate (hydrogen), and potassium phosphate (hydrogen). Examples thereof include phosphates and hydrogen phosphates. The concentration of the inorganic salt in the aqueous solution is not particularly limited and is selected from the range of 0% by weight to the concentration of the saturated solution.

The organic solvent which forms two phases with the aqueous solution of the present invention is not particularly limited as long as it is a solvent which forms two phases with the aqueous solution and does not react with an acidic catalyst.
Acid catalyst, primary carboxylic acid amide, acetaldehyde,
The reaction substrates such as alcohols having 1 to 5 carbon atoms and the reaction by-products such as ethylidene biscarboxylic acid amide and acetaldehyde dialkoxy acetal have low solubility, and N- (1-alkoxyethyl) carboxylic acid amide which is a reaction product. Those having high solubility are preferable. Specific examples of preferable ones include dichloromethane, chlorobenzene,
Dichloroethane, chloroform, etc., halogenated aliphatic hydrocarbons, ethyl acetate, butyl acetate, etc. esters, diethyl ether, diisopropyl ether, etc. ethers, 3-pentanone, methyl isobutyl ketone, etc. ketones, toluene, cymene, etc. Aromatic hydrocarbons and alicyclic hydrocarbons such as cyclohexane can be used. Of these, halogenated aliphatic hydrocarbons are preferable, and among them, dichloromethane and chloroform are particularly preferable. The ratio of the aqueous solution and the organic solvent forming two phases with the aqueous solution is selected from the range of 1 to 30% by weight: 70 to 99% by weight, preferably 1 to 15% by weight: 85 to 99% by weight,
2-5% by weight: 95-98% by weight is particularly preferred.

As the primary carboxylic acid amide used in the present invention, an aliphatic primary carboxylic acid amide can be generally used. Among these, formamide, acetamide, propionamide and the like can be mentioned. Among them, formamide and acetamide are preferable, and acetamide is particularly preferable. As the alcohol, an aliphatic alcohol having 1 to 5 carbon atoms can be used. For example, methanol,
Ethanol, n-propanol, isopropanol, n
-Butanol, sec-butanol, 1-pentanol and the like can be mentioned, and among them, methanol, ethanol, isopropanol and n-butanol are preferable, and methanol is particularly preferable.

Further, ethylidene biscarboxylic acid amide and acetaldehyde dialkyl acetal may be added to the reaction system to carry out the reaction. Examples of the ethylidene biscarboxylic acid amide include ethylidene biscarboxylic acid amide derived from an aliphatic primary carboxylic acid amide such as formamide, acetamide, and propionamide. Among these, ethylidene bisformamide and ethylidene bisacetamide are preferable, and particularly, Ethylidene bisacetamide is preferable, and one derived from the same primary carboxylic acid amide as the primary carboxylic acid amide used as a raw material is used. As acetaldehyde dialkyl acetal, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-
Examples include acetaldehyde dialkyl acetals derived from aliphatic alcohols such as butanol and 1-pentanol. These acetaldehyde dialkyl acetals and alcohols have an equilibrium reaction relationship, and since an alkoxyl group exchange reaction occurs under reaction conditions, a combination of the same type of alcohol and acetaldehyde dialkyl acetals, for example, a combination of methanol and dimethyl acetal is preferable.

The molar ratio of primary carboxylic acid amide to acetaldehyde, alcohol and acetaldehyde dialkyl acetal, ethylidene biscarboxylic acid amide is usually in the range of 1: 1.0 to 50: 0.5 to 5: 0 to 10: 0 to 2. It is selected from among, but among them 1: 2 to 20: 1 to 2
0: 0 to 5: 0 to 1 is particularly preferable. Even if the molar ratio of acetaldehyde to the primary carboxylic acid amide is higher than this, improvement of the conversion rate of primary carboxylic acid cannot be expected, and the amount of acetaldehyde condensate produced increases. Further, if it is less than this, the conversion rate decreases. If the molar ratio of the alcohol to the primary carboxylic acid amide is higher than this, the conversion rate of the primary carboxylic acid amide decreases, the acetaldehyde dialkyl acetal increases, and the productivity decreases.
On the other hand, if the amount is less than this, the production amount of ethylidene biscarboxylic acid amide increases. When the molar ratio of acetaldehyde dialkyl acetal to primary carboxylic acid amide is higher than this, the productivity is lowered and the amount of acetaldehyde dialkyl acetal is reduced. On the other hand, if it is less than this, the conversion rate of the primary carboxylic acid amide decreases, and the production amount of ethylidene biscarboxylic acid amide increases. The reaction temperature is usually selected from the range of 0 to 150 ° C., but 20 to 80 ° C.
Is particularly preferable. If the temperature is lower than 0 ° C, the reaction is slow and undesirable, and if the temperature is higher than 150 ° C, the production of impurities increases, which is not preferable.

The reaction time varies depending on the amount of catalyst used in the reaction, but is usually selected from the range of 0.5 to 20 hours, and 1
~ 5 hours are particularly preferred. Optimum conditions for these reactions differ depending on the type of alcohol and acetaldehyde dialkyl acetal used. Therefore, in order to obtain the desired N- (1-alkoxyethyl) carboxylic acid amide in a high yield, the reaction is suitable within the above range. It is important to set the solvent, raw material composition, reaction temperature, and reaction time. Also,
The pressure can be any of reduced pressure, normal pressure, and increased pressure, but normally normal pressure does not matter.

As the reaction apparatus, a spray tower type, a tank type, a packed tower contacting apparatus or the like for the purpose of contacting two phases of an aqueous solution and an organic solvent forming two phases with the aqueous solution are used. The reaction system may be a continuous system or a batch system. The continuous type may be countercurrent or parallel flow. Countercurrent is agitated Continuously, the raw material, water and light liquid of acidic catalyst are supplied from the tank or the lower part of the tower, and the heavy liquid of the solvent is supplied from the tank or the upper part of the tower to react them. Take out continuously from the tank or the lower part of the tower. In parallel flow, light and heavy liquids are continuously supplied from the top, and products are continuously taken out. In the batch system, raw materials, water, a light liquid of an acidic catalyst and a heavy liquid of a solvent are supplied to a tank to react with each other, and a solvent phase separated into two phases is taken out as a product.

The compounds obtained by the process according to the invention are mainly intermediates, for example for the preparation of N-vinylcarboxylic acid amides, which, as mentioned at the outset, are derived into homo and copolymers and useful chemicals. It Conversion to the corresponding N-vinylcarboxylic acid amide is carried out by a known method, for example, thermal decomposition or catalytic decomposition at 60 to 550 ° C. Examples of the present invention will be shown below,
The present invention is not limited to these examples without departing from the gist of the present invention.

[0019]

【Example】

[Example 1] 17.7 g of acetamide was placed in a three-necked flask (200 ml) equipped with a thermometer and a condenser tube.
(0.3 mol), methanol 4.8 g (0.15 mo
l), 30 g of dichloromethane 90 g (1.06 mol)
Stir at ~ 35 ° C until uniform. 1.75 g of 20% sulfuric acid aqueous solution (1 wt% with respect to the amount of raw material charged) and water
77 g (0.043 mol) was added, and 13.2 g (0.3 mol) of acetaldehyde was added from the dropping funnel over 5 minutes while stirring. After completion of the dropwise addition, the mixture was refluxed at 39 ° C. for 4 hours, the dichloromethane phase was separated with a separating funnel (200 ml), the dissolved sulfuric acid was neutralized, and then quantified by gas chromatography. The acetamide conversion rate was 62%. , N- (1-methoxyethyl) acetamide had a selectivity of 64%, and the by-product ethylidene bisacetamide had a selectivity of 36%.

Example 2 Addition amount of acetamide 0.3
The same operation as in Example 1 was performed except that mol was changed to 0.15 mol. Acetamide conversion rate 82%,
Selectivity of N- (1-methoxyethyl) acetamide 78
%, And the selectivity for ethylidene bisacetamide is 22%.
Met.

[Example 3] Addition amount of acetamide 0.3
The same operation as in Example 1 was performed except that mol was changed to 0.075 mol. Acetamide conversion rate 87
%, The selectivity of N- (1-methoxyethyl) acetamide is 70%, and the selectivity of ethylidene bisacetamide is 30%.
%Met.

[Example 4] The same operation as in Example 1 was conducted except that 2.49 g of 85% phosphoric acid (2.16 wt% with respect to the charged raw material) and water were added in place of the sulfuric acid catalyst.
After reacting for a time, acetamide conversion 89.2%, N-
Selectivity for (1-methoxyethyl) acetamide 80.6
%, And the selectivity for ethylidene bisacetamide is 1
It was 9.4%.

[Example 5] Acetamide 0.75mo
1, methanol 1.5 mol, acetaldehyde 3.0
mol, dichloromethane 10.6 mol, water concentration 5.
The same operation as in Example 1 was performed except that the concentration was adjusted to 7 wt% and acetaldehyde was added over 20 minutes. After reacting for 12 hours,
The acetamide conversion rate was 88.2%, the N- (1-methoxyethyl) acetamide selectivity was 76.0%, and the ethylidene bisacetamide selectivity was 24.0%. To this, 7.08 g (4 wt%) of 20% sulfuric acid was added, and after 4 hours, the acetamide conversion rate was 90%, the N- (1-methoxyethyl) acetamide selectivity was 77.7%, and the ethylidene bisacetamide was selected. The rate was 22.3%.

Example 6 Acetamide 0.375 mo
1, methanol 0.75 mol, acetaldehyde 1.
Acetaldehyde was added over 10 minutes using an aqueous solution prepared by adding 5.3 g of sodium sulfate (adjusted to a 50% sodium sulfate solution) to 5.3 g of water to a catalyst of 5 mol, dichloromethane 5.3 mol, 20% sulfuric acid 7.3 g. The same operation as in Example 3 was performed except for the above. Acetamide conversion rate 8
4.3%, N- (1-methoxyethyl) acetamide selectivity 72%, ethylidene bisacetamide selectivity 2
8. %Met.

Example 7 The same operation as in Example 6 was carried out except that 3.5 g of sodium sulfate was replaced with 1.75 g (adjusted to a 12% sodium sulfate solution) and 5.3 g of water was replaced with 13 g. Acetamide conversion rate 82.1%, N- (1-
The selectivity of methoxyethyl) acetamide was 81.8%, and that of ethylidene bisacetamide was 18.
It was 2%.

[Example 8] Acetamide 0.375 mo
1, methanol 0.375 mol, acetaldehyde 2.25 mol, dichloromethane 5.3 mol, 20%
The same operation as in Example 3 was carried out except that 8.0 g of concentrated sulfuric acid (1 wt% with respect to the charged raw material amount) and 5.5 g (0.3 mol) of water were added to adjust the water concentration to 2 wt%. The acetamide conversion was 78.9%, the N- (1-methoxyethyl) acetamide selectivity was 52.4%, and the ethylidene bisacetamide selectivity was 47.6%.

[Example 9] Acetamide, methanol,
Acetaldehyde (0.375 mol), dichloromethane (5.3 mol), 20% concentrated sulfuric acid (3.3 g, 1 wt% based on the amount of raw material charged) and water, 7.76 g (0.43 m)
The same operation as in Example 3 was performed except that the water concentration was adjusted to 2 wt%. Acetamide conversion 63. %, The selectivity of N- (1-methoxyethyl) acetamide was 82%, and the selectivity of ethylidene bisacetamide was 18%.

Example 10 The same operation as in Example 1 was carried out except that 6.48 g (45 mmol) of ethylidene bisacetamide was added. Acetamide conversion rate 8
8%, the selectivity of N- (1-methoxyethyl) acetamide was 72%, and that of ethylidene bisacetamide was 28%.

Example 11 Acetamide 0.3 mol
Was replaced with 0.2 mol, acetaldehyde 0.3 mol was replaced with 0.4 mol, and acetaldehyde dimethyl acetal 0.2 mol was added, and the same operation as in Example 1 was performed. Acetamide conversion rate 93%, N-
Selectivity of (1-methoxyethyl) acetamide 95.2
%, And the selectivity for ethylidene bisacetamide is 4.8.
%Met.

[Comparative Example 1] Addition amount of acetamide 0.0
75 mol to 0.375 mol, methanol 0.15 m
ol 0.75 mol, acetaldehyde 0.3 mol
In place of 1.5 mol, 5.6 g of 20% concentrated sulfuric acid (1 wt% with respect to the amount of raw material charged) and 4.14 g of water (0.23 m
ol) was added to adjust the water concentration to 7 wt% and no dichloromethane was added, and the same operation as in Example 3 was performed. Acetamide conversion 77.9%, N-
Selectivity for (1-methoxyethyl) acetamide 56.9
%, The selectivity of ethylidene bisacetamide is 43.1.
%Met.

[Comparative Example 2] The same operation as in Example 10 was carried out except that tetrahydrofuran was added instead of dichloromethane. The reaction solution becomes one phase, and the acetamide conversion rate is 9
The yield was 0.6% and the N- (1-methoxyethyl) acetamide yield was 53.6%. Crystals of ethylidene bisacetamide were precipitated as the reaction proceeded, and the yield was 37%.

[0032]

According to the present invention, primary carboxylic acid amide, acetaldehyde and alcohol having 1 to 5 carbon atoms, or if desired, ethylidene biscarboxylic acid amide and acetaldehyde dialkyl acetal are added in the presence of an acidic catalyst. , An aqueous solution and an organic solvent solution that forms two phases with the aqueous solution are simultaneously subjected to the reaction and the extraction and separation, so that N- (1-
Alkylethyl) carboxylic acid amides can be prepared.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // C07B 61/00 300

Claims (4)

[Claims] 1. An N-characterized by reacting at least a primary carboxylic acid amide, acetaldehyde and an alcohol having 1 to 5 carbon atoms in the presence of an acidic catalyst in a solution forming two phases with water and an organic solvent. Process for producing (1-alkoxyethyl) carboxylic acid amide. 2. N- (1) characterized by reacting at least ethylidene biscarboxylic acid amide and an alcohol having 1 to 5 carbon atoms in the presence of an acidic catalyst in a solution forming two phases with water and an organic solvent. -Method for producing alkoxyethyl) carboxylic acid amide. 3. The primary carboxylic acid amide is acetamide,
The alcohol having 1 to 5 carbon atoms is methanol.
The manufacturing method described in. 4. The method according to claim 1, wherein the organic solvent is dichloromethane and / or chloroform.