JPH06100515A - Production on n-@(3754/24)alpha-alkoxyethyl)-carboxlic acid amide - Google Patents

Abstract

PURPOSE:To produce an N-(alpha-alkoxyethyl)-carboxylic acid amide simply and in an excellent and efficient final yield. CONSTITUTION:A N-(alpha-alkoxyethyl)-carboxylic acid amides produced by (a) a first step of reacting a carboxylic acid primary amide with acetaldehyde, a 1-4C alcohol, an ethylidenediscarboxylic acid primary amide and an acetal in the presence of an acidic catalyst, (b) a second step of subjecting the reaction solution obtained by the first step to distillation procedure to give an N-(alpha- alkoxyethyl)-carboxylic acid amid and (c) a step of using acetaldehyde, the alcohol and the ethylidenediscarboxylic acid amide separated in the second step in the first step to produce an N-(alpha-alkoxyethyl)-carboxylic acid amide.

Description

Detailed Description of the Invention

[0001]

The present invention relates to N- (α, which is a compound useful as an intermediate for N-vinyl-carboxylic acid amide and the like.
-Alkoxyethyl) -carboxylic acid amides. N-vinyl-carboxylic acid amide is a compound useful as a raw material for synthesizing a water-soluble polymer, a copolymer in some cases, or a chemical product such as taurine or cysteamine.

[0002]

Conventionally, N- (α-alkoxyethyl)-
Various methods have been proposed as methods for synthesizing 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 biscarboxylic acid amide, and the like. As a method using acetaldehyde as a starting material, in German Patent 1,273,533, a carboxylic acid amide and an aldehyde and an alcohol, or a carboxylic acid amide and an acetal are reacted with hydrochloric acid, thionyl chloride, sulfuryl chloride or the like as a catalyst. Although a method has been disclosed, this method has a very low yield in the case of a straight-chain carboxylic acid amide in addition to limiting the starting carboxylic acid amide to the second amide. For example, the yield of N- (α-ethoxyethyl) -N-methylacetamide from N-methylacetamide and acetaldehyde diethyl acetal is only 26%.

JP-A-62-289549 and JP-A-63-96160 are improved methods of this method.
Although the target N- (α-alkoxyethyl) carboxylic acid amide is obtained in a relatively high yield, acetal and ethylidene biscarboxylic acid amide are by-produced. JP-A-2-3641 describes the possibility of using the acetal by-produced in this reaction by recycling it into 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 aimed at reacting in one step in the presence of a strongly acidic catalyst from three kinds of compounds, which are easily available and inexpensive, such as carboxamide, acetaldehyde and alcohol. N
Since it is possible to synthesize-(α-alkoxyethyl) carboxylic acid amide, it is expected as a method for industrially and conveniently producing N- (α-alkoxyethyl) carboxylic acid amide, but N- (α-alkoxyethyl) carboxylic acid With the production of amides, the treatment of the major by-products, acetal and ethylidene biscarboxylic acid amides, especially ethylidene biscarboxylic acid amides, becomes 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 1 mol of carboxylic acid amide and dimethyl acetal. It is necessary to use an extremely large amount of 20 moles, which has the drawback of extremely low productivity. Further, JP-A-2-9851 reports that N- (α-alkoxyethyl) formamide is similarly synthesized from formamide and acetal, but has the same problem.

As a method of using ethylidene biscarboxylic acid amide as a starting material, there are JP-A 1-100153 and JP-A 2-304053. This method is simple and yields the desired N- (α- by reacting ethylidene bisamide easily produced from inexpensive and inexpensive acetaldehyde and carboxylic acid amide or vinyl ether and carboxylic acid amide with alkanol. Alkoxyethyl) carboxylic acid amides are obtained. However, as a problem of this method, it is necessary to separately synthesize an ethylidene biscarboxylic acid amide, further isolate and use the amide, and after the reaction is completed, an N- (α-alkoxyethyl) carboxylic acid amide is obtained. It can be cited that a complicated operation including extraction is required to separate the carboxylic acid amide produced as a by-product in the same number of moles.

As described above, the conventional methods for synthesizing N- (α-alkoxyethyl) carboxylic acid amides have problems in yield, production of by-products, difficulty in obtaining raw materials, complexity of reaction step and purification step, etc. In terms of points, it is hard to say that it is a satisfactory method.

[0008]

The problem of the present invention is N-
It is an object of the present invention to provide a method for industrially advantageously producing (α-alkoxyethyl) -carboxylic acid amide.
N- with a simple and good final yield without substantial by-products such as ethylidene biscarboxylic acid amide and acetal.
An object of the present invention is to provide a method for efficiently producing (α-alkoxyethyl) -carboxylic acid amide.

[0009]

In view of the above situation, the present inventor has completed the present invention as a result of comprehensively studying the entire manufacturing process including reaction raw materials, catalysts, reaction conditions, reaction operations, and separation steps. . That is, the present invention is N- (α-
In producing (alkoxyethyl) -carboxylic acid amide, (a) carboxylic acid primary amide, acetaldehyde, alcohol having 1 to 4 carbon atoms, ethylidene biscarboxylic acid primary amide and acetal are added, and the reaction is carried out in the presence of an acidic catalyst. The first step, (b) the second step in which the reaction solution obtained in the first step is subjected to a distillation operation to obtain N- (α-alkoxyethyl) -carboxylic acid amide, (c) the acetaldehyde separated in the second step, It is intended to provide a method for producing N- (α-alkoxyethyl) -carboxylic acid amide, which comprises using alcohol, acetal and ethylidene biscarboxylic acid amide again as reaction raw materials in the first step.

The present invention will be described in more detail below. The acidic catalyst used in the first step of the present invention may be either a homogeneous catalyst or a heterogeneous catalyst. Examples of the former include organic acids such as sulfuric acid, nitric acid, hydrochloric acid mineral acids, methanesulfonic acid and p-toluenesulfonic acid. Acid etc. are mentioned. Examples of the latter include acidic cation exchange resins such as Amberlyst, Amberlite, Dowex and Nafion. The amount of the catalyst is not particularly limited, but the homogeneous catalyst is preferably selected from the range of 0.01 to 5% by weight with respect to the charged weight, and particularly preferably 0.05 to 2%. The acidic cation exchange resin of the heterogeneous catalyst is preferably selected from the range of 2 to 15% by weight with respect to the carboxylic acid primary amide.

As the carboxylic acid primary amide of the present invention, an aliphatic carboxylic acid primary amide can be generally used. Among these, formamide, acetamide, propionamide and the like can be mentioned, of which formamide and acetamide are particularly preferable. Alcohol has 1 carbon
It is preferred to use an aliphatic alcohol of ~ 4. For example, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol and the like are preferable, and among them, methanol, ethanol, isopropyl alcohol and n-butanol are preferable. Examples of ethylidene biscarboxylic acid amides include ethylidene biscarboxylic acid amides derived from primary carboxylic acid primary amides such as formamide, acetamide, and propionamide. In this case, the same aliphatic carboxylic acid primary amide as the above-mentioned carboxylic acid primary amide is used. Acetal means acetaldehyde dialkyl acetal, and examples of the alkyl group in this case include alkyl groups derived from aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol and sec-butanol. These acetals and the corresponding alcohols are in an equilibrium reaction relationship, and the combination of the same type of acetal as the alcohol used in the present invention is preferable because the exchange reaction with the alkoxy group occurs under the reaction conditions. And the like.

The molar ratio of carboxylic acid primary amide to acetaldehyde, alcohol and acetal, ethylidene biscarboxylic acid amide is usually 1: 1.5 to 50: 2 to 5.
It is selected from the range of 0: 0.5 to 10: 0.01 to 2, but above all, it is 1: 2 to 20: 4 to 20: 1 to 5: 0.0.
5-1 is especially preferable. Even if the molar ratio of acetaldehyde to carboxylic acid primary amide is higher than this, improvement of the conversion rate of the carboxylic acid primary amide cannot be expected, and the production amount of acetaldehyde condensate increases. Further, if it is less than this, the conversion rate decreases. When the molar ratio of the alcohol to the carboxylic acid primary amide is higher than this, the conversion rate of the carboxylic acid primary amide decreases, the acetal increases, and the productivity decreases. On the other hand, if the amount is less than this, the amount of ethylidene biscarboxylic acid amide produced increases and acetal decreases. When the molar ratio of the acetal to the carboxylic acid primary amide is higher than this, the productivity is lowered and the amount of the acetal is reduced. On the other hand, if the amount is less than this, the conversion rate of the carboxylic acid primary amide decreases, and the production amount of ethylidene biscarboxylic acid amide increases. The molar ratio of ethylidene biscarboxylic acid amide to carboxylic acid primary amide is within this range, and the amount of alkylidene bisamide before and after the reaction is balanced.

The reaction temperature is usually selected in the range of 0 to 150 ° C, preferably 30 to 80 ° C. 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 7 hours, and preferably 1 to 3 hours. Since these reaction conditions differ in optimum conditions depending on the type of alcohol and acetal used, in order to obtain the desired N- (α-alkoxyethyl) -carboxylic acid amide in a high yield, the raw materials suitable for the reaction are in the above range. It is important to set the composition, reaction temperature, and reaction time. Also, the pressure is reduced,
It can be applied under any conditions of normal pressure and pressurization, and can be used in both stirring type and flow type reactors. When a homogeneous catalyst such as sulfuric acid is used as the catalyst, the acid catalyst in the reaction solution is neutralized with an alkali such as sodium hydroxide to remove the neutralized salt, and the reaction solution is sent to the next step. At this time, if an excess amount of alkali is added, a condensation reaction product derived from acetaldehyde is produced, and the reaction solution is colored, so it is preferable to use an equivalent amount of alkali.

Next, in the second step, a distillation column and a packed distillation column are used to carry out distillation separation from light boiling compounds in order. This distillation may be continuous distillation or batch distillation.
Further, in the case of batch distillation, the second step may be carried out in one distillation column. The order of separation is slightly different depending on the type of alcohol or carboxylic acid primary amide used, but it is usually carried out in the order of recovery of acetaldehyde, distillation of alcohol and water, separation of ethylidene biscarboxylic acid amide by filtration, and recovery of acetal. When alcohol and water are azeotropically distilled, alcohol and water are separately separated by a known method. Since N- (α-alkoxyethyl) -carboxylic acid amide is relatively unstable to heat through these operations, the temperature in the distillation vessel should be kept at 150 ° C or lower, preferably 100 ° C or lower during distillation. It is desirable to adjust the degree of vacuum.

Then, the recovered aldehyde, alcohol, acetal and ethylidene biscarboxylic acid amide are returned to the first step and used as a reaction raw material. In the second step, as for acetal and ethylidene biscarboxylic acid amide, the amounts charged in the first step are recovered as they are, so there is no need to newly synthesize acetal or ethylidene biscarboxylic acid amide, or to discard them. As raw materials, carboxylic acid primary amide and the consumed amount of acetaldehyde and alcohol may be added.

Next, as a typical example of the method of the present invention,
Sulfuric acid as a catalyst, acetamide as a carboxylic acid primary amide, isopropyl alcohol as an alcohol,
N- (α-isopropoxyethyl) -acetamide was synthesized by using acetaldehyde diisopropyl acetal as the acetal and ethylidene bisacetamide as the ethylidene biscarboxylic acid amide, and the product was separated. The case of producing vinylacetamide will be described in more detail with reference to the drawings shown as a flow diagram.

In FIG. 1, A is a stirring type reactor, B is a stirring type neutralizing tank, C, D, E, G and I are distillation columns, F is a solid-liquid separator, and H is a decomposition reactor. And numbers 1 to 20
Represents the flow of matter.

First step (N- (α-isopropoxyethyl) -acetamide synthesis reaction); acetamide 3, catalytic amount of sulfuric acid 2, isopropyl alcohol 12 recovered from distillation columns E and I in a stirred reactor A; 19, the amount of acetaldehyde 1 consumed in the reaction, acetaldehyde 8 recovered from the distillation column C, and ethylidene bisacetamide 15 recovered from the solid-liquid separator F are introduced, and N-
A (α-isopropoxyethyl) -acetamide synthesis reaction is performed.

Second step (N- (α-isopropoxyethyl) -acetamide separation step); The reaction liquid 4 is introduced into the stirring neutralization tank B together with calcium hydroxide 5. The catalyst sulfuric acid is neutralized and separated as calcium sulfate. The reaction solution 6 from which the catalyst was neutralized and removed was subjected to atmospheric distillation in a distillation column C and acetaldehyde 8 and isopropyl alcohol, water, diisopropyl acetal, ethylidene bisacetamide and N- (α-isopropoxyethyl)-.
It is separated into a mixture 9 of acetamide. Mix 9 to about 1
It is introduced into a distillation column D depressurized to 00 mmHg, and isopropyl alcohol and water are distilled off by vacuum distillation. Since isopropyl alcohol and water form an azeotropic mixture and cannot be separated as they are, azeotropic distillation E is carried out using benzene as an entrainer to obtain water 13 from the top of the tower and anhydrous isopropyl alcohol 12 from the bottom of the tower. You can 12 is returned to the first step and used as a reaction raw material. The bottom liquid 11 of the distillation column D is a suspension in which ethylidene bisacetamide has reduced solubility because alcohol and water are removed, and ethylidene bisacetamide is precipitated. This is separated in a centrifuge F into a solid ethylidene bisacetamide 15 and a mixture 14 of diisopropyl acetal and N- (α-isopropoxyethyl) -acetamide. Ethylidene bisacetamide 15
Is returned to reactor A. The filtrate 14 is introduced into a distillation column G whose pressure is reduced to about 100 mmHg, and the diisopropyl acetal 16 is distilled off by vacuum distillation. The acetal at the top of the column is returned to the reactor A, and N- (α-isopropoxyethyl) -acetamide 17 is obtained from the bottom of the column.

N-vinylacetamide synthesis step: N- (α-isopropoxyethyl) -acetamide liquid 17 obtained from the bottom of acetal recovery column G is thermally decomposed in decomposition reactor H or catalytic decomposition using an acid catalyst. Is decomposed into N-vinylacetamide and isopropyl alcohol, and a methanol solution 18 of N-vinylacetamide is obtained from the outlet of the decomposition reactor H.

N-vinylacetamide purification step: A methanol solution 18 of N-vinylacetamide obtained from the outlet of the decomposition reactor H is converted into isopropyl alcohol 19 and N-vinylacetamide 20 by vacuum distillation in an N-vinylacetamide distillation column I. To be separated. Isopropyl alcohol 19 obtained from the top of the column is reused in the reactor A in the first step.

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 beginning, 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.

[0023]

【Example】

Example 1 [First Step] In a three-necked flask (5 L) equipped with a thermometer and a dry ice-ethanol trap, 207 g (3.5 mol) of acetamide, 1229 g (20.5 mol) of isopropyl alcohol, and 50.5 g of ethylidene bisacetamide. (0.35 mol), acetaldehyde diisopropyl acetal 1790 g (12.2 mo)
1) was added, and the mixture was stirred and dissolved at 48 to 49 ° C. until uniform. Concentrated sulfuric acid 4.0g (0.1wt% to the charged amount)
Was added to 75 g (1.25 mol) of isopropyl alcohol and stirred, and then 370 g of acetaldehyde
(8.4 mol) was added with a dropping funnel over 10 minutes.
After completion of the dropwise addition, the reaction was carried out at 50 ° C. for 3 hours to neutralize the catalyst, and then quantitative analysis by gas chromatography revealed that the acetamide conversion rate was 100% and N- (α-propoxyethyl).
The acetamide selectivity was 98%, and the by-product ethylidene bisacetamide selectivity was 2%. No increase or decrease in the amount of acetal or ethylidene bisacetamide was observed. To this reaction solution, add 1% of 30% sodium hydroxide aqueous solution.
3.5 g was added to neutralize the sulfuric acid. The generated sodium sulfate was filtered under reduced pressure using a filter paper.

[Second Step] 3721 g of the filtrate of the first step was charged into the heating kettle of a packed type (through-the-packing) distillation column having 20 theoretical plates, and acetaldehyde was distilled off at normal pressure and a reflux ratio of 1 to 3. At this time, 205 g of acetaldehyde,
105 g of isopropyl alcohol was recovered. Subsequently, this distillation column was depressurized to 100 mmHg, and isopropyl alcohol and water were distilled off at a reflux ratio of 3 to obtain 980 each.
g and 65 g were recovered. After cooling the bottom residue to room temperature, 48 g of ethylidene bisacetamide was filtered off. 1 of this filtrate
Distillation under reduced pressure was carried out at a reflux ratio of 3 at 00 mmHg to remove 1750 g of acetaldehyde diisopropyl acetal.

[N-Vinylacetamide Synthesis Step] The liquid practically consisting of N- (α-isopropoxyethyl) -acetamide obtained in the second step was added at a rate of 20 ml / minute and 450 mL / min.
The mixture was heated to 0 ° C. and depressurized to 40 mmHg, and supplied to a stainless reaction tube having an inner diameter of 25 mm and a length of 2 m. A condenser provided at the outlet of the reaction tube condenses the mixture of N-vinylacetamide and isopropyl alcohol produced by the thermal decomposition reaction,
Recovered. The conversion rate of N- (α-isopropoxyethyl) -acetamide was 95%.

[N-Vinylacetamide Purification Step] 10
The reaction liquid obtained in the N-vinylacetamide synthesis step was introduced into the 10-stage glass Oldershaw type rectification column from the top at 200 g / hr. The degree of pressure reduction was 200 mmHg, the reflux ratio was 2, and heating was performed so that the temperature at the top of the column was maintained at 40 ° C. Install a 500 ml flask at the bottom of the rectification column
Heat the flask contents by immersing it in an oil bath at ℃ 155 per hour.
It was extracted with g. The flask withdrawal solution was an isopropyl alcohol solution containing 94% by weight of N-vinylacetamide. 84 g of isopropyl alcohol was withdrawn from the top of the column every hour.

Further, in a rectification column packed with a 5 mm sulzer type packing material having 20 theoretical plates, the flask withdrawal liquid (N-vinylacetamide 94
Isopropyl alcohol solution containing 15% by weight) 155 per hour
introduced in g. The degree of reduced pressure was 2 mmHg, the reflux ratio was 3, and a 500 ml flask was provided in the lower part of the rectification column and immersed in an oil bath at 105 ° C. for heating. The flask contents were withdrawn at 140 g / h. The flask withdrawal liquid was N-vinylacetamide. 18 g of isopropyl alcohol containing a small amount of acetamide was withdrawn from the top of the column every hour.

Example 2 Addition of 15 mmol of ethylidene bisacetamide to 1
The same operation as in Example 1 was performed except that 0 mmol was replaced. The conversion of acetamide was 87%, the selectivity of N- (α-propoxyethyl) acetamide was 84%, the amount of acetal produced was reduced by 1 mmol, and ethylidene bisacetamide reached equilibrium with a yield of 12.6%.

Example 3 Acetaldehyde 8.8 g (0.2 mol) and acetaldehyde diisopropyl acetal 29.2 g (0.2
mol), ethylidene bisacetamide 1 g (7 mmo
The same operation as in Example 1 was carried out except that 1) was used. The acetamide conversion rate was 93.2% and the N- (α-propoxyethyl) acetamide selectivity was 97.8%.
No increase or decrease in acetal and ethylidene bisacetamide was observed and equilibration was achieved.

Example 4 In place of isopropyl alcohol, 35.5 g of ethyl alcohol and acetaldehyde diethyl acetal (0.
The same operation as in Example 3 was performed except that 3 mol) was used. The acetamide conversion rate was 87.5%, the N- (α-ethoxyethyl) acetamide selectivity was 96.3%, and there was almost no increase or decrease in the production of acetoaldediethyl acetal and ethylidene bisacetamide, and the equilibrium was reached.

Example 5 0.7 mol of ethyl alcohol was added to 0.2 mol (9.2 mol).
The same operation as in Example 4 was performed except that g) was replaced. Acetamide conversion rate 94.7%, N- (α-ethoxyethyl)
The selectivity of acetamide was 95.7%, the ethylidene bisacetamide was in equilibrium, but the acetaldehyde diethyl acetal tended to decrease.

Example 6 The same operation as in Example 3 was performed except that n-propyl alcohol was used instead of isopropyl alcohol. Acetamide conversion rate 88.1%, N- (α-propoxyethyl)
With acetamide selectivity of 93%, formation of acetal was balanced, but ethylidene bisacetamide yield was 6.2.
%Met.

Example 7 The same operation as in Example 6 was carried out except that 6.6 g (0.15 mol) of acetaldehyde, 30 g (0.5 mol) of n-propyl alcohol and 1.44 g (10 mmol) of ethylidene bisacetamide were used. . The acetamide conversion was 85.9% and the N- (α-npropoxyethyl) acetamide selectivity was 90%. The ethylidene bisacetamide was 8.4%, which was in equilibrium with the acetal.

Example 8 In place of isopropyl alcohol, 27.0 g of methyl alcohol and acetaldehyde dimethyl acetal (0.
The same operation as in Example 3 was performed except that 3 mol) was used. The acetamide conversion rate was 87.5%, the N- (α-methoxyethyl) acetamide selectivity was 96.3%, and there was almost no increase or decrease in the production of acetaldedimethyl acetal and ethylidene bisacetamide, and the equilibrium was reached.

Example 9 52.3 g (0.3%) of n-butanol and acetaldehyde dibutyl acetal were used in place of isopropyl alcohol.
(mol) was used, and the same operation as in Example 3 was performed.
The acetamide conversion rate was 87.5%, the N- (α-n-butoxyethyl) acetamide selectivity was 96.3%, and there was almost no increase or decrease in the production of acetoaldigebutyl acetal and ethylidene bisacetamide, and the equilibrium was reached.

Comparative Example 1 The same operation as in Example 3 was performed except that ethylidene bisacetamide was not added. Acetamide conversion 93.1
%, The selectivity of N- (α-propoxyethyl) acetamide was 87.8%, and no increase or decrease in the production of acetal was observed in the reaction for 3 hours, but ethylidene bisacetamide showed a further increase in the yield of 11.3%. The yield was 17.7% in 5 hours.
Reached

Comparative Example 2 The same operation as in Example 8 was carried out except that ethylidene bisacetamide was not added. Acetamide conversion 99.6
%, N- (α-methoxyethyl) acetamide yield 5
It was 9.9%, and crystals of ethylidene bisacetamide were precipitated, and the yield was 37%.

Comparative Example 3 5.9 g (0.1 mol) of acetamide, 8.8 g (0.2 mol) of acetaldehyde, and 17.6 g (0.2 mol) of n-amyl alcohol were mixed with acetaldehyde di-n-.
60.6 g (0.3 mol) of amyl acetal and 2 g (14 mmol) of ethylidene bisacetamide were added, and the same operation as in Example 1 was performed. Acetamide conversion rate 99.
The yield was 6% and the yield of N- (α-n amyloxyethyl) acetamide was 59%. The ethylidene bisacetamide yield was 33%, and crystals were precipitated and increased.

[0039]

INDUSTRIAL APPLICABILITY The present invention comprises reacting a carboxylic acid primary amide, acetaldehyde, an alcohol having 1 to 4 carbon atoms, an ethylidene biscarboxylic acid primary amide and an acetal in the presence of an acidic catalyst to obtain an ethylidene bisacetamide or acetal. Simple, with virtually no by-products of
Provided is a method for efficiently producing N- (α-alkoxyethyl) -carboxylic acid amide with a good and efficient final yield.

[Brief description of drawings]

FIG. 1 shows a production method of the present invention and N-using the production method.
It is an example of a flow diagram in the case of producing vinyl acetamide.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C07C 231/08 // C07B 61/00 300

Claims (1)

[Claims] 1. In producing an N- (α-alkoxyethyl) -carboxylic acid amide, (a) a carboxylic acid primary amide, acetaldehyde, an alcohol having 1 to 4 carbon atoms, an ethylidene biscarboxylic acid primary amide and an acetal. The first step of reacting in the presence of an acidic catalyst,
(B) The reaction liquid obtained in the first step is subjected to distillation operation to obtain N.
Second step of obtaining-(α-alkoxyethyl) -carboxylic acid amide, (c) acetaldehyde, alcohol, acetal, ethylidenebiscarboxylic acid amide separated in the second step are used again as reaction raw materials in the first step. A method for producing N- (α-alkoxyethyl) -carboxylic acid amide.