阅读说明：本技术 制备c-h酸性(甲基)丙烯酸系化物的方法 (Method for producing C-H acidic (meth) acrylic compounds ) 是由 M·特雷斯科 M·卡斯帕里 T·舒茨 S·科里尔 于 2019-07-10 设计创作，主要内容包括：本发明涉及C-H酸性(甲基)丙烯酸系化物的制备方法和它们的用途。(The invention relates to a method for producing C-H acidic (meth) acrylic acid-based compounds and to the use thereof.)

1. A process for preparing C-H acidic (meth) acrylic compounds of the formula (I),

CH₂＝CR¹-CO-NH-R²-NH-CO-CH₂-CN (I)

(P)

wherein

R¹: h or methyl

R²：C_nH_mO_xN_y

Wherein

n＝2-15

m＝4-30

x is 0-4 and

y＝0-4

it is characterized in that

a) Reacting an ester of cyanoacetic acid (A) with an excess of diamine (B),

b) removing the unreacted diamine (B) from the reaction solution,

c) reacting the Intermediate Product (IP) obtained in b), i.e. the amino-functionalized cyanoacetamide,

c1) with (meth) acrylic acid esters (MAD), or

c2) Reacting with (meth) acrylic anhydride (MAD) or (meth) acrylic acid halide (MAD),

d) optionally, isolating the product (P) obtained in c) by means of extraction or crystallization.

2. Process according to claim 1, characterized in that the ester of cyanoacetic acid is selected from methyl cyanoacetate and ethyl cyanoacetate.

3. Process according to claim 1, characterized in that the diamine is selected from the group consisting of aliphatic linear or branched or cyclic substituted and unsubstituted diamines and aromatic (ortho, meta or para) substituted diamines.

4. Process according to claim 1, characterized in that the excess of diamine with respect to the ester of cyanoacetic acid is between 10:1 and 1.001: 1.

5. The process according to claim 1, characterized in that the unreacted diamine is removed in step b) by means of distillation, extraction or crystallization.

6. Process according to claim 1, characterized in that the intermediate product is reacted in c1) with an ester selected from the group consisting of: methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ethyl acrylate, butyl acrylate, and esters of higher alcohols of (meth) acrylic acid.

7. The process according to claim 1, characterized in that the intermediate product is reacted in c2) with an alkyl acid halide selected from the group consisting of (meth) acryloyl bromide and (meth) acryloyl chloride.

8. The process according to claim 1, characterized in that the intermediate product is reacted in c2) with a (meth) acrylic anhydride selected from methacrylic anhydride and acrylic anhydride.

9. Process according to claim 1, characterized in that the reaction of the ester of cyanoacetic acid with the diamine is carried out at a temperature of-20 ℃ to 140 ℃, preferably at a temperature of 0 ℃ to 30 ℃.

10. The process according to claim 1, wherein the ratio of alkyl acid ester to intermediate in c1) is between 1.01:1 and 20: 1.

11. The process according to claim 1, wherein the ratio of alkyl acid anhydride or alkyl acid halide to intermediate in c2) is between 0.2:1 and 5: 1.

Technical Field

The present invention relates to a process for the preparation of C-H acidic (meth) acrylates and their use.

Background

The prior art contains methods for preparing methacrylate compound derivatives based on acetoacetamides and acetoacetates.

According to the method described in EP 0013147, the synthesis of C-H acidic monomers based on cyanoacetic acid derivatives is not possible, although the claims include this in the description. In EP 0013417, various aminoalcohols or diamines and their methacrylate derivatives are reacted with diketene and the corresponding acetoacetic acid derivatives are obtained therefrom. These also represent C-H acidic compounds. However, diketene is not suitable even as a starting material for the synthesis of cyanoacetic acid and its carboxylic acid derivatives (esters, amides, etc.) because the carbon skeleton is a C4 host and cyanoacetic acid is a C3 host. To synthesize asymmetrically substituted diamines, EP 0013147 also utilizes protecting group chemistry to temporarily block the amine, thereby protecting it from reaction. This is uneconomical and expensive in terms of process technology due to the additional reaction steps.

Carboxylic acid derivatives of acetoacetic acid tend to produce colored complexes that are not suitable for many clear coat applications.

Disclosure of Invention

It is therefore an object to provide a process for preparing cyanoacetic acid-based C-H acidic (meth) acrylates. One object is in particular to prepare C-H acidic monomers which are free of 1, 3-diketone structures as in acetoacetate.

It is a further object to provide hydrolytically stable (meth) acrylates, so that particularly good storage stability in the product can be achieved.

This object is achieved by a process for preparing C-H acidic (meth) acrylic compounds, which comprises reacting a diamine (B) with an ester (A) of cyanoacetic acid to form an Intermediate Product (IP),

wherein R is²Is C_nH_mO_xN_y，

Wherein

n＝2-15

m＝4-30

x is 0-4 and

y＝0-4。

most particularly preferred here are the methyl and ethyl esters of cyanoacetic acid (Z ═ CH)₃、C₂H₅) Since these are widely commercially available, however, higher esters can also be readily adapted for use in the reaction. As a byproduct of this reaction (as would be expected by one skilled in the art), both amino groups of the diamine react with cyanoacetic acid, forming dicyanoacetamide (BP). This reaction is undesirable because additional process steps are required for separating BP, which has a negative impact on the economic viability and cost of the process.

It is simpler to work with an excess of diamine, which also has a lower boiling point than IP and can therefore be removed more easily than BP, which is just as temperature sensitive as IP. Surprisingly, the formation of BP is greatly suppressed even with small excesses of B, for example with excesses of B of 1.001:1, and with excesses of B of 10:1, particularly preferably of 4:1, a crude product of > 99% IP is obtained after removal of the diamine B. In this case, the isolation of B can be carried out by extraction or crystallization, but in particular by distillation, preferably under reduced pressure. The IP obtained after removal of B can be reacted further as a crude product with (meth) acrylate derivatives (MAD) without further work-up. Here, the reaction may be carried out with an acid halide (c2) (preferably using a base to scavenge the hydrogen halide formed) and also by reaction with an ester of (meth) acrylic acid (c 1). In this respect, mixtures of dioctyltin oxide (DOTO) and isopropyl titanate (IPT) have proven to be particularly suitable as catalysts. However, the reaction of BP with an anhydride of (meth) acrylic acid (c2) has been shown to be particularly effective.

R³OMe (catalyst: IPT/DOTO)

Halogen root

＝O-CO-C(R¹)＝CH₂

R¹＝H、CH₃

Surprisingly, it has been found that with the process according to the invention high conversions are achieved and the amount of by-products is significantly reduced.

The term "(meth) acrylic" herein means both methacrylic (e.g., methyl methacrylate, ethyl methacrylate, etc.) and acrylic (e.g., methyl acrylate, ethyl acrylate, etc.), as well as mixtures thereof.

Diamines

Suitable diamines are selected from the group consisting of aliphatic, straight-chain or branched or cyclic substituted and unsubstituted diamines and aromatic (ortho-, meta-or para-) substituted diamines.

Particularly preferred diamines are selected from the group consisting of ethylenediamine, 1, 3-diaminopropane, 1, 4-diaminobutane, 1, 5-diaminopentane, 1, 6-hexanediamine, 1, 7-diaminoheptane, 1, 8-diaminooctane, 1, 10-diaminodecane, 1, 2-diaminopropane, the cis and trans isomers of isolated 1, 2-diaminocyclohexane and mixtures thereof, the cis and trans isomers of isolated 1, 3-diaminocyclohexane and mixtures thereof, the cis and trans isomers of isolated 1, 4-diaminocyclohexane and mixtures thereof, 1, 3-diamino-2-hydroxypropane, 2, 2-dimethyl-1, 3-propanediamine, the cis and trans isomers of isolated isophoronediamine and mixtures thereof, the cis and trans isomers of the isolated 1, 3-cyclohexanedi (methylamine) and mixtures thereof, the 4,4 '-methylenebis (cyclohexylamine), the cis and trans isomers of the isolated 4,4' -methylenebis (2-methylcyclohexylamine) and mixtures thereof.

In (c2), the ratio of alkyl anhydride or alkyl acid halide to intermediate product is 0.2:1 to 5: 1.

It is particularly preferred to carry out the reaction in a ratio of 0.5:1, since in this case 1 equivalent of the intermediate amine neutralises the acid formed from the anhydride or acid halide.

The ratio 1:1 is most particularly preferred, since in this case, despite the earlier reaction with the carboxylic acid of the anhydride, a large proportion of the hitherto expensive prepared amines will still react further to form the product.

It may also be preferred to operate with an excess of anhydride >1:1, as this helps to achieve full conversion more quickly.

(meth) acrylic anhydride

Reacting the Intermediate (IP) with a (meth) acrylic anhydride selected from methacrylic anhydride and acrylic anhydride in c 2).

Reaction conditions

The reaction in a is carried out at a temperature of between 0 and 120 ℃ during the metering, preferably between 10 and 40 ℃, and at a temperature of up to 100 ℃ in the post-reaction stage and in preparation for the work-up. In c1, in the range from 60 to 140 ℃, preferably 100 and 120 ℃. In c2, 0 to 40 ℃ may be present in the post-reaction up to 100 ℃.

The reaction time lasts 15 minutes to 10 hours.

To avoid the formation of undesired by-products, the temperature is kept as low as possible and an excess of amine is used in a.

Neutralization and post-treatment

The Intermediate Product (IP) can be used further without work-up.

Preferred process variants

The Intermediate Product (IP) from step b is dissolved in the solvent while hot (since otherwise it would solidify into glass) and therefore reacts significantly better. A suitable solvent is H₂O, MTBE, THF, acetonitrile, dioxane, MAD, and alcohol. Such selection will be apparent to those skilled in the art based on the respective purposes of the reaction.

In step c2, a compound selected from H is used₂O, MTBE, THF, acetonitrile, dioxane, MAD, and an alcohol.

By extraction or crystallization

The product (P) can be used further without work-up. It is also possible, if desired, to remove all low boilers therefrom under reduced pressure, to recrystallize it by addition of a polar solvent, or to extract it by addition of an immiscible solvent.

It has been found that the C-H acidic (meth) acrylates of the invention are hydrolytically stable and therefore stable for long term storage.

The C-H acidic (meth) acrylic compounds have many fields of application. Preference is given to the use in coatings and paints, in particular in clearcoats. Likewise, they can also be used as polymerizable monomers for the preparation of polymers which can be crosslinked at room temperature using ketones, aldehydes, isocyanates and activated double bonds.

Detailed Description

The examples given below better illustrate the invention without limiting it to the features disclosed therein.

Example (b):

example 1: preparation of N- (2-ethylamino) -2-cyanoacetamide

600g (10.0mol) of ethylenediamine were initially charged into a 2 liter four-necked round bottom flask with a sabre stirrer, stirrer motor, thermometer and 500ml addition funnel. 248g (2.5mol) of methyl cyanoacetate are metered dropwise in the course of 60 minutes so that the reaction temperature does not exceed 30 ℃. During this time, the four-necked round bottom flask was cooled in an ice-water bath. During the addition of methyl cyanoacetate, the reaction mixture gradually turned pink and then pale purple. To complete the reaction, the reaction mixture was stirred at room temperature for an additional 90 minutes.

Subsequently, excess ethylenediamine was removed under reduced pressure. For this purpose, the reaction mixture was heated to 100 ℃ (oil bath temperature) and the volatile constituents were distilled off over a period of 2 hours at a pressure of up to 5 mbar.

The product obtained was a dark glassy solid with a purity of 97.9 area% (determined using GC-RV). The product yield was 309g (95%).

Comparative example 1: preparation of N, N' -ethylene bis-methacrylamide

A40% aqueous solution of ethylenediamine (25.5g, 0.17mol) was initially charged to a 250ml four-necked round bottom flask equipped with a sabre stirrer, stirrer motor, thermometer and 100ml addition funnel. 26g (0.17mol) of methacrylic anhydride were metered in over the course of 60 minutes, so that the reaction temperature did not exceed 30 ℃. During this time, the four-necked round bottom flask was cooled in an ice-water bath. During the addition of methacrylic anhydride, a white solid was formed.

The white solid was isolated by filtration and dried. It is N, N' -ethylene bis-methacrylamide, 74.8 area% pure (determined using GC-RV). The product yield was 20g (60%).

Example 2: preparation of N- (2-cyanoethylamidoethyl) methacrylamide

A mixture of 147g (1.2mol) of N- (2-ethylamino) -2-cyanoacetamide and 600g (6.0mol) of methyl methacrylate was initially charged to a 1-liter four-necked round-bottomed flask with air inlet, sabre-type stirrer, stirrer motor and a 50cm long, 29mm thick mirror-surface column (mirrorcolumn) with random packing filled with 6X 6 Raschig rings. To this was added 7mg (10ppm) 4-hydroxy-2, 2,6, 6-tetramethylpiperidin-1-oxyl and 0.15g (200ppm) hydroquinone monomethyl ether, followed by 7.4g of a mixture comprising 65.6% by weight of dioctyltin oxide and 34.4% by weight of tetraisopropyl titanate.

The reaction mixture was heated at reflux, with the methanol formed distilling off as an azeotrope via a column with random packing. After about 3.5 hours, the conversion, determined by GC, was 58%.

Example 3: preparation of N- (2-cyanoethylaminoethyl) methacrylamide 312g (2.4mol) of N- (2-ethylamino) -2-cyanoacetamide from example 1 were dissolved in 468g of water in a 2 l three-necked round-bottomed flask with a guillotine stirrer, stirrer motor, thermometer and 500ml addition funnel. 370g (2.4mol) of methacrylic anhydride were slowly added dropwise thereto, a light brown precipitate being formed. The reaction mixture was then stirred at 80 ℃ for a further 1.5 h.

The resulting clear deep red reaction mixture was removed low boiling substances therefrom under reduced pressure, concentrated to 646g, and 400g of isopropyl alcohol was added thereto. This resulted in the formation of a precipitate which was isolated by filtration.

The product was obtained as a brown crystalline solid with a purity of 77.0 area% (determined using GC-RV). The product yield was 346g (73.9%).

Example 4: preparation of N- (2-butylamino) -2-cyanoacetamide

353g (4.0mol) of 1, 4-diaminobutane were melted at about 30 ℃ in a 1 liter four-necked round bottom flask with a military knife stirrer, stirrer motor, thermometer and 250ml addition funnel. 99g (1.0mol) of methyl cyanoacetate are metered dropwise in the course of 30 minutes, so that the reaction temperature is maintained at about 30 ℃ to 40 ℃. During this time, the four-necked round bottom flask was cooled in an ice-water bath. During the addition of methyl cyanoacetate, the reaction mixture gradually turned a strong yellow color. To complete the reaction, the reaction mixture was stirred at room temperature for an additional 90 minutes, wherein the reaction mixture turned red.

Subsequently, excess 1, 4-diaminobutane was removed under reduced pressure. For this purpose, the reaction mixture was heated to 100 ℃ (oil bath temperature) and the volatile constituents were distilled off over a period of 2.5 hours at a pressure of up to 2 mbar.

The product obtained was a dark glassy solid with a purity of 89.1 area% (determined using GC-RV). The product yield was 146g (84%).

Example 5: preparation of N- (2-cyanoethylaminobutyl) methacrylamide in a 1 l four-necked round-bottomed flask with a guillotine stirrer, stirrer motor, thermometer and 500ml addition funnel, 360g (0.93mol) of N- (2-butylamino) -2-cyanoacetamide from example 4 were dissolved in 540g of water and cooled to 0 ℃ in an ice-water bath. 143g (0.93mol) of methacrylic anhydride dissolved in 300ml of methanol are slowly added dropwise thereto. Subsequently, the reaction mixture was stirred at room temperature overnight, wherein the reaction mixture turned green.

The reaction mixture was concentrated to 263g at 80 ℃ and 35 mbar under reduced pressure. The residue was dissolved in 160g of isopropanol, and the resulting solution was stored at room temperature. This resulted in the formation of a precipitate which was isolated by filtration.

The product was obtained as a yellow crystalline solid. The purity was about 94.0 area% (determined using GC-RV).

Example 6: preparation of N- (2-hexylamino) -2-cyanoacetamide

465g (4.0mol) of 1, 6-diaminohexane were melted at about 41 ℃ in a 1 liter four-necked round bottom flask with a military knife stirrer, stirrer motor, thermometer and 250ml addition funnel. 99g (1.0mol) of methyl cyanoacetate are metered dropwise into it over the course of 30 minutes, so that the reaction temperature is maintained at about 50 ℃ to 75 ℃. During the addition of methyl cyanoacetate, the reaction mixture gradually turned a strong yellow color. To complete the reaction, the reaction mixture was stirred at about 50 ℃ to 75 ℃ for an additional 90 minutes, wherein the reaction mixture turned red.

Subsequently, excess 1, 6-diaminohexane was removed under reduced pressure. For this purpose, the reaction mixture was heated to 120 ℃ (oil bath temperature) and the volatile constituents were distilled off over a period of 4 hours at a pressure of up to 2 mbar.

The product obtained was a dark glassy solid with a purity of about 100 area% (determined using GC-RV). The product yield was 172g (94%).

Example 7: preparation of N- (2-cyanoethylamidobutyl) methacrylamide

31g (0.2mol) of methacrylic anhydride and 150g of water were initially charged to a 1 liter four-necked round-bottomed flask with a military knife stirrer, stirrer motor, thermometer and 500ml addition funnel and cooled to 0 ℃ in an ice-water bath.

360g (0.93mol) of N- (2-hexylamino) -2-cyanoacetamide from example 6 are dissolved in 3240g of methanol at 60 ℃ and cooled to room temperature. This solution was added to methacrylic anhydride over a period of 30 minutes via an addition funnel. The reaction temperature was kept below 20 ℃. The reaction mixture was then stirred at room temperature for a further 3 hours.

The product formed was detected in the reaction mixture using GC-RV and could be isolated by crystallization from isopropanol.

Analysis of

Gas Chromatography (GC)

The instrument comprises the following steps: 7820A from Agilent Technologies

Column: the total mass of DB5, 30m,film of 0.25 μm

Temperature program:

injection was carried out at 60 ℃ and then held for 2 minutes. Followed by heating to 240 ℃ at 20 ℃/min and, after this temperature has been reached, holding at 240 ℃ for 8 minutes.