Method for preparing C-H acidic (meth)acrylates

1. A method for preparing C—H acidic (meth)acrylates of formula (I):

CH 2 ═CR 1 —CO—NH—R 2 —NH—CO—CH 2 —CN  (I)

(P)

wherein:

R 1 is H or methyl;

R 2 is C n H m O x N y ;

wherein:

n=2-15;

m=4-30;

x=0-4; and

y=0-4;

wherein said method comprises:

a) reacting an ester of cyanoacetic acid (A) with a diamine (B) in excess;

b) removing unreacted diamine (B) from the reaction solution to obtain the intermediate product (IP), an amino-functionalized cyanoacetamide;

c) obtaining product (P) by reacting intermediate product (IP) obtained in step b) with either:

c1) (meth)acrylic acid esters (MAD); or

c2) (meth)acrylic anhydride (MAD) or (meth)acryloyl halide (MAD);

d) optionally isolating (P) by extraction or crystallization.

2. The method of claim 1 , wherein the ester of cyanoacetic acid is selected from the group consisting of: of methyl cyanoacetate; and ethyl cyanoacetate.

3. The method of claim 1 , wherein the diamine is an aliphatic, linear or branched or cyclic substituted or unsubstituted diamine; or an aromatic (ortho, meta or para) substituted diamine.

4. The method of claim 1 , wherein the excess of diamine to ester of cyanoacetic acid is between 10:1 and 1.001:1.

5. The method of claim 1 , wherein unreacted diamine in step b) is removed by means of distillation, extraction or crystallization.

6. The method of claim 1 , wherein the reaction of the intermediate product in c1) is carried out with esters selected from the group consisting of: methyl (meth)acrylate; ethyl (meth)acrylate; butyl (meth)acrylate; ethyl acrylate; butyl acrylate; and higher alcohols of (meth)acrylate.

7. The method of claim 1 , wherein the intermediate product in c2) is reacted with alkyl acid halides selected from the group consisting of: (meth)acryloyl bromides; and (meth)acryloyl chlorides.

8. The method of claim 1 , wherein the intermediate product in c2) is reacted with (meth)acrylic anhydrides selected from the group consisting of: methacrylic anhydride; and acrylic anhydride.

9. The method of claim 1 , wherein the reaction of an ester of cyanoacetic acid with a diamine takes place at temperatures between −20° C. and 140° C.

10. The method of claim 1 , wherein the reaction of an ester of cyanoacetic acid with a diamine takes place at temperatures between 0° C. and 30° C.

11. The method of claim 1 , wherein the ratio of alkyl acid esters to intermediate product in c1) is between 1.01:1 and 20:1.

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