Patent ID: 7674929

Claim:
A process for preparing β-aminopropionic acid derivatives comprising: (i) reacting a primary amine selected from the group consisting of isophoronediamine, 3,3′-dimethyl-4,4′-diaminodicyclo-hexylmethane, 4,4′-diaminodicyclohexylmethane, 4,4′-diaminodiphenylmethane, hexamethylenediamine, 2-methyl-pentamethylene-diamine, polyetheramine D 230 and 1,13-diamino-4,7,10-trioxatridecane, with an acrylic acid derivative to obtain a reaction mixture comprising a first β-aminopropionic acid derivative and unconverted acrylic acid derivative, and (ii) reacting the unconverted acrylic acid derivative with a secondary amine to produce a second β-aminopropionic acid derivative and to obtain a reaction mixture comprising the first β-aminopropionic acid derivative, the second β-aminopropionic acid derivative and unconverted secondary amine; (iii) removing the unconverted secondary amine by distillation, and/or (iv) removing the second β-aminopropionic acid derivative by distillation; wherein 0.9 to 1.10 mole of the acrylic acid derivative is used per mole of the primary amino groups of the amine of value.