Preparation of acrylic acid derivatives from α- or β-hydroxy carboxylic acids

A process for preparing an α, β-unsaturated amide, α,β-unsaturated N-substituted amide or α,β-unsaturated N,N-disubstituted amide of formula (I)

• wherein R1, and R2 are independently H, C1-C6 alkyl, cycloalkyl, or R1 and R2 can form a ring, wherein the ring is selected from the group consisting of morpholine, piperazine, piperidine and pyrrolidine, R3 is H or C1-C4 alkyl and R4 is H, methyl or ehtyl which process comprises the steps of
• a) forming an aqueous solution comprising at least one of
• an α- or β-hydroxycarboxylic acid;
• an α- or β-hydroxycarboxylic salt;
• an α- or β-hydroxycarboxylic ester;
• or
• cyclic lactide, 3,6-dimethyl-1, 4-dioxane-2, 5-dione
• and
• b) heating the aqueous solution of step a) in the presence of an amine or an amine salt of the α- or β-hydroxycarboxylic acid, wherein amidation and dehydration occurs
• optionally in the presence of a dehydration and/or amidation catalyst.