Method for producing alpha,beta-unsaturated carboxylic acid-n,n-disubstituted amide and method for producing 3-alkoxycarboxylic acid-n,n-disubstituted amide

A method for producing an α,β-unsaturated carboxylic acid-N,N-disubstituted amide, the method comprising:

• adding a vapor-phase-polymerization inhibitor to an N,N-disubstituted-β-amino acid-N′,N′-disubstituted amide in liquid form;
• decomposing the N,N-disubstituted-β-amino acid-N′,N′-disubstituted amide at 200 to 300° C. and at a pressure of 0.15 to 0.95 MPa, to thereby produce an α,β-unsaturated carboxylic acid-N,N-disubstituted amide in vapor form;
• and
• adding a liquid-phase-polymerization inhibitor to the α,β-unsaturated carboxylic acid-N,N-disubstituted amide.

A method for producing an α,β-unsaturated carboxylic acid-N,N-disubstituted amide, the method comprising:

• (I) adding an α,β-unsaturated carboxylic acid to a secondary amine, to obtain a resultant mixture, and allowing reaction of the resultant mixture to proceed under pressurized conditions, to obtain a first product;
• (II) reacting the first product with a secondary amine by a countercurrent contact system, to obtain a second product;
• and
• (III) decomposing the second product in the presence of a polymerization inhibitor added thereto.