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

Abstract

The invention is directed to a technique for effectively producing an amide compound suitable for use as a solvent or a detergent on a large scale and at low cost.

1 . 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. 
 
     
     
         2 . The method of  claim 1 , wherein the vapor-phase-polymerization inhibitor comprises at least one polymerization inhibitor selected from the group consisting of N-nitrosophenylhydroxylamine ammonium salt, N-nitrosophenylhydroxylamine aluminum salt, N-nitrosophenylhydroxylamine zinc salt, and N-nitrosophenylhydroxylamine iron salt, and
 wherein the liquid-phase-polymerization inhibitor comprises at least one polymerization inhibitor selected from the group consisting of copper dithiocarbamate, phenothiazine, hydroquinone, benzoquinone, and hydroquinone monomethyl ether.   
     
     
         3 . The method of  claim 1 , wherein the vapor-phase-polymerization inhibitor is added in an amount of 0.06 to 2 mass % with respect to the N,N-disubstituted-β-amino acid-N′,N′-disubstituted amide. 
     
     
         4 . The method of  claim 1 , wherein the liquid-phase-polymerization inhibitor is added in an amount of 100 to 10,000 mass ppm with respect to the α,β-unsaturated carboxylic acid-N,N-disubstituted amide. 
     
     
         5 . The method of  claim 1 , wherein the N,N-disubstituted-β-amino acid-N′,N′-disubstituted amide is decomposed in the presence of at least one solid acid catalyst selected from the group consisting of alumina, silica-alumina, a cation exchange resin, and zeolite. 
     
     
         6 . 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. 
 
     
     
         7 . The method of  claim 6 , wherein, in (I), the reaction is carried out under such conditions that a ratio by mole of the secondary amine to the α,β-unsaturated carboxylic acid, secondary amine/α,β-unsaturated carboxylic acid, is 3 to 10, and a temperature of the reaction is 10 to 60° C. 
     
     
         8 . The method of  claim 6 , wherein the first product produced is a carboxylic acid having a boiling point of 150° C. or higher, and
 wherein the secondary amine employed in (II) has a boiling point of 110° C. or lower. 
 
     
     
         9 . The method of  claim 6 , wherein the polymerization inhibitor employed in (III) is a vapor-phase-polymerization inhibitor and a liquid-phase-polymerization inhibitor. 
     
     
         10 . The method for producing a 3-alkoxycarboxylic acid-N,N-disubstituted amide, the method comprising:
 reacting an α,β-unsaturated carboxylic acid-N,N-disubstituted amide produced by the method of  claim 1 , with an alcohol.