Patent ID: 7064235

Claim:
A process for making an iminodiacetic acid compound from a monoethanolamine substrate, the process comprising: continuously or intermittently introducing said monoethanolamine substrate into a dehydrogenation reaction zone; contacting said monoethanolamine substrate with a metal-containing catalyst in said dehydrogenation zone to form a dehydrogenation product comprising a glycine intermediate; continuously or intermittently introducing at least a portion of said glycine intermediate from said dehydrogenation product into a cyanomethylation reaction zone; contacting said glycine intermediate with a cyanide source and a formaldehyde source in said cyanomethylation reaction zone to form a cyanomethylation product comprising an N-cyanomethylated glycine intermediate; introducing an acid into said cyanomethylation reaction zone before and/or as the reaction between said glycine intermediate, cyanide and formaldehyde proceeds to control the pH in said cyanomethylation reaction zone; continuously or intermittently introducing at least a portion of said N-cyanomethylated glycine intermediate from said cyanomethylation product into a hydrolysis reaction zone; and contacting said N-cyanomethylated glycine intermediate with a hydroxide source in said hydrolysis reaction zone to form a hydrolysis product comprising an iminodiacetic acid compound, wherein said monoethanolamine substrate has the formula: and R 1 is hydrogen, hydrocarbyl, or substituted hydrocarbyl.