| abstract |
Process for preparing one or more complexing agents selected from methylglycinediacetic acid, glutamic acid diacetic acid and salts thereof n Process for preparing one or more complexing agents selected from methylglycinediacetic acid, glutamic acid diacetic acid and salts thereof by catalytic dehydrogenation of N,N-bis(2-hydroxyethyl)alanine and/or N,N-bis(2-hydroxyethyl)glutamic acid and/or salts thereof in the presence of alkali metal hydroxide, where a catalyst comprising copper and zirconium dioxide is used, the activation of which is a reduction, wherein the precursor of the catalyst in question has a degree of crystallization K, defined as n n n n n n K n = n n n n I n K n n ยท n 100 n n n n I n K n n + n n I n A n n n n n , n n n n n in the range from 0 to 50%. |