Process for preparing chelating agents

Claim 1

A process for preparing an ortho-substituted phenolic amino acid compound having the formula: ##STR14## wherein: (a) Z is H or OH; and (b) each X is selected from a group consisting of hydrogen; an alkyl group having 1-4 carbon atoms; --COOH; and --SO 3 M, wherein M is selected from a group consisting of an alkali metal ion, 1/2 of an alkaline earth metal ion, and an ammonium ion having the formula ##STR15## in which each of R 1 , R 2 , R 3 and R 4 is selected from a group consisting of hydrogen, an alkyl group having 1-4 carbon atoms, and a hydroxyalkyl group having 1-4 carbon atoms; said process comprising: (i) forming a resulting mixture by admixing: (a) an inert reaction medium selected from a group consisting of water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, an admixture of water and the alcohol, acetic acid, and an admixture of water and acetic acid; (b) a phenol or mixture of phenols, each having the formula ##STR16## (c) an acid having the formula ##STR17## or a source of this acid, said source having the formula ##STR18## in which Y is an alkali metal ion, 1/2 of an alkaline earth metal ion, or the ammonium ion having the formula ##STR19## (d) a formaldehyde source selected from a group consisting of an aqueous formaldehyde solution, trioxane, and paraformaldehyde; and (ii) maintaining the resulting mixture at a temperature and for a time effective for forming the compound, and at a pH of about 2 to about 6, the inert reaction medium being provided in an amount effective for dissolving the phenol.