| 摘要 |
A method for prepg. N-phosphonomethyl glycine comprises (a) reacting glycine with para-formaldehyde in C1-2 alkanol in the presence of NEt3 to obtain bis-N, N-hydroxymethylglycine, (b) reacting with low purity dialkyl hydrogen phosphite contg. monoalkyl hydrogen phosphite at 20-50 deg. C to give selectively N-(N-hydroxymethyl) phosphonomethylglycine alkyl ester, (c) demethyloling and partially dealkylating by reacting with HCl at below 50 deg. C, (d) distg. at pH 7.0-7.5 to provide alkanol contg. no alkylal, (e) adding HCl to residues to complete dealkylating, and (f) neutralizing with alkali. The cpd. is useful as a herbicide.
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