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General comment For the glycine process, the glycine-to-glyphosate conversion, as the main production process, usually takes place by one enterprise. The intermediates, chloroacetic acid and glycine, are generally produced by different enterprises. The glycine-toglyphosate part has a characteristic of an “one-pot” reaction. First, paraformaldehyde undergoes depolymerization catalyzed by triethylamine in anhydrous methanol. Second, it reacts with glycine and dimethylphosphonate (DMPP) via the Mannich reaction in the same solution. Third, concentrated aqueous hydrochloric acid (31%) is added and heated to reflux, thus the glyphosate is formed. Recovery of methylchloride is very important for the glycine process. The glycine process has two sources of methylchloride byproduct. One is from the synthesis of DMPP by reaction of PCl3 with anhydrous methanol via the Arbuzov reaction. The second is from the acidic hydrolysis of the Mannich reaction intermediates. |
