Preparation of ammonium glyphosate via a gas-solid reaction system

Abstract

Solid N-phosphonomethylglycine or glyphosate acid in "wet cake" form is charged to a suitable mixer/reactor. A stoichiometric equivalent of anhydrous ammonia gas is fed to the mixer for direct reaction with the glyphosate acid as it is agitated within the mixer. A water Jacket containing circulating water or other suitable heat transfer facilitating means readily known to those in the art is adapted to the mixer and used to remove heat from the reactor produced by the exothermic reaction. The moisture content of the glyphosate wet cake, the design of the mixer including a preferred close tolerance relation between the inner walls of the reactor and its mixing impellers together with the relative location of the ammonia gas inlet in the mixer/reactor and maintenance of a reaction temperature of about 60.degree. C. or below are all important process variables. The ammonium glyphosate thereby produced is a highly sorptive, water-soluble powder suitable for end use as a plant growth regulator or as a herbicide without further processing. Due to the highly sorptive character of the reaction product, however, it is particularly well-suited for further formulation to absorb/adsorb an exceptionally high level of adjuvants such as wetting agents, anti-foaming agents and, in particular, surfactants.

Dependencies are inferred from the claim text.