Ammonia → Ammonium glyphosate ammonium oxalate

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Reaction Steps

This example demonstrates a continuous process for preparation of a dry pesticidal composition. Glyphosate acid wet cake, oxalic acid dihydrate, liquid anhydrous ammonia, surfactant, and water are added to a mixer to form an ammonium glyphosate/ammonium oxalate paste composition. The paste was prepared in a co-rotating twin-screw mixer/reactor with 2-inch diameter screws (manufactured by Readco, York, Pa.). Approximately 35 lb/hr of glyphosate acid wet cake containing approximately 12–13% by weight moisture and 6.48 lb/hr of oxalic acid dihydrate were pre-blended and then metered into the mixer at a rate of approximately 41.48 lb/hr. The surfactant was injected into the mixer at a rate of approximately 0.7 lb./hr. Liquid anhydrous ammonia was injected into the mixer at a rate of approximately 4.14 lb/hr. Water was injected into the mixer at a rate of about 2 lb/hr to attain a total moisture content of approximately 20% by weight combining all components added to the mixer. The ammonia reacted with the glyphosate acid and oxalic acid dihydrate to produce an ammonium glyphosate/ammonium oxalate paste. Water vapor flashed from the paste product at the exit of the mixer. The moisture content of the resulting paste was approximately 8–10% by weight. The pH of a 1% solution of the resulting paste in water was approximately pH 4.

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