Patent ID: 7771494

Claim:
A process for the preparation and recovery of an N-(phosphonomethyl)glycine product, the process comprising: oxidizing an N-(phosphonomethyl)iminodiacetic acid substrate in an oxidation reaction zone to produce an aqueous oxidation reaction solution comprising N-(phosphonomethyl)glycine product; precipitating N-(phosphonomethyl)glycine product crystals from the aqueous oxidation reaction solution to produce an aqueous product slurry comprising precipitated N-(phosphonomethyl)glycine product crystals and mother liquor saturated or supersaturated in N-(phosphonomethyl)glycine product; separating at least a portion of the aqueous product slurry into a solids-enriched slurry fraction comprising N-(phosphonomethyl)glycine product crystals and a solids-depleted mother liquor fraction; contacting the solids-depleted mother liquor fraction with a selective membrane to produce a retentate enriched in N-(phosphonomethyl)glycine product relative to the solids-depleted mother liquor fraction and a permeate depleted in N-(phosphonomethyl)glycine product relative to the solids-depleted mother liquor fraction, wherein the solids-depleted mother liquor fraction initially contacted with the selective membrane is saturated or supersaturated in N-(phosphonomethyl)glycine product; and precipitating N-(phosphonomethyl)glycine product crystals from the retentate.