Control of N-(phosphonomethyl)iminodiacetic acid conversion manufacture of glyphosate

Patent metadata

Field	Value
Publication number	US-11802835-B2
Application number	US-202117348250-A
Country	US
Kind code	B2
Filing date	Jun 15, 2021
Priority date	Apr 1, 2005
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

This invention relates to the preparation of N-(phosphonomethyl)glycine (“glyphosate”) from N-(phosphonomethyl)iminodiacetic acid (“PMIDA”), and more particularly to methods for control of the conversion of PMIDA, for the identification of reaction end points relating to PMIDA conversion and the preparation of glyphosate products having controlled PMIDA content.

First claim

What is claimed is:

1. A method for monitoring or detecting conversion of N-(phosphonomethyl)iminodiacetic acid to N-(phosphonomethyl)glycine or an intermediate for N-(phosphonomethyl)glycine during catalytic oxidation of N-(phosphonomethyl)iminodiacetic acid in an aqueous medium, the method comprising:
introducing the aqueous medium into an oxidation reaction zone, wherein the aqueous medium contains a mass of N-(phosphonomethyl)iminodiacetic acid;
contacting N-(phosphonomethyl)iminodiacetic acid with molecular oxygen in said aqueous medium within said oxidation reaction zone in the presence of a catalyst, thereby effecting the catalytic oxidation of N-(phosphonomethyl)iminodiacetic acid and producing N-(phosphonomethyl)glycine or said intermediate;
measuring an amount of molecular oxygen consumed in said oxidation reaction zone; and
estimating a proportion of N-(phosphonomethyl)iminodiacetic acid that has been converted to N-(phosphonomethyl)glycine or said intermediate in said oxidation reaction zone, said estimating comprising comparing the amount of molecular oxygen consumed in said oxidation reaction zone with the mass of N-(phosphonomethyl)iminodiacetic acid introduced into the oxidation reaction zone and a unit oxygen consumption required for oxidation of N-(phosphonomethyl)iminodiacetic acid to N-(phosphonomethyl)glycine or said intermediate.

2. The method of claim 1 , comprising acquiring a plurality of measurements of the amount of molecular oxygen consumed in said oxidation reaction zone.

3. The method of claim 1 , wherein said oxidation reaction zone is contained within a batch oxidation reactor, and estimating said proportion of N-(phosphonomethyl)iminodiacetic acid that has been converted comprises comparing a cumulative consumption of molecular oxygen during the catalytic oxidation with an initial charge of N-(phosphonomethyl)iminodiacetic acid introduced into said oxidation reaction zone.

4. The method of claim 1 , wherein said oxidation reaction zone is contained within a continuous reactor, and estimating said proportion of N-(phosphonomethyl)iminodiacetic acid that has been converted comprises comparing the amount of molecular oxygen consumed in said oxidation reaction zone over a select period of time versus a quantity of N-(phosphonomethyl)iminodiacetic acid introduced into said oxidation reaction zone over said select period of time.

5. The method of claim 1 , further comprising measuring an instantaneous rate of oxygen consumption as a function of time at high conversion and adjusting the estimated proportion of N-(phosphonomethyl)iminodiacetic acid that has been converted to account for said measured instantaneous rate of oxygen consumption;
wherein samples are taken during a period of non-zero order reaction to provide a basis for estimating an effective kinetic rate constant or a function thereof during the catalytic oxidation at high conversion; and
wherein an estimated effective kinetic rate constant or function thereof is used in estimating residual N-(phosphonomethyl)iminodiacetic acid content of an aqueous reaction medium in a subsequent batch from an instantaneous rate of oxygen consumption during a non-zero order portion of such subsequent batch.

6. A method for monitoring or detecting conversion of N-(phosphonomethyl)iminodiacetic acid to N-(phosphonomethyl)glycine or an intermediate for N-(phosphonomethyl)glycine during catalytic oxidation of N-(phosphonomethyl)iminodiacetic acid in an aqueous medium, the method comprising:
introducing the aqueous medium into an oxidation reaction zone, wherein the aqueous medium contains N-(phosphonomethyl)iminodiacetic acid;
contacting N-(phosphonomethyl)iminodiacetic acid with molecular oxygen in said aqueous medium within said oxidation reaction zone in the presence of a catalyst, thereby effecting the catalytic oxidation of N-(phosphonomethyl)iminodiacetic acid and producing N-(phosphonomethyl)glycine or said intermediate;
continually or repetitively measuring an amount of oxygen that is consumed in said oxidation reaction zone;
monitoring an instantaneous rate of oxygen consumption in the oxidation reaction zone in the conversion of N-(phosphonomethyl)iminodiacetic acid to N-(phosphonomethyl)glycine or said intermediate; and
estimating a residual concentration of N-(phosphonomethyl)iminodiacetic acid in said aqueous medium within said oxidation reaction zone, said estimating comprising comparing said instantaneous rate of oxygen consumption with the mass of aqueous medium containing N-(phosphonomethyl)iminodiacetic acid that is introduced into the oxidation reaction zone.

7. The method of claim 6 , comprising monitoring the instantaneous rate of oxygen consumption during non-zero order conversion of N-(phosphonomethyl)iminodiacetic acid to N-(phosphonomethyl)glycine or said intermediate.

8. The method of claim 6 , wherein samples are taken during a period of non-zero order reaction to provide a basis for estimating an effective kinetic rate constant or a function thereof during a period of continuing reaction at high conversion; and an estimated effective kinetic rate constant or function thereof is used in estimating residual N-(phosphonomethyl)iminodiacetic acid content of an aqueous reaction medium from an instantaneous rate of oxygen consumption in a subsequent operation.

9. The method of claim 8 , wherein an estimated effective kinetic rate constant is adjusted based on a rate of decline of a rate of oxygen consumption as a function of time during a non-zero order oxidation reaction.

10. The method of claim 6 , wherein said oxidation reaction zone is contained within a continuous reactor, and the conversion is estimated by comparing a consumption of oxygen in said oxidation reaction zone over a select period of time versus a quantity of N-(phosphonomethyl)iminodiacetic acid introduced into said oxidation reaction zone over said select period of time.

Assignees

• Monsanto Technology Llc

Inventors

• Soleta Donald D
• Rogers Peter E
• Casanova Eduardo A
• Byrd Robert E
• Haupfear Eric A

Classifications

• G01N31/22

  using chemical indicators (G01N31/02 takes precedence) · CPC title

• B01J2219/00202

  at the reactor outlet · CPC title

• Y10T436/207497

  Molecular oxygen · CPC title

• Y10T436/209163

  Dissolved or trace oxygen or oxygen content of a sealed environment · CPC title

• G01N2021/3595

  using FTIR · CPC title