Glyphosate [N-(phosphonomethyl) glycine] is a chemical compound, organophosphorus herbicide discovered in 1970 by John Franz, a chemist at Monsanto© , the US multinational company that incorporated Glyphosphate into Roundup©, the world's best-selling herbicide.

The name describes the structure of the molecule:

• "Glypho-" indicates that the compound is a glycophosphate, which is a functional group containing a phosphate and a glycine group.
• "-sate" indicates that the compound is a phosphonic acid salt.

The synthesis process takes place in different steps:

• Preparation of phosphonic acid. Starting from a compound containing a phosphonic group, such as phosphonic acid itself, a neutralization is performed with an appropriate base to form the corresponding phosphonic acid salt.
• Preparation of ammonium glycinate. Glycine reacts with ammonia to form ammonium glycinate.
• Condensation reaction. The phosphonic acid and ammonium glycinate are reacted in the presence of a condensing agent, such as formaldehyde, to form glyphosate.
• Purification. The synthesized glyphosate undergoes purification processes, such as crystallization or distillation, to obtain the final pure glyphosate product.

It takes the form of a fine white powder. Soluble in water, insoluble in common organic solvents. Non-flammable.

Safety

In 2015, the World Health Organisation reclassified glyphosate as possibly carcinogenic to humans (1).

In July 2023, EFSA published a study that does not confirm the concerns raised so far about glyphosate: No critical areas of concern; data gaps identified (2).

What it is used for and where

It is a non-selective, non-residual herbicide used against annual or biennial herbaceous monocotyledonous broadleaf weeds, herbaceous dicotyledons and perennial malignant weeds in rubber, mulberry, tea, orchards, sugarcane, cereals, peas, beans, oilseed rape, flax and mustard. As a direct spray in vines and olives, orchards, pastures, forestry with use up to 4.3 kg/ha.

Prevents the synthesis of essential aromatic amino acids necessary for protein biosynthesis. Inhibitor of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), an enzyme in the aromatic acid biosynthetic pathway. Highly absorbed by soil.

Glyphosate studies

Appearance
pH	4.0~8.5
Boiling Point	465.8±55.0°C at 760 mmHg
Melting Point	230°C
Flash Point	235.5±31.5°C
Density	1.7±0.1 g/cm3
Refractive Index	1.576
Water Solubility	1.2 g/100 mL
Glyphosate mass	355.0±17.0 g/l
Glyphosate Isopropylamine Salt	480 g/l
Nitroso glyphosate	≤1.0 mg/kg
Formaldehyde	≤0.8%
Ammonium	≥75.7%
PSA	116.67000
LogP	-2.36
Vapour Pressure	0.0±2.5 mmHg at 25°C
Storage	4°C
Safety

• Molecular Formula  C₃H₈NO₅P
• Linear Formula   (HO)_2P(O)CH₂NHCH₂CO₂H
• Molecular Weight     169.07
• Exact Mass   169.014008
• CAS  1071-83-6
• UNII    4632WW1X5A
• EC Number   213-997-4
• DSSTox Substance ID  DTXSID1024122
• IUPAC  2-(phosphonomethylamino)acetic acid
• InChI=1S/C3H8NO5P/c5-3(6)1-4-2-10(7,8)9/h4H,1-2H2,(H,5,6)(H2,7,8,9) 
• InChl Key      XDDAORKBJWWYJS-UHFFFAOYSA-N
• SMILES   C(C(=O)O)NCP(=O)(O)O
• MDL number  MFCD00055350
• PubChem Substance ID    329756808
• ChEBI  27744
• ICSC    0160
• NSC   151063
• RTECS   MC1075000
• UN   3077    2783
• Beilstein    2045054
• NACRES NA.24

Synonyms:

• Glyphosate, N-(Phosphonomethyl)glycine
• Roundup^©

References______________________________________________________________________

(1) Van Bruggen AHC, He MM, Shin K, Mai V, Jeong KC, Finckh MR, Morris JG Jr. Environmental and health effects of the herbicide glyphosate. Sci Total Environ. 2018 Mar;616-617:255-268. doi: 10.1016/j.scitotenv.2017.10.309.

(2) Glyphosate: no critical areas of concern; data gaps identified | EFSA (europa.eu)