Dimethyl Phosphite

Dimethyl Phosphite (CAS 868-85-9), commonly abbreviated as DMP, is a reactive organophosphorus ester used as a chemical intermediate and stabilizer.

Where is Dimethyl Phosphite used?

• Agrochemical manufacturing: key intermediate in producing organophosphate and phosphonate pesticides, herbicides, and fungicides
• Polymer and plastics: antioxidant stabilizer in PVC and polyolefin formulations
• Pharmaceutical manufacturing: synthetic intermediate for active pharmaceutical ingredients, particularly in phosphonate-based drug synthesis
• Water treatment: production of scale inhibitors and corrosion control agents applied in industrial cooling and boiler systems
• It functions primarily as a building block in the synthesis of phosphonate compounds.
• Flame retardant applications.
• Intermediate in the manufacture of lubricants.
• Steel corrosion inhibitor.

Good to know: The compound acts as an effective stabilizer where it inhibits thermal degradation during processing.

Formulation notes

• Decomposes on contact with humid air above 220°C, producing phosphoric acid and methanol.
• Aqueous solution is a strong acid; reacts violently with bases, acids and oxidants.
• Partial oxidation by oxidizing agents may release toxic phosphorus oxides.

Typical specification

• Colorless liquid.
• Auto-ignition temperature is 237°C.
• Vapour pressure is 0.135 kPa at 20°C.

Regulatory status

• Classified under HS code 29202100 in the 2026 tariff nomenclature.
• IARC classified dimethyl phosphite as possibly carcinogenic to humans (Group 2B).
• Classified as carcinogen category 3B under MAK.
• Explicitly named as a controlled precursor in the Spanish regulation.

Storage, packaging and handling

• Explosive limits in air are 5.8–38.1 vol%.
• Store in a dry area without drains or sewer access, separated from food and feed.

Frequently asked questions about Dimethyl Phosphite

What is the water solubility of dimethyl phosphite?

Water solubility is greater than 10 g/100 mL at 20°C.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.