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Diethyl phosphite

CAS Number
762-04-9
EC Number
212-091-6
Chemical Formula
C4H11O3P
Molecular Weight
137.09 g/mol

Description

Diethyl phosphite ( CAS 762-04-9 ), also referred to commercially as diethyl phosphonate or DEP, is a reactive organophosphorus compound used as a chemical intermediate and functional additive across multiple industrial sectors. It acts as a building block for synthesizing phosphorus-containing compounds and delivers antioxidant, stabilizing, and lubrication functions in finished formulations. In lubricant and metalworking fluid formulations, DEP functions as an extreme-pressure additive. It serves as an antiwear agent, reducing metal surface degradation under high-load conditions. Pharmaceutical manufacturers use it as a key intermediate in the synthesis of active pharmaceutical ingredients, particularly antiviral and antiparasitic compounds. In agrochemical production, it serves as a precursor in the manufacture of organophosphate pesticides and herbicides. Polymer and plastics processors incorporate DEP as a flame retardant additive and stabilizer. This helps to meet flammability and thermal performance requirements in end products. Diethyl phosphite is supplied as a clear, colorless to pale yellow liquid in drum and IBC quantities, with bulk tanker supply available. Technical grade is the standard commercial offering, with purity levels typically at 98% or higher. Pharmaceutical-intermediate-grade material with controlled impurity profiles is available from select manufacturers. This material is designed to support API synthesis qualification requirements. The product is handled according to strict industrial safety protocols to ensure consistent quality and performance across all applications. Contact us for supply of Diethyl phosphite Request Quote

Other Names (Synonyms)

phosphorous acid diethyl ester | diethyl phosphonate | diethyl hydrogenphosphite | Phosphonic acid diethyl ester | Diethoxyphosphine oxide | Diethyl acid phosphite | Hydrogen diethyl phosphite | O,O-Diethyl phosphonate | DEP

Key Technical Features

  • High Purity Grade standard
  • Consistent Batch Quality
  • Full Regulatory & REACH Support
  • Global Logistics Network enabled

Physical Properties

Melting Point<25 °C
Boiling Point50-51 °C @ Press: 2 Torr
Density1.072 g/cm³
Flash Point180 °F
Appearancecolourless liquid
ColorColorless
FormLiquid
Water Solubilitymiscible (hydrolysis)
Vapor Pressure7hPa at 20℃
Refractive Indexn 20/D 1.407(lit.)
Log P-0.15

Safety & Handling

Danger
GHS05· CorrosiveGHS07· Irritant

Hazard Statements

H315Causes skin irritation
H317May cause an allergic skin reaction
H318Causes serious eye damage
H319Causes serious eye irritation
H335May cause respiratory irritation

Precautionary Statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.
P264Wash … thoroughly after handling.
P271Use only outdoors or in a well-ventilated area.
P272Contaminated work clothing should not be allowed out of the workplace.
P280Wear protective gloves/protective clothing/eye protection/face protection.
P317Get emergency medical help.
P319Get medical advice/attention if you feel unwell.
P321Specific treatment (see … on this label).
P405Store locked up.
P501Dispose of contents/container in accordance with local regulations.
P265Wash … thoroughly after handling.
P352IF ON SKIN: Wash with plenty of water.
P340IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P317Get emergency medical help.
P317Get emergency medical help.
P317If eye irritation persists: Get medical advice/attention. Get emergency medical help.
P364Take off contaminated clothing and wash it before reuse.
P233Store in a well-ventilated place. Keep container tightly closed.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code29209014
Storage Class10 - Combustible liquids
WGK (Germany)1