Диметилпфенилфосфонат

Description

Dimethylpphenylphosphonate (phenylphosphonic acid dimethyl ester) is an organophosphorus compound of the phosphonate class: the phosphorus atom is bonded to a phenyl ring and two methoxy groups. It is used as a fire retardant (flame retardant) and as an intermediate product in the organic synthesis of pesticides and pharmaceutical substances.

Basic Attributes

• CAS No.: 2240-41-7
• Chemical formula: C8H11O3P
• English name: Dimethyl P-phenylphosphonate
• Molecular Weight: 186.14
• Accurate weight: 186.14
• NSC Number: 62258
• DSSTox ID: DTXSID20176933
• HS code: 2931900090
• PSA Specifications: 35.5
• XLogP3: 0.9

Physico-chemical characteristics

• Density: 1.2±0.1 g/cm3
• Boiling point: 103–104 °C at 4 Torr
• Flash point: 154 °C
• Refractive index: 1.484

Scope of application

The phosphorus-containing structure of dimethylphenylphosphonate gives it flame retardant properties: the compound is used in the preparation of phosphorus-containing modified polyesters (for example, lactone-modified polyesters based on polycaprolactone, adipic acid and trimethylolpropane) for fire-retardant polyurethane coatings. In addition, the substance is used as a reagent, catalyst and substrate in scientific research, as well as as an intermediate in the synthesis of other organophosphorus pesticides and pharmaceutical substances.

Synonyms

Phosphonic acid, P-phenyl-, dimethyl ether; phosphonic acid, phenyl-, dimethyl ether; dimethylphosphonate; dimethylphenylphosphonate; dimethylbenzenephosphonate; dimethoxyphenylphosphine oxide; O,O-dimethylphenylphosphonate.

Mechanism of fire retardant action

Phosphonate flame retardants of this type act predominantly in the condensed phase of a burning polymer: during thermal decomposition, the phosphorus-containing fragment promotes the formation of a protective charred layer on the surface of the material, which slows down heat transfer and prevents the release of flammable volatile pyrolysis products to the flame. Covalent incorporation of dimethylphenylphosphonate into the polyester chain through polycondensation reduces the migration of fire retardant from the finished coating during operation compared to additional fire retardants.

Chemical features

In the molecule, the phosphorus(V) atom is connected to the phenyl ring directly (P-C bond), and not through an oxygen atom, which distinguishes phosphonates from phosphates and gives them increased hydrolytic and thermal stability. Two methoxy groups, upon alkaline or acid hydrolysis, can be converted into phenylphosphonic acid, which is used for further functionalization of the compound in the synthesis of more complex organophosphorus structures.

Safety Information

• RTECS number: TA0378000
• The substance is moderately toxic and requires careful handling and the use of personal protective equipment.

Storage and transportation conditions

Store in a tightly closed container in a cool, dry, ventilated area, away from heat and open flame - flash point 154°C. When working, use skin, eye and respiratory protection, taking into account the moderate toxicity of the organophosphorus compound. The compound is relatively stable under normal storage conditions, but in order to avoid gradual hydrolysis of the ester bonds, it is advisable to avoid prolonged contact with air moisture.