Phenyl dichlorophosphate
[CAS 770-12-7]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Carboxylic esters and their derivatives
• Name: Phenyl dichlorophosphate
• Synonyms: Phenyl phosphorodichloridate
• Molecular Formula: C₆H₅Cl₂O₂P
• Molecular Weight: 210.98
• CAS Registry Number: 770-12-7
• EC Number: 212-220-6
• SMILES: C1=CC=C(C=C1)OP(=O)(Cl)Cl

Properties

• Density: 1.5±0.1 g/cm³ Calc.^*, 1.418 g/mL (Expl.)
• Melting point: -1 °C (Expl.)
• Boiling point: 242.0±9.0 °C 760 mmHg (Calc.)^*, 241 - 243 °C (Expl.)
• Flash point: 99.1±26.4 °C (Calc.)^*, 112 °C (Expl.)
• Solubility: Decomposes in water (Expl.)
• Index of refraction: 1.536 (Calc.)^*, 1.523 (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05;GHS07;GHS09 Danger
• Risk Statements: H302-H314-H318-H411
• Safety Statements: P260-P264-P264+P265-P270-P273-P280-P301+P317-P301+P330+P331-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P321-P330-P363-P391-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	4	H302
Serious eye damage	Eye Dam.	1	H318
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Acute toxicity	Acute Tox.	3	H311

• Transport Information: UN 1760

chemBlink Chemical Story

Phenyl dichlorophosphate, CAS 770-12-7, is an organophosphorus reagent also called phenyl phosphorodichloridate or phenyl phosphoryl dichloride. Its formula can be written C6H5OP(O)Cl2: a phosphoryl phosphorus bears one phenoxy group and two reactive chlorine atoms. Sigma-Aldrich identifies it specifically as a reagent for preparing phosphate diesters.

The two P-Cl bonds make the reagent a useful phosphorus electrophile. Alcohols, phenols, amines and other nucleophiles can attack phosphorus and replace chloride. Because there are two chlorides, substitution can be performed stepwise, allowing two groups to be installed around the same phosphorus center. This provides a route to unsymmetrical phosphate derivatives when reaction conditions and order of addition are controlled.

The phenoxy group already present in the starting reagent can act as part of the desired product or as a group that is manipulated later. This makes phenyl dichlorophosphate a useful intermediate in organophosphate chemistry, where chemists often need to control which oxygen- or nitrogen-containing groups occupy each position around phosphorus.

Its reactivity also explains its hazards. Sigma-Aldrich classifies the material as corrosive. Like many phosphoryl chlorides, it is sensitive to moisture because water attacks the electrophilic phosphorus center, replacing P-Cl bonds and producing acidic hydrolysis products. Dry handling conditions are therefore important when selective substitution is required.

Phenyl dichlorophosphate is chemically interesting because it offers two programmable reaction sites on one phosphorus atom. Compared with a reagent bearing only one P-Cl bond, it gives the chemist another stage of substitution and therefore another opportunity to build molecular asymmetry. The molecule is less a final product than a compact phosphorus construction platform.

References:
1. Sigma-Aldrich, Phenyl dichlorophosphate, CAS 770-12-7, product P22389.
2. PubChem/ChemIDplus, Phenyl dichlorophosphate, CAS 770-12-7.
3. Corbridge DEC. Phosphorus: Chemistry, Biochemistry and Technology. 6th ed. CRC Press, 2013.

Read more stories