Phosphorus oxychloride

Phosphorus oxychloride, an industrial chemical raw material. A colorless transparent liquid with a pungent odor, it vigorously fumes in moist air, hydrolyzing into phosphoric acid and hydrogen chloride, further generating H[P2O4Cl3].

Basic Information

• Chinese Name: Phosphorus oxychloride

• English Name: Phosphorus oxychloride

• Alias: Trichlorophosphine; Phosphoryl chloride

• Chemical Formula: POCl3

• Molecular Weight: 153.33

• CAS Registry Number: 10025-87-3

• EINECS Registry Number: 233-046-7

• Melting Point: 1.25°C

• Boiling Point: 105.8°C

• Appearance: Colorless clear liquid

• Odor: Pungent odor

• Relative Density: 1.675

• Hazard Label: 20 (Corrosive acid)

Introduction

Name

Chinese Name: Phosphorus oxychloride

Chinese Aliases: Phosphoryl chloride; Trichlorooxophosphorus; Phosphorus oxychloride; Phosphoryl chloride; Oxychlorophosphorus; Chlorooxophosphorus; Trichlorooxophosphorus

English Aliases: Phosphorus oxychloride, Phosphorus oxide trichloride, Phosphoryl chloride, Fosforoxychlorid; OPCl3; Oxychlorid fosforecny; oxychloridfosforecny; Phosphoroxidchlorid; Phosphortrichloridoxid; Phosphorus chloride oxide (POCl3); Phosphorus oxytrichloride; Phosporus Oxychloride; phosphoric trichloride

Chemical Formula: POCl3

Molecular Formula: POCl3

Relative Molecular Mass: 153.33

Properties: Colorless clear liquid. Pungent odor. Hygroscopic. Decomposes with heat upon contact with water and ethanol. Relative density (d25) 1.675. Melting point 1.25°C. Boiling point 105.8°C. Moderately toxic, LD50 (rat, oral) 380 mg/kg. Lachrymatory and corrosive.

Storage: Store sealed in a cool, dry place.

Uses

Basic Information

Chinese Name: Phosphorus oxychloride English Name: Phosphorus oxychloride

Aliases: Trichlorophosphine; Oxychlorophosphorus; Phosphoryl chloride; Phosphoryl chloride; Trichlorooxophosphorus

CAS No.: 10025-87-3

EINECS Number: 233-046-7

Molecular Formula: POCl3

Molecular Weight: 153.33

Hazard Label: 20 (Corrosive acid)

Packaging Category: II

Main Components: Content: Industrial grade ≥99.0%.

Appearance and Properties: Colorless transparent liquid with a pungent odor, vigorously fumes in moist air, hydrolyzing into phosphoric acid and hydrogen chloride, further generating H[P2O4Cl3].

Melting Point (°C): 1.25

Boiling Point (°C): 107 °C

Relative Density (water=1): 1.68 (15.5°C) d(25)=1.645

Relative Vapor Density (air=1): 5.3

Vapor Pressure (kPa): 5.33 (27.3°C)

Solubility: Soluble in alcohol, soluble in water.

Stability and Reactivity: Stable

Hazard Characteristics: Violent decomposition upon contact with water, generating large amounts of heat and dense smoke, even explosion. Corrosive to many metals, especially under moist air conditions.

Incompatible Materials: Strong reducing agents, active metal powders, water, alcohols.

Preparation Methods

Chlorination Hydrolysis Method: Add phosphorus trichloride to the reactor, introduce chlorine gas while dripping water, control the chlorine-to-water ratio at about 3.94, with chlorine gas introduction and water dripping rates of 25~35 kg/h and 6.25~8.8 kg/h, respectively. Heat with jacket steam to 105~109°C to vaporize the reactants in the reactor, condense through a condenser, and then reflux back into the reactor. Introduce a second time to continue chlorinating residual phosphorus trichloride. Reflux until the reactant color is pure white and the residual phosphorus trichloride content is below 0.2%, then it can be drawn off from the condenser as the finished phosphorus oxychloride product.

PCl3 + Cl2 + H2O → POCl3 + 2HCl↑

The hydrogen chloride gas generated by the reaction is absorbed by water to form dilute hydrochloric acid.

Alternatively, use the reaction of phosphorus pentachloride with phosphorus pentoxide. However, both reactants are solid, resulting in poor reaction efficiency. Chlorinating a mixture of PCl3 and P4O10 with chlorine gas, where the generated PCl5 simultaneously reacts with P4O10, yields better results. The produced POCl3 itself can serve as the reaction solvent:

Hydrolysis of phosphorus pentachloride also produces POCl3, but with many side reactions, making the reaction difficult to control.

Uses

Used in the production of phosphate esters such as diphenyl-isooctyl phosphate and triethyl phosphate, plastic plasticizers, organophosphorus pesticides, long-acting sulfonamide drugs, etc. Also used as a dye intermediate, chlorinating agent and catalyst in organic synthesis, flame retardant.

Electronic grade phosphorus oxychloride is used in the solar industry, integrated circuits, discrete devices, optical fiber preforms, etc., as a liquid phosphorus source and can also prepare phosphate esters.

In the semiconductor industry, it is mainly used as an N-type doping source, with optimal reaction effects at 0°C.

Emergency Response

Skin Contact: Immediately remove contaminated clothing and rinse thoroughly with plenty of running water for at least 15 minutes. Seek medical attention.

Eye Contact: Immediately lift eyelids and rinse thoroughly with plenty of running water or saline for at least 15 minutes. Seek medical attention.

Inhalation: Quickly move to fresh air. Keep airways clear. If breathing is difficult, administer oxygen. If breathing stops, perform artificial respiration immediately. Seek medical attention.

Ingestion: Rinse mouth with water, and if no corrosive symptoms are present, perform gastric lavage. Avoid oils. Seek medical attention.

Respiratory Protection: When exposure to its vapor is possible, wear a self-priming filtering gas mask (full facepiece) or isolated respirator. For emergency rescue or evacuation, recommend wearing an air respirator.

Eye Protection: Already covered in respiratory protection.

Body Protection: Wear acid and alkali resistant rubber clothing.

Hand Protection: Wear acid and alkali resistant rubber gloves.

Other Protections: No smoking, eating, or drinking at the work site. Shower and change clothes after work. Store contaminated clothing separately and wash before reuse. Maintain good hygiene habits.

Leakage Emergency Treatment: Quickly evacuate personnel from the leakage contaminated area to a safe zone and immediately isolate 150m, strictly restrict access. Recommend emergency personnel wear self-contained positive pressure breathing apparatus and acid and alkali resistant work clothes. Do not directly contact the leakage. Cut off the leakage source as much as possible. Small leakage: Absorb with sand, vermiculite, or other inert materials. Large leakage: Construct dikes or dig pits to contain. Clear under expert guidance.

Hazardous Combustion Products: Hydrogen chloride, phosphorus oxides, phosphine.

Fire Extinguishing Methods: Extinguishing agents: Dry powder, dry sand. Do not use water.

Management Methods

Operational Management: Enclosed operation, ensure ventilation. Operations should be mechanized and automated as much as possible. Operators must receive special training and strictly follow operating procedures. Recommend operators wear self-priming filtering gas masks (full facepiece), acid and alkali resistant rubber clothing, and acid and alkali resistant rubber gloves. Avoid generating fumes. Prevent release of fumes and vapor into the workplace air. Avoid contact with reducing agents, active metal powders, alcohols. Especially avoid contact with water. Handle gently during transportation to prevent damage to packaging and containers. Equip with leakage emergency treatment equipment. Empty containers may contain hazardous residues.

Storage Management: Store in a cool, dry, well-ventilated warehouse. Keep away from fire and heat sources. Warehouse temperature should not exceed 25°C, relative humidity should not exceed 75%. Packaging must be sealed and kept dry. Store separately from reducing agents, active metal powders, alcohols, etc. Do not store together. Storage area should be equipped with leakage emergency treatment equipment and suitable containment materials.

Transportation Management: For railway transport, strictly follow the Ministry of Railways' "Dangerous Goods Transport Rules" dangerous goods compatibility table for loading. Ensure packaging is intact when shipping, and loading is stable. During transport, ensure containers do not leak, collapse, fall, or damage. Strictly prohibit mixed transport with reducing agents, active metal powders, alcohols, food chemicals, etc. Transport vehicles should be equipped with leakage emergency treatment equipment. Protect from exposure to sun, rain, and high temperatures during transport. Follow designated routes during road transport and avoid stops in residential and densely populated areas.

Waste Management: Before disposal, refer to national and local regulations. Pour into sodium bicarbonate solution, spray with ammonia water while adding crushed ice. After the reaction stops, flush into the wastewater system with water.