Tributyl Phosphate, TBP, 126-73-8 , 20046-30-4

Tributyl Phosphate, TBP, 126-73-8 , 20046-30-4

TRIBUTYL PHOSPHATE (TBP)

Tributyl Phosphate / Tributil Fosfat / Tri-n-butyl Phosphate / Phosphoric Acid Tributyl Ester
CAS Numbers: 126-73-8, 20046-30-4
EC Number: 204-800-2

1. IDENTIFICATION INFORMATION

2. PHYSICAL PROPERTIES

3. CHEMICAL PROPERTIES

General Structure:

        O
        ||
(C₄H₉O) - P - (OC₄H₉)
        |
        (OC₄H₉)

Hydrolysis Reaction:

(C₄H₉O)₃P=O + H₂O  —[H⁺/OH⁻]—> (C₄H₉O)₂P=O(OH) + C₄H₉OH (Dibutyl phosphate)
(C₄H₉O)₂P=O(OH) + H₂O  —[H⁺/OH⁻]—> (C₄H₉O)P=O(OH)₂ + C₄H₉OH (Monobutyl phosphate)
(C₄H₉O)P=O(OH)₂ + H₂O  —[H⁺/OH⁻]—> H₃PO₄ + C₄H₉OH (Phosphoric acid)

Metal Complexation (Uranium - PUREX Process):

UO₂²⁺ (uranyl ion) + 2 (C₄H₉O)₃P=O → [UO₂((C₄H₉O)₃P=O)₂]²⁺

4. PRODUCTION PROCESS

Reaction Equation:

POCl₃ + 3 C₄H₉OH  —[Base]—> (C₄H₉O)₃P=O + 3 HCl

Alternative Production Routes:

5. AVAILABLE FORMS AND SPECIFICATIONS

Typical Specifications (Technical Grade):

6. APPLICATIONS

6.1. Nuclear Industry (Solvent Extraction – PUREX Process) – Largest Use

PUREX Process Details:

• TBP concentration: 15-40% (typically 30% TBP in kerosene or dodecane)

• Extraction medium: Nitric acid solution

• Complexation: UO₂(NO₃)₂ + 2 TBP → UO₂(NO₃)₂·2TBP

6.2. Plasticizer Industry

6.3. Functional Fluids

6.4. Flame Retardants

6.5. Solvent and Processing Aids

6.6. Defoamer (Antifoam Agent)

6.7. Metal Extraction and Hydrometallurgy

6.8. Textile Industry

6.9. Chemical Industry

6.10. Other Applications

7. PUREX PROCESS DETAILS

Extraction Chemistry:

Note: The PUREX process is used for reprocessing spent nuclear fuel to recover plutonium and uranium.

8. TBP VS OTHER PHOSPHATE ESTERS

9. SAFETY AND HEALTH INFORMATION (GHS CLASSIFICATION)

10. HAZARD STATEMENTS (H-CODES)

11. SAFETY STATEMENTS (P-CODES)

12. TOXICOLOGICAL INFORMATION

Health Effects:

13. FIRST AID MEASURES

14. FIRE FIGHTING MEASURES

15. ENVIRONMENTAL INFORMATION

16. STORAGE AND HANDLING

Handling Notes:

• Use in well-ventilated areas

• Avoid skin and eye contact

• Use appropriate PPE (nitrile or neoprene gloves, safety goggles)

• Keep away from ignition sources (combustible)

• Avoid release to the environment

17. TRANSPORT INFORMATION

Note: Some classifications may consider TBP as a combustible liquid with flash point >140°C.

18. REGULATORY INFORMATION

Nuclear Regulatory: Subject to nuclear regulatory controls in many countries (used in nuclear fuel reprocessing)

19. OTHER NAMES AND SYNONYMS

Database Identifiers:

20. SUMMARY AND IMPORTANT WARNINGS

SUMMARY:

Tributyl phosphate (TBP, C₁₂H₂₇O₄P, CAS 126-73-8) is a colorless, odorless liquid with a density of 0.976 g/cm³ at 20°C, boiling point of 289°C, and flash point of 146°C. It is an organophosphate ester (trialkyl phosphate) produced by the esterification of phosphorus oxychloride (POCl₃) with butanol. TBP is best known as the primary extractant in the PUREX process (Plutonium Uranium Reduction EXtraction) for nuclear fuel reprocessing, where it extracts uranium, plutonium, and thorium from nitric acid solutions (typically 30% TBP in kerosene or dodecane). Other major applications include plasticizer for cellulose esters (nitrocellulose, cellulose acetate), vinyl resins, plastics, and rubber; functional fluids (aircraft hydraulic fluids, brake fluids, lubricant additives, heat transfer fluids); flame retardants for textiles and plastics; solvent and processing aid for inks, resins, adhesives, and pigment grinding; defoamer (antifoam agent) for detergent solutions, emulsions, paints, and antifreeze; metal extraction for rare earth elements and base metals; textile processing (mercerization aid); and various other industrial applications.

Key Properties:

Main Application Areas:

Key Safety Points:

• IRRITANT: Causes skin and eye irritation (H315, H319)

• HARMFUL: Harmful if swallowed (H302)

• RESPIRATORY EFFECTS: May cause respiratory irritation, drowsiness, dizziness (H335, H336)

• COMBUSTIBLE: Flash point 146°C; keep away from heat and ignition sources

• LOW TOXICITY: Oral LD50 ~1,200-3,000 mg/kg; not classified as carcinogen

• USE PPE: Protective gloves (nitrile, neoprene), safety goggles, protective clothing

• VENTILATION: Use in well-ventilated area

• STORAGE: Cool, dry area; avoid strong oxidizing agents and strong bases

IMPORTANT WARNINGS:

Nuclear Industry Applications (PUREX Process): TBP is the primary extractant used in the PUREX (Plutonium Uranium Reduction EXtraction) process for reprocessing spent nuclear fuel. It selectively extracts uranium (UO₂²⁺) and plutonium (Pu⁴⁺) from nitric acid solutions while leaving fission products in the aqueous phase. The extraction efficiency is highly dependent on nitric acid concentration (optimal at 2-4 M). TBP is typically used as a 15-40% solution (most commonly 30%) in an aliphatic diluent such as kerosene or dodecane. The process involves extraction, scrubbing, and stripping steps to recover fissile materials. Due to its nuclear applications, TBP is subject to strict regulatory controls in many countries.

Plasticizer Applications: TBP is an effective plasticizer for cellulose esters (nitrocellulose, cellulose acetate, cellulose acetobutyrate), vinyl resins (PVC), and various plastics and rubbers. It improves flexibility, reduces brittleness, and enhances processability. In adhesives, TBP increases flexibility and reduces brittleness of the cured adhesive film.

Functional Fluids: TBP is used as a component in fire-resistant aircraft hydraulic fluids (Type IV fluids) due to its high flash point and thermal stability. It is also used in specialty brake fluids, as a lubricant additive (anti-wear and extreme pressure properties), and as a heat transfer fluid (high thermal stability up to ~200°C). In transformer oils, TBP can be used as a dielectric fluid component.

Flame Retardant Properties: TBP acts as a flame retardant in plastics and textiles by promoting char formation and reducing flammability. It is particularly effective in PVC compounds (as a flame retardant plasticizer), polyurethane foams, and engineering plastics. The phosphorus content of TBP (approximately 11.6% P) contributes to its flame retardant efficacy.

Defoamer (Antifoam) Applications: TBP is an effective defoamer in various industrial processes due to its low water solubility and surface-active properties. It is used in detergent solutions, aqueous emulsions, water-based paints, antifreeze solutions, and textile processing baths. TBP destabilizes foam bubbles by reducing surface tension and spreading on the liquid surface.

Metal Extraction and Hydrometallurgy: Beyond nuclear applications, TBP is used in hydrometallurgy for extracting and separating rare earth elements, base metals (cobalt, nickel, zinc), and lithium from leach solutions. It is also used in the purification of phosphoric acid (removal of impurities by solvent extraction). The selectivity of TBP for different metal ions depends on the acid concentration and the presence of complexing agents.

Hydrolysis and Degradation: TBP slowly hydrolyzes in water, especially at elevated temperatures or in acidic/basic conditions. The primary degradation products are dibutyl phosphate (DBP) and monobutyl phosphate (MBP), and ultimately phosphoric acid and butanol. In nuclear applications, radiation-induced degradation produces DBP and MBP, which can form undesirable complexes and reduce extraction efficiency. TBP used in nuclear applications is typically treated for radiolytic stability.

Storage Compatibility: TBP is compatible with stainless steel, glass, HDPE, and PTFE. Avoid storage in aluminum or other reactive metal containers (potential for slow reaction). Protect from strong oxidizing agents (nitric acid at high concentrations, perchlorates, permanganates) and strong bases. TBP should be stored in tightly closed containers to prevent moisture absorption (hydrolysis) and contamination.

Environmental Fate: TBP is readily biodegradable and has low bioaccumulation potential (Log P = 3.8). It has moderate aquatic toxicity. However, its degradation products (DBP, MBP, phosphoric acid) are less toxic and more environmentally benign. Do not discharge concentrated TBP to sewers or water bodies.

Regulatory Status in Nuclear Applications: The use and transport of TBP for nuclear applications (especially for reprocessing spent nuclear fuel) are subject to strict national and international regulations, including IAEA safeguards and export controls. TBP itself is not a controlled substance, but its use in nuclear fuel cycles is regulated.

Industrial vs Consumer Products: TBP is primarily an industrial chemical used in manufacturing and processing. Consumer products containing TBP include construction/building materials (flame retardant plastics), hydraulic fluids (in industrial equipment), and ink/toner/colorant products. Direct consumer exposure is limited.

Important Disclaimer: This Technical Data Sheet (TDS) is for informational purposes only. For complete safety, handling, storage, and regulatory compliance information, always refer to the official Safety Data Sheet (SDS) provided by the manufacturer/supplier. Tributyl phosphate is an irritant and is harmful if swallowed. Use appropriate personal protective equipment. Use in well-ventilated areas. Keep away from ignition sources. For nuclear applications, follow all applicable regulatory requirements and safety protocols. In case of spill or fire, follow emergency procedures. Seek medical attention for significant exposures.