Triisobutyl phosphate
[CAS# 126-71-6]

Identification

• Classification: Organic raw materials >> Inorganic acid ester
• Name: Triisobutyl phosphate
• Synonyms: Phosphoric acid triisobutyl ester
• Molecular Formula: C₁₂H₂₇O₄P
• Molecular Weight: 266.32
• CAS Registry Number: 126-71-6
• EC Number: 204-798-3
• SMILES: CC(C)COP(=O)(OCC(C)C)OCC(C)C

Properties

• Density: 1.0±0.1 g/cm³, Calc.^*, 0.967 g/mL (4 ºC)
• Index of Refraction: 1.427, Calc.^*, 1.42
• Boiling Point: 261.2±8.0 ºC (760 mmHg), Calc.^*, 205 ºC
• Flash Point: 125.8±38.8 ºC, Calc.^*, 150 ºC

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H317-H412
• Precautionary Statements: P261-P272-P273-P280-P302+P352-P321-P333+P317-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin sensitization	Skin Sens.	1B	H317
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Skin sensitization	Skin Sens.	1A	H317
Respiratory sensitization	Resp. Sens.	1	H334
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319

Discovory and Applicatios

Triisobutyl phosphate (TIBP) is an organophosphorus compound primarily known for its role as a solvent, plasticizer, and defoaming agent in various industrial processes. TIBP was first synthesized as part of the broader development of alkyl phosphates, compounds known for their solvent properties and widespread use in multiple applications. TIBP’s structure, consisting of three isobutyl groups attached to a phosphate backbone, gives it unique chemical properties, including low viscosity, high stability, and an ability to dissolve various materials, which makes it an ideal choice for industrial uses.

The discovery of triisobutyl phosphate came from the exploration of organophosphate chemistry in the early to mid-20th century. Researchers were seeking to develop new chemical agents that could serve as both efficient solvents and plasticizers, especially in the context of evolving industrial demands for materials with improved performance characteristics. TIBP was identified as a candidate for these applications due to its desirable chemical stability and effectiveness as a solvent for both organic and inorganic compounds.

One of the earliest and most significant applications of triisobutyl phosphate is in the extraction and separation of metals, particularly in the nuclear industry. TIBP is used in solvent extraction processes, such as liquid-liquid extraction, to separate uranium and plutonium from other fission products in spent nuclear fuel. This application, known as the PUREX (Plutonium Uranium Redox EXtraction) process, utilizes TIBP as a solvent to selectively extract uranium and plutonium ions from an acidic solution of dissolved nuclear fuel. The stability and efficiency of TIBP in such harsh conditions have made it an indispensable component of nuclear fuel reprocessing.

Beyond its role in the nuclear industry, TIBP is widely used as a plasticizer. Plasticizers are added to materials such as polymers to increase their flexibility, durability, and ease of processing. Triisobutyl phosphate, in particular, is valued for its ability to improve the mechanical properties of synthetic resins, including polyvinyl chloride (PVC) and other plastics. By reducing the brittleness of these materials, TIBP helps in the production of more versatile and durable plastic products, which are used in a range of applications from packaging to automotive components.

Triisobutyl phosphate is also employed as a defoaming agent in various industrial processes. In many operations, such as in the production of paints, adhesives, and coatings, unwanted foam formation can hinder efficiency and quality. TIBP's surface-active properties make it an effective defoamer, helping to reduce or eliminate foam and improve the overall performance of industrial processes. Its low volatility and non-reactivity contribute to its effectiveness in environments where chemical stability is required.

Another notable application of TIBP is as a solvent in the production of nitrocellulose-based lacquers and coatings. Nitrocellulose is used in paints, varnishes, and lacquers for wood finishing and other applications due to its quick-drying properties and durable finish. Triisobutyl phosphate acts as a solvent in these formulations, improving the ease of application and the overall quality of the finish. Its ability to dissolve nitrocellulose without compromising the integrity of the final product makes it a valuable component in these industrial coatings.

In the agricultural sector, TIBP has been used as a component in pesticide formulations. It serves as a co-solvent or carrier solvent, helping to dissolve active ingredients and improve the distribution and effectiveness of pesticides when applied to crops. Its role in agriculture highlights its versatility across different industries where it can facilitate the delivery of chemical agents.

The environmental impact and safety profile of triisobutyl phosphate have been subjects of study, particularly in industrial contexts where exposure may occur. TIBP is generally regarded as having low acute toxicity, although it can cause irritation to the skin, eyes, and respiratory system upon prolonged exposure. Its environmental persistence has also raised concerns, leading to research into its biodegradability and the development of safe handling and disposal guidelines.

In summary, triisobutyl phosphate is a versatile chemical with a wide range of applications across industries such as nuclear energy, plastics, coatings, and agriculture. Its ability to function as a solvent, plasticizer, and defoaming agent makes it a valuable tool in numerous industrial processes, and its discovery represents a key development in the field of organophosphorus chemistry.