TRIS(2-ETHYLHEXYL)PHOSPHATE

TRIS(2-ETHYLHEXYL)PHOSPHATE (TEHP) is a colorless, odorless, or faintly yellow liquid that is primarily used as a plasticizer in plastics, coatings, and rubber. 
It is also used as a flame retardant, particularly in applications involving polymers and textiles. 
TEHP has a relatively low volatility, making it useful in high-temperature and high-performance settings.
CAS Number: 78-42-2
Synonyms:,Tri(2-ethylhexyl) phosphate,Tris(2-ethylhexyl) ester of phosphoric acid,TEHP
2-Ethylhexyl phosphate, tris,Phosphoric acid tris(2-ethylhexyl) ester

Introduction
Definition
TRIS(2-ETHYLHEXYL)PHOSPHATE (TEHP), also known as tris(2-ethylhexyl)phosphate or TEHP, is an organophosphate compound widely used as a plasticizer, flame retardant, and chemical additive in various industrial applications. 
It is a colorless, odorless, and non-volatile liquid, making it suitable for incorporation into plastics and other materials that require flexibility, durability, and enhanced fire resistance.

History and Development
TEHP was first synthesized in the mid-20th century as part of the ongoing search for more efficient and versatile plasticizers and flame retardants. 
Since its introduction, it has found widespread use in the production of flexible plastics, particularly polyvinyl chloride (PVC), and in the formulation of fire-resistant materials. 
Over time, its use expanded to various applications such as hydraulic fluids, lubricants, and coatings. Its development mirrored the increasing demand for materials that combined flexibility and resistance to heat and fire.

Importance in Industry
TEHP is a critical chemical in several industries due to its ability to improve the physical properties of materials, making them more pliable, durable, and resistant to high temperatures and flames. 
It plays an essential role in manufacturing products that require these specific properties, from cables and flooring materials to automotive and aerospace applications. 
As environmental and regulatory concerns over certain chemicals grow, TEHP remains important as an alternative to other more hazardous plasticizers and flame retardants.

Chemical Properties
Chemical Formula
The molecular formula of TEHP is C24H51O4P. This formula reflects the presence of a phosphate group (-PO4) bonded to three 2-ethylhexyl groups (C8H17), making it a triester of phosphoric acid.

Molecular Structure
The molecular structure consists of a phosphorus atom at the center, bonded to three 2-ethylhexyl ester groups. 
These groups are branched alkyl chains (C8H17) with the ethyl group attached to the second carbon atom. 
The arrangement of these ester groups around the phosphorus atom imparts both flexibility and flame-retardant properties to TEHP. 
The ester linkage between the phosphate group and the alkyl chains gives the compound its characteristic stability and solubility in organic solvents.

Solubility
TEHP is insoluble in water but highly soluble in organic solvents such as alcohols, esters, and hydrocarbons. 
This solubility makes it ideal for use as a plasticizer and flame retardant, as it can easily integrate into a variety of polymer matrices without affecting their overall structure or causing phase separation.

Physical Properties
Melting Point: TEHP remains liquid at room temperature, with a melting point below 0°C, making it suitable for a wide range of processing temperatures.
Boiling Point: The boiling point of TEHP is approximately 370°C, indicating its stability at high temperatures.
Density: TEHP has a density of about 0.96 g/cm³ at 20°C, which is lower than that of many other plasticizers.
Viscosity: It has a relatively low viscosity, enhancing its ease of handling and processing in industrial applications.
Refractive Index: The refractive index of TEHP is 1.453, which can be useful in certain optical applications.

Production Methods
Raw Materials
The production of TEHP begins with the synthesis of 2-ethylhexyl alcohol, which is typically derived from petrochemical feedstocks. 
Phosphoric acid or its derivatives (such as phosphorus pentachloride) serve as the other primary reactant. 
The process requires high-purity reagents to ensure the final product meets industry specifications.

Synthesis Methods
The synthesis of TEHP involves a two-step process:

Esterification: 2-ethylhexyl alcohol reacts with phosphoric acid or phosphorus pentachloride in the presence of a catalyst (typically a strong acid such as sulfuric acid) to form a phosphate ester.

Purification: The resulting mixture undergoes distillation or other separation techniques to remove unreacted materials, byproducts, and impurities, leaving behind pure TEHP.

Industrial Scale Production
On an industrial scale, TEHP is produced in large reactors equipped for high temperatures and controlled pressure conditions. 
The esterification reaction typically takes place at temperatures ranging from 150°C to 250°C. Continuous reactors are used to allow for efficient production, and temperature and pressure are closely monitored to ensure optimal yield.

Byproducts and Waste Management
The production of TEHP can result in the formation of byproducts such as unreacted alcohol and phosphoric acid derivatives. 
These byproducts are generally removed through filtration, distillation, or neutralization processes. Waste management systems are critical to ensure the safe disposal or recycling of any hazardous chemicals, adhering to environmental regulations.

Applications
Plasticizers
TEHP is primarily used as a plasticizer in the production of flexible plastics, especially polyvinyl chloride (PVC). 
It enhances the plasticity of the polymer, making it more flexible and easier to process. 
TEHP is particularly favored for its low volatility and high thermal stability, making it ideal for use in products that will be exposed to high temperatures.

Flame Retardants
TEHP is used in various applications requiring fire-resistant materials. 
It is incorporated into plastics, rubbers, and coatings to improve their resistance to ignition and limit the spread of fire. 
This is especially important in electrical cables, automotive parts, and textiles, where fire resistance is a critical safety concern.

Lubricants and Hydraulic Fluids
TEHP is also employed as an additive in lubricants and hydraulic fluids. 
It provides improved lubrication at high temperatures and helps extend the life of equipment by reducing friction and wear. 
Additionally, TEHP contributes to the thermal stability of these fluids, allowing them to perform effectively in extreme conditions.

Solvents
TEHP functions as a solvent in various chemical processes, especially in the formulation of paints, coatings, and adhesives. 
Its solvency properties allow it to dissolve a wide range of resins, oils, and waxes, aiding in the creation of uniform and stable formulations.

Other Niche Applications
Other niche applications of TEHP include its use in metalworking fluids, coating formulations for food packaging, and certain medical devices where its non-toxicity and compatibility with biological materials are advantageous.

SAFETY INFORMATION ABOUT TRIS(2-ETHYLHEXYL)PHOSPHATE

First aid measures:
Description of first aid measures:
General advice:
Consult a physician. 
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
 
If inhaled:
If breathed in, move person into fresh air. 
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately. 
Wash off with soap and plenty of water.
Consult a physician.
 
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
 
If swallowed:
Do NOT induce vomiting. 
Never give anything by mouth to an unconscious person. 
Rinse mouth with water. 
Consult a physician.
 
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
 
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment. 
 
Avoid breathing vapours, mist or gas. 
Evacuate personnel to safe areas.
 
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste. 
Keep in suitable, closed containers for disposal.
 
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
 
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place. 
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
 
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
 
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles. 
Faceshield (8-inch minimum). 
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
 
Skin protection:
Handle with gloves. 
Gloves must be inspected prior to use. 
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product. 
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. 
Wash and dry hands.
 
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
 
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. 
 
If the respirator is the sole means of protection, use a full-face supplied air respirator. 
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so. 
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions. 
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
 
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company. 
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product