Quick Search
Description
Trioctyl Trimellitate (TOTM) is a high-performance trimellitate ester plasticizer widely used in polyvinyl chloride (PVC), chlorinated polymers, synthetic rubber, and specialty polymer formulations requiring exceptional thermal stability and long-term permanence. It is produced by the esterification of trimellitic anhydride (TMA) with 2-ethylhexanol, resulting in a high-molecular-weight ester with excellent resistance to migration, volatilization, extraction, and aging.
TOTM is considered one of the premium permanent plasticizers for demanding applications where conventional phthalate plasticizers may not provide sufficient long-term stability. Its outstanding heat resistance allows flexible PVC products to maintain their mechanical properties even after prolonged exposure to elevated temperatures. As a result, TOTM is extensively used in automotive wire insulation, electrical cables, medical devices, industrial hoses, roofing membranes, high-temperature seals, synthetic leather, and specialty PVC compounds.
Because of its low volatility, excellent dielectric properties, and superior resistance to oils and extraction fluids, Trioctyl Trimellitate has become one of the preferred plasticizers for applications requiring long service life, high reliability, and excellent safety performance.
________________________________________
CAS Number
CAS Number: 3319-31-1
________________________________________
Synonyms
• Trioctyl Trimellitate
• TOTM
• Tris(2-ethylhexyl) Trimellitate
• Tris(2-ethylhexyl) Benzene-1,2,4-tricarboxylate
• Trimellitic Acid Trioctyl Ester
• Trioctyl Benzene Tricarboxylate
• High-Temperature Plasticizer
• Permanent Plasticizer
• Trimellitate Ester Plasticizer
________________________________________
Physical Properties
Trioctyl Trimellitate is supplied as a clear, colorless to pale yellow oily liquid possessing very low volatility and excellent thermal stability.
Typical characteristics include:
• Appearance: Clear, colorless to pale yellow liquid
• Physical state: Liquid
• Odor: Mild characteristic odor
• Molecular formula: C₃₃H₅₄O₆
• Molecular weight: 546.78 g/mol
• Density: Approximately 0.984–0.990 g/cm³ (25°C)
• Boiling point: Greater than 390°C
• Flash point: Approximately 245–255°C
• Pour point: Approximately −46°C
• Water solubility: Practically insoluble
• Viscosity: High
Its exceptionally low volatility significantly reduces plasticizer loss during long-term service.
________________________________________
Chemical Properties
TOTM is a triester of trimellitic acid containing three branched 2-ethylhexyl ester groups attached to an aromatic benzene ring. The molecular structure provides high permanence, excellent compatibility with PVC, and superior resistance to migration.
Important chemical characteristics include:
• High molecular weight
• Excellent plasticizing efficiency
• Extremely low volatility
• Excellent thermal stability
• Outstanding oxidation resistance
• High dielectric strength
• Excellent extraction resistance
• Superior migration resistance
• Good weather resistance
• Excellent hydrolytic stability
These properties make TOTM particularly suitable for high-temperature electrical and automotive applications.
________________________________________
Manufacturing Process
Commercial Trioctyl Trimellitate is produced through catalytic esterification of trimellitic anhydride with excess 2-ethylhexanol.
Typical manufacturing stages include:
• Purification of trimellitic anhydride
• Addition of 2-ethylhexanol
• Catalytic esterification
• Removal of reaction water
• Neutralization
• Vacuum stripping
• Filtration
• Purification
• Quality control analysis
• Packaging
The finished product is carefully purified to minimize residual acidity and maximize ester content.
________________________________________
Mechanism of Action
TOTM functions as an external plasticizer by penetrating between adjacent polymer chains and reducing intermolecular forces.
Its principal mechanisms include:
• Increasing polymer chain mobility
• Improving flexibility
• Reducing brittleness
• Enhancing low-temperature performance
• Improving thermal aging resistance
• Reducing plasticizer migration
• Increasing long-term durability
Unlike many lower molecular weight plasticizers, TOTM remains strongly retained within PVC matrices because of its large molecular size.
