Trioctyl Trimellitate (TOTM)

About This Product

Trioctyl trimellitate, TOTM with CAS number 3319-31-1, is a clear viscous liquid produced by esterifying trimellitic anhydride with 2-ethylhexanol. Where a phthalate carries two ester groups on the benzene ring, a trimellitate carries three. That third ester chain raises molecular weight substantially, and plasticiser permanence scales directly with molecular weight. A larger molecule is more strongly entangled within the polymer matrix, has a much lower vapour pressure and diffuses far more slowly, so it stays in the compound under conditions that would drive a conventional plasticiser out. The practical consequence is heat rating: PVC plasticised with TOTM holds its flexibility through continuous service at 105 and 125 degrees Celsius, where a DOP compound would embrittle as plasticiser volatilised away. That makes it the standard for high-temperature electrical cable, for automotive under-bonnet wiring, and for medical tubing and blood bags where extraction into the fluid contents must be minimised. The costs are price, higher viscosity making processing harder, and slightly poorer low-temperature flexibility. It is used in high-temperature cable and wire insulation, automotive wiring, medical tubing and blood bags, gaskets and industrial hose. Bio Green Chem supplies TOTM to specification on assay, acidity, water, colour, volatiles, viscosity and specific gravity.