Tricresyl phosphate

  Tricresyl phosphate (TCP), also called tricresylphosphate, tri-o-cresyl phosphate (TOCP), tritolyl phosphate, tolyl phosphate, or tri-o-tolyl ester of phosphoric acid, is an organic compound, an organophosphate, an ester of phosphoric acid. It is a colorless or pale yellow viscous virtually nonflammable liquid insoluble in water, with melting point at -40 °C and boiling point at 240-255 °C. Its flash point is above 225 °C. Its chemical formula is C₂₁H₂₁O₄P.

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Tricresyl Phosphate is a known neurotoxin. Liquid tricresyl phosphate is irritiating to skin and eyes. At high temperatures, vapors are irritating to eyes.

Its CAS number is [78-30-8] and its SMILES structure is O=P(Oc2ccccc2C)(Oc3ccccc3C)Oc1ccccc1C.

Commercial tricresyl phosphate is a mixture of ortho, meta, and para cresyl isomers. The mixture has CAS number [1330-78-5], the m- isomer is [563-04-2], the p- isomer is [78-32-0].

Tricresyl phosphate is manufactured by reaction of cresols with phosphorus oxychloride.

In alkaline medium it undergoes hydrolysis to cresol and dicresyl phosphate.

Uses

Tricresyl phosphate is used as a plasticizer in nitrocellulose and acrylate lacquers and varnishes and in polyvinyl chloride, a flame retardant in plastics and rubbers, as a gasoline additive as a lead scavenger for tetra-ethyl lead, in hydraulic fluids, as a heat exchange medium, for waterproofing of materials, as a solvent for extractions, a solvent for nitrocellulose and other polymers, and an intermediate in organic synthesis. It is also used as an AW additive and EP additive in lubricants, and as a hydraulic fluid. As a gasoline additive, it also helps preventing engine misfires.

Jake

Main article: Jamaican ginger

During early 20th century during the Prohibition, tri-ortho-cresyl phosphate was used as an adulterant for Jamaican ginger ("jake"), thought to be non-toxic and preserving its drinkability while fooling the U.S. Treasury Department's requirements for alcohol adulterants. However it turned out that TOCP is a potent killer of certain cells in the nervous system in human beings, especially in the spinal cord. This type of paralysis is now referred to as organophosphate-induced delayed neuropathy (OPIDN). Large numbers of jake users began to lose the use of their feet and sometimes their hands. Lucky users recovered full or partial use, but for most, the loss was permanent.

Air Crews

Air crews around the world continue to link certain neurological ill health effects to chronic exposure to tricresyl phosphate which can contaminate the air supply known as bleed air on commercial and military aircraft [1][2][3][4]