Tricresyl phosphate (TCP) is a non-flammable, viscous clear liquid;
insoluble in water, It is stable in neutral and acidic media at normal
temperatures. But it is readily hydrolysed in an alkaline medium, producing
dicresyl phosphate and cresol. Commercial TCP is the mixture of isomers (ortho-,
meta-, and para-isomers). TCP is produced by the reaction of cresols (or
cresylic acid) with phosphorus oxychloride. Tricresyl phosphate is used;
- as
a solvent and thinner for nitrocellulose, paints acrylate lacquers, and
varnishes.
- as a plasticizer for PVC processing
- as an ingredient for
flame-retardant in plastics, rubbers and in hydraulic systems.
- as a heat
exchange media
- as an additive in high-pressure cooling lubricants
- as a
lead scavenger in gasoline.
Esters
of phosphoric acid (called organophosphates) are used in industrial
applications as flame-retardants and plasticizers (affording some
flame retardancy) in plastics, rubbers and varnishes. Organophosphates
are the most commonly used flame-retardants in that group. Hydraulic
fluids and lubricants also contain organophosphates such as tricresyl
phosphates, triaryl or trialkyl phosphates to enhance their properties
in use. Organophosphates are used as defoamers in antifreze solutions,
in pulp and paper production and for oil field drilling needs. They
can be used as antifoam agents in detergent solutions, and in various
emulsions, paints, and adhesives. Some alkyl phosphates are used
as adhesive promoters and for corrosion protection in coatings.
Phosphoric acid alkyl esters produced generally by the reaction
of either alcohols, alcohol ethoxylates or phenyl ethoxylates with
polyphosphoric acid or phosphorous pentoxide are anionic surfactants
which have the main feature of the stability in alkaline conditions
over other surfactants. They have a wide range of properties including
outstanding wetting, emulsification, lubrication, coupling activity
and detergency. They exhibit the properties of anti-wear and corrosion
inhibition either as free esters or in the forms of metal and amine
salts. They are also used as alkylation agent for nitrogen
heterocyclic compounds and as catalysts to produce phenolic and
urea resins. They are used as solvents in liquid-liquid extractants
or separation agent of metals. They are is used as heat exchange
media and as pigment grinding assistants and antifoam agents.
Synthetic high-temperature lubricating oil consisting of tri-o-cresyl phosphate
2%, tri-m-cresyl phosphate 42%, tri-p-cresyl phosphate 31%, tris(dimethylphenyl)
phosphates 18%, tris(ethylphenyl) phosphate 6%, other triaryl phosphates 1%. |