Phosphate tricresyl

Among the aromatic phosphate esters, tricresyl phosphates with one or more o-cresyl groups are of toxicological importance (17). 

They show a completely different clinical picture following poisoning in human beings and some animal species than that resulting from alkyl phosphate poisoning. 

In the past, tricresyl phosphates have caused numerous mass poisoning incidents, for example, as plasticizers for PVC and in contaminated edible oils and machine-gim oil. The largest incidence of poisoning occurred in 1929/1930 in the United States following consumption of ginger spirit which was adulterated with tricresyl phosphate, ginger paralysis (18). 

In contrast, in 2-year feed studies to rats using small doses, there was no evidence of carcinogenic activity of tricresyl phosphate (19). 

More medical and biochemical details concerning the acute toxic action of tricresyl phosphates are beyond the scope of this chapter, but are documented in the literature (18,20). 

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Triaryl phosphates are produced from the corresponding phenols (usually mixtures) by reaction with phosphoms oxychloride, usually in the presence of a catalyst (94—96). They are subsequently distilled and usually washed with aqueous bases to the desired level of purity. Tricresyl phosphate was originally made from petroleum-derived or coal-tar-derived cresyflc acids, ie, cresols, variously admixed with phenol and xylenols. Discovery of the toxicity of the ortho-cresyl isomers led manufacturers to select cresols having very Httle ortho-isomer. 

The commercial tricresyl phosphate product is essentially a -isomer mixture. Typical products of this class are Ak2o s Lindol [1330-78-5] ... 

The plastici2er performance of isopropylphenyl diphenyl phosphate [28108-99-8], [68937-41-7], [68782-95-6], C2 H2 04P, is close to that of tricresyl phosphate. It is made from the product of isopropylation of phenol by propylene. The phosphate is a mixture of mainly 0- and -isomers and contains a distribution of different levels of alkylation (101,102). 

A particular mode of neurotoxicity was discovered for tricresyl phosphate that correlated with the presence of the o-cresyl isomer (or certain other specific aLkylphenyl isomers) in the triaryl phosphates. Many details of the chemistry and biochemistry of the toxic process have been elucidated (139,140,143—146). The use of low ortho-content cresols has become the accepted practice in industrial production of tricresyl phosphate. Standard in vivo tests, usually conducted with chickens sensitive to this mode of toxicity, have been developed for premarket testing of new or modified triaryl phosphates. As of 1992, the EPA called for extensive new toxicity and environmental data on this group of products (147). The Vederal e ster AoQ xm. ci. calling for this... 

Ester fluids are modified with additives in much the same manner as petroleum oils. They are stabili2ed with an oxidation inhibitor, eg, 0.5 wt % phenothia2ine. Improved load capacity for gears and rolling bearings in aircraft engines is provided by 1—5% tricresyl phosphate. Zinc... 

Liquid phosphate esters, eg, tricresyl phosphate [1330-78-5] are one of two types of fire-resistant hydraulic fluids (qv). Fire-resistant fluids account for less than 10% of the total fluids market. Phosphoms-based fluids generally are stable at high temperatures in addition to being fire resistant. Approximately 10,000 t of organophophoms compounds were used in hydraulic fluids in 1994. The manufacture of these materials consumed ca 4000 t of POCI3. 

Applications. The capabiHties of a gc/k/ms in separating and identifying components in complex mixtures is very high for a broad spectmm of analytical problems. One area where k information particularly complements ms data is in the differentiation of isomeric compounds. An example is in the analysis of tricresyl phosphates (TCPs) used as additives in a variety of products because of thek lubricating and antiwear characteristics (see Lubrication and lubricants). One important use of TCPs is in hydrauHc fluid where they tenaciously coat metal surfaces thereby reducing friction and wear. Tricresyl phosphate [1330-78-5] (7.2 21 exists in a variety of isomeric forms and the commercial product is a complex mixture of these isomers. 

Fig. 3. Infrared absorption data for the four tricresyl phosphate isomers present in hydrauHc oil. a, Trimetacresyl phosphate b, metametaparacresyl phosphate c, metaparaparacresyl phosphate d, triparacresyl phosphate. The P=0 stretch between 1300 and 1350 cm is marked as is the phenyl—phosphate vibration around 965 cm . Also included are the metacresyl (875 cm ) and paracresyl (820 cm ) frequencies.

The polysulfide base material contains 50—80% of the polyfunctional mercaptan, which is a clear, amber, sympy Hquid polymer with a viscosity at 25°C of 35, 000 Pa-s(= cP), an average mol wt of 4000, a pH range of 6—8, and a ntild, characteristic mercaptan odor. Fillers are added to extend, reinforce, harden, and color the base. They may iaclude siUca, calcium sulfate, ziac oxide, ziac sulfide [1314-98-3] alumina, titanium dioxide [13463-67-7] and calcium carbonate. The high shear strength of the Hquid polymer makes the compositions difficult to mix. The addition of limited amounts of diluents improves the mix without reduciag the set-mbber characteristics unduly, eg, dibutyl phthalate [84-74-2], tricresyl phosphate [1330-78-5], and tributyl citrate [77-94-1]. 

Plasticizers. Addition of softeners to NBR improve tack and adhesion properties. The most common plasticizers are esters (dibutyl phthalate, tricresyl phosphate), ester gums, alkyd resins, etc. 

Tricliloro-l, 2,2-trifluoroethane, 132 Tricresyl phosphates, 132 Tricyclohexyltin hydroxide, 132 Triethyl aluminum, 132 Triethylamine, 132 Triethyl phosphite, 132 Trifluorobromomethane, 132 Trifluoroethane, 132 Trifluoromethane, 132 Trifluralin, 132 Triisobutyl aluminum, 133 Trikem SA, 146... 

Cresylic acid is mainly used as degreasing agent and as a disinfectant of a stabilized emulsion in a soap solution. Cresols are used as flotation agents and as wire enamel solvents. Tricresyl phosphates are produced from a mixture of cresols and phosphorous oxychloride. The esters are plasticizers for vinyl chloride polymers. They are also gasoline additives for reducing carbon deposits in the combustion chamber. 

The solvent action of mineral oil base stocks can cause skin problems and prolonged exposure may have been the origin of a few skin cancers . The use of additives that might be in any way harmful to health, e.g. ortho-tricresyl phosphate (anti-wear) and sodium mercaptobenzothiazole (anticorrosion) has been discontinued where skin contact is likely. 

Weigh 6.0 g of tricresyl phosphate into a 150-ml beaker, add 75 ml of tet-rahydrofuran (THF), and stir the mixture on a magnetic stirrer. Weight 4.0 g of PVC powder onto a folded piece of smooth paper. Adjust the stirring rate so that the vortex of the liquid in the beaker just reaches the magnetic follower and add the PVC powder in a slow stream. Do not allow the solid to coagulate into lumps before it has dissolved. Pour the solution into a screw cap bottle and seal until required. 

FIG. 2 Results of white-light interferometric microscopy observation near the triple line of a drop of tricresyl phosphate (TCP) on a soft silicone rubber (RTV 615, General Electric Co.). 

However, on rigid substrates, the growth of dry zones is accompanied by a rim of excess liquid with width X (Fig. 10). As the dewetting proceeds, X increases. For short times and < K, the growth of dry patches is controlled only by surface tension forces and the dewetting speed is constant. A constant dewetting speed of 8 mm-s has been measured when a liquid film of tricresyl phosphate (TCP) dewets on Teflon PFA, a hard fluoropoly-mer of low surface free energy (p. = 250 MPa, 7 = 20 mJ-m ). 

Equation (52) allows us to estimate the impact of viscoelastic braking on the capillary flow rate. As an example, we will consider that the liquid is tricresyl phosphate (TCP, 7 = 50 mN-m t = 0.07 Pa-s). The viscoelastic material is assumed to have elastic and viscoelastic properties similar to RTV 615 (General Electric, silicone rubber), i.e., a shear modulus of 0.7 MPa (E = 2.1 MPa), a cutoff length of 20 nm, and a characteristic speed, Uo, of 0.8 mm-s [30]. TCP has a contact angle at equilibrium of 47° on this rubber. 

Triphenyl/Tricresyl phosphate Phenol/cresols, POCI3... 

VI a) Tricresyl phosphate, aliphatic ketones and esters, dioxane. polyesters... 

Thin Laver Chromatography. - The technique has been applied to the determination of tricresyl phosphate in edible oils,265 and insecticides in tobacco leaves.264... 

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