ТРИ-o-КРЕЗИЛФОСФАТ

Химические свойства

Tricresyl phosphates are available as the o-isomer (TOCP), the m-isomer (TMCP), and p-isomer (TPCP). The ortho-isomer is the most toxic of the three; the meta-and para-isomers are relatively inactive. The commercial product may contain the ortho-isomer as a contaminant unless special precautions are taken during manufacture. Pure tri-para-cresyl phosphate is a solid, and ortho-and meta-are liquids (see below). The tri-o-cresyl phosphate will be discussed here as the specific example of these compounds because it is the most toxic of the tricresyl phosphates and specifically regulated by OSHA. TOCP is a colorless to pale yellow, odorless liquid or solid (below 52/F/11℃).

Физические свойства

Tri-o-cresyl phosphate is a colorless to pale yellow, odorless to faint aromatic-like liquid, and it is a solid below the 25.6 °C melting point. It is sparingly soluble in water, but is slightly soluble in ethanol and very soluble in ethyl ether (Budavari, 1996). The vapor pressure of TOCP is 0.00002mm Hg at room temperature, but is 10mm Hg at 265 °C (Bisesi, 1994). It decomposes slightly upon boiling (bp 410 °C) (Budavari, 1996).

Использование

Tri-o-cresyl phosphate is used widely as a gasoline additive, plasticizer, fire retardant, solvent, extreme pressure additive, intermediate in pharmaceutical manufacturing, water-proofing agent, heat exchange medium, and as a lead scavenger in gasoline.

Методы производства

Prepared from cresol and phosphorus oxychloride, phosphoric acid, or phosphorus pentachloride. The grades of cresol commonly used are the isomeric (o-, m-, /p-), and meta-para mixtures from coal tar and cresylic acid from petroleum. Purification of the product is based on the intended use; the commercial product is generally obtained as a mixture. A 'refined grade' of tricresyl phosphate is prepared by vacuum distillation, or alternatively by washing with 2% NaOH and water (Lowenheim and Moran 1975).

Опасность

Toxic by ingestion and skin absorption. The oisomer is highly toxic. TLV: 0.1 mg/m3 (skin); not classifiable as a Human Carcinogen.

Угроза здоровью

TOCP is a highly poisonous compound. Its toxicity is greater than that of the meta- or para-isomer. The toxic routes are inhalation, ingestion, and absorption through the skin; and the symptoms varied with the species and the route of admission.
Ingestion of 40–60 mL of the liquid can be fatal to humans. An oral dose of 6–7 mg/kg has produced serious paralysis in humans (Patty 1949). The toxic symptoms from oral intake can be gastrointestinal pain, diarrhea, weakness, muscle pain, kidney damage, and paralysis. The target organs are the gastrointestinal tract, kidney, central nervous system, and neuromuscular system.
LD50 value, oral (rabbits): 100 mg/kg
Somkuti et al. (1987) reported testicular toxicity of TOCP in adult leghorn roosters. Birds dosed with 100 mg/kg/day exhibited limb paralysis in 7–10 days. Such symptoms are characteristics of delayed neurotoxicity caused by organophosphorus compounds. Analysis at the termination of 18 days indicated a significant inhibition of neurotoxic esterase activity in both brain and testes, and a decrease in sperm motility and brain acetylcholinesterase activity.
TOCP caused adverse reproductive effects in mice, such as increased maternal mortality and a decreased number of viable litters. An LD50 value of 515 mg/kg/day is reported
(Environmental Health Research and Testing 1987)..

Пожароопасность

Noncumbustible solid; vapor pressure 0.02 torr at 150°C (302°F); fire retardant.

Промышленное использование

1. As additive to extreme pressure lubricants.
2. As a non-flammable fluid in hydraulic systems.
3. As plasticizer in lacquers and varnishes.
4. As plasticizer in vinyl plastics manufacture.
5. As flame retardant.
6. As lead scavenger in gasoline.
7. As solvent for nitrocellulose, in cellulosic molding compositions.

Профиль безопасности

Poison by subcutaneous, intramuscular, intravenous, and intraperitoneal routes. Moderately toxic by ingestion. Most of the cases of tri-o-cresyl phosphate poisoning have followed its ingestion. In 1930, some 15,000 persons were affected in the United States, and of these, 10 died. The responsible material was found to be an alcoholic drink known as Jamaica ginger, or "jake." This beverage had been adulterated with about 2% of tri-o-cresyl phosphate. The affected persons developed a polyneuritis, which progressed, in many cases, with degeneration of the peripheral motor nerves, the anterior horn cells, and the pyramidal tracts. Sensory changes were absent. Since 1930 there have been several other outbreaks of poisoning following ingestion of the material. Tri-ocresyl phosphate is more toxic than the mform, and much more so than tri-p-cresyl phosphate or triphenyl phosphate. Experimental reproductive effects. flame. Can react with oxidizing materials. To fight fire, use CO2, dry chemical. When heated to decomposition it emits highly toxic fumes of POx. See also PHOSPHATES. Combustible when exposed to heat or

Возможный контакт

Tricresyl phosphate is used as an additive in hydraulic fluids; as a plasticizer; pigment dispersant; flame retardant; as a plasticizer for chlorinated rubber; vinyl plastics; polystyrene, polyacrylic, and polymethacrylic esters; as an adjuvant in milling of pigment pastes; as a solvent and as a binder in nitrocellulose and various natural resins, and as an additive to synthetic lubricants and gasoline. It is also used in the recovery of phenol in coke-oven wastewaters.

Экологическая судьба

Biological. A commercial mixture containing tricresyl phosphates was completely degraded by indigenous microbes in Mississippi River water to carbon dioxide. After 4 wk, 82.1% of the theoretical carbon dioxide had evolved (Saeger et al., 1979).
Chemical/Physical. Tri-o-cresyl phosphate hydrolyzed rapidly in Lake Ontario water, presumably to di-o-cresyl phosphate (Howard and Doe, 1979). When an aqueous solution containing a mixture of isomers (0.1 mg/L) and chlorine (3 to 1,000 mg/L) was stirred in the dark at 20 °C for 24 h, the benzene ring was substituted with one to three chlorine atoms (Ishikawa and Baba, 1988).
Decomposes at temperatures greater than 424 °C (Dobry and Keller, 1957).

Перевозки

UN2574 Tricresyl phosphate with >3% ortho (o-) isomer, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

Несовместимости

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Contact with magnesium may cause explosion. Organophosphates, such as tricresyl phosphate, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrideds and active metals. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides.

Утилизация отходов

TOCP is dissolved in a combustible solvent and burned in a chemical incinerator equipped with an afterburner and scrubber.