Cresol phosphate esters

The first commercial trialkyl phosphate esters (TAP) were tricresyl phosphate (TCP) and trixylenyl phosphate (TXP), referred to as "natural" phosphate esters because the cresols and xylenols used as raw materials are derived from petroleum oil or coal tar (Marino and Placek 1994). These products are not commercially significant at present however, at waste disposal sites, contaminants from older product formulations may be encountered, particularly those containing the neurotoxic tri-o/T/io-cresyl phosphate isomer. "Synthetic" phosphate esters are derived from synthetic feedstocks. Specific synthetic reactions have been developed to produce triaryl, trialkyl, and alkyl Aryl esters. The triaryl phosphates are currently... 

Murray [91] has described a gas chromatographic method for the determination in water of triarylphosphate esters (lmol S-140, tricresyl phosphate, cresol phosphate). These substances are used commercially as lubricant oil and plastic additives, hydraulic fluids and plasticisers. The method involves extraction from the samples, hydrolysis and measurement of the individual phenols by gas chromatography as the trimethylsilyl derivatives. The lower detection limit was about 3ppm. 

Faiqle and Klochow [805] applied gas chromatography to the determination of traces of sulphate (and nitrate and phosphate) in rainwater. The dissolved salts are freeze dried and converted to the corresponding silver salts. These are then converted to the n-butyl esters with the aid of //-buty l iodide, the butyl esters being determined by gas chromatography. Sulphate (and phosphate) are determined simultaneously on a column containing 3% OV-17 on Chromasorb, while nitrate is determined separately with 3% of tri-p-cresol phosphate on Chromasorb. 

The reaction temperature increases with increasing extent of conversion, the hydrochloride formed escaping as a gas. The excess phenol is distilled off when the reaction is complete. The phosphate esters can be purified by distillation. o-Cresol may not be used in the manufacture of cresyl phosphate on ecological grounds. Isopropyl-phenyl phosphate can, however, be produced using phenol mixtures, which are obtained by the alkylation of phenol with propene. 

The largest commercial organic phosphate esters then on the market were tricresyl and triphenyl phosphate. Both of these esters were produced by the reaction of phosphorus oxychloride with the phenol or the cresol, usually as a mixture of para- and metacresol (equations 4,5). 

Early production of phosphate esters was based on the crude cresylic acid fraction or tar acids from coal tar residue distillation. This feedstock is a complex mixture of cresols, xylenols and other materials. It includes significant quantities of... 

Miscellaneous Alkylating Agents. Noller and Dutton have studied the trialkyl phosphates as alkylation agents. They found that ethers are formed by using one equivalent of the trialkyl phosphate per mole of phenol. The 5delds of the ether in Table 14-1 are based on the amount of the alkyl radical available and hence are a measure of the relative alkylating ability of the various sulfate or phosphate esters. Dialkyl oxalates and ethyl-6-bromosorbate have also been used to alkylate phenol [Pg.818]

Synonyms Cresyl diphenyl phosphate Diphenyl cresol phosphate DPCF Methylphenyl diphenyl phosphate Monocresyl diphen phosphate Phosphoric acid methylphenyl diphenyl ester Tolyl diphenyl phosphate... 

BHT consumption in Western Europe and the USA in 1985 was around 9,0001. Phosphate esters, which are used as additives for lubricants, are produced from m-/p-cresol mixtures. 

Phenols and cresols 5% tv/tv of various phosphate esters of phenols no 120 cm X 4.5 mm column, Pye-Argon chromatograph [14]... 

As one of the first plasticizers used on a commercial scale, TCP was originally produced using natural feedstock that is, petroleum-derived (mixtures of ortho, meta, and para) cresols. With the success of TCP, variations of this phosphate ester became popular. Cresyl diphenyl phosphate (CDP) and trixylenyl phosphate (TXP) each in their own right were found to be useful and offered distinct characteristics such as low volatility and good temperature stability (Fig. 9.1). 

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. 

More problems are encountered with plasticisers because most extracts from polymer compositions are mixtures and, when separated by TLC, the amount of the individual fractions is often too small for convenient examination by 1H 1-NMR spectroscopy. Moreover, the original plasticisers themselves are often mixtures. For example, tricresyl (tritolyl)phosphate is based on mixed cresols, while most of the higher phthalate esters are based on complex mixtures of alcohols. 

The 4-nitrohenzyl group, used in the synthesis of phosphorylated serine, is introduced by the phosphoramidite method and can he cleaved with TFMSA/MTB/tn-cresol/l,2-ethanedithiol/TFA, 4h, 0°C to rt. A-Methylmorpholine at 80°C also cleaves a 4-nitrohenzyl phosphate triester. This ester is more acid stable than the benzyl ester. ... 

Tritolyl Phosphate. Phosphoric acid iristmethyi-phenyl) ester tricresyl phosphate TCP PX-917 Celluflex Kronitex LindoL CiiH O P mol wt 368.36. C 68.47%, H 5.75%. O 17-37%. P S+4]%. A mixture of isomeric tritolyl phosphates, usually excludiug the very toxic 0rtho isomer as much as possible. Prepd from cresol and phosphoric oxychloride, phosphoric acid or pentachloride Prahl, UJ5 pat. 2,305,240 (1957) Bondy, Gumb. Brit pat. 890,642 (1962 to Coalite and Chem Prod ) Faith. Keyes Clark s Industrial Chemicals, F. A, Lowenheim M, K, Moran Eds, (Wiley-Interscience, New York, 4th ed., ]975) pp 849-853. 

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