Triaryl phosphate esters

Intermediate-duration inhalation exposures to aerosols of a few organophosphate ester hydraulic fluids (Durad MP280 and "triaryl phosphate ester") produced lethal neurotoxic effects in chickens and rabbits (MacEwen and Vemot 1983 Siegel 1965). Rats and hamsters appear to be less susceptible to the neurotoxic action of organophosphate esters tests of several organophosphate fluids produced no deaths in rats exposed to substantial aerosol concentrations. 

A triaryl phosphate ester, tributoxyethyl phosphate, was detected at a mean concentration of 11.3 ng/g in 41 of 115 human adipose tissue samples taken from cadavers from Kingston and Ottawa, Canada (LeBel and Williams 1986). Because triaryl phosphate esters have been found in Canadian drinking water and... 

Triaryl phosphate esters are thermally stable, high-boiling (>350°C) materials. They can volatilize without significant decomposition into the flame zone, where they decompose. Flame inhibition reactions, similar to the halogen radical trap theory, have been proposed (6) ... 

Three flame retardants were compared in this study, namely, a brominated polycarbonate oligomer (58% bromine), a brominated polystyrene (68% bromine), and a brominated triaryl phosphate ester (60% bromine plus 4% phosphorus). These are described in Table I. Figures 1 and 2 compare the thermal stability of the brominated phosphate with commercial bromine-containing flame retardants by thermogravimetric analysis (TGA) and by differential scanning calorimetry (DSC). The brominated phosphate melts at 110°C and shows a 1% weight loss at 300°C. Brominated polycarbonate and brominated polystyrene are polymeric and are not as volatile at elevated temperatures as the monomeric flame retardants. 

Ishikawa et al. [3] developed procedures to determine the trialkyl and triaryl phosphate esters in sediment, involving extraction with dichloromethane (for water) or acetone (for sediment), followed by gas chromatography using a flame photometric detector and gas chromatography-mass spectrometry after clean-up through a Florisil column. 

Phosphorus is a common component of additives and appears most commonly as a zinc dialkyl dithiophosphate or triaryl phosphate ester, but other forms also occur. Two wet chemical methods are available, one of which (ASTM D1091) describes an oxidation procedure that converts phosphorus to aqueous orthophosphate anion. This is then determined by mass as magnesium pyrophosphate or photochemically as molybdivanadophosphoric acid. In an alternative test (ASTM D4047), samples are oxidized to phosphate with zinc oxide, dissolved in acid, precipitated as quinoline phosphomolybdate, treated with excess standard alkali, and back-titrated with standard acid. Both of these methods are used primarily for referee samples. Phosphorus is most commonly determined using x-ray fluorescence (ASTM D4927) or ICP (ASTM D4951). 

Triaryl phosphates Isobutylated or isopropylated triaryl phosphate esters Flame retardants with excellent permanence Electrical cable and general applications requiring flame retardancy - tents, conveyor belting etc. 

Hammett (and related sigma) relationships have been applied to aquatic reactions of several classes of aromatic contaminants. For example, alkaline hydrolysis of triaryl phosphate esters fits a Hammett relationship (Table 3) is t he sum of the substituent constants for the aromatic groups and k0 is the hydrolysis rate constant for triphenyl phosphate (0.27 M 1 s-1 t1/2 = 30 days at pH 8). Triaryl esters thus hydrolyze much more rapidly than trialkyl or dialkyl-monoaryl esters under alkaline conditions. Rates of photooxidation of deprotonated substituted phenols by singlet oxygen have been found to be correlated with Hammett a constants (Scully and Hoigne, 1987). The electronic cllects of substituents on pKa values of substituted 2-nitrophenols also fit a I lammett relationship this, of course, is not a kinetic LFER. Two compounds (4-phenyl-2-NP and 3-methyl-2-NP) did not fit the relationship and were not included in the regression. Steric effects may account for the discrepancy for the latter compound. Nitrophenols are used as intermediates in synthesis of dyes and pesticides and also used directly as herbicides and insecticides. 

Triaiyl phosphates are prepared by phosphorylation of alkyl phenols without phosphorylation catalyst. This simplifies purification of the plasticizer by eliminating the need to withdraw the pirrified product as a distillate. Mixed alkyl diaiyl esters are produced in the presence of a catalytic amoimt of an alkali metal phenoxide. The plasticizer needs to be separated by distillation. Figure 2.39 shows the distillation process of pmifi-cation of triaryl phosphates. A crude triaryl phosphate ester reaction mixtrrre is passed... 

Figure 2.39. Purification process of triaryl phosphate esters. [Adapted from Aal R A, Chen N H C, Chapman J K, US Patent 3,945,891, 1976.]...

Kronitex, Triaryl phosphate ester, FMC Corp., Process Additives Div. 

Key A, dlbromostyrene and derivatives B, tetrabromophthalic anhydride and derivatives C, hexabromocyclododecane and derivatives D. tetrabromobisphenol A and derivatives E, brominated diphenyl oxides F, tribromophenol and derivatives G. intumescent FRs H. triaryl phosphate esters i, bisphosphates J, trialkyl phosphates K. antimony-based and other synergists. 

B) Triaryl phosphate ester. (Q Saligenin cyclic phosphate ester. 

Santiclzer 143 is a proprietary, modified triaryl phosphate ester, designed for use as a flame-retardant plasticizer for a variety of polymer systems. 

Santiclzer 154 plasticizer is a triaryl phosphate ester with flame-retardant properties suitable for use in a variety of polymer systems. 

PROT—for enhancing the flame retardance of CR, triaryl phosphate ester and chlorinated paraffin can replace process oils part for part. The compatibUity needs to be watched carefully. 

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