Toxic aromatic amines

Aliphatic amines such diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA) give fast cures at room temperature. They also have the disadvantages of short pot-lives, poor peel strength, high volatility and high toxicity. Aromatic amines such as m-phenylenediamine (MPDA) have lower volatility, but are still toxic, cure more slowly and have a longer pot-life. They impart better heat resistance but may require heat to activate cure. Acid anhydrides such as phthalic anhydride also provide long pot-lives at room temperature, but only cure at elevated temperatures. 

Toxic aromatic amines which constitute a very important class of environmental pollutants can be easily detected by electrochemical DNA biosensors. The electrochemical biosensing strategy was developed by Wang s group based on the intercalative behavior of aromatic amines onto an immobilized dsDNA layer... 

Environmental Impact of Ambient Ozone. Ozone can be toxic to plants, animals, and fish. The lethal dose, LD q, for albino mice is 3.8 ppmv for a 4-h exposure (156) the 96-h LC q for striped bass, channel catfish, and rainbow trout is 80, 30, and 9.3 ppb, respectively. Small, natural, and anthropogenic atmospheric ozone concentrations can increase the weathering and aging of materials such as plastics, paint, textiles, and mbber. For example, mbber is degraded by reaction of ozone with carbon—carbon double bonds of the mbber polymer, requiring the addition of aromatic amines as ozone scavengers (see Antioxidants Antiozonants). An ozone decomposing polymer (noXon) has been developed that destroys ozone in air or water (157). 

Other Reactants. Other reactants are used in smaller amounts to provide phenoHc resins that have specific properties, especially coatings appHcations. Aniline had been incorporated into both resoles and novolaks but this practice has been generally discontinued because of the toxicity of aromatic amines. Other materials include rosin (abietic acid), dicyclopentadiene, unsaturated oils such as tung oil and linseed oil, and polyvalent cations for cross-linking. 

Aromatic amine curing agents sensitizers, longterm health effects, absorbed through skin respiratory irritants sensitizers moderate to high toxicity... 

Aromatic Amine and Nitrocompounds, Their Toxicity and Potential Dangers , US Public Health Bull No 271, Washington, DC (1941), 105 6) Davis (1943), 140... 

The glycolysis of rigid polyurethane foams produces polyol products which can be reintroduced into the production cycle of PUR insulation materials to form materials with properties practically equivalent to dtose of materials produced using virgin polyols. Aromatic amines produced as by-products in die glycolysis process are toxic and therefore undesired side products. The most frequently observed side product is diphenylmedianediamine (DMDA), which is formed... 

The behavior of the different amines depends on at least four factors basicity, nucleophilicity, steric hindrance and solvation. In the literature (16), 126 aliphatic and aromatic amines have been classified by a statistical analysis of the data for the following parameters molar mass (mm), refractive index (nD), density (d), boiling point (bp), molar volume, and pKa. On such a premise, a Cartesian co-ordinate graph places the amines in four quadrants (16). In our preliminary tests, amines representative of each quadrant have been investigated, and chosen by consideration of their toxicity, commercial availability and price (Table 1). 

Davis KR, Schultz TW, Dumont JN (1981) Toxic and teratogenic effects of selected aromatic amines on embryos of the amphibian Xenopus laevis. Arch Environ Contamin... 

Some of the reaction products of polymerisation and cure can be toxic, for example, aromatic amines from hydrolysis of isocyanates and bisphenol A from... 

Decrease of toxicity after addition of adapted biomass may indicate biological degradation of aromatic amines... 

Another chemical class of drugs associated with inducing a lupus is the hydrazines. As with aromatic amines, there are few examples because most hydrazines are toxic. Hydralazine is second only to procainamide with respect to the incidence of lupus associated with its use [14], Although its present use is infrequent, the finding that it is... 

A new effective metal-ffee radical approach by Murphy et al generates the free radical by treatment with tetrathiafulvalene (TTF).1491 As depicted in scheme 16 the aromatic amine 79 is transformed into the diazonium salt 81 which on treatment with TTF leads to the radical 82. The following stereoselective cyclization gives the hexahydrocarba-zole scaffold 80, a substructure of alkaloids like aspi-dospermidin, strychnin and vinblastin. Also the non-toxic tris(trimethylsilyl)silane was employed for domino reactions, eg. for the preparation of the alkaloid aspidospermidin. 

Of some importance as textile dyes are aza analogues of polymethine (cyanine) dyes. Azacarbocyanines result when Fischer s aldehyde is heated with primary aromatic amines. Thus Cl Basic Yellow 11 (6.220) is obtained when Fischer s aldehyde is condensed with 2,4-dimethoxyaniline. The equivalent reaction with 2-methylindoline gives Cl Basic Yellow 21 (6.221), which has superior light fastness but has been classified by ETAD as toxic [73]. The tinctorially strong golden yellow diazacarbocyanine dye Cl Basic Yellow 28 (6.222) is prepared by coupling diazotised p-anisidine with Fischer s base (6.223), followed by quaternisation with dimethyl sulphate. Some triazacarbocyanine dyes are also used commercially. 

Increased risk of hydralazine-induced lupus, increased levels of isoniazid with an increased risk of neurotoxicity, increased risk of bladder cancer in individuals exposed to aromatic amines Increased risk of serious toxicity to mercaptopurine and azathioprine... 

Liquid chromatographic techniques have been frequently employed for the separation and identification of the toxic decomposition products of synthetic dyes. Thus, the amount of aromatic amines formed from azo dyes in toys has been determined. The chemical structures of the dyes included in the investigation are listed in Fig. 3.60. The dyes were... 

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