1 -Naphthylamine toxicology

Toxicology. AT-phenyl-P-naphthylamine (PBNA) is carcinogenic to experimental animals in some studies. 

Toxicology of Certain Azo Dyes. It has been known for over 100 years that certain amines used to manufacture synthetic dyes caused bladder cancer, especially 2-naphthylamine, benzidine and 4-aminodiphenyl. All the major dyestuff manufacturers abandoned the use of these amines in the production of dyes in the early 1970s. 

The difference between the enthalpies of formation of gas-phase 1- and 2-naphthylamine of some 22 kJmol-1 is troubling. It is quite inexplicable when the likewise related differences between 1- and 2-methylnaphthalene, and of 1- and 2-naphthol, all but vanish50. The accuracy of the enthalpy of formation values can be assessed with equation 10, which is related to equation 2, and is expected to be thermoneutral when all substances are in the same phase. For the solid or liquid phase and for 1-naphthylamine, and for the solid-phase 2-naphthylamine, the enthalpy of reaction is in the range of — 1.1 to 5.4 kJ mol-1. For gas-phase 2-naphthylamine, the enthalpy of reaction is the discrepant —21 kJmol-1. There being no apparent reason why this reaction should not be approximately thermoneutral also, a calculated enthalpy of formation of gaseous 2-naphthylamine is ca 155 kJ mol-151. However, in clear conscience we cannot recommend remeasurement of either (or even better, both) naphthylamines because the 2-isomer is such a powerful carcinogen. Perhaps with appropriate substitution that is simultaneously sterically and electronically innocuous and that also renders the amine toxicologically innocuous, relevant measurements can (and thus should) be made. 

Hueper began work in November 1934 as chief pathologist of what was named the Haskell Laboratory. In experiments on dogs, he was able to show that beta-naphthylamine, and not other chemicals used in the plant, produced bladder tumors similar to those observed in the diseased employees. This finding, published in 1938 in the Journal of Industrial Hygiene and Toxicology, was a landmark in cancer research, the first experimental demonstration that a synthetic organic chemical causes cancer. 

Synonyms 1-Benzeneazo-2-naphthylamine 1-Benzene-azo-p-naphthylamine Cl 11380 Ext. D C Yellow No. 9 FD C Yellow No. 3 Food yellow 10 1-(Phenylazo)-2-naphthalenamine Solvent yellow 5 Yellow AB Empiricai C16H13N3 Formuia C6H5N2C10H6NH2 Properties Orange or red platelets sol. in alcohol, oils insol. in water m.w. 247.32 m.p. 102-104 C Toxicology LDLo (oral, rabbit) 1000 mg/kg, (subcut., rabbit) 1000 mg/kg mod. toxic by ing., subcut. routes questionable carcinogen experimental tumorigen mutagenic data TSCA listed... 

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