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Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame retardants in, for example, textiles, computers, television sets, and other electrical appliances. present also in humans. The environmental levels of the PBDEs are, however, still in general lower than those of polychlorinated biphenyls (PCBs). However, while the levels of PCBs generally are decreasing, those of the PBDEs are increasing in, for example, human milk. In the present study 32 individual PBDE congeners were synthesized and characterized. Physicochemical parameters including melting points and UV, 1H NMR, and mass spectra are reported Twenty-nine monobrominated to heptabrominated diphenyl ethers were synthesized by the couping between four diphenyliodonium salts and nine phenolates. One tetrabromodiphenyl ether and two hexabromodiphenyl ethers were synthesized by bromination of two different PBDEs. Twenty-one of the PBDEs and two of the iodonium salts, 2,2′,4,4′-tetrabromodiphenyliodonium chloride and 3,3′,4,4′-tatrabromodiphenyliodonium chloride, are to the authors' knowledge described for the first time. These synthesized reference compounds will aid in the identification and quantification of PBDEs present in environmental samples and will allow further assessment of PBDE toxicity.

The described synthesis of synthetic lubricants based on polyphenyl ethers requires an analytical characterization of the isomerization step, which is important to the process optimization.The separation of the intermediates succeeds with gas chromatography; the isomers are determined using a retention index system.The obtained results are compared with the composition of the final product, which was investigated by HPLC analysis.Keywords.Gas chromatography; Polyphenyl ethers; Lubricants, synthetic.