Congeners and their Properties
Please answer and explain where appropriate
The brominated flame retardants consist of 209 congeners with different physical-chemical properties and therefore behave differently in the environment.
Congener/ Water Solublity (mol/L)/Log KOA/Log KOW/Human BMF
4, 4'-dibromo / 6.57 x 10-7 / 8.64 / 5.86 / -
2,2',4,4'-tetrabromo / 3.04 x 10-8 / 9.80 / 6.78 / 98
2,2',4,4',5-pentabromo / 7.74 x 10-9 / 11.2 / 7.39 / 98
2,2',4,4',5,5'-hexaabromo / 7.82 x 10-11/12.15 / 8.05/ -
2,2',4,4',5,5',6,6'- decabromo / - / 13.1 / 9.9 / 8
(a) How many congeners exist in the monobromo homolog group? Draw their structures.
(b) Calculate the molecular weights of the 5 congeners listed above.
(c) What do the trends of log KOA, log KOW, and the negative log of water solubility vs. molecular weight indicate about the relationship between molecular weight and:
-solubility and mobility in water?
-potential for long range transport in air?
-hydrophobicity?
(d) Why is BMF higher for tetra and penta homologs than for deca homolog?