Volume 7, Issue 7 (July 2010)
Chemical Clustering for Risk Assessment: Fatty Alcohol Alkoxylates
Fatty alcohol alkoxylates are non-ionic surface active compounds comprised of a hydrophobic fatty alcohol moiety of variable chain length linked to a hydrophilic polyalkoxylate chain of repeating alkylene oxide subunits containing ethylene and propylene oxides. Materials falling inside this group that are derived from a fatty alcohol and ethylene oxide alone are referred to as fatty alcohol ethoxylates. The unifying features of this class include (1) the use of fatty alcohol fractions drawn from alkyl chains between 4 and 100 carbons in length, each with deliberately wide or narrow ranges and falling within or across specific groups, and (2) the chemical addition to these fractions of specific numbers of repeating structural units of an alkylene oxide in molar ratios ranging from 2 to 100 for ethylene oxide and from 0 to 30 for propylene oxide. A useful rationale establishing the cohesiveness of grouping, or “clustering,” of this family of chemistry is described based on a comparison of similarities across chemical structures contained in the cluster, the continuum of predictable change in associated physiochemical properties, and the accompanying consistency in underlying biological data. A semiquantitative approach is described using the accessible non-confidential information.