Aerobic biotransformation studies of two trifluoromethoxy-substituted aliphatic alcohols and a novel fluorinated C3-based building block

Abstract

Abstract Fluorinated substances play a significant role for many industrial and consumer products, but many of these chemicals are attributed with an adverse ecological profile and persistence in the environment. Herein, three potentially more environmentally benign substitutes were assessed for aerobic biotransformation, namely 3-(trifluoromethoxy)-propan-1-ol (TFMPrOH), 6-(trifluoromethoxy)-hexan-1-ol (TFMHxOH) and 1-(2,2,3,3,4,4,4-heptafluorobutoxy)-propan-2-ol (HFBPrOH). Analytical techniques involved different HPLC–ESI-MS/MS techniques as well as determination of fluoride in order to assess the extent of mineralization. The two trifluoromethoxy-substituted alcohols showed very different results concerning mineralization. Whereas TFMPrOH only yielded approximately 15% fluoride, TFMHxOH reached nearly quantitative release of fluoride after 37 days. The latter one yielded 6-trifluoromethoxy hexanoic acid (TFMHxA) as well as trifluoromethyl carbonate (TFMC) as transient transformation products, both of which were entirely degraded. TFMC was also detected during biotransformation of TFMPrOH, however, the major transformation product was 3-trifluoromethoxy-propanoic acid (TFMPrA), which did not show any further degradation within a 47 days period. The third compound under investigation, HFBPrOH, expectedly yielded perfluorobutanoic acid as a stable biotransformation product. Several acidic biotransformation intermediates as well as heptafluorobutan-1-ol were identified and a biotransformation pathway was postulated. TFMHxOH might therefore be incorporated into fluorinated substances, for instance by ester linkages assuming that biotransformation of such substances would yield the alcohol.