Ozonation of Tamoxifen and Toremifene: Reaction Kinetics and Transformation Products
Publikation: Beiträge in Zeitschriften › Zeitschriftenaufsätze › Forschung › begutachtet
Standard
in: Environmental Science and Technology, Jahrgang 52, Nr. 21, 06.11.2018, S. 12583-12591.
Publikation: Beiträge in Zeitschriften › Zeitschriftenaufsätze › Forschung › begutachtet
Harvard
APA
Vancouver
Bibtex
}
RIS
TY - JOUR
T1 - Ozonation of Tamoxifen and Toremifene
T2 - Reaction Kinetics and Transformation Products
AU - Knoop, Oliver
AU - Hohrenk, Lotta L.
AU - Lutze, Holger V.
AU - Schmidt, Torsten C.
N1 - Publisher Copyright: © 2018 American Chemical Society.
PY - 2018/11/6
Y1 - 2018/11/6
N2 - The oxidation of the two antiestrogenic pharmaceuticals tamoxifen and toremifene with ozone in water was investigated concerning kinetics, reaction pathway, and transformation product formation. For both compounds a high dependency of second order rate constants and products on pH was determined. In case of full protonation of the amine (cation) ozone attacks with a second order rate constant of 1.57 × 10 4 M -1 s -1 for tamoxifen and 4.37 × 10 3 M -1 s -1 for toremifene. The neutral tertiary amine has an unexpected high second order rate constant of 3.17 × 10 8 M -1 s -1 for tamoxifen and 1.46 × 10 8 M -1 s -1 for toremifene. For the reaction of ozone and the tertiary amine only N-oxide formation was observed. pK a values for tamoxifen (9.49 ± 0.22) and toremifene (9.57 ± 0.22) can be reported based on experimental data. Eight transformation products (TPs) were observed and identified based on MS/MS spectra or a reference standard. Products observed derived from Criegee reaction and hydroxylation as well as N-oxide formation. Further TPs from reactions with TAM products were combinations of N-oxides, Criegee products and hydroxylation products. Thus, reaction pathways can be derived and primary and secondary TPs distinguished for the first time.
AB - The oxidation of the two antiestrogenic pharmaceuticals tamoxifen and toremifene with ozone in water was investigated concerning kinetics, reaction pathway, and transformation product formation. For both compounds a high dependency of second order rate constants and products on pH was determined. In case of full protonation of the amine (cation) ozone attacks with a second order rate constant of 1.57 × 10 4 M -1 s -1 for tamoxifen and 4.37 × 10 3 M -1 s -1 for toremifene. The neutral tertiary amine has an unexpected high second order rate constant of 3.17 × 10 8 M -1 s -1 for tamoxifen and 1.46 × 10 8 M -1 s -1 for toremifene. For the reaction of ozone and the tertiary amine only N-oxide formation was observed. pK a values for tamoxifen (9.49 ± 0.22) and toremifene (9.57 ± 0.22) can be reported based on experimental data. Eight transformation products (TPs) were observed and identified based on MS/MS spectra or a reference standard. Products observed derived from Criegee reaction and hydroxylation as well as N-oxide formation. Further TPs from reactions with TAM products were combinations of N-oxides, Criegee products and hydroxylation products. Thus, reaction pathways can be derived and primary and secondary TPs distinguished for the first time.
KW - Chemistry
KW - Amines
KW - chemical reactions
KW - kinetic parameters
KW - order
KW - water treatment
UR - http://www.scopus.com/inward/record.url?scp=85055569746&partnerID=8YFLogxK
U2 - 10.1021/acs.est.8b00996
DO - 10.1021/acs.est.8b00996
M3 - Journal articles
C2 - 30221510
AN - SCOPUS:85055569746
VL - 52
SP - 12583
EP - 12591
JO - Environmental Science and Technology
JF - Environmental Science and Technology
SN - 0013-936X
IS - 21
ER -