Prediction of Hydrolysis Products of Organic Chemicals under Environmental pH Conditions

Abstract

Cheminformatics-based software tools can predict the molecular structure of transformation products using a library of transformation reaction schemes. This paper presents the development of such a library for abiotic hydrolysis of organic chemicals under environmentally relevant conditions. The hydrolysis reaction schemes in the library encode the process science gathered from peer-reviewed literature and regulatory reports. Each scheme has been ranked on a scale of one to six based on the median half-life in a data set compiled from literature-reported hydrolysis rates. These ranks are used to predict the most likely transformation route when more than one structural fragment susceptible to hydrolysis is present in a molecule of interest. Separate rank assignments are established for pH 5, 7, and 9 to represent standard conditions in hydrolysis studies required for registration of pesticides in Organisation for Economic Co-operation and Development (OECD) member countries. The library is applied to predict the likely hydrolytic transformation products for two lists of chemicals, one representative of chemicals used in commerce and the other specific to pesticides, to evaluate which hydrolysis reaction pathways are most likely to be relevant for organic chemicals found in the natural environment.

The Acidity of Atmospheric Particles and Clouds

“…Once in the particle phase, they are vulnerable to hydrolysis, which shortens their lifetime in the environment but may lead to the formation of toxic degradation products (Tebes-Stevens et al, 2017). Aerosol acidity was also recently shown to enhance airborne nicotine levels and resulting thirdhand smoke exposure (DeCarlo et al, 2018).…”

Grafting redox-active molecules on graphene oxide through a diamine linker: length optimization for electron transfer

“…4). [38][39][40][41] The phenomenon was confirmed by CV and FTIR analysis. The CV curve of GO 2a showed oxidation and reduction peaks at 0.0 V and −0.1 V, respectively.…”

Improved oxidative biostability of porous shape memory polymers by substituting triethanolamine for glycerol

“…Additionally, IPDI may further fragment, producing amines, but this is expected to again occur in low concentrations in this environment, and more importantly, these are aliphatic diamines and will be less cytotoxic compared with aromatic hydrolysis products. It is not known whether the main contribution to this minimal fragmentation is oxidation or acid‐catalyzed hydrolysis, but the rates of mass loss indicate that the diisocyanate component and the urethane linkages play a minimal role in the oxidative degradation process …”