Experimental determination of solvent-water partition coefficients and Abraham parameters for munition constituents. (October 2016)

• Record Type: Journal Article
• Authors: Liang, Yuzhen; Kuo, Dave T.F.; Allen, Herbert E.; Di Toro, Dominic M.
• Is Part Of: Chemosphere. Volume 161(2016)
• Page Start: 429
• Page End: 437
• Publication Date: 2016-10
• Subjects: LFER -- Abraham parameter -- Partitioning -- RDX -- HMX -- ABSOLV; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2016.07.028
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: There is concern about the environmental fate and effects of munition constituents (MCs). Polyparameter linear free energy relationships (pp-LFERs) that employ Abraham solute parameters can aid in evaluating the risk of MCs to the environment. However, poor predictions using pp-LFERs and ABSOLV estimated Abraham solute parameters are found for some key physico-chemical properties. In this work, the Abraham solute parameters are determined using experimental partition coefficients in various solvent-water systems. The compounds investigated include hexahydro-1, 3, 5-trinitro-1, 3, 5-triazacyclohexane (RDX), octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetraazacyclooctane (HMX), hexahydro-1-nitroso-3, 5-dinitro-1, 3, 5-triazine (MNX), hexahydro-1, 3, 5-trinitroso-1, 3, 5-triazine (TNX), hexahydro-1, 3-dinitroso-5- nitro-1, 3, 5-triazine (DNX), 2, 4, 6-trinitrotoluene (TNT), 1, 3, 5-trinitrobenzene (TNB), and 4-nitroanisole. The solvents in the solvent-water systems are hexane, dichloromethane, trichloromethane, octanol, and toluene. The only available reported solvent-water partition coefficients are for octanol-water for some of the investigated compounds and they are in good agreement with the experimental measurements from this study. Solvent-water partition coefficients fitted using experimentally derived solute parameters from this study have significantly smaller root mean square errors (RMSE = 0.38) than predictions using ABSOLV estimated solute parameters (RMSE = 3.56) for the investigated compounds. Additionally, the predictions for various physico-chemical properties using the experimentally derived solute parameters agree with available literature reported values with prediction errors within 0.79 log units except for water solubility of RDX and HMX with errors of 1.48 and 2.16 log units respectively. However, predictions using ABSOLV estimated solute parameters have larger prediction errors of up to 7.68 log units. This large discrepancy is probably due to the missing R2 NNO2 and R2 NNO2 functional groups in the ABSOLV fragment database. Graphical abstract: Highlights: Physical-chemical properties of munition constituents were investigated. Partition coefficients in various solvent-water systems were determined. The Abraham solute parameters were determined from these experiments. Large errors were found for predictions using ABSOLV estimated solute parameters. Predictions using solute parameters from this work have smaller errors.