Experimental thermochemical data of CWA simulants: Triethyl phosphate, diethyl methylphosphonate, malathion and methyl salicylate

Abstract

This work focuses on the determination of important thermochemical properties of several chemical warfare agent (CWA) simulants: diethyl methylphosphonate (DEMP, CAS 683-08-9, 1), triethyl phosphate (TEP, CAS 78-40-0, 2), malathion (CAS 121-75-5, 3) and methyl salicylate (MS, 119-36-8, 4). Enthalpies of vaporization ΔlgHmo (298.15 K) (1: 56.8 ± 0.8 kJ mol−1; 2: 63.9 ± 0.9 kJ mol−1; 3: 101.4 ± 1.8 kJ mol−1; 4: 59.3 ± 0.8 kJ mol−1) and vapor pressures psat (298.15 K) (1: 43.9 Pa; 2: 12.5 Pa; 3: 1.4 mPa; 4: 14.5 Pa) were determined by the transpiration method in the ambient temperature range. The results were compared with existing literature values and critically evaluated. Data of DEMP 1, TEP 2 and MS 4 show agreement with most literature vaes, while results of malathion 3 show a significant disagreement with the scarce available literature p-T data.