Studies on the importance of nature of substituent on the thermodynamic and transport properties of liquid mixtures at various temperatures

The speed of sound for the binary mixtures of trichloroethylene with branched alcohols has been determined at 303.15 K. The branched alcohols include 2-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 2-butanol, and 2-methyl-2-propanol. Further, isentropic compressibilities (Ks) and deviation in isentropic compressibilities (ΔKs) have been computed from the sound velocity and density data derived from excess volumes. The results show that ΔKs values are positive over the entire range of composition for the systems trichloroethylene + 3-methyl-1-butanol, + 2-butanol, and + 2-methyl-2-propanol, and an inversion of sign from negative to positive is observed for the remaining systems trichloroethylene + 2-propanol and + 2 methyl-1-propanol.

Speed of Sound and Isentropic Compressibilities of Trichloroethylene with Branched Alcohols at 303.15 K

This study presents an investigation into the gas phase thermal decomposition of captafol, a sulfenimide fungicide which consists of a thiotetrachloroethyl (–SCCl2CHCl2) group bonded to a tetrahydrophthalimide (C6H8(CO)2N–) moiety. The experiments were performed on a bench type apparatus, under conditions representing both under and well-ventilated non-flaming fires. The analyses of gaseous species relied on Fourier transform infra-red spectroscopy (FTIR) and micro gas chromatography (µGC), resulting in the identification and quantification of 11 gaseous products; among them, phosgene, thiophosgene and hydrogen cyanide. Gas chromatography - quadrupole mass spectrometry (GC-QMS) was employed to analyse the condensed products and volatile organic compounds (VOC), while a GC equipped with an ion trap mass spectrometer (GC-ITMS) was used to quantify polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). The GC-QMS analysis determined several VOC toxicants; viz., trichloroethylene, tetrachloroethylene, benzonitrile and chlorinated benzenes. At higher temperature (600 °C), the oxidation of captafol led to the formation of mono- to hepta- CDD/F congeners including the most toxic 2,3,7,8-TCDD. In addition, the experimental results were compared to those of the other two sulfenimide fungicides, captan and folpet, both of which contain the thiotrichloromethyl (–SCCl3) moiety rather than the thiotetrachloroethyl group of captafol. It appears that the thiotetrachloroethyl group in captafol is responsible for the difference in the toxic pollutants formed, particularly influencing the distribution and yields of PCDD/F congeners. Combined with quantum chemical calculations, the results presented in this article provide an insightful understanding of fire chemistry of the sulfenimide fungicides, especially the pathways to the formation of major toxicants during the oxidative thermal decomposition of captafol.

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Toxicants formed in fires of captafol pesticide

The densities (ρ), speed of sound (u) values, and viscosities (η) were reported for binary mixtures of 2-chloroaniline with benzene derivatives (chlorobenzene, bromobenzene and nitrobenzene) over the entire composition range at T = 303.15–318.15 K and at atmospheric pressure 0.1 MPa. The excess properties, such as excess molar volume, excess isentropic compressibility and deviation in viscosity were calculated from experimental data. The excess properties were correlated by the Redlich–Kister equation. The partial molar volumes, partial molar isentropic compressibilities, excess partial molar volumes and excess partial molar isentropic compressibilities were calculated for all the binary systems throughout the composition range and also at infinity dilutions. The VE results are analyzed in the light of Prigogine–Flory–Patterson theory. Analysis of each of the three contributions viz. interactional, free volume and P* effect to VE showed that interactional and P* contributions are positive for all systems, the free volume effect is negative for all the mixtures. The variations of these parameters with composition and temperature were discussed in terms of intermolecular interactions prevailing in these mixtures.

A. Krishnaiah

Papers

Excess volumes of binary mixtures of trichloroethylene with some aliphatic, alicyclic and aromatic hydrocarbons