Reaction of chloroform in a non-oxidative atmosphere using dielectric barrier discharge

Summary form only given. In this paper we present the results of a study of the reaction of chloroform under non-oxidative conditions, in a non thermal plasma. Reactions were at atmospheric pressure, in a double dielectric barrier discharge reactor. The non-oxidative atmosphere provides a distinct advantage as it precludes the formation of hazardous and undesired products such as COCl2, compounds which have been observed during reaction under oxidative conditions1. We postulate a mechanism for formation of major gas phase product species in the reaction, along with the characterization of the polymer formed during the reaction. A detailed description of the reactor and power supply are provided in our prior publication2. The concentration of chloroform in the feed was maintained at a constant level of 1 %, the remainder being argon. Applied voltage for the experiments was varied over the range 12-16 kV (peak to peak). The conversion of chloroform was found to increase with an increase in the applied voltage, the highest being 66.7% at 16 kV. Micro-GC and GC were used to analyze the gas phase products except the acid gases, for which an FTIR was used. The major gas phase product species observed were CH2Cl2, C2HCl3, C2Cl4, CCl4 and HCl. A mass balance of 97% was obtained for reaction at 16 kV. GPC and NMR (1-D and 2-D) techniques were employed to characterize the polymer obtained. The polymer is non-cross linked and dissolves readily in THF. This is a very important characteristic from a practical point of view. Molecular weight of the polymer obtained were characterized as follows: Mn 47400 g mol-1, Mw 80100 g mol-1. The polydispersity was estimated to be 1.69. Evidence of CH2 groups adjoining CHCl groups in the polymer backbone chain, CHCl2 groups and double bonds is seen in the NMR spectra.