Thermal Decomposition of Phosphorus and Sulphur Compounds

摘要

Most industrial chemical processes consist of highly complex sequence of interrelated reactions in which neutral and charged molecular fragments are known to play major roles. These molecular fragments are normally very reactive and are present in small quantities, which are difficult to detect experimentally. Accordingly, in order to postulate a mechanism for a given chemical process, conventional end product analysis aids in the selection of a suitable mechanism(s). Consequently, the improvement of industrial chemical processes is often achieved by semiempirical experimentation. The determination of detailed mechanism would permit the development of rational strategies for removing undesired products and enhancing the yield of desired ones. Chemical warfare agents (CWAs), e.g., G-series and VX nerve agents, are highly electrophilic organophosphonate derivatives, some-of-which are known inhibitors of acetylcholinesterase (1). Because of the relative ease of preparation of CWAs, effective decontamination procedures need also to be developed. The most direct way of destroying a CWA is through incineration (2-8), which can totally decompose their toxic and hazardous products. This process requires a detailed understanding of the high temperature decomposition kinetics of the CWA of interest. However, for such highly toxic chemicals, this information is not available. The lack of understanding is not surprising since even at the present time there are serious uncertainties regarding the detailed high temperature chemistry of CWAs. In addition, CWAs and/or some of their decomposition products may act as inhibitors or promoters of the combustion (3). Since combustion is a manifestation of exothermic chemical change, obviously, some consideration of what occurs at the molecular level must be the first step towards developing any degree of understanding.