![Direct VUV photolysis of chlorinated methanes and their mixtures in a nitrogen stream [An article from: Chemosphere]](https://www.ebooknetworking.net/books/B00/0PC/bigB000PC0670.jpg)
Direct VUV photolysis of chlorinated methanes and their mixtures in a nitrogen stream [An article from: Chemosphere]
Description
This digital document is a journal article from Chemosphere, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
The gas-phase decomposition of CCl"4, CHCl"3 and CH"2Cl"2 and their binary mixtures was studied in a flow-type reactor in a nitrogen gas stream, using a low-pressure mercury vapour lamp covered with a high-purity silica quartz sleeve. The 184.9nm vacuum-ultraviolet (VUV) light emitted is able to rupture the C-Cl bond in these target substances. For H-containing compounds, the decomposition takes place not only by direct photolysis, but also by H abstraction by ^?Cl formed during the direct photolysis of the target substances. The relative contributions of direct photolysis and ^?Cl-sensitized reactions to the decomposition were estimated at different initial concentrations. The addition of CCl"4 to CHCl"3 or CH"2Cl"2 increased their decomposition rates via increase of the ^?Cl concentration, whereas the addition of CH"2Cl"2 to CHCl"3 decreased its degradation rate, suggesting that CH"2Cl"2 acts as a ^?Cl radical scavenger. The variation of the product distribution confirms the effect of the composition of the irradiated gas mixtures on the relative contributions of ^?Cl-sensitized reactions and direct photolysis.
Description:
The gas-phase decomposition of CCl"4, CHCl"3 and CH"2Cl"2 and their binary mixtures was studied in a flow-type reactor in a nitrogen gas stream, using a low-pressure mercury vapour lamp covered with a high-purity silica quartz sleeve. The 184.9nm vacuum-ultraviolet (VUV) light emitted is able to rupture the C-Cl bond in these target substances. For H-containing compounds, the decomposition takes place not only by direct photolysis, but also by H abstraction by ^?Cl formed during the direct photolysis of the target substances. The relative contributions of direct photolysis and ^?Cl-sensitized reactions to the decomposition were estimated at different initial concentrations. The addition of CCl"4 to CHCl"3 or CH"2Cl"2 increased their decomposition rates via increase of the ^?Cl concentration, whereas the addition of CH"2Cl"2 to CHCl"3 decreased its degradation rate, suggesting that CH"2Cl"2 acts as a ^?Cl radical scavenger. The variation of the product distribution confirms the effect of the composition of the irradiated gas mixtures on the relative contributions of ^?Cl-sensitized reactions and direct photolysis.
