TABLE III: Relative Concentrations of Ethanes and Ethylenes in CH4/CD4 Experiment (FTIR Measurements) caled" obsd caled" obsd C¡H¡ 34 ± 2 36 ± 4 C^3 4 ± 2 34 ± 2 CD3CH3 49 ± 2 (49)» CD2CH2 49 ± 2 (51)6 C2D6 17 ± 2 15 ± 2 C2D4 17 ± 2 15 ± 2 "For kH/kB = 1.4 ± 0.1. 6By difference.other ethane and CD2CH2 is,the only other ethylene, the contribution of these species may be determined by difference. Table III presents these results together with calculated values based on the kinetic isotope effect (&hAd = 1.4 ± 0.1) and a statistical distribution since the mixed species are more likely than the symmetrical ones. The uncertainty in the magnitude of the kinetic isotope effect is due to the small difference in the results obtained with CH4 alone. The experimental results are in excellent agreement with the calculations and show that exchange of H and D in the product hydrocarbons is insignificant and that the product distribution reflects the relative concentrations of CH3 and CD3.The results may therefore be interpreted as confirmatory evidence for the coupling of methyl radicals in this catalytic system. However, the absence of any significant hydrogen exchange between CH4 and CD4 and also between the product C2 hydrocarbons is surprising since MgO exhibits activity for CH4/D2 exchange at 300 °C16 and activity for CH4/CD4 exchange at 400 °C.17 It is therefore likely that the methyl coupling reaction occurs almost exclusively in the gas phase. This is in agreement with Lunsford's conclusion10 that at least 40-45% of the C2 products were accounted for by gas-phase methyl coupling. The results also suggest that ethane is the source of the ethylene since the distribution of the deuteriated ethylenes is not significantly different from that of the ethanes. It is possible that conversion of ethane to ethylene also occurs predominantly in the gas phase since
TABLE III: Relative Concentrations of Ethanes and Ethylenes in CH4/CD4 Experiment (FTIR Measurements) caled" obsd caled" obsd C¡H¡ 34 ± 2 36 ± 4 C^3 4 ± 2 34 ± 2 CD3CH3 49 ± 2 (49)» CD2CH2 49 ± 2 (51)6 C2D6 17 ± 2 15 ± 2 C2D4 17 ± 2 15 ± 2 "For kH/kB = 1.4 ± 0.1. 6By difference.other ethane and CD2CH2 is,the only other ethylene, the contribution of these species may be determined by difference. Table III presents these results together with calculated values based on the kinetic isotope effect (&hAd = 1.4 ± 0.1) and a statistical distribution since the mixed species are more likely than the symmetrical ones. The uncertainty in the magnitude of the kinetic isotope effect is due to the small difference in the results obtained with CH4 alone. The experimental results are in excellent agreement with the calculations and show that exchange of H and D in the product hydrocarbons is insignificant and that the product distribution reflects the relative concentrations of CH3 and CD3.The results may therefore be interpreted as confirmatory evidence for the coupling of methyl radicals in this catalytic system. However, the absence of any significant hydrogen exchange between CH4 and CD4 and also between the product C2 hydrocarbons is surprising since MgO exhibits activity for CH4/D2 exchange at 300 °C16 and activity for CH4/CD4 exchange at 400 °C.17 It is therefore likely that the methyl coupling reaction occurs almost exclusively in the gas phase. This is in agreement with Lunsford's conclusion10 that at least 40-45% of the C2 products were accounted for by gas-phase methyl coupling. The results also suggest that ethane is the source of the ethylene since the distribution of the deuteriated ethylenes is not significantly different from that of the ethanes. It is possible that conversion of ethane to ethylene also occurs predominantly in the gas phase since
“…On the basis of the conducted research, it was found (Graven et al 1966) that the most durable catalyst is 10%V/Al 2 O 3 , for which the highest conversion of DMMP after 20 h of the experiment was obtained. It also has much longer durability than other materials (e.g., 1%Pt/Al 2 O 3 ), described in publications (Ratliff et al 2009;Cao et al 2001).…”
Section: Thermocatalysismentioning
confidence: 96%
“…500 ppm organic compound was introduced into the reactor. The catalyst tested showed high activity in (Graven et al 1966) the DMMP decomposition reaction, which increased as the process temperature increased reaching a conversion close to 100% at a temperature of approximately 450 °C (Fig. 5).…”
Section: Thermocatalysismentioning
confidence: 98%
“…A comparison of similar experiments carried out on the surface of molybdenum shows that transition metals may be suitable for the thermocatalytic oxidation of organophosphorus compounds. This is due to the fact that the removal of phosphorus, arising during the DMMP decomposition reaction, from the surface of molybdenum, takes place at a lower temperature (Graven et al 1966). Ratliff et al (2009) describe the results of the research on the thermocatalytic distribution of sarin simulant-DMMP-concentration of which was 1300 ppm.…”
Section: Thermocatalysismentioning
confidence: 99%
“…Thus, it has been shown (Popiel et al 2014;Graven et al 1966) that DMMP decomposition results in: CO 2 , methanol and P 2 O 5 . For comparison, it is worth noting that during the analysis of DMMP by mass spectroscopy during electron ionization the decomposition products were methyl methylphosphonate and methylphosphonic acid.…”
The decontamination of chemical warfare agents (CWAs) from structures, environmental media and even personnel has become an area of particular interest in recent years due to increased homeland security concerns. This article reviews applications of catalytic methods used for decontamination of CWAs. Most attention was given to the following methods: thermocatalysis, photocatalysis and enzyme catalysis among the many methods of catalytic CWA decomposition. Unfortunately, there are not enough data obtained with real CWAs due to the difficulty in handling, so we have described also data available for CWAs simulants. These methods can be useful for decontamination systems that can reduce the damage caused by possible terrorism.
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