Hydrocarbons mixing ratios

Jobson B. T., Parrish D. D., Goldan P., Kuster W., Fehsenfeld F. C., Blake D. R., Blake N. J., and Niki H. (1998) Spatial and temporal variability of nonmethane hydrocarbon mixing ratios and their relation to photochemical lifetime. J. Geophys. Res. 103, 13557-13567. 

Jing, L.H., S.M. Steinberg, and B.J. Johnson Aldehyde and monocyclic aromatic hydrocarbon mixing ratios at an urban site in Las Vegas, Nevada, Journal of the Air Waste Management Association, 51 (2001) 1359-... 

Fig. 2 shows the liquid product distributions over catalysts. Main product over ferrierite is C5 hydrocarbon, while products were distributed over mainly C,-C, over HZSM-5. Table 4 shows the effect of mixing ratio on product distribution. While HZSM-5/PP ratio does not affect product distribution, higher amount of gas is obtained with increasing ferrierite/PP ratio. This is ascribed to the increased possibility of polypropylene diffusion into pore as the amount of ferrierite is increased. 

Carbon monoxide (CO) strongly influences the concentration of the radical OH in the tropical atmosphere. CO oxidation can lead to either production or destruction of ozone, depending on the NOx mixing ratio. Tropical soils are either a sink or a weak source of CO, where photochemical oxidation of methane and other hydrocarbons and biomass burning emissions are the predominant CO sources. 

Experiments were carried out between 720° and 985°C with 1-butene and between 760°and 925°C with the mixed isomers of 2-butene, using steam dilution corresponding to a steam hydrocarbon weight ratio of between 0.17 and 1.2 g/g. All runs were isobaric at total pressure of 1.0 psig. Material balances generally fell within dz 2% for all of the experiments. Tables I and II summarize the individual run conditions, the observed yields and conversions, and the calculated rate constants for pyrolysis of 1-butene and the 2-butenes, respectively. 

By comparison, the average CO mixing ratio in Earth s troposphere is —0.12 ppmv and it is produced from a variety of anthropogenic and biogenic sources such as fossil fuel combustion, biomass burning, and oxidation of methane and other hydrocarbons. Most of the CO in Earth s troposphere is destroyed by reaction with OH radicals, which are also important for the catalytic... 

The presence of halogen-containing radicals can play a substantial role in chemical processes in the atmosphere. Chlorine atoms react much faster with alkanes than OH, the effect of which has been clearly observed in the Arctic troposphere in connection with the sunrise ODEs (Ramacher et al., 1997 Ariya et al., 1997 Song and Carmichael, 1999). The high reactivity of chlorine with hydrocarbons may explain the relatively high CH2O volume mixing ratios of... 

Performances of each catalyst is shown in Figure 1. The ethanol synthesis catalyst (Fe-based catalyst. Cat. 1) have both functions of F-T synthesis and alcohol synthesis. The main products were hydrocarbons, ethanol and methanol. With the increase of CO in reaction gas, the yield of ethanol increased[l]. The Cu-based catalyst (Cat. 2) converted CO2 to CO with selectivity more than 70% at a temperature range from 270 to 370°C, and other products were methanol and a slight amount of methane. Ethanol and C2 hydrocarbons were not produced. In order to harmonize the three functions, C-C bond growth, partial reduction of CO2 to CO, and OH insertion to products, the mixed ratio of Fe-based catalyst to Cu-based catalyst was coordinated at the range from Cu/Fe =... 

The stratosphere as a sink was first identified by Seiler and Junge (1969). The flux of CO into the stratosphere is caused by a decline of CO mixing ratios above the tropopause toward a steady-state level lower than that normally found in the upper troposphere (see Fig. 1-14). In the lower stratosphere, CO is produced from methane and other long-lived hydrocarbons, and it is consumed by reaction with OH as in the troposphere, but the rate of vertical mixing is much slower (Seiler and Warneck, 1972 Warneck et al., 1973). The flux of CO from the troposphere into the stratosphere can be derived from the observed gradient of the CO mixing ratio above the tropopause in a manner described in Section 4.3 for methane. The loss rate obtained, llOTg/yr, is small compared with that for the reaction of CO with OH radicals. 

Table 6-2. Mixing Ratios (ppbv) of Major Hydrocarbons in Several U.S. Cities (Arnts and Meeks, 1981 Sexton and Westberg, 1984) and in Sidney, Australia (Nelson et al., 1983)...

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