Ethene mixing ratios

Table 6-11. Mixing Ratios (pptv) of C4 and C5 Alkanes, Ethene, and Propene in the Marine Atmosphere Near the Ocean Surface... 

Another example where interferents are significant is the case of HCN, whose protonated signal is at miz 28. O2 + is always present to some extent in the drift tube when air is used as the inlet gas, as discussed in Section 3.3.2, and this ion can transfer its charge in collisions with ethene leading to an ion with the same nominal mIz as protonated HCN. If this contribution is not taken into account the HCN measurements will be compromised. Knighton et al. have estimated that if ethene is present it can contribute 0.1 ppbv HCN equivalent per ppbv of ethene when the O2 intensity is at 2% of the H3O+ level [49]. Knighton et al. also calibrated their PTR-MS instrument at various HCN mixing ratios, temperatures and relative humidities, and developed a model to accurately account for the temperature and humidity dependences of the PTR-MS sensitivities for the detection of HCN. 

Ionic liquids operate in true biphasic mode. While the recovery and recyclability of ionic liquid was found to be more efficient than with the conventional AICI3 catalyst (red oil), the selectivity for the monoalkylated aromatic hydrocarbon was lower. In this gas-liquid-liquid reaction, the solubility of the reactants in the ionic phase (e.g. the benzene/ethene ratio in the ionic phase) and the mixing of the phases were probably critical. This is an example in which the engineering aspects are of the utmost importance. 

Table 16.12 compares the POCP values derived by Dement et al. (1996, 1998) and Andersson-Skold et al. (1992) to the MIR approach of Carter (1994). While the general trends in reactivities predicted by each approach are qualitatively similar, there are quantitative differences. For example, the POPC values for the simple alkanes relative to ethene are larger than the MIR values. This reflects in part the details of the mechanisms used in the calculations and the time scale over which the reactions are followed as well as differences in the assumed pollutant mix into which the VOC is injected, such as the VOC/NO ratio. 

The first catalyst used by Ziegler et al. [5,82] for the polymerization of ethene was a mixture of TiCU and A1(C2H5)3, each of which is soluble in hydrocarbons. In combination they form an olive-colored insoluble complex that is very unstable. Its behavior is very sensitive to a number of experimental parameters, such as Al/Ti ratio, temperature and time of mixing of all components, and absolute and relative concentrations of reactants [83]. After complexation, TiC is reduced by a very specific reduction process. This reduction involves alkylation of TiC with aluminum alkyl molecules followed by a dealkylation reduction to a trivalent state ... 

We consider in the following a world-scale steam cracker plant with a production capacity of 125th ethene (Figure 6.6.8). The plant runs on light-run naphtha that is heated in the convection zone of the crack oven to 600 °C. The naphtha is mixed with water vapor (4.5 MPa, 257.5°C) to realize a steam-to-naphtha ratio of 0.45. This mixture is introduced to the main crack oven, which is an 80m tubular reactor at 850°C. The residence time of the feedstock in this hot section of the crack oven is 0.5 s. Following the crack oven, the product mixture is quenched to 200°C. In a first distillation column light components (C1-C5) are separated from the heavier pyrolysis products (Cs+). 

Finally Fig. 5 shows the dependence of the mixed and the true r parameters on the conversion, in relation to the Al ratios of 5 1 (o, ) and 20 1 (x,A). Here we have tried to investigate a possible dependence of the copolymerization parameters on the overall concentration of the active species. The results in Fig. 5 show that the effect of both AlATi ratios on the r parameter with increasing conversion is the same. In offier words, wiffi increasing the AI/Ti ratio both of the ethene homopolymerization and copolymerization active centres increase shnultaneourdy. 

Mixed (ox) and true ( ) parameters of ethene / 1-hexene copolymers in dependence on conversion at different ratios Ai Ti. 

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