Ethylene-oxygen mixtures

The catalyst (spheres or rings with a diameter of 3-10 mm) contains 7-20% silver on high-purity a-AI203 having a surface of only <2 m2/g. Cesium or another alkali or earth alkali salt is added in an amount of 100-500 mg/kg catalyst for upgrading the selectivity. However, small amounts of halogen compounds, e.g., dichloroethane, are added to the ethylene/oxygen mixture to inhibit the total oxidation of the ethylene. 

For example, the industrial synthesis of vinyl chloride involves a mixture of ethylene, chlorine and oxygen. This is carried out in such a way that hydrogen chloride which forms during the reaction keeps the ethylene/oxygen mixture outside the LEL - UEL range. 

AITs for ethylene-oxygen mixtures at 1 bar in stainless steel were reduced by 30-40°C by coating the vessel walls with boron trioxide. 

Fig. 17. The character of etching of platinum foils in ethylene/oxygen mixtures is a function of gas phase composition. Under excess fuel conditions between 500 and 700°C, carbon films containing platinum particles form on top of the foil. TEM micrograph of a carbon film formed after 40 h of treatment at 587°C in a fuel excess O2/C2H4 mixture (region IV). (Reprinted with permission from (55). Copyright 1985 American Chemical Society.)...

Fig. 18. Etching in ethylene/oxygen mixtures of platinum thin films on Si02 substrates in an impinging jet reactor dramatically illustrate that metal is volatilized under some conditions Hole formation in (a) region II and (b) region IV (see Fig. 16). In all other regions of the phase diagram and in any single product or reactant gas no metal was removed from the films (120).

The EO is produced commercially using ethylene/oxygen mixtures in a ratio of 3 1 or 4 1 at 513-543 K (240-270 °C) and between 15 and 25 atm [16]. The fractional coverage (0o) of the silver by oxygen atoms under operating conditions can be calculated from these data and the heat of adsorption of 123 kj/mol using the Langmuir isotherm... 

In [2], it was reported that good estimates for the propulsive performance measures of a stoichiometric ethylene-oxygen mixture initially at 1 atm are about... 

---