Ethylene oxide -carbon dioxide mixture

The first thorough investigation of the mechanism of ethylene oxidation on silver surfaces was undertaken by Twigg,1171 who passed a mixture of air and ethylene at 200-350° over fine glasB wool ooated with metallic silver and obtained ethylene oxide, carbon dioxide, and water vapor. The reaction appeared to oonsist of two independent overall processes, which could be depicted separately as shown in Eq. (09) and (100). Of the two reactants, only oxygen was actually o... 

One version of the gas phase process was developed by National Distillers Products (now Quantum Chemical) in the USA and another independently in Germany by Bayer together with Hoechst. In both versions, ethylene is reacted with acetic acid and oxygen on a palladium-containing fixed-bed catalyst at 5-10 bar and 175-200°C to form vinyl acetate and water. The explosion limit restricts the O2 content in the feed mixture so that the ethylene conversion is relatively small ( 10%). The acetic acid conversion is 20-35% with selectivi-ties to vinyl acetate of up to 94% (based on C2H4) and about 98-99% (based on AcOH). The most important side reaction of this process is the total oxidation of ethylene to carbon dioxide and water. Other by-products are acetaldehyde, ethyl acetate and heavy ends. After a multistep distillation the vinyl acetate purity is 99.9% with traces of methyl acetate and ethyl acetate that do not affect the subsequent use in polymerization. 

SYNS ANHYDRIDE CARBONIQUE et OXYDE d ETHYLENE MELANGES (FRENCH) ETHYLENE OXIDE and CARBON DIOXIDE MIXTURES pOT) OXYFUME 20 OXYFUME 30... 

ETHYLENE OXIDE and CARBON DIOXIDE MIXTURES (DOT) see EJOOOO ETHYLENE OXIDE, ETHYL- see BOX750 ETHYLENE OXIDE POLYMER see EJO02S ETHYLENE OXIDE and PROPYLENE OXIDE BLOCK POLYMER see PJK200... 

Ethylene oxide forms explosive mixtures in air at concentrations ranging from. f to 80% by volume. The explosion hazard is eliminated when the gas is mixed with sufUeicnt concentrations of carbon dioxide. Carhoxide is a commercial sterilant containing 10% ethylene oxide and 9()%> carbon dioxide by volume that can be handled and released in air without danger of explosion. Sterilization is aeeompiishcd in a sealed, autoclave-like chamber or in gas-impermeable bags. 

The displacing effect observed in mixtures is not identical at all pressures. Lorenz and Wiedbrauck,16 in studying adsorption of mixtures of ethylene and carbon dioxide, found the adsorption of ethylene to be greater than that of carbon dioxide at low pressures, whereas at higher pressures this is reversed.17 Richardson and Wood-house18 observed that at 2870 millimeters pressure, carbon dioxide and nitrous oxide are adsorbed in almost equal volumes whereas at 72 millimeters pressure, two-thirds of the adsorbed gas is nitrous oxide. 

ETHYLENE OXIDE and CARBON DIOXIDE MIXTURE, with more than 6% 1062 55 METHYL BROMIDE... 

ETHYLENE OXIDE and CARBON DIOXIDE MIXTURE with more than 9% but 1064 13 METHYL MERCAPTAN... 

Resorcinol carboxylation with carbon dioxide leads to a mixture of 2,4-dihydroxyben2oic acid [89-86-1] (26) and 2,6-dihydroxyben2oic acid [303-07-1] (27) (116). The condensation of resorcinol with chloroform under basic conditions, in the presence of cyclodextrins, leads exclusively to 2,4-dihydroxyben2aldehyde [95-01-2] (28) (117). Finally, the synthesis of l,3-bis(2-hydroxyethoxy)ben2ene [102-40-9] (29) has been described with ethylene glycol carbonate in basic medium (118), in the presence of phosphines (119). Ethylene oxide, instead of ethyl glycol carbonate, can also be used (120). 

The composition of the gas mixture, which is introduced into the tube bundle reactor (tubes of 6-12 m length and 20-50 mm diameter, filled with the Ag catalyst) consists of 15-50 vol % ethylene, 5-9% oxygen, as much as 60% methane as dilution gas, and 10-15% carbon dioxide. The reaction therefore proceeds above the upper explosion limit. The ethylene conversion runs up to 10% per cycle through the reactor. The ethylene oxide selectivity amounts to 75-83 % maximum. The formed ethylene oxide is recovered by scrubbing with water and the newly formed carbon dioxide is separated from the cycle gas, e.g., by hot potash washing process. 

Ethylene oxide gas is highly explosive in mixtures of >3.6% vN in air, in order to reduce this explosion hazard it is usually supplied for sterilization purposes as a 10% mix with carbon dioxide, or as an 8.6% mixture with HFC 124 (2 chloro-1,1,1,2 tetrafluoroethane) which has replaced fluorinated hydroearbons (freons). Alternatively, pure ethylene oxide gas can be used at below atmospheric pressure in sterihzer chambers from which all air has been removed. 

When used as a sterilizer for medical equipment, ethylene oxide has to be handled using concentrations in carbon dioxide or a freon that are lower than 10% (the mixture would combust in air). Bases catalyse the polymerisation. 

Ethylene is to be converted by catalytic air oxidation to ethylene oxide. The air and ethylene are mixed in the ratio 10 1 by volume. This mixture is combined with a recycle stream and the two streams are fed to the reactor. Of the ethylene entering the reactor, 40% is converted to ethylene oxide, 20% is converted to carbon dioxide and water, and the rest does not react. The exit gases from the reactor are treated to remove substantially all of the ethylene oxide and water, and the residue recycled. Purging of the recycle is required to avoid accumulation of carbon dioxide and hence maintain a constant feed to the reactor. Calculate the ratio of purge to recycle if not more than 8% of the ethylene fed is lost in the purge. What will be the composition of the corresponding reactor feed gas ... 

Cold sterilisation can be carried out with a mixture of 90% carbon dioxide and 10% ethylene oxide, the carbon dioxide has a stabilising effect on the ethylene oxide and reduces the risk of explosion. 

Interaction of chlorine with methane is explosive at ambient temperature over yellow mercury oxide [1], and mixtures containing above 20 vol% of chlorine are explosive [2], Mixtures of acetylene and chlorine may explode on initiation by sunlight, other UV source, or high temperatures, sometimes very violently [3], Mixtures with ethylene explode on initiation by sunlight, etc., or over mercury, mercury oxide or silver oxide at ambient temperature, or over lead oxide at 100°C [1,4], Interaction with ethane over activated carbon at 350°C has caused explosions, but added carbon dioxide reduces the risk [5], Accidental introduction of gasoline into a cylinder of liquid chlorine caused a slow exothermic reaction which accelerated to detonation. This effect was verified [6], Injection of liquid chlorine into a naphtha-sodium hydroxide mixture (to generate hypochlorite in situ) caused a violent explosion. Several other incidents involving violent reactions of saturated hydrocarbons with chlorine were noted [7],... 

Type 4A sieves. The pore size is about 4 Angstroms, so that, besides water, the ethane molecules (but not butane) can be adsorbed. Other molecules removed from mixtures include carbon dioxide, hydrogen sulphide, sulphur dioxide, ammonia, methanol, ethanol, ethylene, acetylene, propylene, n-propyl alcohol, ethylene oxide and (below -30°) nitrogen, oxygen and methane. The material is supplied as beads, pellets or powder. 

For example, carbon dioxide from air or ethylene nitrogen oxides from nitrogen methanol from ethyl ether. In general, carbon dioxide, carbon monoxide, ammonia, hydrogen sulphide, mercaptans, ethane, ethylene, acetylene, propane and propylene are readily removed at 25°. In mixtures of gases, the more polar ones are preferentially adsorbed). 

The following procedure is based on the reaction of an aqueous solution of cobalt(II) chloride with the equivalent amount of (2-aminoethyl)carbamic acid, followed by oxidation with hydrogen peroxide and the subsequent formation of bis(ethylene-diamine)cobalt(III) ions. The bis(ethylenediamine)cobalt(lII) species are converted to the carbonato complex by reaction with lithium hydroxide and carbon dioxide. During the entire preparation a vigorous stream of carbon dioxide is bubbled through the reaction mixture. This procedure appears to be essential in order to minimize the formation of tris(ethylenediamine)cobalt(III) chloride as a by-product. However, the formation of a negligible amount of the tris salt cannot be avoided. The crude salts have a purity suitable for preparative purposes. The pure salts are obtained by recrystallization from aqueous solution. 

The addition of a gas to a reaction mixture (commonly the hydrogen halides, fluorine, chlorine, phosgene, boron trifluoride, carbon dioxide, ammonia, gaseous unsaturated hydrocarbons, ethylene oxide) requires the provision of safety precautions which may not be immediately apparent. Some of these gases may be generated in situ (e.g. diborane in hydroboration reactions), some may be commercially available in cylinders, and some may be generated by chemical or other means (e.g. carbon dioxide, ozone). An individual description of the convenient sources of these gases will be found under Section 4.2. 

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