Ethylene oxide reaction with oxygen

With Ammonia and Amines. Ethylene oxide reacts with ammonia to form a mixture of mono-, di-, and triethanolamines. Nitrogen is a stronger nucleophile than oxygen (59). A small amount of water is essential for the reaction (60). 

Oxidation of CI2BC2H4BCI2 occurs slowly in dry air, vigorously in oxygen at temperatures above 0°C. At 0°C, reaction with oxygen occurs smoothly, with consumption of 1 mole of oxygen per mole of the addition product. Under these conditions, HCl, BCI3, and variable amounts of ethylene are the principal products. Possible mechanisms of this reaction have been discussed (53). 

Finally, titanium silicates have also been extensively investigated for the epoxida-tion of olefins. The reaction of ethylene over a silver-supported catalyst to ethylene oxide is one of the few large-scale industrial oxidation reactions with molecular oxygen as the oxidant. Numerous studies have shown TS-1 to be effective at selectively forming propylene oxide (PO) from propylene using hydrogen peroxide as the oxidant. This is a more environmentally friendly route to PO than the currently used chlorhydrin route, and it is likely that this process will see commercialization in the near future. 

It is then necessary to periodically regenerate lead oxide by reaction with oxygen. In the second step, stilbene is cross-metathesized with ethylene over a classical W03/Si02 based catalyst. In order to prevent polymerization of styrene, this second reaction is also made at high temperature ( > 400°C). 

In the absence of light, most polymers are stable for very long periods at ambient temperatures. However, above room temperature many polymers start to degrade in an air atmosphere even without the influence of light. For example, a number of polymers show a deterioration of mechanical properties after heating for some days at about 100 °C and even at lower temperatures (e.g., polyethylene, polypropylene, poly(oxy methylene), and poly(ethylene sulfide)). Measurements have shown that the oxidation at 140 °C of low-density polyethylene increases exponentially after an induction period of 2 h. It was concluded that thermal oxidation, like photooxidation, is caused by autoxidation, the difference merely being that the radical formation from the hydroperoxide is now activated by heat. The primary reaction can be a direct reaction with oxygen (Van Krevelen and Nijenhuis 2009) ... 

Valuable products are produced from the oxidation of both ethylene and propylene (Figs. 1 and 2). Ethylene is epoxidized with oxygen in the vapor phase over a silver catalyst, and propylene is epoxidized with an alkyl hydroperoxide in the liquid phase using a molybdeniim catalyst system. Vinylic oxidation products or their stable isomers, including acetaldehyde, acetone, and vinyl acetate, have been manufactured by a series of related catalytic reactions. These reactions occur either in solutions of palladium complexes or on the surfaces of supported palladium catalysts. Bismuth molybdate is an effective catalyst for allylic oxidations of propylene, which are of paramount importance to the chemical industry. Propylene is oxidized in the vapor phase to give acrolein for acrylic acid manufacture or, in the presence of ammonia, to give acrylonitrile. Second- and third-generation catalysts,... 

Oxidation of ethylene in alcohol with PdCl2 in the presence of a base gives an acetal and vinyl ether[106,107], The reaction of alkenes with alcohols mediated by PdCl2 affords acetals 64 as major products and vinyl ethers 65 as minor products. No deuterium incorporation was observed in the acetal formed from ethylene and MeOD, indicating that hydride shift takes place and the acetal is not formed by the addition of methanol to methyl vinyl etherjlOS], The reaction can be carried out catalytically using CuClj under oxygen[28]. 

A typical oxidation is conducted at 700°C (113). Methyl radicals generated on the surface are effectively injected into the vapor space before further reaction occurs (114). Under these conditions, methyl radicals are not very reactive with oxygen and tend to dimerize. Ethane and its oxidation product ethylene can be produced in good efficiencies but maximum yield is limited to ca 20%. This limitation is imposed by the susceptibiUty of the intermediates to further oxidation (see Figs. 2 and 3). A conservative estimate of the lower limit of the oxidation rate constant ratio for ethane and ethylene with respect to methane is one, and the ratio for methanol may be at least 20 (115). 

Polyall lene Oxide Block Copolymers. The higher alkylene oxides derived from propjiene, butylene, styrene (qv), and cyclohexene react with active oxygens in a manner analogous to the reaction of ethylene oxide. Because the hydrophilic oxygen constitutes a smaller proportion of these molecules, the net effect is that the oxides, unlike ethylene oxide, are hydrophobic. The higher oxides are not used commercially as surfactant raw materials except for minor quantities that are employed as chain terminators in polyoxyethylene surfactants to lower the foaming tendency. The hydrophobic nature of propylene oxide units, —CH(CH2)CH20—, has been utilized in several ways in the manufacture of surfactants. Manufacture, properties, and uses of poly(oxyethylene- (9-oxypropylene) have been reviewed (98). 

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