Ethylene oxidation, catalytic

Technically, acetaldehyde is mainly made by the oxidation of ethylene using a CuCl2/PdCl2 catalyst system.. Although some acetic acid is still prepared by the catalytic oxidation of acetaldehyde, the main process is the catalytic oxidation of paraffins, usually -butane. 

In the early versions, ethylene cyanohydrin was obtained from ethylene chlorohydrin and sodium cyanide. In later versions, ethylene oxide (from the dkect catalytic oxidation of ethylene) reacted with hydrogen cyanide in the presence of a base catalyst to give ethylene cyanohydrin. This was hydrolyzed and converted to acryhc acid and by-product ammonium acid sulfate by treatment with about 85% sulfuric acid. 

In Europe, where an abundant supply of anthracene has usually been available, the preferred method for the manufacture of anthraquinone has been, and stiU is, the catalytic oxidation of anthracene. The main problem has been that of obtaining anthracene, C H q, practically free of such contaminants as carbazole and phenanthrene. Many processes have been developed for the purification of anthracene. Generally these foUow the scheme of taking the cmde anthracene oil, redistilling, and recrystaUizing it from a variety of solvents, such as pyridine (22). The purest anthracene may be obtained by azeotropic distillation with ethylene glycol (23). 

Catalytic oxidation of ethylene produces ethylene oxide, which is hydrolyzed to ethylene glycol. Ethylene glycol is a monomer for the production of synthetic fibers. Chapter 7 discusses chemicals based on ethylene, and Chapter 12 covers polymers and copolymers of ethylene. 

Vinyl acetate was originally produced hy the reaction of acetylene and acetic acid in the presence of mercury(II) acetate. Currently, it is produced hy the catalytic oxidation of ethylene with oxygen, with acetic acid as a reactant and palladium as the catalyst ... 

Epoxides such as ethylene oxide and higher olefin oxides may be produced by the catalytic oxidation of olefins in gas-liquid-particle operations of the slurry type (S7). The finely divided catalyst (for example, silver oxide on silica gel carrier) is suspended in a chemically inactive liquid, such as dibutyl-phthalate. The liquid functions as a heat sink and a heat-transfer medium, as in the three-phase Fischer-Tropsch processes. It is claimed that the process, because of the superior heat-transfer properties of the slurry reactor, may be operated at high olefin concentrations in the gaseous process stream without loss with respect to yield and selectivity, and that propylene oxide and higher... 

The catalytic oxidation of ethylene to ethylene epoxide (also known... 

Table 14. Catalytic activity and selectivity of the 12g x 80g Au/ X40S preparations and 2g x 500g Au/XC72R (a) and 2g preparations (b) in the ethylene glycol oxidation.

Chromium zeolites are recognised to possess, at least at the laboratory scale, notable catalytic properties like in ethylene polymerization, oxidation of hydrocarbons, cracking of cumene, disproportionation of n-heptane, and thermolysis of H20 [ 1 ]. Several factors may have an effect on the catalytic activity of the chromium catalysts, such as the oxidation state, the structure (amorphous or crystalline, mono/di-chromate or polychromates, oxides, etc.) and the interaction of the chromium species with the support which depends essentially on the catalysts preparation method. They are ruled principally by several parameters such as the metal loading, the support characteristics, and the nature of the post-treatment (calcination, reduction, etc.). The nature of metal precursor is a parameter which can affect the predominance of chromium species in zeolite. In the case of solid-state exchange, the exchange process initially takes place at the solid- solid interface between the precursor salt and zeolite grains, and the success of the exchange depends on the type of interactions developed [2]. The aim of this work is to study the effect of the chromium precursor on the physicochemical properties of chromium loaded ZSM-5 catalysts and their catalytic performance in ethylene ammoxidation to acetonitrile. 

Ethylene oxide, used for the production of ethylene glycol and PEO, is obtained by the catalytic oxidation of ethylene. Ethylene glycol, used in the production of PET, is produced by the hydrolysis of ethylene oxide. 

Vinyl acetate was produced by the catalytic acetylation of acetylene, but this monomer is now produced by the catalytic oxidative condensation of acetic acid and ethylene (structure 17.32). Other vinyl esters can be produced by the transesterification of vinyl acetate with higher boiling carboxylic acids. 

Acrylic acid can be prepared by the catalytic oxidative carbonylation of ethylene or by heating formaldehyde and acetic acid in the presence of KOH. 

It may be mentioned briefly that also for other catalytic oxidations, e.g., for those of ethylene and of anthracene, multicomponent catalysts proved to be very effective. For the anthracene oxidation, the following... 

Tetralone has been prepared by a variety of methods, but the only practical procedures are relatively recent ones involving reduction of /9-naphthyl methyl ether with sodium and alcohol2 or with sodium and liquid ammonia,3 high-pressure catalytic hydrogenation of /9-naphthol,4 or catalytic oxidation of 2-tetralol by hydrogen transfer with ethylene.6... 

Conversion of alkenes to epoxides The simplest epoxide, ethylene dioxide, is prepared by catalytic oxidation of ethylene, and alkenes are also oxidized to other epoxides by peracid or peroxy acid (see Section 5.7.2). 

Alkenes undergo a number of oxidation reactions in which the C=C is oxidized. The simplest epoxide, ethylene oxide, is prepared hy catalytic oxidation of ethylene with Ag at high temperatures (250 °C). 

More recently, direct catalytic oxidative condensation of methane to ethane (with metal oxides),57,82-84 as well as to ethylene and acetylene (via high-temperature chlorinative conversion) was explored.76 In all these processes, however, a significant portion of methane is lost by further oxidation and soot formation. The selectivity in obtaining ethane and ethylene (or acetylene), respectively, the first C2 products, is low. There has, however, been much progress in metal-oxide-catalyzed oxidative condensation to ethane. 

Alkylation. Friedel-Crafts alkylation (qv) of benzene with ethylene or propylene to produce ethylbenzene [100-41 -4], CgH10, or isopropylbenzene [98-82-8], C9H12 (cumene) is readily accomplished in the liquid or vapor phase with various catalysts such as BF3 (22), aluminum chloride, or supported polyphosphoric acid. The oldest method of alkylation employs the liquid-phase reaction of benzene with anhydrous aluminum chloride and ethylene (23). Ethylbenzene is produced commercially almost entirely for styrene manufacture. Cumene [98-82-8] is catalytically oxidized to cumene hydroperoxide, which is used to manufacture phenol and acetone. Benzene is also alkylated with C1Q—C20 linear alkenes to produce linear alkyl aromatics. Sulfonation of these compounds produces linear alkane sulfonates (LAS) which are used as biodegradable deteigents. 

In a separate investigation MargeHs and Roginekii1107 carried nut catalytic oxidation of ethylene at 350° over vanadium pentoxidc. reportedly similar to metallic silver in catalytic properties. TVv asoertainod that carbon dioxide was formed faster from, ethylene oxide, or from acetaldehyde under comparable conditions, than from ethylene itself. Further, they noted the formation of carbon monoxide, and determined that its rate of formation was considerably greater than that of carbon dioxide, increasing still more in the presence of adtk-d ethylene oxide. The addition of ethylene oxide also appeared to depro both ethylene oxide and acetaldehyde formation. They concluded that reactions leading to carbon dioxide and water did not proceed by wav of ethylene oxide, but by way of some other intermediates, and tlmt-this process could occur either on the catalyst surface or in the gas phase. 

The existing literature contains airpriungly few references dealing with controlled oxidation of ethylene oxides. Mention has been nuulr (see section UL1.C.) of the catalytic oxidation of ethylene oxide to carbon dioxide and water at high temperatures. This section will hi-devoted to the relatively few known publications describing niililrr oxidative reactions. 

A method of considerable industrial importance for the large-scale preparation of ethylene oxide is direct oxidation of ethylene at elevated temperatures over a suitably prepared metallic silver catalyst. Although the reaction may be written aa indicated in Eq. (09), in actual practice only about half the ethylene is converted into ethylene oxide, the remainder being oxidized further to carbon dioxide and water. In spite of this seeming disadvantage, catalytic oxidation appears at present to bo economically competitive with chlorohydrin formation aa a means for the commercial production of ethylene oxide.MM Unfortunately, other olefins, such as propylene and mo-butylene for example, apparently give only carbon dioxide and water under the usual oxidation conditions,1310 so that until now the patent hu balance ethylene oxide has been the only representative accessible by tins route. 

Traditionally, ethanol has been made from ethylene by sulfation followed by hydrolysis of the ethyl sulfate so produced. This type of process has the disadvantages of severe corrosion problems, the requirement for sulfuric acid reconcentration, and loss of yield caused by ethyl ether formation. Recently a successful direct catalytic hydration of ethylene has been accomplished on a commercial scale. This process, developed by Veba-Chemie in Germany, uses a fixed bed catalytic reaction system. Although direct hydration plants have been operated by Shell Chemical and Texas Eastman, Veba claims technical and economic superiority because of new catalyst developments. Because of its economic superiority, it is now replacing the sulfuric acid based process and has been licensed to British Petroleum in the United Kingdom, Publicker Industries in the United States, and others. By including ethanol dehydrogenation facilities, Veba claims that acetaldehyde can be produced indirectly from ethylene by this combined process at costs competitive with the catalytic oxidation of ethylene. 

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