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Pressure oxidation of hydrocarbons

In considering the pressure oxidation of hydrocarbons with oxygen to form alcohols and aldehydes, it will be well to review some of the phenomena connected with the non-catalytic combustion of hydrocarbons under pressure, since the literature regarding the oxidation to form oxygenated products is very meagev. J... [Pg.175]

In general, the oxidized product from the pressure oxidation of hydrocarbons from ethane up to butane or higher in molecular weight may be expected to consist of a mixture of oxygenated organic compounds comprising alcohols, aldehydes, ketones, acids, esters, etc., together with water... [Pg.201]

Fig. 60.—Layout of equipment proposed for the pressure oxidation of hydrocarbons. Fig. 60.—Layout of equipment proposed for the pressure oxidation of hydrocarbons.
Oxidation of Hydrocarbons. Ethanol is one of a variety of oxygen-containing compounds produced by the oxidation of hydrocarbons. Ethanol is reported to be obtained in a yield of 51% by the slow combustion of ethane (158,159). When propane is oxidi2ed at 350°C under a pressure of 17.2 MPa (170 atm) (160,161), 8% of the oxygen is converted to ethanol. Lower conversions to ethanol are obtained by oxidi2ing butane. Other oxidation systems used to produce ethanol and acetaldehyde (162—164) and methods for separating the products have been described in the patent Hterature. [Pg.407]

The chain mechanism is complicated when two hydrocarbons are oxidized simultaneously. Russell and Williamson [1,2] performed the first experiments on the co-oxidation of hydrocarbons with ethers. The theory of these reactions is close to that for the reaction of free radical copolymerization [3] and was developed by several researchers [4-9], When one hydrocarbon R H is oxidized in the liquid phase at a sufficiently high dioxygen pressure chain propagation is limited only by one reaction, namely, R OO + R H. For the co-oxidation of two hydrocarbons R1 and R2H, four propagation reactions are important, viz,... [Pg.214]

Phenols usually terminate two chains in the oxidation of hydrocarbons and solid polymers (see Chapter 15). The study of the/ value dependence on partial dioxygen pressure showed, however, that the stoichiometric coefficient of inhibition has a tendency to increase with decreasing the dioxygen pressure and, in an inert atmosphere, it is markedly higher than in dioxygen [83]. The results of/ value estimation (f—vi/vInH, phenol concentration was measured spectroscopically) are given in Table 19.13. [Pg.678]

Some reactions, especially oxidations of hydrocarbons, are characterized by regions of temperature and pressure in which mild explosions occur. These mild explosions are accompanied by cool flames, which manifest themselves by the appearance of luminescence and by sudden changes in temperature and pressure, during which there is an audible click from the reaction mixture. Figure 6.4 shows the increase in pressure found during a series of mild explosions. [Pg.252]

The formation of odd oxygen species under pressurized conditions is possible even in the wavelength region that is somewhat longer than the dissociation threshold at 242.4 nm this is important as the initial reaction in the laser-induced oxidation of hydrocarbons in the hydrocarbon/02/supercritical C02 mixtures at 248 nm [5],... [Pg.130]

Numerous papers have appeared discussing the oxidation of hydrocarbons. For example, the effects of pressure on product yields in the nitrogen oxide (NO ) photo-oxidations of aromatic hydrocarbons such as toluene and o-xylene have been described and a study has been reported of the mechanism of the photo-oxidation of /3,/3-dimethylstyrene. Photo-oxidation of cis-a,a -dimethylstilbene using [Ru(bipy)3] or tetraphenylporphine as sensitizer leads to the dioxetane (19), whereas with Rose Bengal or Methylene Blue the... [Pg.381]

Nucleation of new particles has been demonstrated in laboratory studies from the oxidation of hydrocarbons to form partly oxidized material of lower vapor pressure (e.g., Griffin et al., 1999 Koch et al., 2002). This process also occurs in the... [Pg.2038]

When the catalyst is immobilized within the pores of an inert membrane (Figure 25.13b), the catalytic and separation functions are engineered in a very compact fashion. In classical reactors, the reaction conversion is often limited by the diffusion of reactants into the pores of the catalyst or catalyst carrier pellets. If the catalyst is inside the pores of the membrane, the combination of the open pore path and transmembrane pressure provides easier access for the reactants to the catalyst. Two contactor configurations—forced-flow mode or opposing reactant mode—can be used with these catalytic membranes, which do not necessarily need to be permselective. It is estimated that a membrane catalyst could be 10 times more active than in the form of pellets, provided that the membrane thickness and porous texture, as well as the quantity and location of the catalyst in the membrane, are adapted to the kinetics of the reaction. For biphasic applications (gas/catalyst), the porous texture of the membrane must favor gas-wall (catalyst) interactions to ensure a maximum contact of the reactant with the catalyst surface. In the case of catalytic consecutive-parallel reaction systems, such as the selective oxidation of hydrocarbons, the gas-gas molecular interactions must be limited because they are nonselective and lead to a total oxidation of reactants and products. For these reasons, small-pore mesoporous or microporous... [Pg.460]

The present volume deals with the low-temperature oxidation of hydrocarbons but in this chapter it is necessary to consider a much wider range of combustion conditions and to draw upon information drawn from the chemistry of a broad range of compounds. The two main reasons for this are, first, the experimental methods used to obtain data required to simulate low-temperature oxidation often operate at temperatures and pressures well removed from those of the oxidation processes. Second, in trying to assess the quality of data for the relatively narrow range of low-temperature oxidation conditions, it is necessary to consider all of the experimental results available over the whole range of temperatures and pressures accessible. It also follows from these points that it is necessary to extrapolate and interpolate experimental results to conditions relating to low-temperature oxidation. Such techniques are an important aspect of evaluation and are also considered in this chapter. [Pg.236]

If there is little or no change in the number of moles of material as a result of reaction an average gas temperature may also be interpreted during the post-compression period from the instantaneous pressure by use of equation (6.18). Experiments are normally performed under relatively dilute conditions (—80% inert gas) and, in general, the number of moles of product and reactant are approximately equal during the slow oxidation of hydrocarbons. Equation (6.16) is the most satisfactory reference temperature for the compressed gas but it is not valid in all circumstances. The application of equations (6.16)-(6.18) was tested by Griffiths et al. [50]. [Pg.572]

The chain reaction sustains itself until it is terminated by direct combination of H and Cl, probably at the walls of the containing vessel. Such a reaction therefore tends to propagate itself without further encouragement until the reactants are exhausted. There are many examples of chain reactions in organic chemistry, where the active intermediate is often a free radical such as CH 3. Sometimes these are undesirable e.g. in the premature oxidation of hydrocarbons under pressure, which causes knocking in internal combustion engines) and it is necessary to inhibit them by suitable additives which operate by terminating the chains. [Pg.192]

When the temperature increases, the equilibrium shifts in the direction of higher dissociation pressure of the oxide and the surface becomes more and more populated with electrophilic oxygen species. When used as catalysts in oxidation of hydrocarbons, such oxides may show high selectivity to partial oxidation products at low temperatures, wherein the surface coverage with transient electrophilic oxygen forms is low. Under such conditions the conversion is very low. On raising the temperature the selectivity to partial oxidation products rapidly decreases, whereas the conversion in total oxidation increases, becoming the predominant reaction... [Pg.4]

In the atmospheric pressure synthesis of hydrocarbons from hydrogen and carbon monoxide. Elvins32 showed experimentally that reduced un-suoported catalysts of cobalt, copper, or manganese prepared by ignition of the nitrates gave much greater conversions than the reduced precipitated oxides. [Pg.24]

Blyumberg, E. R., Z. K. Maizus, and N. M. Emanuel. 1965. The liquid-phase oxidation of n-butane at temperatures and pressures near to the critical. In The oxidation of hydrocarbons in the liquid phase, ed. N. M. Emanuel. New York Macmillan. [Pg.520]


See other pages where Pressure oxidation of hydrocarbons is mentioned: [Pg.180]    [Pg.467]    [Pg.467]    [Pg.180]    [Pg.467]    [Pg.467]    [Pg.422]    [Pg.424]    [Pg.63]    [Pg.222]    [Pg.75]    [Pg.223]    [Pg.59]    [Pg.1592]    [Pg.385]    [Pg.205]    [Pg.147]    [Pg.499]    [Pg.316]    [Pg.1022]    [Pg.250]    [Pg.206]    [Pg.385]    [Pg.679]    [Pg.144]    [Pg.154]    [Pg.156]    [Pg.175]    [Pg.200]    [Pg.250]    [Pg.308]    [Pg.351]    [Pg.10]    [Pg.87]   
See also in sourсe #XX -- [ Pg.175 , Pg.200 ]




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