Oxidation Liquid phase process

Methyl ethyl ketone MEK (2-butanone) is a colorless liquid similar to acetone, but its boiling point is higher (79.5°C). The production of MEK from n-butenes is a liquid-phase oxidation process similar to that used to... 

The TS-1 catalysed hydroxylation of phenol to a 1 1 mixture of catechol and hydroquinone (Fig. 2.16) was commercialized by Enichem (Romano et ai, 1990). This process offers definite advantages, such as higher selectivities at higher phenol conversions, compared to other catalytic systems. It also illustrates another interesting development the use of solid, recyclable catalysts for liquid phase (oxidation) processes to minimize waste production even further. 

Research on liquid-phase oxidation processes has opened up a tremendous area for research on free radical mechanisms. Such research will be concerned, not with hypothetical particles like those studied a few years ago, but with thoroughly material active centers, amenable to investigation by experimental techniques currently in use. Problems of foremost importance are involved in correlating data on unit processes... 

The four remaining papers all deal with the catalysis of liquid-phase oxidation processes by transition metal ions (6). A. T. Betts and N. Uri show in particular how metal complexes can either catalyze or inhibit oxidation according to their concentration. In this investigation, various hydrocarbons (especially 2,6,10,14-tetramethylpentadecane) were used as substrates, and metal ions were present either as salicylaldimine or di-isopropylsalicylate chelates. These compounds are considerably soluble in non-polar media, and this makes it possible to examine their effect over a much wider range of concentration than is usually accessible in this type of work. These studies show that catalyst-inhibitor conversion is always... 

Heterolytic liquid-phase oxidation processes are more recent than homolytic ones. The two major applications are the Wacker process for oxidation of ethylene to acetaldehyde by air, catalyzed by PdCl2-CuCl2 systems,98 and the Arco oxirane" or Shell process100 for epoxidation of propylene by f-butyl or ethylbenzene hydroperoxide catalyzed by molybdenum or titanium complexes. These heterolytic reactions require less drastic conditions than the homolytic ones... 

Some of the Group VIII metals have uses as oxidation catalysts (5). All except platinum do however tend to oxidize under vigorous conditions, such as are used in ammonia oxidation and the Andrussow process, for which only platinum and its alloys are acceptable catalysts. Under milder conditions both platinum and palladium have somewhat limited applications in liquid-phase oxidation processes, as for example in the carbohydrate field. 

The AMOCO Chemical Corp. developed from the late 1950s until the middle of the 1960s, a liquid-phase oxidation process [3f, 4], performed at 190-205 °C and 1.5-3 MPa, to obtain in one step fiber-grade terephthalic acid (99.99 %) reaching... 

It is to be noted that in vapor phase processes such as those described by James the acids produced are aldehydic in nature and may depend upon this aldehydic character for utilization in the form of condensed products such as low grade resins, etc. Attempts to recover these acids in the form of sodium soaps usually leads to the formation of resins due to the resinify-ing action of the caustic. On the other hand, the numerous claims for the liquid phase oxidation process usually mention the formation of simple carboxylic acids or hydroxy-carboxylic acids which may be used to form edible fats by esterification with glycerol. This seems to indicate the somewhat milder oxidation possible in the liquid phase process. 

Polymer-zeolite composite membranes are also studied in rectors, either as interphase contactors in liquid phase oxidation processes [65] or for improving the properties of Nafion in fuel cells applications [66],... 

Catalytic properties of complexes of multi-valenced metals with poly(ethylene glycol) (PEG) and polyurethane (PU) have been studied during liquid-phase oxidation processes such as the liquid-phase oxidation of hydrocarbons (phenanthrene, tetralin, cyclohexene), decomposition of hydroperoxides, hydrocarbons and decomposition of hydrogen peroxide [101 -106]. The kinetics of these reactions have been studied. The rate and selectivity of a particular reaction process depend not only on the properties... 

Alexander JM. (1990) Gas phase ignition in liquid phase oxidation processes a recipe for disaster. Trans Inst. Chem. Eng. (UK), B68 17-23. 

Wang L, Cheng Y, Wang Q, Li X. (2007) Progress in the research and development of p-xylene liquid phase oxidation process. Frontiers Chem Eng China, l(3) 317-326. 

The benefits of SCF reaction engineering are supposed to be highest for liquid-phase oxidation processes with mass transfer limitations for molecular oxygen. The reported results show some inconsistency with regard to a possible improvement by setting the SCF conditions. 

A series of multiphase reactions after SO2 is taken into fog and rain droplets followed by liquid phase oxidation processes by O3 and H2O2 are described in Chap. 7, Sect. 7.6.2. 

Here, the uptake of SO2 to clouds and fog droplet, liquid phase oxidation processes to sulfuric acid, and the acidification of water droplets are considered. As seen in Chap. 2, Sect. 2.4.1, multiphase reaction processes of atmospheric molecules consist of (1) transport and diffusion of gaseous molecules to the gas-liquid surface, (2) uptake of gaseous molecules to liquid phase, (3) diffusion in the bulk liquid, and (4) chemical reactions in the bulk liquid phase (Schwartz and Freiberg 1981). 

Liquid Phase Oxidation Processes for Hydrogen Sulfide Removal 733... 

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