Oxygen ethylbenzene

Ethylbenzene Hydroperoxide Process. Figure 4 shows the process flow sheet for production of propylene oxide and styrene via the use of ethylbenzene hydroperoxide (EBHP). Liquid-phase oxidation of ethylbenzene with air or oxygen occurs at 206—275 kPa (30—40 psia) and 140—150°C, and 2—2.5 h are required for a 10—15% conversion to the hydroperoxide. Recycle of an inert gas, such as nitrogen, is used to control reactor temperature. Impurities ia the ethylbenzene, such as water, are controlled to minimize decomposition of the hydroperoxide product and are sometimes added to enhance product formation. Selectivity to by-products include 8—10% acetophenone, 5—7% 1-phenylethanol, and <1% organic acids. EBHP is concentrated to 30—35% by distillation. The overhead ethylbenzene is recycled back to the oxidation reactor (170—172). 

Dehydrogenation, Ammoxidation, and Other Heterogeneous Catalysts. Cerium has minor uses in other commercial catalysts (41) where the element s role is probably related to Ce(III)/Ce(IV) chemistry. Styrene is made from ethylbenzene by an alkah-promoted iron oxide-based catalyst. The addition of a few percent of cerium oxide improves this catalyst s activity for styrene formation presumably because of a beneficial interaction between the Fe(II)/Fe(III) and Ce(III)/Ce(IV) redox couples. The ammoxidation of propjiene to produce acrylonitrile is carried out over catalyticaHy active complex molybdates. Cerium, a component of several patented compositions (42), functions as an oxygen and electron transfer through its redox couple. 

The second important process for propylene oxide is epoxidation with peroxides. Many hydroperoxides have been used as oxygen carriers for this reaction. Examples are t-butylhydroperoxide, ethylbenzene hydroperoxide, and peracetic acid. An important advantage of the process is that the coproducts from epoxidation have appreciable economic values. 

Ethylbenzene hydroperoxide is produced by the uncatalyzed reaction of ethylbenzene with oxygen ... 

Recently, Nam, Fukuzumi, and coworkers succeed in an iron-catalyzed oxidation of alkanes using Ce(IV) and water. Here, the generation of the reactive nonheme iron (IV) 0x0 complex is proposed, which subsequently oxidized the respective alkane (Scheme 16) [104]. With the corresponding iron(II) complex of the pentadentate ligand 31, it was possible to achieve oxidation of ethylbenzene to acetophenone (9 TON). 0 labeling studies indicated that water is the oxygen source. 

Chlorine-enhancement may offer a partial solution. The addition of the chlorinated olefin TCE, PCE, or TCP to air/contaminant mixtures has recently been demonstrated to increase quantum yields substantially [1, 2, 6]. We recently have extended this achievement [3], to demonstrate TCE-driven high quantmn efficiency conversions at a reference feed concentration of 50 mg contaminant/m air not only for toluene but also for other aromatics such as ethylbenzene and m-xylene, as well as the volatile oxygenates 2-butanone, acetaldehyde, butsraldehyde, 1-butanol, methyl acrylate, methyl-ter-butyl-ether (MTBE), 1,4 dioxane, and an alkane, hexane. Not 1 prospective contaminants respond positively to TCE addition a conventional, mutual competitive inhibition was observed for acetone, methanol, methylene chloride, chloroform, and 1,1,1 trichloroethane, and the benzene rate was altogether unaffected. 

The United States Environmental Protection Agency (U.S. EPA) has identified several hundred MTBE-contaminated sites that have performed treatment of soil and groundwater to remove or destroy MTBE.1 Many of these sites have also treated other fuel components, primarily benzene, toluene, ethylbenzene, and xylene (BTEX), and some have treated fuel oxygenates other than MTBE. Although others have reported about treatment technologies for MTBE cleanup,2 only limited information has been published about cleanup of other oxygenates. These oxygenates include ether compounds, such as ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), diisopropyl ether (DIPE), and tert-amyl ethyl ether (TAEE), as well as alcohol compounds, such as tert-butyl alcohol (TBA), tert-amyl alcohol (TAA), ethanol, and methanol. 

In general, the mechanistic model established for the ODH of ethylbenzene can be adapted to alkanes (Fig. 15.11(d)). In situ XPS analyses of CNT catalysts during ODH of n-butane show sensitive response of the band located at 531.2 eV, which is assigned to carbonyl oxygen [63]. If oxygen is removed from the atmosphere, the intensity of... 

One method (EPA 8020) that is suitable for volatile aromatic compounds is often referred to as benzene-toluene-ethylbenzene-xylene analysis, although the method includes other volatile aromatics. The method is similar to most volatile organic gas chromatographic methods. Sample preparation and introduction is typically by purge-and-trap analysis (EPA 5030). Some oxygenates, such as methyl-f-butyl ether (MTBE), are also detected by a photoionization detector, as well as olefins, branched alkanes, and cycloalkanes. 

In the late nineteenth century and up to World War II coal was the major starting material for the organic chemical industry. When coal is heated in the absence of oxygen, coke and volatile by-products called coal tars are created. All sorts of organic chemicals can be isolated from coal tar - benzene, toluene, xylenes, ethylbenzene, naphthalene, creosotes, and many others (including Hofmann and Perkin s aniline). The organic chemical industry also draws upon other natural products, such as animal fats and vegetable oils, and wood by-products. 

This indirect oxidation route takes two steps. In the first, a hydrocarbon, such as iso butane or ethylbenzene, is oxidized. The source of the oxygen is air. The reaction takes place just by mixing the ingredients and heating them to 250-300°F at 50 psi, producing a hydroperoxide. In the second step, the oxidized hydrocarbon reacts with propylene in a liquid phase and in the presence of a metal catalyst at 175-225°F and 550 psi to produce PO yields of better than 90%. The process flow is shown in Figure 11—3. 

The catalyst consists of basic and acid sites in a microporous structure provided by zeolite and microporous materials [58-62]. Basic sites are provided by framework oxygen and/or occluded CsO. Acid sites are provided by the Cs cation and, possibly, additives such as boric and phosphoric acids. The addition of Cu and Ag increased the activity [63, 64]. Incorporation of li, Ce, Cr and Ag also has been shown to increase the styrene to ethylbenzene product ratio [65]. The reactivity of catalysts is sensitive to the presence of occluded CsO, which is in turn influenced by the preparative technique as shown by Lacroix and co-authors [64] and pointed out by Lercher [61]. 

This iron-sulfur oxygenase [EC 1.14.12.11] catalyzes the reaction of molecular oxygen with toluene and NADH to produce (15 ,27 )-3-methylcyclohexa-3,5-diene-l,2-diol and NAD. This reductase is an iron-sulfur flavo-protein (FAD) that contains ferredoxin. Ethylbenzene, 4-xylene, and some halogenated toluenes can likewise undergo conversion to the corresponding cw-dihydro-diols. 

Since approximately 2.2 lb of /-butyl alcohol would be produced per 1 lb of propylene oxide, an alternative reactant in this method is ethylbenzene hydroperoxide. This eventually forms phenylmethylcarbinol along with the propylene oxide. The alcohol is dehydrated to styrene. This chemistry was covered in Chapter 9, Section 6 as one of the syntheses of styrene. Thus the side product can be varied depending on the demand for substances such as /-butyl alcohol or styrene. Research is being done on a direct oxidation of propylene with oxygen, analogous to that used in the manufacture of ethylene oxide from ethylene and oxygen (Chapter 9, Section 7). But the proper catalyst and conditions have not yet been found. The methyl group is very sensitive to oxidation conditions. 

Aliphatic side chains of aromatics, such as cumene [65] and ethylbenzene [66] are oxidized to the corresponding alcohols and ketones by oxygen on FePcY and CoPcY respectively (Scheme 4). Propylene is oxidized on CoPcX to small amounts of carbon dioxide and acetone and higher amounts of formaldehyde and acetaldehyde [79]. 

The first variant works with isobutane as the hydroperoxide precursor, which is oxidized to TBHP by molecular oxygen. During the epoxidation of propene, TBHP is transformed to ferf-butanol, which is converted to methyl ferf-butyl ether. The second procedure employs ethylbenzene, which is oxidized by molecular oxygen to phenyl ethyl hydroperoxide, which transfers an oxygen to propene and so is reduced to phenylethanol. This by-product of the process is converted to styrene, a versatile bulk chemical. 

The technology is applicable to chlorinated and nonchlorinated VOCs methyl tertiary butyl ether (MTBE) dichloroethylene (DCE), trichloroethylene (TCE), and tetrachloroethylene (per-chloroethylene, PCE) dichloroethane (DCA) vinyl chloride alcohols ethers ketones and halogenated and nonhalogenated paraffinic, olefinic, aliphatic, and aromatic hydrocarbons. It is very effective at treating benzene, toluene, ethylbenzene, and xylene (BTEX) compounds and any oxygenate, such as acetone or isopropanol. 

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