Monomer ethylbenzene

Benzene and para-xylene are the most sought after components from reformate and pygas, followed by ortho-xylene and meta-xylene. While there is petrochemical demand for toluene and ethylbenzene, the consumption of these carmot be discussed in the same way as the other four. Toluene is used in such a large quantity in gasoline blending that its demand as a petrochemical pales in comparison. Fthylbenzene from reformate and pygas is typically dealkylated to make benzene or isomerized to make xylenes. On-purpose production of petrochemical ethylbenzene (via ethylene alkylation of benzene) is primarily for use as an intermediate in the production of another petrochemical, styrene monomer. Ethylbenzene plants are typically built close coupled with styrene plants. 

ABB Lummus Global/UOP Styrene monomer Ethylbenzene Innovative oxidative reheat technology, 30%-50% expansion of existing SM units with minimal investment for new equipment 5 2001... 

ABB Lummus Global/UOP Styrene monomer Ethylbenzene Vapor-phase dehydrogenation of EB to styrene monomer, high-temperature, deep-vacuum design, 99.9% purity, 97% selectivity 51 1997... 

In Figure I we compare emission spectra for polystyrene in dilute solution and as a solid film, and for a model monomer, ethylbenzene, in dilute solution. Polystyrene in solution exhibits, in addition to a monomer-like emission, a broad excimer emission maximizing at emission spectrum is not unique to high molecular weight polymer. Indeed, 1,3-diphenylpropane exhibits (la,8) very similar total emission spectra. The excimer emission lifetime is (4) 12.5 ns in CH2CI2 at room temperature, while monomer-like emission decay and excimer emission rise times are reported (2) to be of the order of a nanosecond in cyclohexane solution. 

The monomer ethylbenzene is made from petroleum-derived benzene and ethylene. Free radical polymerization is usually carried out in the gas phase with an iron oxide or other metal oxide catalyst yielding PS resin ... 

To see how the different mapping schemes proposed in the literatures for PS were able to reproduce the atomistic structure, we plotted the intermolecular radial distribution functions (RDFs) between the centers of mass of PS monomers, ethylbenzene (EB) molecules, or both, obtained from the CG model proposed by... 

Ethylbenzene. This alkylben2ene is almost exclusively used as an intermediate for the manufacture of styrene monomer [100-42-5]. A small amount (<1%) is used as a solvent and as an intermediate in dye manufacture (1,39,40). The current ethylben2ene growth rate projections for 1990—1995 range from 3.0 to 3.5%/yr (39). 

Ethyltoluene is manufactured by aluminum chloride-cataly2ed alkylation similar to that used for ethylbenzene production. All three isomers are formed. A typical analysis of the reactor effluent is shown in Table 9. After the unconverted toluene and light by-products are removed, the mixture of ethyltoluene isomers and polyethyltoluenes is fractionated to recover the meta and para isomers (bp 161.3 and 162.0°C, respectively) as the overhead product, which typically contains 0.2% or less ortho isomer (bp 165.1°C). This isomer separation is difficult but essential because (9-ethyltoluene undergoes ring closure to form indan and indene in the subsequent dehydrogenation process. These compounds are even more difficult to remove from vinyltoluene, and their presence in the monomer results in inferior polymers. The o-ethyltoluene and polyethyltoluenes are recovered and recycled to the reactor for isomerization and transalkylation to produce more ethyltoluenes. Fina uses a zeoHte-catalyzed vapor-phase alkylation process to produce ethyltoluenes. 

The dehydrogenation of the mixture of m- and -ethyltoluenes is similar to that of ethylbenzene, but more dilution steam is required to prevent rapid coking on the catalyst. The recovery and purification of vinyltoluene monomer is considerably more difficult than for styrene owing to the high boiling point and high rate of thermal polymerization of the former and the complexity of the reactor effluent, which contains a large number of by-products. Pressures as low as 2.7 kPa (20 mm Hg) are used to keep distillation temperatures low even in the presence of polymerization inhibitor. The finished vinyltoluene monomer typically has an assay of 99.6%. 

Styrene. Commercial manufacture of this commodity monomer depends on ethylbenzene, which is converted by several means to a low purity styrene, subsequendy distilled to the pure form. A small percentage of styrene is made from the oxidative process, whereby ethylbenzene is oxidized to a hydroperoxide or alcohol and then dehydrated to styrene. A popular commercial route has been the alkylation of benzene to ethylbenzene, with ethylene, after which the cmde ethylbenzene is distilled to give high purity ethylbenzene. The ethylbenzene is direcdy dehydrogenated to styrene monomer in the vapor phase with steam and appropriate catalysts. Most styrene is manufactured by variations of this process. A variety of catalyst systems are used, based on ferric oxide with other components, including potassium salts, which improve the catalytic activity (10). 

Commercial polystyrenes are normally rather pure polymers. The amount of styrene, ethylbenzene, styrene dimers and trimers, and other hydrocarbons is minimized by effective devolatilization or by the use of chemical initiators (33). Polystyrenes with low overall volatiles content have relatively high heat-deformation temperatures. The very low content of monomer and other solvents, eg, ethylbenzene, in PS is desirable in the packaging of food. The negligible level of extraction of organic materials from PS is of cmcial importance in this appHcation. 

DATA BOUNDARY Ethylene plant pumps ethylbenzene - styrene monomer plant... 

Data from an existing collection system were analyzed for failure modes and distribution. The results of Pareto analyses indicate the principal causes of failure. A few values of mean times to maintenance action (MTBM) are given for ethylene plant pumps (85 electric driven centrifugal pumps over a 19-month period), and ethylbenzene-styrene monomer plant equipment from 10 months data 4 gas compressors, 3 screw conveyors, 121 pumps, and 235 other items... 

Uses Ethylbenzene is used primarily to make styrene. Styrene is used to make polystyrene, a low-cost and versatile polymer. It is also copolymerized with other vinyl monomers to make rubber (SBR) and moldable plastics (ABS). 

The incrrase of surface area and pore volume enhanced the production of ethylbenzene by promoting further hydrogenation of the degraded styrene fragments. High degradation temperature favored the selectivity to styrene monomer. 

EBMax A continuous, liquid-phase process for making ethylbenzene from ethylene and benzene, using a zeolite catalyst. Developed by Raytheon Engineers and Constructors and Mobil Oil Corporation and first installed at Chiba Styrene Monomer in Japan in 1995. Generally similar to the Mobil/Badger process, but the improved catalyst permits the reactor size to be reduced by two thirds. 

Consider a fixed-bed catalytic reactor (FBCR), with axial flow, for the dehydrogenation of ethylbenzene (A) to styrene (S) (monomer). From the information given below, calculate the temperature (TIK) in the first-stage bed of the reactor,... 

Uses Manufacture of ethylbenzene (preparation of styrene monomer), dodecylbenzene (for detergents), cyclohexane (for nylon), nitrobenzene, aniline, maleic anhydride, biphenyl, benzene hexachloride, benzene sulfonic acid, phenol, dichlorobenzenes, insecticides, pesticides, fumigants, explosives, aviation fuel, flavors, perfume, medicine, dyes, and many other organic chemicals paints, coatings, plastics and resins food processing photographic chemicals nylon intermediates paint removers rubber cement antiknock gasoline solvent for fats, waxes, resins, inks, oils, paints, plastics, and rubber. 

There are nine chemicals in the top 50 that are manufactured from benzene. These are listed in Table 11.1. Two of these, ethylbenzene and styrene, have already been discussed in Chapter 9, Sections 5 and 6, since they are also derivatives of ethylene. Three others—cumene, acetone, and bisphenol A— were covered in Chapter 10, Sections 3-5, when propylene derivatives were studied. Although the three carbons of acetone do not formally come from benzene, its primary manufacturing method is from cumene, which is made by reaction of benzene and propylene. These compounds need not be discussed further at this point. That leaves phenol, cyclohexane, adipic acid, and nitrobenzene. Figure 11.1 summarizes the synthesis of important chemicals made from benzene. Caprolactam is the monomer for nylon 6 and is included because of it importance. 

FIGURE 6.3 Molecular weight of polystyrene (PS) as a function of solvent and solvent concentration A = -butylmercaptan, B = carbon tetrabromide, C = carbon tetrachloride, D = o-cresol, E = p-cresol, F = m-cresol, G = phenol, H = s-ec-butylbenzene, 1 = cumene, J = ethylbenzene, K = chloroform, L = -heptant, M = toluene, N = benzene, where [S] = concentration of chain-transfer agent and [M] = concentration of styrene monomer. 

By-products formed during their preparation (e.g., ethylbenzene and divinyl-benzenes in styrene acetaldehyde in vinyl acetate) added stabilizers (inhibitors) autoxidation and decomposition products of the monomers (e.g., perox-... 

Ethylbenzene is almost exclusively (> 99%) used as an intermediate for the manufacture of styrene monomer. Styrene production, which uses ethylbenzene as a starting material, consumes approximately 50% of the world s benzene production. Less than 1% of the ethylbenzene produced is used as a paint solvent or as an intermediate for the production of diethylbenzene and acetophenone. The ethy lbenzene present in recovered mixed xylenes is largely converted to xylenes or benzene (Coty et al., 1987 Caimella, 1998). 

EB/SM (ethylbenzene/styrene monomer) process. Styrene can also be made by PO/SM (propylene oxide/styrene monomer) process). This process starts by oxidizing ethylbenzene (C6H5CH2CH2) to its hydroperoxide (C6H5CH(OOH)CH3), which is then used to oxidize propylene (CH3CH = CH2) to produce propylene oxide (CH3CH2CHO) and phenylethanol (C6H5CH(OH)CH3). The phenylethanol is then dehydrated to give... 

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