Ethylbenzene commercial production

Hydrogen peroxide is commercially produced by autooxidation of ethyl anthraquinol in a solvent such as toluene or ethylbenzene. The product ethyl anthraquinone is reduced by hydrogen over supported nickel or platinum catalyst to regenerate hack the starting material, ethyl anthraquinol for a continuous production of H2O2. The reaction steps are ... 

Alkylation of benzene for the production of ethylbenzene, the raw material for making styrene and subsequently synthetic rubber, was also greatly expanded during the war because of the shortage of natural rubber. The catalyst in most of the original ethylbenzene units was aluminum chloride, but other catalysts are now preferred by many refiners. Alkylation for the production of ethylbenzene was the first large-scale alkylation process used for the production of petrochemicals. Since that time, others, such as cumene, dodecylbenzene, alkylated phenols, diisopropylbenzene, and secondary butylbenzene, have been added to the list, and others have been developed and should soon be in commercial production. 

MCM-22 is a commercial catalyst with a production history of over seven years, and operation history of over five years. Catalyst performance in these applications has been outstanding. In MCM-22 s first ethylbenzene commercial application at Denka s Chiba Styrene Monomer Company Ltd., a cycle length of over three years has been demonstrated without any significant aging of the catalyst or change in yields. Like ZSM-5, MCM-22 is regenerable, and is environmentally inert. 

Two variants of the Oxirane process are used (Figure 1) for the commercial production of propene oxide (PO) [29]. They differ in the hydrocarbon (isobutane or ethylbenzene (EB)) that is the precursor of the hydroperoxide, and, hence, in the alcohol co-product. ARCO operates both processes using a homogeneous molybdenum catalyst. Shell, in contrast, operates only the EB variant and uses a heterogeneous Ti /Si02 catalyst. 

Propylene oxide (PO) is a versatile chemical intermediate used in a wide range of industrial and commercial products. Current world production is over 6 million metric torts a year. While several processes exist, the Shell Chemicals companies have derived a strong competitive advantage by using and continually developing their proprietary styrene monomer propylene oxide (SMPO) technology, a process in which propylene and ethylbenzene (EB) are converted into PO and styrene monomer (SM), respectively. Worldwide, there are now five world-scale SMPO plants based on Shell technology, the most recent one started up in 2006 in China. 

We have developed an effective method for the selective autoxidation of alky-laromatic hydrocarbons to the corresponding benzylic hydroperoxides using 0.5 mol% NHPI as a catalyst and the hydroperoxide product as an initiator. Using this method we obtained high selectivities to the corresponding hydroperoxides, at commercially viable conversions, in the autoxidation of cyclohexylbenzene, cumene and ethylbenzene. The highly selective autoxidation of cyclohexylbenzene to the 1-hydroperoxide product provides the basis for a coproduct-free route to phenol and the observed inq)rovements in ethylbenzene hydroperoxide production provide a basis for in roving the selectivity of the SMPO process for styrene and propene oxide manufacture. 

The commercial production of styrene nowadays is carried out almost exclusively by catalytic dehydrogenation of ethylbenzene. Toray has developed a process for recovery from pyrolysis gasoline, which contains 3 to 5% styrene. The method involves hydrogenation of the aliphatic diene components of a close-cut pyrolysis gasoline (130 to 140 °C) followed by extractive distillation with dimethyl-acetamide. 

Indirect oxidation of propylene is an important route for propylene oxide production that proceeds in two reaction steps. The first step is the formation of a peroxide from alkanes, aldehydes, or adds by oxidation with air or oxygen. The second reaction step is the epoxidation of propylene to PO by oxygen transfer from the peroxide with formation of water, alcohol, or acid. The catalytic oxidation of propylene with organic hydroperoxides is nowadays a successful commercial production route (51% of world capacity). Two organic hydroperoxides dominate the processes (i) a process using isobutane (peroxide tert-butyl hydroperoxide, co-product tert-butyl alcohol), which accounts for 15% of the world capacity and (ii) a process using ethylbenzene (peroxide ethylbenzene hydroperoxide, co-product styrene) that accounts for 33% of the world capacity. The process via isobutane is presented by ... 

Ethylbenzene Separation. Ethylbenzene [100-41-4] which is primarily used in the production of styrene, is difficult to separate from mixed Cg aromatics by fractionation. A column of about 350 trays operated at a refluxTeed ratio of 20 is required. No commercial adsorptive unit to accomplish this separation has yet been installed, but the operation has been performed successhiUy in pilot plants (see Table 5). About 99% of the ethylbenzene in the feed was recovered at a purity of 99.7%. This operation, the UOP Ebex process, requires about 40% of the energy that is required by fractional distillation. 

Commercially, autoxidation is used in the production of a-cumyl hydroperoxide, tert-huty hydroperoxide, -diisopropylbenzene monohydroperoxide, -diisopropylbenzene dihydroperoxide, -menthane hydroperoxide, pinane hydroperoxide, and ethylbenzene hydroperoxide. 

The second new zeoHte-basedhquid-phase process was developed by Chemical Research licensing Company (CR L). The process is based on the concept of catalytic distillation, ie, reaction and separation in the same vessel. The concept has been appHed commercially for the production of MTBE (48—51) but has not yet been appHed commercially for the production of ethylbenzene. 

AlCl and Hydrogen Chloride Catalyst. Historically, AIQ processes have been used more extensively for the production of ethylbenzene than for the production of cumene. In 1976, Monsanto developed an improved cumene process that uses an AIQ. catalyst, and by the mid-1980s, the technology had been successfully commercialized. The overall yields of cumene for this process can be as high as 99 wt % based on benzene and 98 wt % based on propylene (60). 

Catalysts. Nearly aU. of the industrially significant aromatic alkylation processes of the past have been carried out in the Hquid phase with unsupported acid catalysts. For example, AlCl HF have been used commercially for at least one of the benzene alkylation processes to produce ethylbenzene (104), cumene (105), and detergent alkylates (80). Exceptions to this historical trend have been the use of a supported boron trifluoride for the production of ethylbenzene and of a soHd phosphoric acid (SPA) catalyst for the production of cumene (59,106). 

Two catalysts have emerged as commercially viable. The Mobil—Badger ethylbenzene process, which has been in commercial use since 1980, employs a ZeoHte catalyst and operates in the gas phase. A Hquid-phase ethylbenzene process joindy Hcensed by Lummus and UOP uses a Y-type ZeoHte catalyst developed by Unocal. This Hquid-phase process was commercialized in 1990. The same Y-type ZeoHte catalyst used for the production of ethylbenzene is being offered for the production of cumene but has not yet been commercialized. 

Hydroperoxide Process. The hydroperoxide process to propylene oxide involves the basic steps of oxidation of an organic to its hydroperoxide, epoxidation of propylene with the hydroperoxide, purification of the propylene oxide, and conversion of the coproduct alcohol to a useful product for sale. Incorporated into the process are various purification, concentration, and recycle methods to maximize product yields and minimize operating expenses. Commercially, two processes are used. The coproducts are / fZ-butanol, which is converted to methyl tert-huty ether [1634-04-4] (MTBE), and 1-phenyl ethanol, converted to styrene [100-42-5]. The coproducts are produced in a weight ratio of 3—4 1 / fZ-butanol/propylene oxide and 2.4 1 styrene/propylene oxide, respectively. These processes use isobutane (see Hydrocarbons) and ethylbenzene (qv), respectively, to produce the hydroperoxide. Other processes have been proposed based on cyclohexane where aniline is the final coproduct, or on cumene (qv) where a-methyl styrene is the final coproduct. 

In recent years alkylations have been accompHshed with acidic zeoHte catalysts, most nobably ZSM-5. A ZSM-5 ethylbenzene process was commercialized joiatiy by Mobil Co. and Badger America ia 1976 (24). The vapor-phase reaction occurs at temperatures above 370°C over a fixed bed of catalyst at 1.4—2.8 MPa (200—400 psi) with high ethylene space velocities. A typical molar ethylene to benzene ratio is about 1—1.2. The conversion to ethylbenzene is quantitative. The principal advantages of zeoHte-based routes are easy recovery of products, elimination of corrosive or environmentally unacceptable by-products, high product yields and selectivities, and high process heat recovery (25,26). 

In 1869 Berthelot- reported the production of styrene by dehydrogenation of ethylbenzene. This method is the basis of present day commercial methods. Over the year many other methods were developed, such as the decarboxylation of acids, dehydration of alcohols, pyrolysis of acetylene, pyrolysis of hydrocarbons and the chlorination and dehydrogenation of ethylbenzene." ... 

There are several other examples of ZSM-5 being used commercially to reduce waste and give high product selectivity. One of these is the alkylation of benzene with ethene to produce ethylbenzene selectively. The pore size of ZSM-5 successfully minimizes dialkylation reactions whilst the ability to regenerate the catalyst avoids waste issues associated with older catalysts such as aluminium chloride. 

Among the wide variety of organic reactions in which zeolites have been employed as catalysts, may be emphasized the transformations of aromatic hydrocarbons of importance in petrochemistry, and in the synthesis of intermediates for pharmaceutical or fragrance products.5 In particular, Friede 1-Crafts acylation and alkylation over zeolites have been widely used for the synthesis of fine chemicals.6 Insights into the mechanism of aromatic acylation over zeolites have been disclosed.7 The production of ethylbenzene from benzene and ethylene, catalyzed by HZSM-5 zeolite and developed by the Mobil-Badger Company, was the first commercialized industrial process for aromatic alkylation over zeolites.8 Other typical examples of zeolite-mediated Friedel-Crafts reactions are the regioselective formation of p-xylene by alkylation of toluene with methanol over HZSM-5,9 or the regioselective p-acylation of toluene with acetic anhydride over HBEA zeolites.10 In both transformations, the p-isomers are obtained in nearly quantitative yield. 

In commercial xylene isomerization, it is desirable that the necessary ethylbenzene conversion is accompanied by a minimum conversion (transalkylation) of xylenes, since the latter constitutes a downgrading to less valuable products. The ability of ZSM-5 to convert ethylbenzene via transalkylation in high selectivity, as shown in Table II, leads to high ultimate p-xylene yields in a commercial process. With a simulated commercial feed containing 85% m- and o-xylene and 15% ethylbenzene, we have obtained the data shown in Table III. It is seen that for a given ethylbenzene conversion, the xylene loss... 

The ODH of ethylbenzene to styrene is a highly promising alternative to the industrial process of non-oxidative dehydrogenation (DH). The main advantages are lower reaction temperatures of only 300 500 °C and the absence of a thermodynamic equilibrium. Coke formation is effectively reduced by working in an oxidative atmosphere, thus the presence of excess steam, which is the most expensive factor in industrial styrene synthesis, can be avoided. However, this process is still not commercialized so far due to insufficient styrene yields on the cost of unwanted hydrocarbon combustion to CO and C02, as well as the formation of styrene oxide, which is difficult to remove from the raw product. 

The chemical uses for ethylene prior to World War II were limited, for the most part, to ethylene glycol and ethyl alcohol. After the war, the demand for styrene and polyethylene took off, stimulating ethylene production and olefin plant construction. Todays list of chemical applications for ethylene reads like the WTiat s What of petrochemicals polyethylene, ethylbenzene (a precursor to styrene), ethylene dichloride, vinyl chloride, ethylene oxide, ethylene glycol, ethyl alcohol, vinyl acetate, alpha olefins, and linear alcohols are some of the more commercial derivatives of ethylene. The consumer products derived from these chemicals are found everywhere, from soap to construction materials to plastic products to synthetic motor oils. 

The alpha-methyl styrene can be recovered as a product or catalytically treated with hydrogen and converted back to cumene for recycling. The acetophenone has some commercial use in pharmaceuticals and at one time was used to make ethylbenzene. A high purity phenol is sometimes made by a crystallization step, since phenol freezes at about 109°F. With alpha-methyl styrene recycled, the ultimate yield is about 97%. 

Ethylbenzene is a high volume petrochemical used as the feed stock for the production of styrene via dehydrogenation. Ethylbenzene is currently made by ethylene alkylation of benzene and can be purified to 99.9%. Ethylbenzene and styrene plants are usually built in a single location. There is very little merchant sale of ethylbenzene, and styrene production is about 30x10 t/year. For selective adsorption to be economically competitive on this scale, streams with sufficiently high concentration and volume of ethylbenzene would be required. Hence, although technology has been available for ethylbenzene extraction from mixed xylenes, potential commercial opportunities are limited to niche applications. 

No commercial process is offered at this time for side chain alkylation of toluene with methanol for styrene and ethylbenzene production. In the literature the reaction is typically carried out at toluene to methanol molar ratios from 1.0 7.5 to 5 1 from 350 to 450 °C at atmospheric pressures. In some cases inert gas is introduced to assist vaporizing the liquid feed. In other cases H2 is co-fed to improve activity, selectivity and stability. Exelus recently claimed 80% yields in their ExSyM process at full methanol conversion using a 9 4 toluene methanol feed ratio at 400-425 °C and latm (101 kPa) in a bench-scale operation. This performance appears to be... 

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