Phthalic Anhydride from o-Xylene

Uses A little over half of the phthalic anhydride produced is used 

Aristech Chemical, ExxonMobil, Koppers, Stepan, Sterling Chemical. 

Plasticizers are very high-boiling liquids that when mixed with polymers like poly(vinyl chloride) modify the properties of the polymer to produce a material with added flexibility without losing other desirable properties such as strength. They are commonly made by reacting phthahc anhydride with a long-chain alcohol (typically eight carbons). 

There are over 400 different commercial alkyd resin formulations based on phthalic anhydride used in the coatings business. Alkyd resins for paints are made by reacting phthalic anhydride with a poly-alcohol (usually from naturally occurring sources rather than synthetic) that contains unreacted double bonds. The paint dries by the resin crosslinking through reaction of the double bonds under the influence of oxygen in the air. 

Both terephthalic acid (TPA) and dimethyl terephthalate (DMT) are used exclusively for the manufacture of polyesters for textile fibers (e.g,. Dacron ), films, soft-drink bottles, and engineering resins for automotive applications. The glycol used for most TPA-based polyesters is ethylene glycol. The polyester is then known as polyethylene terephthalate, or PET. 

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Detailed modelling of the fixed bed production of phthalic anhydride from o-xylene is discussed by Froment and Bischoff (1990), involving both axial and radial temperature profile effects. 

The selective oxidation of hydrocarbons with dioxygen is of immense industrial importance [ 1 ]. A general problem in this area is to obtain high selectivi-ties, particularly at high substrate conversions. The reasons for this are twofold oxidation can occur at different C-H bonds in a molecule, leading to a low primary selectivity, and the initially formed product is often more reactive than the substrate and is oxidized further, ultimately to carbon dioxide and water, leading to low secondary selectivities. Hence examples of industrial processes tend to involve the oxidation of hydrocarbons in which one particular C-H bond is significantly more reactive, for example, cumene hydroperoxide from cumene, and/or the product is relatively stable towards further oxidation, for example, maleic anhydride from n-butane, phthalic anhydride from o-xylene... 

Phthalic anhydride from o-xylene V205/Ti02... 

Xylene. Egloff states 24) that the annual production of phthalic anhydride from o-xylene is now 8,000,000 pounds, augmenting the inadequate supply from naphthalene. 

Propylene Ammonoxidntion Phthalic Anhydride from o-xylene... 

Desulfurization of petroleum feedstock (FBR), catalytic cracking (MBR or FI BR), hydrodewaxing (FBR), steam reforming of methane or naphtha (FBR), water-gas shift (CO conversion) reaction (FBR-A), ammonia synthesis (FBR-A), methanol from synthesis gas (FBR), oxidation of sulfur dioxide (FBR-A), isomerization of xylenes (FBR-A), catalytic reforming of naphtha (FBR-A), reduction of nitrobenzene to aniline (FBR), butadiene from n-butanes (FBR-A), ethylbenzene by alkylation of benzene (FBR), dehydrogenation of ethylbenzene to styrene (FBR), methyl ethyl ketone from sec-butyl alcohol (by dehydrogenation) (FBR), formaldehyde from methanol (FBR), disproportionation of toluene (FBR-A), dehydration of ethanol (FBR-A), dimethylaniline from aniline and methanol (FBR), vinyl chloride from acetone (FBR), vinyl acetate from acetylene and acetic acid (FBR), phosgene from carbon monoxide (FBR), dichloroethane by oxichlorination of ethylene (FBR), oxidation of ethylene to ethylene oxide (FBR), oxidation of benzene to maleic anhydride (FBR), oxidation of toluene to benzaldehyde (FBR), phthalic anhydride from o-xylene (FBR), furane from butadiene (FBR), acrylonitrile by ammoxidation of propylene (FI BR)... 

Various data of an economic type, concerning the production of phthalic anhydride from o-xylene and naphthalene, are given in Table 13.7. 

The method for producing maleic anhydride by the oxidation of benzene is largely analogous to processes for producing phthalic anhydride from o-xylene (see Chapter 7.1.1 and Figure 5.39). 

This design example is suggested from hydrocarbon oxidation processes such as benzene oxidation into maleic anhydride or the synthesis of phthalic anhydride from o-xylene. These strongly exothermic processes are carried out in multitubular reactors cooled by molten salt that is circulating around the tubes and that exchanges heat to an internal or external boiler. The length of the tubes is 3 m and their internal diameter is 2.54 cm. One reactor may contain 2500 tubes in parallel and even 10,000 or more in the latest versions. In German processes the... 

You have recendy joined the TBWS Chemical Corporatiom One of TBWS s major businesses has always been production of phthalic anhydride from naphthalene. Phthalic anhydride production is integrated as part of a large chemical plant, in which naphthalene is produced and in which phthalic anhydride is immediately used to make polyester resins. In recent years, there have been some problems. Some end users have complained about the quality of the resins produced and have taken their business to other companies that produce phthalic anhydride from o-xylene. Therefore, our plant, which had been designed to produce 100,000 metric tons/year of phthalic anhydride from naphthalene, was scaled back to about 80,000 metric tons/year several years ago. We are now forced to scale down production once again due to the loss of another large customer. Marketing informs us that we may lose additional customers. 

An optimized preliminary design of a plant to make phthalic anhydride from o-xylene using the... 

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