Phthalic anhydride applications

The commercial possibilities for epoxy resins were first recognized by DeTrey Fmres in Switzerland and DeVoe and Raynolds in the United States (1,2). In 1936, DeTrey Fmres produced a low melting bisphenol A-based epoxy resin that gave a thermoset composition with phthalic anhydride. Application of the hardened composition was foreseen in dental products, but initial attempts to market the resin were unsuccessful. The patents were licensed to CIBA AG of Basel, Switzerland (now CIBA-GEIGY), and in 1946 the first epoxy adhesive was shown at the Swiss Industries Fair and samples of casting resin were offered to the electrical industry. 

The properties of the polymers may be modified by mixing abphatic acids or anhydrides with the phthalic anhydride. Many alkyd resins find application in the paint industry. 

Fluidized bed reactors were first employed on a large scale for the catalytic cracking of petroleum fractions, but in recent years they have been employed for an increasingly large variety of reactions, both catalytic and non-catalytic. The catalytic reactions include the partial oxidation of naphthalene to phthalic anhydride and the formation of acrylonitrile from propylene, ammonia, and air. The noncatalytic applications include the roasting of ores and Tie fluorination of uranium oxide. 

Phthalic anhydride is a significant commercial product. Its main area of application is in synthetic resins and plasticizers. The production capacity worldwide was about 3.62 million t in 1997. 

The ability to incorporate a large amount of the bulky and highly aliphatic DCPD moiety into a UPR polymer achieved two things. First, because DCPD is even less expensive than phthalic anhydride, a very cost-effective UPR is created. Secondly, the bulkiness of the DCPD moiety prevents the polymers stacking-up too closely, and consequently, reduces the shrinkage during curing. These two factors make such resins ideal for uses such as boat construction and tub and shower applications. 

Fluidised catalysts are also used in the synthesis of high-grade fuels from mixtures of carbon monoxide and hydrogen, obtained either by coal carbonisation or by partial oxidation of methane. An important application in the chemical industry is the oxidation of naphthalene to phthalic anhydride, as discussed by Riley(131). The kinetics of this reaction are much slower than those of catalytic cracking, and considerable difficulties have been experienced in correctly designing the system. 

In the primary application of phthalic acid, life is rather transitory. Almost all phthalic acid is used to make phthalic anhydride. When orthoxylene is used as the starting base chemical, phthalic acid is formed but immediately dehydrates (loses a molecule of water) to form phthalic anhydride, as shown in Figure 18-3. 

Applications. Phthalic anhydride is used largely to make plasticizer for polyvinyl chloride. It is also a feed for alkyd resins and. for unsaturated polyesters that are widely used in construction, rharine, and synthetic marble applications. Other minor applications are dyes, esters, drying oil modifiers and pharmaceutical intermediates. 

The dimensional stability of low density, water blown rigid PU foams for pour-in-place thermal insulation applications was improved by the use of a phthalic anhydride based polyester polyol containing a dispersed cell opening agent. The foam systems obtained allowed some of the carbon dioxide to be released through the cell windows immediately after filling of the cavity, and to be rapidly replaced by air. Studies were made of the flowability, density, open cell content, dimensional stability, mechanical properties, thermal conductivity and adhesion (particularly to flame treated PE) of these foams. These properties were examined in comparison with those of HCFC-141b blown foams. 21 refs. 

Crosslinking of epoxy plastics through the hydroxyl groups of the repeat unit is used for prepolymers with low epoxide group contents. The most common curing agent is phthalic anhydride although other acid anhydrides such as tetrahydrophthalic, nadic methyl, and chloroendic anhydrides are used in specialty applications ... 

Commodities are large-volume, low-price, homogeneous, and standardized chemicals produced in dedicated plants and used for a large variety of applications. Prices are cyclic and fully transparent. Petrochemicals, basic chemicals, heavy organic and inorganic chemicals (large-volume) monomers, commodity fibers, and plastics are all part of commodities. Typical examples of single products are ethylene, propylene, caprolactame, methanol, BTX (benzene, toluene, xylenes), phthalic anhydride, poly (vinyl chloride) soda, and sulfuric acid. 

Polyesters [2] find use in fibers [poly(ethylene terephthalate), poly(ethylene oxybenzoate), poly(ester ethers), poly(ester amides), etc.] [1], coatings (especially unsaturated polyesters) [4], plasticizers, adhesives, polyurethane base resins, films, etc. Cross-linked polyesters prepared from glycerol and phthalic anhydride (alkyd resins) have been reviewed [20], High-melting poly aryl esters have been investigated for high-temperature applications. 

Another sulfur dioxide application in oil refining is as a selective extraction solvent in the Edeleanu process (323), wherein aromatic components are extracted from a kerosene stream by sulfur dioxide, leaving a purified stream of saturated aliphatic hydrocarbons which are relatively insoluble in sulfur dioxide. Sulfur dioxide acts as a cocatalyst or catalyst modifier in certain processes for oxidation of 0-xylene or naphthalene to phthalic anhydride (324,325). 

The oxidation of aromatic hydrocarbons originating from coal is one of the first organic gas phase oxidation processes carried out on an industrial scale. The development of these processes was initiated by the discovery that the V2Os catalyst used for the oxidation of sulphur dioxide was also applicable to the partial oxidation of benzene to maleic anhydride and naphthalene to phthalic anhydride. Remarkably, V2Os-based catalysts are still used in these processes today as they appear superior to any other type of catalyst. 

Fractionation of polyesters, prepared from phthalic anhydride and ethylene glycol carbonate and initiated by sodium benzoate or by KC1 (Fig. 5) revealed a broad molecular weight distribution 42). This indicates a wide application of transfer reactions and participation of macromolecules in transfer reactions. 

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