Phthalic acid from naphthalene

From a few primaries actually present among the numerous constituents of coal-tar—notably benzene, toluene, phenol, naphthalene, and anthracene—were prepared, as time went on, several hundred intermediates, such as aniline from benzene, bcnzaldehyde from toluene, and phthalic acid from naphthalene. These led in... 

Examples Enanthol from castor oil phthalic acid from naphthalene. 

Phthalic acid from naphthalene. Naphthalene can be oxidized to phthalic... 

Fumaric acid may be prepared by heating maleic acid, with or without catalysts. It is also obtained as by-product in the manufacture of phthalic anhydride from naphthalene. The acid is a solid melting at 284°C. Fumaric acid is sometimes preferred to maleic anhydride as it is less corrosive, it tends to give lighter coloured products and the resins have slightly greater heat resistance. 

Synthesis from Phthalic Acid and Naphthalene.— This was found when anthranilic acid was synthesized from ortho-phthalic acid which, as has been stated, may in turn be synthesized from naphthalene, a cheap abundant compound. The conversion of naphthalene into or//fo-phthalic acid we have given (p. 689) as resulting from chlorination and subsequent oxidation. 

Polycarboxylic acid anhydrides by oxidation of aromatic compounds, e.g.—phthalic anhydride from naphthalene or o-xylene and also maleic anhydride from benzene... 

The production of benzoic acid from naphthalene, practised up to the end of World War II, is possible in one stage, without the isolation of the intermediate phthalic acid. Oxidation of naphthalene is carried out at 340 °C with zinc oxide. This decarboxylates the phthalic acid in the gas-phase however, conversion in this reaction is not complete, and the benzoic add must be separated from the phthalic acid. Separation is possible by dissolving the phthalic acid in water. 

Theoretical approaches to catalysis in the 1920s drew some criticism from those working at the laboratory bench. One such critic was Charles R. Downs, who had developed vapor-phase oxidation processes for making maleic acid from benzene and phthalic anhydride from naphthalene for Barrett Chemical Co. (20) ... 

During the manufacture of phthalic anhydride from naphthalene and 6>-xylene, small amounts of MA, citraconic anhydrides, and benzoic acid are coproduced.MA comprises 6% of the product.In some cases, after removal of phthalic anhydride by condensation, the exhaust gases are scrubbed with water. In many cases, the aqueous solution of maleic acid is recovered in the form of fumaric acid. Koppers in the United States recovers 10 MM lb of MA from the phthalic plant. ... 

Yourfacility receives toluene and naphthalene (both listed toxic chemicals) from an off-site location. You react the toluene with air to form benzoic acid and react the naphthalene with sulfuric acid, which forms phthalic acid and also produces sulfur dioxide fumes. Your facility processes toluene and naphthalene. Both are used as reactants to produce benzoic acid and phthalic acid, chemicals not on the section 313 list. 

Besides the technical method starting from naphthalene, phthalic acid and its substituted derivatives can be prepared by oxidation of o-xylene to phthalic acid with potassium permanganate. This compound can be subsequently transformed via an anhydride, imide, and amide to a derivative of phthalonitrile, which is the more convenient starting material for several coordination compounds. The synthesis of the ferf-butyl-substituted dicarbonitrile, which is a very common starting material for highly soluble phthalocyanines, is shown below.97,105... 

Dinitro-o-phthalic Acid. Prisms from eth. mp 225—6°. Very sol in w, ale. eth insol in llgr, C disulfide and benz. Can be prepd by the oxidation of 5,7-dinitro-l,2,3,4-tetrahydro-naphthalene with 30% boiling nitric acid or by other methods given in the Refs. The barium salt, Cg H2 (N02)2 04. Ba is expl... 

Anthraquinone itself is traditionally available from the anthracene of coal tar by oxidation, often with chromic acid or nitric acid a more modern alternative method is that of air oxidation using vanadium(V) oxide as catalyst. Anthraquinone is also produced in the reaction of benzene with benzene-1,2-dicarboxylic anhydride (6.4 phthalic anhydride) using a Lewis acid catalyst, typically aluminium chloride. This Friedel-Crafts acylation gives o-benzoylbenzoic acid (6.5) which undergoes cyclodehydration when heated in concentrated sulphuric acid (Scheme 6.2). Phthalic anhydride is readily available from naphthalene or from 1,2-dimethylbenzene (o-xylene) by catalytic air oxidation. 

Until 1959, all the phthalic anhydride was made from coal tar naphthalene, the double-benzene ring compound also shown in Figure 18—3 was easily oxidized directly to phthalic acid. But with phthalic anhydride being only a small share of coal oil, and with the demand for phthalic anhydride escalating rapidly, coal tar became an inadequate source. The frantic search for an alternative route led to the development of the recovery process for ortho-xylene from refinery aromatics streams discussed in Chapter 3 and the... 

Phthalic acid (1,2-benzene dicarboxylic acid), isophthalic acid (1,3-benzene dicarboxylic acid), and terephthalic acid (1,4-benzene dicarboxylic acid) are made by the selective oxidation of the corresponding xylenes. Terephthalic acid may also be produced from the oxidation of naphthalene and by the hydrolysis of terephthalonitrile. 

TEMPERATURE TRANSFER STANDARD. A device for the transfer of a temperature scale from one standardizing laboratory to another. One form consists of a sample of a purified material, the freezing point of which (when realized by a prescribed technique) is reproducible within narrow limits. Materials commonly employed are metals, such as zinc and tin, and organic compounds, such as benzoic acid, phenol, naphthalene, and phthalic anhydride. Another form is a tungsten ribbon-filament lamp, characterized by a stable lamp current-brightness temperature relation. This device is particularly useful for temperatures above 1.050WC. 

Heterogeneous oxidative processes operate at high temperatures (250-450 6C) and are useful for the synthesis of acrolein and acrylic acid from propylene over bismuth molybdate catalysts, the synthesis of maleic and phthalic anhydrides from the oxidation of benzene (or C4 compounds) and naphthalene (or o-xylene) respectively over vanadium oxide,101 arid the synthesis of ethylene oxide from ethylene over silver catalysts.102... 

As an oxidant, mercury may be used in the presence of sulphuric acid. One of the most important examples of this is the oxidation of naphthalene to phthalic acid, nsed on the large scale in the first stage of the process for preparing indigo from tin hydrocarbon. 

Naphthalene, also known as tar camphor, and its alkyl derivatives, such as l-(2-propyl)naph-thalene (Figure 13.10), are important industrial chemicals. Used to make mothballs, naphthalene is a volatile white crystalline solid with a characteristic odor. Coal tar and petroleum are the major sources of naphthalene. Numerous industrial chemical derivatives are manufactured from it. The most important of these is phthalic anhydride (Figure 13.10), used to make phthalic acid plasticizers, which are discussed in Chapter 14. 

Literature references on the ozonation of A07 indicate that the molecule in such an oxidative degradation is cleaved at the point where the azo bond is attached to the naphthalene moiety giving rise to the intermediate, 1,2 naphthoquinone (NQ) [260,261]. This intermediate is oxidized subsequently to a phthalic acid derivative. The spectrum of the photolyzed A07 was found to be similar, especially in the area of 1400 to 1800 cm-1, to the spectra of the photolyzed naphthoquinone samples. It is reasonable to conclude therefore that naphthoquinone is an intermediate from the photosensitized degradation of A07 on Ti02. The naphthoquinone then undergoes further degradation to form a phthalic acid derivative. The end product of oxidation of A07 is an aromatic carboxylic acid as characterized from the peak at 1700 cm-1. 

The details of this synthesis will be explained under naphthalene (p. 766). The synthesis of anthranilic acid from ortho-i hthalic acid takes place according to the following reactions. Phthalic acid, or better phthalic anhydride, by treatment with ammonia yields phthal-amidic acid, which in turn yields phthalimide. 

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