Phthalic acid industrial source

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. 

ORIGIN/INDUSTRY SOURCES/USES manufacture of phthalic and anthranilic acids, naphthols, sulfonic acid, synthetic resins, celluloid, lampblack, smokeless powder, hydronaphthalenes salicylic acid indigo medication synthetic tanning chemicals surfactants insecticide wood preservative... 

The Cg alkylaromatics fraction is formed by ethylbenzene and the three xylene isomers. Ethylbenzene is used as a raw material to produce styrene by dehydrogenation, or oxidative dehydrogenation. Para-xylene and ortho-xylene are catalytically oxidized to give terephthalic and phthalic acid. The meta-xylene isomer can also be oxidized to give isophthalic acid. The major industrial source of these products is the catalytic reforming of naphthas. The Cyclar process, can also produce xylenes from propane and butane. However, using this process, xylenes are formed less selectively than toluene or benzene in the BTX. 

Until the mid-1950s the main raw material source for the European plastics industry was coal. On destructive distillation coal yields four products coal tar, coke, coal gas and ammonia. Coal tar was an important source of aromatic chemicals such as benzene, toluene, phenol, naphthalene and related products. From these materials other chemicals such as adipic acid, hexamethylenedia-mine, caprolactam and phthalic anhydride could be produced, leading to such important plastics as the phenolic resins, polystyrene and the nylons. 

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