Naphthalene industrial source

Sources of Raw Materials. Coal tar results from the pyrolysis of coal (qv) and is obtained chiefly as a by-product in the manufacture of coke for the steel industry (see Coal, carbonization). Products recovered from the fractional distillation of coal tar have been the traditional organic raw material for the dye industry. Among the most important are ben2ene (qv), toluene (qv), xylene naphthalene (qv), anthracene, acenaphthene, pyrene, pyridine (qv), carba2ole, phenol (qv), and cresol (see also Alkylphenols Anthraquinone Xylenes and ethylbenzenes). 

The petroleum industry is now the principal suppHer of ben2ene, toluene, the xylenes, and naphthalene (see BTX processing Feedstocks). Petroleum displaced coal tar as the primary source for these aromatic compounds after World War II because it was relatively cheap and abundantly available. However, the re-emergence of king coal is predicted for the twenty-first century, when oil suppHes are expected to dwindle and the cost of producing chemicals from coal (including new processes based on synthesis gas) will gradually become more competitive (3). 

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. 

Before the advent of the petrochemical industry carbocyclic aromatic compounds, such as naphthalene, phenol, and pyridine, provided the source of many important industrial chemicals including dyestuffs, while the monocyclic compounds continue to play an important role as fuels and starting materials. 

A number of years ago. coal tar was the primary, if not the sole, source lor hundreds of important organic chemicals and derivatives, notably the phenols, cresols, naphthalene, and anthracene, as well as other important coal lar end-prralucls, such as solvent naphtha and pitch. In recent years, synthetic processes Tor the production of phenol, the cresols and later the xylcnols. have been developed and thus, to a large extent, have pushed coal lar into the background as a source of feedstocks for (he chemical industry. 

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. 

Traditionally, the source of benzene and toluene has been coal. Coke is produced for use in the steel industry and a by-product of this process is coal tar which, when distilled, provides benzene, toluene, xylenes, phenol and cresols (methylphenols), and naphthalene, the most abundant single component. 

The Bureau of Mines is a source of many chemical statistics. The monthly Coke and Coal Chemicals report, part of the bureau s Mineral Industry Surveys, contains, in addition to data on oven and beehive coke production, figures on production of ammonium sulfate, ammonia liquor, naphthalene, benzene, toluene, xylene, solvent naphtha, pyridine, crude coal tar, and cresote oil. Sales and end-of-month stock figures are also shown in the report. A useful feature of the report is the year-end supplement which gives year s totals by months. 

Many of the organic contaminants which were found in Lippe river water were also present in the source samples (see Table 3). The sewage effluent sample and the Seseke river showed the best accordance with the compound spectrum of the Lippe river. However, also in the two tributaries from the rural upper reaches of the river, numerous specific contaminants like 9-methylacridine (No. 8), alkyl phosphates (Nos. 31, 32) and chlorinated alkyl phosphates (Nos. 34, 36) appeared. In the effluent of a pharmaceutical plant, only a few Lippe river contaminants like n-alkanes (No. 1), naphthalene (No. 3), TXIB (No. 21) and caffeine (No. 67) were detected (see Table 3). Therein, mainly structural relatives of androstanone like 3p-hydroxy-5p-androstan-17-one, 3a-hydroxy-5p-androstan-17-one and androstan-50-3,17-dione were present. These compounds are probably by-products of the synthesis of hormone preparations. Some polycyclic aromatic compounds, halogenated compounds and terpenoids were not detected in the source samples (see the underlined compounds in Table 3) and probably have another origin. Representative sampling of various input sources have to be carried out to prove the origin of these compounds. Hexachlorobutadiene (No. 38) and bis(chloropropyl)ethers (No. 44) appear exclusively at the lower reaches of the Lippe river (see Table 1), downstream the chemical plants in Marl. They are attributed to inputs of the chlorochemical industry (see section 3.1). Hence, this suggests their input by an industrial point source. 

Halogenated naphthalenes in Teltow Canal sediments are specific pollutants reflecting the industrial point source emission. Chlorinated naphthalenes are known environmental pollutants, which are emitted due to their usage as technical additives, as a result of pyrolytic processes or as an impurity associated with PCB products (Haglund et al. 1993 Jamberg et al. 1993). In the extractable fraction mono- and dichlorinated naphthalenes were determined with total concentrations between 120 and 493 pg/kg. The peak pattern was similar to the congener distribution of technical mixtures (Halowax 1000, Halowax 1001) (Falandysz 1998). The concentration of 1-bromonaphthalene ranged between the limit of quantification (LOQ) and 250 pg/kg (see Table 1). 

The concentrations of tetrabutyl tin range from 130 pg/kg TOC at sample site B to 14 pg/kg TOC at sample sites E and F and is below the LOQ at sample site D. The emission of this well known Elbe-specific compound was formerly linked to an industrial point source situated near the confluence of the Mulde and the Elbe rivers (Wilken et al., 1994, Schwarzbauer, 1997). Mono- and disubstituted chloronaphthalenes were also detected with concentrations between the LOQ at sample sites not influenced by Elbe derived contaminations and 70 and 100 pg/kg TOC at sample site B. These low chlorinated naphthalenes occur in the sediments with patterns similar to those of technical agents (e.g. Halowax 1000) and were formerly identified with comparable isomer distributions in sediments of the Elbe river and its tributaries (Schwarzbauer 1997, Schwarzbauer et al. 2001). On the contraiy the origin of the Elbe specific contaminant 4,4 -d ic h Iorodiphcnylsul tidc detected at sample sites A,B,C,E and F with concentrations ranging from 7 to 45 pg/kg TOC is still unknown. 

Naphthalene (NAF-thuh-leen) is a white crystalline volatile solid with a characteristic odor often associated with mothballs. The compound sublimes (turns from a solid to a gas) slowly at room temperature, producing a vapor that is highly combustible. Naphthalene was first extracted from coal tar in 1819 by English chemist and physician John Kidd (1775- l85i). Coal tar is a brown to black thick liquid formed when soft coal is burned in an insufficient amount of air. It consists of a complex mixture of hydrocarbons, similar to that found in petroleum. Kidd s extraction of naphthalene was of considerable historic significance because it demonstrated that coal had other important applications than its use as a fuel. It could also be utilized as the source of chemical compounds with a host of important commercial and industrial uses. Naphthalene s chemical structure was determined by the German chemist Richard August Carl Emil Erlenmeyer (1825-1909). Erlenmeyer showed that the naphthalene molecule consists of two benzene molecules joined to each other. 

Polynuclear aromatics are hydrocarbons containing more than one fused benzenoid ring. These substances primarily occur in coal, coal tar, heavy oil, diesel fnel and many petroleum products. They are also found in soils, sediments, solid wastes, many wastewaters, emission from indnstrial boilers and tobacco smoke at trace concentrations. In the PAH class, U.S. EPA has hsted 16 compounds as priority pollutants in potable water and wastewater and 22 componnds in soil and solid wastes. Except naphthalene most PAH compounds have little commercial applications. However, they may be generated from various sources or industrial operations the exposure to which may pose risk to human health. Many PAHs may cause cancers, affecting a variety of tissues. However, only benzo[a]pyrene is a potent human carcinogen, while naphthalene, benzo[a]anthracene. 

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