Production of anthracene

While it is possible to recover the bicyclic naphthalene from pyrolysis products of coal and petroleum-derived raw materials, the tricyclic anthracene can be isolated only from high-temperature coal tar, since anthracene is present only in small amounts in other pyrolysis products and in the residues of catalytic hydrocarbon conversion. 

Synthetic production of anthracene has gained no industrial significance so far, since sufficient quantities are present in coal tar in theory, supplies of around 150,000 tpa of anthracene are available to meet a demand of some 20,000 tpa. 

The feedstock for anthracene production from coal tar is the anthracene fraction ( anthracene oil ), which boils between 300 and 400 °C and contains around 6% anthracene (Table 11.1). 

The first stage in the production of anthracene is the recovery of a 25 to 30% anthracene concentrate by crystallization, which can be carried out in two stages to increase the yield. The crystallizate, known as anthracene cake , is generally concentrated to around 50% by vacuum distillation. The main co-boiling compound of 50 s anthracene is phenanthrene while carbazole is reduced to below 2%. Subsequent refining to yield pure anthracene , containing over 95%, is normally achieved by recrystallization in polar solvents, such as acetophenone, mixtures of cyclohexanol/cyclohexanone or N-methylpyrrolidone in addition, distillation or azeotropic distillation with ethylene glycol can be used for purification. 

The quality of anthracene obtained by this method is sufficient for the manufacture of anthraquinone by the usual processes. Because of hydrogen transfer during coal tar refining, the fore-runnings which arise during the distillation of the anthracene cake are enriched with 9,10-dihydroanthracene, which can be converted into anthracene by oxidation with air. This anthracene, recoverable by subsequent crystallization, is distinguished by an exceptionally low nitrogen content. 

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Problmn 10.3 What is the Diels-Alder addition product of anthracene and ethene ... 

Product distribution data (Table V) obtained in the hydrocracking of coal, coal oil, anthracene and phenanthrene over a physically mixed NIS-H-zeolon catalyst indicated similarities and differences between the products of coal and coal oil on the one hand and anthracene and phenanthrene on the other hand. There were differences in the conversions which varied in the order coal> anthracene>phenanthrene coal oil. The yield of alkylbenzenes also varied in the order anthracene >phenanthrene>coal oil >coal under the conditions used. The alkylbenzenes and C -C hydrocarbon products from anthracene were similar to the products of phenanthrene. The most predominant component of alkylbenzenes was toluene and xylenes were produced in very small quantities. Methane was the most and butanes the least predominant components of the gaseous product. The products of coal and coal oil were also found to be similar. The most predominant components of alkylbenzenes and gaseous product were benzene and propane respectively. The data also indicated distinct differences between products of coal origin and pure aromatic hydrocarbons. The alkyl-benzene products of coal and coal oil contained more benzene and xylenes and less toluene, ethylbenzene and higher benzenes when compared to the products from anthracene and phenanthrene. The gaseous products of coal and coal oil contained more propane and butanes and less methane and ethane when compared to the products of anthracene and phenanthrene. The differences in the hydrocracked products were obviously due to the differences in the nature of reactants. Coal and coal oil contain hydroaromatic, naphthenic, heterocyclic and aliphatic structures, in addition to polynuclear aromatic structures. Hydrocracking under severe conditions yielded more BTX as shown in Table VI. The yields of BTX obtained from coal, coal oil, anthracene and phenanthrene were respectively 18.5, 25.5, 36.0, and 32.5 percent. Benzene was the most... 

On the other hand, plausible oxidation products of anthracene, acenaphthylene, fluorene, and benz [a] anthracene — anthracene-9,10-quinone, acenaphthene-9,10-dione, fluorene-9-one, and benz[a]anthracene-7,12-quinone — were found transiently in... 

The principles made use of in the design of the catalytic oxidation apiiaratns described for use in phthalic anhydride and maleic acid production may be applied to the design of apparatus for the oxidation to partial oxidation products of anthracene, toluene, and other organic compounds derived from coal-tar, petroleum, and miscellaneous sources. 

Kasparova, M. and Siatka, T. 2001. Effect of chitosan on the production of anthracene derivatives in tissue culture of Rheum pahnatum L. Ceska Slav Farm., 50 249-253. 

Figure 11.1 Flow diagram for production of anthracene from anthracene oil...

This synthesis, in common with the production of anthracene based on diphenyl-methane by Friedel-Crafts reaction and dehydrogenation, has had no industrial significance to date. 

World production of anthracene from coal tar is around 20,000 tpa. Rutgers-wrfe/West Germany, with around 8,000 tpa and Nippon Steel Chemical/Japan, with around 3,000 tpa are the major producers. 

FIGURE 7.23 The Diels-Alder product of anthracene-9-methanol and A-methylmaleknide. This compound possesses diastereotopic methylene protons, Hf and Hg. 

FIGURE 7.24 The 500 MHz NMR spectrum (CDCI3) of the Diels-Alder product of anthracene-9-methanol and A -methylmaleimide. The insets show expansions of the regions from 3.25 to 3.40 ppm and 4.7 to 5.2 ppm. The eight aromatic ring protons are not shown. Pavia, D. L., G. M. Lampman, G. S. Kiiz, R. 

Identification of Aromatic Hydrocarbons. Picric acid combines with many aromatic hydrocarbons, giving addition products of definite m.p. Thus with naphthalene it gives yellow naphthalene picrate, C oHg,(N08)jCeHiOH, m.p. 152°, and with anthracene it gives red anthracene picrate, C 4Hio,(NOj)jCeHjOH, m.p. 138 . For practical details, see p. 394. 

Make a concentrated solution of anthracene in hot acetone. To about 2 ml. of this solution add a cold concentrated acetone solution of picric acid drop by drop, and note the formation of a red coloration which becomes deeper on further addition of the acid. If excess of picric acid is added, however, the solution becomes paler in colour, and this is to be avoided if possible. Boil to ensure that both components are in solution and then transfer to a small porcelain basin or watch-glass ruby-red crystals of anthracene picrate separate out on cooling. The product, however, is often contaminated with an excess of either anthracene or of picric acid, which appear as yellowish crystals. 

The theory of sublimation, t.e. the direct conversion from the vapour to the sohd state without the intermediate formation of the liquid state, has been discussed in Section 1,19. The number of compounds which can be purified by sublimation under normal pressure is comparatively small (these include naphthalene, anthracene, benzoic acid, hexachloroethane, camphor, and the quinones). The process does, in general, yield products of high purity, but considerable loss of product may occur. 

Many valuable chemicals can be recovered from the volatile fractions produced in coke ovens. Eor many years coal tar was the primary source for chemicals such as naphthalene [91-20-3] anthracene [120-12-7] and other aromatic and heterocycHc hydrocarbons. The routes to production of important coal-tar derivatives are shown in Eigure 1. Much of the production of these chemicals, especially tar bases such as the pyridines and picolines, is based on synthesis from petroleum feedstocks. Nevertheless, a number of important materials continue to be derived from coal tar. 

In the dyestuff industry, anthraquinone still ranks high as an intermediate for the production of dyes and pigments having properties unattainable by any other class of dyes or pigments. Its cost is relatively high and will remain so because of the equipment and operations involved in its manufacture. As of May 1991, anthraquinone sold for 4.4/kg in ton quantities. In the United States and abroad, anthraquinone is manufactured by a few large chemical companies (62). At present, only two processes for its production come into consideration manufacture by the Friedel-Crafts reaction utilizing benzene, phthahc anhydride, and anhydrous aluminum chloride, and by the vapor-phase catalytic oxidation of anthracene the latter method is preferred. 

Timber-preservation creosotes are mainly blends of wash oil, strained anthracene oil, and heavy oil having minor amounts of oils boiling in the 200—250°C range. Coal-tar creosote is also a feedstock for carbon black manufacture (see Carbon, carbon black). Almost any blend of tar oils is suitable for this purpose, but the heavier oils are preferred. Other smaller markets for creosote were for fluxing coal tar, pitch, and bitumen in the manufacture of road binders and for the production of horticultural winter wash oils and disinfectant emulsions. 

The principal sources of feedstocks in the United States are the decant oils from petroleum refining operations. These are clarified heavy distillates from the catalytic cracking of gas oils. About 95% of U.S. feedstock use is decant oil. Another source of feedstock is ethylene process tars obtained as the heavy byproducts from the production of ethylene by steam cracking of alkanes, naphthas, and gas oils. There is a wide use of these feedstocks in European production. European and Asian operations also use significant quantities of coal tars, creosote oils, and anthracene oils, the distillates from the high temperature coking of coal. European feedstock sources are 50% decant oils and 50% ethylene tars and creosote oils. 

The synthetic procedure described is based on that reported earlier for the synthesis on a smaller scale of anthracene, benz[a]anthracene, chrysene, dibenz[a,c]anthracene, and phenanthrene in excellent yields from the corresponding quinones. Although reduction of quinones with HI and phosphorus was described in the older literature, relatively drastic conditions were employed and mixtures of polyhydrogenated derivatives were the principal products. The relatively milder experimental procedure employed herein appears generally applicable to the reduction of both ortho- and para-quinones directly to the fully aromatic polycyclic arenes. The method is apparently inapplicable to quinones having an olefinic bond, such as o-naphthoquinone, since an analogous reaction of the latter provides a product of undetermined structure (unpublished result). As shown previously, phenols and hydro-quinones, implicated as intermediates in the reduction of quinones by HI, can also be smoothly deoxygenated to fully aromatic polycyclic arenes under conditions similar to those described herein. 

Both phenanthrene and anthracene have a tendency to undergo addition reactions under the eonditions involved in eertain eleetrophilic substitutions. For example, in the nitration of anthracene in the presence of hydrochloric acid, an intermediate addition product can be isolated. This is a result of the relatively close balance in resonance stabilization to be regained by elimination (giving an anthracene ring) or addition (resulting in two benzenoid rings). 

The reaction of benzyl radicals wdth several heterocyclic compounds W as more extensively studied by Waters and Watson, " - who generated benzyl radicals by decomposing di-tert-butyl peroxide in boiling toluene. The products of the reaction with acridine, 5-phenyl-acridine, 1 2- and 3 4-benzacridine, and phenazine were studied. Acridine gives a mixture of 9-benzylacridine (17%) (28) and 5,10-dibenzylacridan (18%) (29) but ho biacridan, w hereas anthracene gives a mixture of 9,10-dibenzyl-9,10-dihydroanthracene and 9,9 -dibenzyl-9,9, 10,10 -tetrahydrobianthryl. This indicates that initial addition must occur at the meso-carbon and not at the nitrogen atom. (Similar conclusions were reached on the basis of methylations discussed in Section III,C.) That this is the position of attack is further supported by the fact that the reaction of benzyl radicals with 5-... 

Equimolar amounts of anthracene,/ -benzoquinone, and aluminum chloride give the faintly yellow adduct in 15 minutes. The product is unstable to heat turning yellow at 207°, turning red at 210°, and slowly charring. When 2 molar equivalents of anthracene are used, the bis adduct is obtained, mp 230°, unobtainable in the absence of the catalyst. 

For the acylation of naphthalene, the ionic liquid gives the highest reported selectivity for the 1-position [95]. The acetylation of anthracene at 0 °C was found to be a reversible reaction. The initial product of the reaction between acetyl chloride (1.1 equivalents) and anthracene is 9-acetylanthracene, formed in 70 % yield in less than 5 minutes. The 9-acetylanthracene was then found to undergo diacetylation reactions, giving the 1,5- and 1,8-diacetylanthracenes and anthracene after 24 hours (Scheme 5.1-64). 

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