2- phenanthrene,

5 Phenanthrene. Studies in the sulfonation of phenanthrene 52 indicated a positional order of reactivity of 3 2 9 1 This is different from the theoretical order of 9 1 4 3 2, because of steric hindrance which accounts for the complete absence of the 4-isomer. Reaction of phenanthrene 52 with chlorosulfonic acid (one equivalent) in boiling chloroform affords the 2- and 3-sulfonic acids 53 and 54 (Equation 16) (85% yield of the mixture of isomers was isolated as the lead sulfonates).  

Next to anthracene, the higher condensed aromatics which are of commercial importance are phenanthrene, fluorene, fluoranthene and pyrene. Worldwide production of these polynuclear aromatics is around 2,000 tpa. 

Phenanthrene is present in coal tar at a concentration of about 5% it was discovered by Rudolph Fittig and Eugen Ostermayer in 1872. 

In nature, phenanthrene compounds occur in alkaloids, such as morphine. 

As a feedstock for the production of phenanthrene, the filtrate from pure anthracene production is particularly suitable (see Chapter 11.1), containing around 65% phenanthrene with an anthracene content below 10%. Distillation produces 90% pure phenanthrene the major contaminants, in terms of quantity. 

Anthracene can be separated from the other polycyclics by adduct formation (Diels-Alder reaction) with maleic anhydride. 

The third hydrocarbon consisting of condensed benzene nuclei similar to naphthalene and anthracene is known as phenanthrene. It has the composition C14H10 and is thus isomeric with anthracene. It is found associated with the latter in the coal tar distillate boiling above 270° and is separated by solution in carbon disulphide (p. 793). It is a solid crystallizing in colorless flakes, m.p. 99°, b.p. 340°. It is only slightly soluble in water, a little more soluble in alcohol and soluble in ether. 

Synthesis from Stilbene and Di-tolyl.— Two similar syntheses indicate the constitution of phenanthrene. When stilbene, (p. 762), 

CeHs—CH = CH—CeHs is heated it loses two hydrogens andphenan-threne results. Also ortho-di-tolyl, CH3—C6H4—C6H4—CH3, when heated loses four hydrogens and yields phenanthrene. These reactions yielding the same product must necessarily be represented as follows  

Expressing a compound of this constitution by means of benzene rings we have  

Such a formula represents a compound consisting of three condensed benzene nuclei. More conclusive proof of the constitution is afforded by other syntheses and by the decomposition of the hydrocarbon. 

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Compounds containing olefine links may be oxidised to 1,2-diketones, as in C4H CH CHC Hs -> C HjCO-COC H. Anthracene is readily oxidised to anthraquinone, but phenanthrene is almost unaffected. 

Benzene, toluene, anthracene, phenanthrene, biphenyl. Aromatic hydrocarbons with unsaturated side-chains. Styrene, stilbene. 

Naphthalene, CioHs, colourless solid, m.p. 80°, insoluble in water, soluble in alcohol, characteristic odour. Anthracene, CjH4 C2H2 CjH4, m.p. 216°, white crystals when pure, with a faint blue fluorescence, but often very pale yellow crystals insoluble in water, slightly soluble in alcohol. Phenanthrene, m.p. 98°, and biphenyl, m.p. 69°, are white solids. 

The purpose of this eornpuLer project is Lo examine several polynuclear aromatic hydrocarbons and to relate their electron density patterns to their carcinogenic activity. If nucleophilic binding to DN.A is a significant step in blocking the normal transcription process of DN.A, electron density in the hydrocarbon should be positively correlated to its carcinogenic potency. To begin with, we shall rely on clinical evidence that benzene, naphthalene, and phenanthrene... 

Diphenic acid. Phenanthrene upon oxidation in acetic acid solution at 85° with 30 per cent, hydrogen peroxide gives diphenic acid (diphenyl-2 2 -di-carboxyHc acid) no phenanthraquinone is formed under these experimental conditions. The reaction is essentially an oxidation of phenanthrene with peracetic acid. (For another method of preparation, see Section I V,74.)... 

Chapter IV. a-Chloromethylnaphthalene (IV,23) benzylamine (Gabriel synthesis) (IV,39) i r.N -dialkylanilines (from amines and trialkyl orthophosphates) (IV,42) a-naphthaldehyde (Sommelet reaction) (IV,120) a-phenyl-cinnamic acid (Perkin reaction using triethylamine) (IV,124) p-nitrostyrene (IV,129) p-bromonaphthalene and p naphthoic acid (from 2 naphthylamine-1 -sulphonic acid) (IV,62 and IV,164) diphenic acid (from phenanthrene) (IV,165). 

It is interesting to note that recent evidence shows that even extra-terrestrially formed hydrocarbons can reach the Earth. The Earth continues to receive some 40,000 tons of interplanetary dust every year. Mass-spectrometric analysis has revealed the presence of hydrocarbons attached to these dust particles, including polycyclic aromatics such as phenanthrene, chrysene, pyrene, benzopyrene, and pentacene of extraterrestrial origin indicated by anomalous isotopic ratios. 

Notice that anthracene cannot be represented by any single Lewis structure m which all three rings correspond to Kekule formulations of benzene but phenanthrene can... 

Naphtho- (naphthalene) Perylo- (perylene) Phenanthro- (phenanthrene)... 

Troost and Olavesen investigated the application of an internal standardization to the quantitative analysis of polynuclear aromatic hydrocarbons. The following results were obtained for the analysis of the analyte phenanthrene using isotopically labeled phenanthrene as an internal standard... 

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