Phenanthrene

Structural formula
General
Surname	Phenanthrene
Molecular formula	C 14 H 10
Brief description	colorless tablets or leaves
External identifiers / databases
CAS number 85-01-8 EC number 201-581-5 ECHA InfoCard 100.001.437 PubChem 995 ChemSpider 970 DrugBank DB08381 Wikidata Q422037
properties
Molar mass	178.23 g mol −1
Physical state	firmly
density	1.18 g cm −3 (25 ° C)
Melting point	98.5 ° C
boiling point	340 ° C
Vapor pressure	12 m Pa (20 ° C)
solubility	almost insoluble in water (1.15 mg l −1 at 25 ° C) soluble in benzene , diethyl ether and glacial acetic acid
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 302-410 P: 262-272
Authorization procedure under REACH	of particular concern : very persistent and very bioaccumulative ( vPvB )
Toxicological data	1800 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Phenanthrene (composed of Phen yl and Anthr ac s ) is a colorless to pale yellow, crystalline solid. It is a polycyclic aromatic hydrocarbon , contains three fused benzene rings and belongs to the phene group . The aromatic character is somewhat more pronounced compared to the isomeric anthracene , which is shown by a higher delocalization energy of 387 kJ / mol compared to 351.5 kJ / mol for anthracene. Phenanthrene is found in the anthracene fraction in coal tar , from which it is essentially obtained. A derivative of phenanthrene, steran , is the basic structure for steroids . Phenanthrene is used for the synthesis of colorants .

Occurrence

Phenanthrene occurs naturally in the form of the very rare mineral ravatite .

synthesis

The synthesis of phenanthrene was first presented in 1932 by the English chemist Robert Downs Haworth (1898–1990) and is therefore also known as the Haworth synthesis.

The following synthesis steps are described in the literature:

In the first step naphthalene 1 by means of Friedel-Crafts acylation by succinic anhydride 2 acylated. The resulting keto acid 3 is then reduced by a Clemmensen reduction with zinc amalgam and hydrochloric acid , so that the naphthalene derivative 4 is formed. By adding sulfuric acid , water is then split off. Subsequent internal electron rearrangements, which lead to the splitting off of a proton, result in ketone 5 . Another Clemmensen reduction then follows, with the hydrocarbon 6 being formed. The dehydrogenation with selenium in the last step provides phenanthrene 7 .

properties

Mesomerism and aromaticity

Phenanthrene has a pronounced aromatic character due to its relatively large delocalized electron system . Consequently, five equivalent mesomeric boundary structures can be formulated:

Physical Properties

The colorless to yellowish crystals are odorless and fluoresce when dissolved in benzene . Highly pure phenanthrene melts at 98.5 ° C. The heat of fusion is 18.13 kJ / mol. At 72.8 ° C., a higher order phase transition is observed, with a polymorphic conversion from a low-temperature to a high-temperature crystal form taking place. The boiling point is 340 ° C. According to Antoine, the vapor pressure function results from log ₁₀ (P) = A− (B / (T + C)) (P in bar, T in K) with A = 4.51922, B = 2428.448 and C = −70.96 in the temperature range from 373 K to 423 K or with A = 4.68940, B = 2673.320 and C = −40.7 in the temperature range from 477 K to 620 K. Phenanthrene is almost insoluble in water (0.0011 g / l) It is readily soluble in carbon tetrachloride , ether , benzene, toluene and other non-polar organic solvents .

The flash point of the melt is 171 ° C. The ignition temperature is above 450 ° C.

Chemical properties

The chemical behavior is characterized by the special reactivity in the 9 and 10 positions. The bromination leads to 9,10-dibromo-9,10-dihydrophenanthrene. When this compound is heated, an aromatic system is formed again with elimination of HBr with 9-bromophenanthrene.

A reduction with lithium leads to 9,10-dihydrophenanthrene. The oxidation with chromium-VI-oxide gives 9,10-phenanthrenequinone . A nitration or sulphonation is also performed in the 9-position.

Commercially available phenanthrene contains anthracene impurities. A photochemical reaction of anthracene with N , N -dimethylaniline makes it possible to obtain highly pure (99.8%) phenanthrene. This reaction forms 9- (4-dimethylaminophenyl) -9,10-dihydroanthracene, which is removed by hydrochloric acid .

Hazards and Metabolism

Phenanthrene irritates the eyes and skin, it is hazardous to water ( WGK 3). In the body, phenanthrene is oxidized to naphthalene-1,2-diol .

Individual evidence

1. ↑ ^{a b c d e f g h i j k} Entry on phenanthrene in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
2. ↑ ^{a b c d} U. Gloistein, M. Epple, HK Cammenga: Influencing the Solid-Solid Phase Transition in Phenanthrene by Suitable Doping. In: Journal of Physical Chemistry . 214, Muenchen Germany 2000, pp. 379-388.
3. ↑ ^{a b} Phenanthrene data sheet (PDF) from Merck , accessed on September 5, 2016.
4. ↑ Entry on phenanthrene. In: Römpp Online . Georg Thieme Verlag, accessed on December 22, 2014.
5. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on January 21, 2019.
6. ↑ ^{a b c} Hauptmann , Graefe, Remane: Textbook of organic chemistry. 2nd edition, Deutscher Verlag der Grundstoffindustrie, Leipzig 1980, p. 268.
7. ↑ L. Nasdala, IV Pekov: Ravatite, C ₁₄ H ₁₀ , a new organic mineral species from Ravat, Tadzhikistan. In: European Journal of Mineralogy. 5, 1993, pp. 699-705; Abstract In: New Mineral Names. (PDF; 611 kB), In: American Mineralogist. 1994, 79, p. 389.
8. ^ RD Haworth: Syntheses of alkylphenanthrenes In: Journal of the Chemical Society (1932), p. 1125, doi: 10.1039 / JR9320001125 .
9. ↑ E. Broad Maier and G. Jung: Organic Chemistry , Georg Thieme, 2012, ISBN 9783135415079 , p 183rd
10. ^ Zerong Wang: Comprehensive Organic Name Reactions and Reagents , Wiley, 2010, ISBN 9780470638859 , pp. 1342-1343, doi: 10.1002 / 9780470638859 .
11. ^ J. Kroupa, J. Fousek, NR Ivanov, B. Brezina, V. Lhotska: In: Ferroelectrics. 79, 1988, p. 189.
12. ↑ AG Osborn, DR Douslin: Vapor Pressures and Derived Enthalpies of Vaporization for Some Condensed Ring Hydrocarbons. In: Journal of Chemical & Engineering Data . 20, 1975, pp. 229-231.
13. ^ FS Mortimer, RV Murphy: The Vapor Pressures of Some Substances Found in Coal Tar. In: Journal of Industrial and Engineering Chemistry . 15, 1923, pp. 1140-1142.
14. ↑ CG Screttas, GI Ioannou, M. Micha-Screttas: in: Journal of Organometallic Chemistry . 511, 1996, pp. 217-226.
15. ↑ J. Schmidt: In: Chemical reports . 44, 1911, pp. 1491, 1498.
16. ↑ Sandqvist: Justus Liebigs Annalen der Chemie . 392, 1912, p. 77.
17. ↑ Dieter Wöhrle, Michael W. Tausch, Wolf-Dieter Stohrer: Photochemistry: Concepts, Methods, Experiments. John Wiley & Sons, 1998, ISBN 978-3-527-29545-6 .