2-Ethylanthraquinone

2-Ethylanthraquinone
Names
	Other names 2-Ethyl-9,10-anthracenedione
Identifiers
CAS Number	84-51-5 ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL42355 ;
ChemSpider	6514 ;
ECHA InfoCard	100.001.396
EC Number	201-535-4;
CompTox Dashboard (EPA)	DTXSID5044994 ;
	InChI InChI=1S/C16H12O2/c1-2-10-7-8-13-14(9-10)16(18)12-6-4-3-5-11(12)15(13)17/h3-9H,2H2,1H3 Key: SJEBAWHUJDUKQK-UHFFFAOYSA-N ; InChI=1/C16H12O2/c1-2-10-7-8-13-14(9-10)16(18)12-6-4-3-5-11(12)15(13)17/h3-9H,2H2,1H3 Key: SJEBAWHUJDUKQK-UHFFFAOYAW;
	SMILES O=C2c1c(cccc1)C(=O)c3c2ccc(c3)CC;
Properties
Chemical formula	C16H12O2
Molar mass	236.27 g/mol
Appearance	white to yellowish crystals or powder
Density	1.231g/cm3
Melting point	105 °C (221 °F; 378 K)
Boiling point	415.4 @ 760mmHg
Hazards
Flash point	155.4 °C,
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

2-Ethylanthraquinone also called2-Ethyl-9,10-anthraquinone ‎ is an aromatic organic compound with the formula C₁₆H₁₂O₂. The slightly yellow powder is used in the production of hydrogen peroxide (H₂O₂).

Production

2-Ethylanthraquinone is prepared from the reaction of phthalic anhydride and ethylbenzene: C₆H₄(CO)₂O + C₆H₅CH₂CH₃ → C₆H₄C₂O₂C₆H₃C₂H₅ + H₂O. Both phthalic anhydride and ethylbenzene are readily available but are mainly used in the large-scale production of plastics.

Uses

Hydrogen peroxide is produced industrially by the anthraquinone process which involves using 2-alkyl-9,10-anthraquinones for hydrogenation. Many derivatives of anthraquinone are used but 2-Ethylanthraquinone is common because of its high selectivity. The hydrogenation of the unsubsituted ring can reach 90% selectivity by using 2-ethylanthraquinone. Hydrogenation follows the Riedl-Pfleiderer, or autoxidation, process:

The hydrogenation of 2-ethylanthrahydroquinone is catalyzed by palladium metal. During hydrogenation both 2-ethylanthrahydroquinone and tetrahydroanthraquinone are produced. The tetrahydro derivative of 2-alkylanthraquinone is easily hyrdrogenated but is more difficult to oxidize. This has led to a split in production methods, with current research focusing on the effectiveness of the tetrahydro system. The formation of the tetrahyrdo derivative can be suppressed through use of special catalysts, solvents, and conditions. A working solution must be able to keep the 2-ethylanthraquinone dissolved in the hyrdrogenation, oxidation, and extraction steps. Since hydroquinones dissolve better in polar solvents, and quinones dissolve better in aromatic nonpolar solvents, a solvent mixture must be used. Some suggested mixtures are polyalkylated benzenes and alkyl phosphates or tetraalkyl ureas, trimethylbenzenes and alkylcyclohexanol esters, and methylnaphthalene and nonyl alcohols.

References