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2-Ethylanthraquinone is an
The
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
that is a derivative of anthraquinone
Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula . Isomers include various quinone derivatives. The term anthraquinone however refers to the isomer, 9,10-anthraquinone (IUPAC: 9,10-dioxo ...
. This pale yellow solid is used in the industrial production of hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%†...
(H2O2).Römpp CD 2006, Georg Thieme Verlag 2006
Production
2-Ethylanthraquinone is prepared from the reaction ofphthalic anhydride
Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It is the anhydride of phthalic acid. Phthalic anhydride is a principal commercial form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used commer ...
and ethylbenzene
Ethylbenzene is an organic compound with the formula . It is a highly flammable, colorless liquid with an odor similar to that of gasoline. This monocyclic aromatic hydrocarbon is important in the petrochemical industry as an reaction intermedia ...
:
:C6H4(CO)2O + C6H5Et → C6H4(CO)2C6H3Et + H2O.
Both phthalic anhydride and ethylbenzene are readily available, being otherwise used in the large-scale production of plastics.
Uses
Hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%†...
is produced industrially by the anthraquinone process
The anthraquinone process is a process for the production of hydrogen peroxide, which was developed by BASF. The industrial production of hydrogen peroxide is based on the reduction of oxygen, as in the direct synthesis from the elements. Instead ...
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 unsubstituted ring can reach 90% selectivity by using 2-ethylanthraquinone. Hydrogenation follows the Riedl-Pfleiderer, or autoxidation
Autoxidation (sometimes auto-oxidation) refers to oxidations brought about by reactions with oxygen at normal temperatures, without the intervention of flame or electric spark. The term is usually used to describe the gradual degradation of organi ...
, process:
The hydrogenation
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a Catalysis, catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or S ...
of 2-ethylanthraquinone is catalyzed by palladium
Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...
. Hydrogenation produces both 2-ethylanthrahydroquinone and tetrahydroanthraquinone. The tetrahydro derivative of 2-alkylanthraquinone is easily hydrogenated but is more difficult to oxidize. The formation of the tetrahydro derivative can be suppressed through the selection of catalysts, solvents, and reaction conditions. Some suggested solvent mixtures are polyalkylated benzenes and alkyl phosphates or tetraalkyl ureas, trimethylbenzenes and alkylcyclohexanol esters, and methylnaphthalene and nonyl alcohols.
References