1,4-Dihydroxyanthraquinone
Encyclopedia
1,4-Dihydroxyanthraquinone, also called quinizarin or Solvent Orange 86, is an organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 derived from anthroquinone. Quinizarin is an orange or red-brown crystalline powder. It is formally derived from anthraquinone
Anthraquinone
Anthraquinone, also called anthracenedione or dioxoanthracene is an aromatic organic compound with formula . Several isomers are possible, each of which can be viewed as a quinone derivative...

 by replacement of two hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 atoms by hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...

 (OH) groups. It is one of ten dihydroxyanthraquinone
Dihydroxyanthraquinone
A dihydroxyanthraquinone is any of several isomeric organic compounds with formula , formally derived from an anthraquinone by replacing two hydrogen atoms by hydroxyl groups. Dihyroxyantraquinones have been studied since the early 1900s, and include some compounds of historical and current...

 isomers and occurs in small amounts (as a glycoside
Glycoside
In chemistry, a glycoside is a molecule in which a sugar is bound to a non-carbohydrate moiety, usually a small organic molecule. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme...

) in the root of the madder
Madder
Rubia is a genus of the madder family Rubiaceae, which contains about 60 species of perennial scrambling or climbing herbs and sub-shrubs native to the Old World, Africa, temperate Asia and America...

 plant, Rubia tinctorum
Rubia tinctorum
Rubia tinctorum, the common madder or dyer's madder, is a plant species in the genus Rubia.The plant's roots contain several polyphenolic compounds like 1,3-Dihydroxyanthraquinone , 1,4-Dihydroxyanthraquinone , 1,2,4-Trihydroxyanthraquinone and 1,2-dihydroxyanthraquinone...

.

Production

Quinizarin is produced by the reaction of phthalic anhydride
Phthalic anhydride
Phthalic anhydride is the organic compound with the formula C6H42O. It is the anhydride of phthalic acid. This colourless solid is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. In 2002, approximately 4.6 billion kilograms were...

 and 4-chlorophenol followed by hydrolysis of the chloride:
C6H4(CO)2O + ClC6H4OH → C6H4(CO)2C6H2(OH)Cl + H2O
C6H4(CO)2C6H2(OH)Cl + H2O → C6H4(CO)2C6H2(OH)2 + HCl

It can also be prepared less efficiently from phthalic anhydride
Phthalic anhydride
Phthalic anhydride is the organic compound with the formula C6H42O. It is the anhydride of phthalic acid. This colourless solid is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. In 2002, approximately 4.6 billion kilograms were...

 and hydroquinone
Hydroquinone
Hydroquinone, also benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, having the chemical formula C6H42. Its chemical structure, shown in the table at right, has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid...

.

Uses

Quinizarin is an inexpensive dye that is used to colour gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

 and some heating oil
Heating oil
Heating oil, or oil heat, is a low viscosity, flammable liquid petroleum product used as a fuel for furnaces or boilers in buildings. Home heating oil is often abbreviated as HHO...

s. It is used as an intermediate for the synthesis of indanthrene- and alizarin
Alizarin
Alizarin or 1,2-dihydroxyanthraquinone is an organic compound with formula that has been used throughout history as a prominent dye, originally derived from the roots of plants of the madder genus.Alizarin was used as a red dye for the English parliamentary "new model" army...

-derived dyes. The OH groups can be replaced by chloride. Chlorination
Chlorination
Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water...

 and bromination afford other dyes. Amination (replacement of one OH by ArNH) with aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

 derivatives followed by sulfonation affords other dyes such as Acid Violet 43. It is also used to form lake pigment
Lake pigment
A lake pigment is a pigment manufactured by precipitating a dye with an inert binder, usually a metallic salt. The word lake is a homonym of lake as body of water and does not refer to it....

s with calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

, barium
Barium
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with...

, and lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

.

See also

  • Hydroxyanthraquinone
    Hydroxyanthraquinone
    A hydroxyanthraquinone is any of several organic compounds with formula C14H9O2, which can be viewed as derivatives of an anthraquinone through replacement of one hydrogen atom by an hydroxyl group ....

  • 1,2-Dihydroxyanthraquinone (alizarin)
  • 1,3-Dihydroxyanthraquinone
    1,3-Dihydroxyanthraquinone
    1,3-Dihydroxyanthraquinone, also called purpuroxanthin or xanthopurpurin is an organic compound with formula that occurs in the plant Rubia cordifolia . It is one of ten dihydroxyanthraquinone isomers...

     (purpuroxanthin)
  • Trihydroxyanthraquinone
    Trihydroxyanthraquinone
    A trihydroxyanthraquinone or trihydroxyanthracenedione is any of several isomeric organic compounds with formula , formally derived from anthraquinone by replacing three hydrogen atoms by hydroxyl groups. They include several historically important dyes...

  • Quinalizarin
    Quinalizarin
    Quinalizarin or 1,2,5,8-tetrahydroxyanthraquinone is an organic compound with formula . It is one of many tetrahydroxyanthraquinone isomers, formally derived from anthraquinone by replacement of four hydrogen atoms by hydroxyl groups....

    (1,2,5,8-tetrahydroxyanthraquinone)
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