Indanthrone blue

{{Short description|Organic dye made from 2-aminoanthraquinone}} {{Chembox | verifiedrevid = 414758183 | ImageFile_Ref = {{chemboximage|correct|??}} | ImageFile = Indanthren.svg | ImageSize = 220px | ImageName = Skeletal formula | ImageFile1 = Indanthrone-3D-balls.png | ImageSize1 = 240px | ImageName1 = Ball-and-stick model | PIN = 6,15-Dihydrodinaphtho[2,3-''a'':2′,3′-''h'']phenazine-5,9,14,18-tetrone | OtherNames = C.I. vat blue 4, carbon paper blue, blue O, carbanthrene blue 2R, fenan blue RSN, graphtol blue RL, medium blue, monolite fast blue 3R, indanthrene, indanthrone, pigment blue 60, C.I. 69800 |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 6435 | InChI = 1/C28H14N2O4/c31-25-13-5-1-3-7-15(13)27(33)21-17(25)9-11-19-23(21)29-20-12-10-18-22(24(20)30-19)28(34)16-8-4-2-6-14(16)26(18)32/h1-12,29-30H | InChIKey = UHOKSCJSTAHBSO-UHFFFAOYAY | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C28H14N2O4/c31-25-13-5-1-3-7-15(13)27(33)21-17(25)9-11-19-23(21)29-20-12-10-18-22(24(20)30-19)28(34)16-8-4-2-6-14(16)26(18)32/h1-12,29-30H | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = UHOKSCJSTAHBSO-UHFFFAOYSA-N | CASNo = 81-77-6 | CASNo_Ref = {{cascite|correct|CAS}} | UNII_Ref = {{fdacite|correct|FDA}} | UNII = R68OT0N83K | PubChem = 6690 | SMILES = O=C6c5c4Nc3c(c2C(=O)c1ccccc1C(=O)c2cc3)Nc4ccc5C(=O)c7ccccc67 | Beilstein = 367131 }} |Section2={{Chembox Properties | C=28 | H=14 | N=2 | O=4 | Appearance = dark blue solid | Density = 1.6 g/ml | MeltingPt = 470-500 °C (decomposes) | BoilingPt = | Solubility = Insoluble }} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}

'''Indanthrone blue''', also called '''indanthrene''', is an organic compound with the formula {{chem2|(C14H6O2NH)2}}. It is a dark blue solid that is a common dye as well as a precursor to other dyes.<ref>{{cite book |doi=10.1002/14356007.a02_355 |chapter=Anthraquinone Dyes and Intermediates |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2000 |last1=Bien |first1=Hans-Samuel |last2=Stawitz |first2=Josef |last3=Wunderlich |first3=Klaus |isbn=3527306730 }}</ref>

==Preparation and structure== The compound is made by oxidation of 2-aminoanthraquinone in the presence of potassium hydroxide.

:frameless|upright=3|synthesis of indanthrone|440px|center :Procedure for producing indanthrone from 2-aminoanthraquinone. By dimerization of 2-aminoanthraquinone]] ('''1''') under strongly alkaline conditions at 220-235 °C, the intermediate '''3''' is obtained in two steps, which cyclizes intramolecularly and is oxidized to indanthrone '''5'''.<ref>{{citation|author=Heinrich Zollinger|date=2003|edition=3.|isbn=3-906390-23-3|location=Weinheim|pages=289|publisher=WILEY-VCH Verlag|title=Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments|url={{Google books|0Ynge4E5rqYC||page=289|plainurl=yes}}}}</ref>

Owing to intermolecular hydrogen bonding, indanthrone is insoluble. It can be modified by installing tert-butyloxycarbonyl groups in place of the N-H groups to give an organic-soluble "latent pigment." Processing of such derivatives has affording crystals of the parent pigment.<ref>{{cite journal |last1=Liu |first1=Tang-Hao |last2=Cheng |first2=Wen-Tung |last3=Huang |first3=Kou-Tung |title=Crystallization and morphology of indanthrone converted from latent pigment in the solution with photo acid generator |journal=Dyes and Pigments |date=2014 |volume=105 |pages=137–144 |doi=10.1016/j.dyepig.2014.01.021}}</ref>

==Applications== Indanthrone is utilized as a blue pigment (C.I. Pigment Blue 60), primarily in the process of vat dyeing, often referred to as C.I. Vat Blue 4.<ref name=herbst>W. Herbst, K. Hunger: ''Industrial Organic Pigments. Preparation, properties, application''. 2nd ed., Wiley-VCH, Weinheim 1995, ISBN 3-527-28744-2.</ref> Indanthrone is a vat dye, synthesized to provide highest color fastness for the dyeing and printing of predominantly cellulose-based textile fibers. Fabrics dyed with indanthrene fulfill the highest standards and exhibit exceptional wash fastness, boil fastness, light fastness, weather fastness and chlorine fastness.

It is a pigment that can be used in the following media: acrylic, alkyd, casein, encaustic, fresco, gouache, linseed oil, tempera, pastel, and watercolor painting. It is used to dye unmordanted cotton and as a pigment in quality paints and enamels. As a food dye, it has number 130, but it is not approved for use in either the United States or the European Union.<ref>[https://web.archive.org/web/20090611073852/http://www.fda.gov/ForIndustry/ColorAdditives/ColorAdditiveInventories/ucm115641.htm Summary of Color Additives for Use in the United States in Foods, Drugs, Cosmetics, and Medical Devices], Food and Drug Administration</ref><ref>[http://www.food.gov.uk/safereating/additivesbranch/enumberlist Current EU approved additives and their E Numbers], Food Standards Agency</ref> It has excellent light fastness, but may bleed in some organic solvents.

Indanthrone blue was the first example of the brand "Indanthren" (an acronym for ''Indigo from anthracene'') introduced by BASF in 1901.<ref name=roempp>{{RömppOnline|Name=Indanthron-Pigmente|Datum=16. Januar 2013|ID=RD-09-00459}}</ref><ref>{{cite web |title=Marken - Registerauskunft - Indanthren |url=https://register.dpma.de/DPMAregister/marke/register/51151/DE |website=DPMAregister |accessdate=29 August 2020 |language=de |quote=Anmeldetag: 05.08.1901 / Inhaber: BASF AG}}</ref><ref>{{cite book |last1=Zollinger |first1=Heinrich |title=Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments |year=2003 |publisher=John Wiley & Sons |isbn=978-3-906390-23-9 |page=255 |url=https://books.google.com/books?id=0Ynge4E5rqYC&pg=PA255 |accessdate=29 August 2020 |quote=The German word ''Indanthren'' is an acronym for ''Indigo aus Anthrazen''}}</ref> One result is that even now, in Japan vat dyes are commonly described as ''threne'' dyes (スレン染料), derived from the Japanese transliteration of the brand.<ref>{{cite web |title=Colourful World III |url=http://www.eonet.ne.jp/~hss50111/content05.html |website=www.eonet.ne.jp |accessdate=29 August 2020 |quote=バット染料の主たる製造元は、ドイツの化学会社でありその時の商標が、 “インダンスレン” であったことからスレン染料と呼ぶ場合も多くあります}}</ref><ref>{{cite web |title=アルテモンド豆知識 / スレン染料 |url=http://www.artemondo.co.jp/mame/knowledge/threne.htm |website=www.artemondo.co.jp |quote=スレン染料（threne dye）とは、バット染料（vat dye）の俗称}}</ref>

== Signifigance of Indigo Pure BASF in Indanthrene Blue == The color and vat dye that came before Indanthrene Blue was Indigo Pure BASF. This synthesis consisted of Phenylglycocoll acid mixed and fused with Caustic soda which transforms into an alkaline solution. When this Alkaline solution makes contact with oxygen, the color Indigo precipitates/appears. This process would be replicated in various ways to create Indanthrene blue and its derivatives. Indigo Pure BASF contributed to the research as a cornerstone of its progress as the chemists at BASF took 17 years to research and synthesize this vat dye.<ref>Gesellschaft Deutscher Chemiker. Chemische Berichte. Weinheim/Bergsr. [etc.]: VCH Verlagsgesellschaft mbH. [etc.],</ref><ref>"1865 – 1901 / The Age of Dyes". ''BASF''. 04/15/2026. Retrieved 04/15/2026.</ref>

==Other studies==

As an organic semiconductor, indanthrone has been considered as a photocatalyst for oxygen generation from water utilizing solar energy.<ref>C. A. Linkous, D. K. Slattery: ''Solar photocatalytic hydrogen production from water using a dual bed photosystem''. In ''Proceedings of the 2000 Hydrogen Program Annual Review, Volume I''. ([https://www.eere.energy.gov/hydrogenandfuelcells/pdfs/28890v.pdf PDF]).</ref><ref>D. K. Slattery et al: ''Semiempirical MO and Voltammetric estimation of ionization potentials of organic pigments. Comparison to gas phase ultraviolet photoelectron spectroscopy''. In: ''Dyes and Pigments'' 49, 2001, pp. 21-27.</ref> Indanthrone's characteristic as a nonlinear optics light absorber, allows for its use as an ''optical limiter'', which can be employed, for instance, in laser protective filters.<ref>Y.-P. Sun, J. E. Riggs: ''Organic and inorganic optical limiting materials. From fullerenes to nanoparticles''. In ''International Reviews in Physical Chemistry.'' 18, no. 1, 1999, pp. 43-90.</ref>

==Related compounds== Indrathren Blue CLB (PubChem CID 5483458, registry number 6492-78-0) is a related blue dye.

==References== {{reflist}}

{{Authority control}} {{DEFAULTSORT:Indanthrone Blue}} Category:Anthraquinone dyes