Brazilin

Brazilin
Brazilin
Identifiers
CAS number 474-07-7 N
PubChem 73384
ChemSpider 66104 YesY
ChEBI CHEBI:3170 YesY
ChEMBL CHEMBL598951 YesY
Jmol-3D images Image 1
Image 2
Properties
Molecular formula C16H14O5
Molar mass 286.28 g mol−1
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Brazilin is a red pigment obtained from the wood of the brazilwood family (Caesalpinia sp), and is also known as Natural Red 24. Brazilin has been used since at least the Middle Ages to dye fabric, and has been used to make paints and inks as well. The specific color produced by the pigment depends on its manner of preparation: in an acidic solution brazilin will appear yellow, but in an alkaline preparation it will appear red. Brazilin is closely related to the blue-black dye haematoxylin, having one less hydroxyl group. Brazilein is the name for the oxidised pigment[1].

Contents

Sources of brazilin

Many members of the genus Caesalpinia produce brazilin, including brazilwood (C. echinata) and sappanwood (C. sappan). The sappanwood is found in India, Malaysia, and Sri Lanka, the latter being a major supplier of the wood to Europe during the early Middle Ages. Later, discovery of brazilwood in the new world led to its rise in popularity with the dye industry and eventually its over-exploitation. Brazilwood is now classified as an endangered species.

Extraction and preparation

There are many ways to extract and prepare brazilin. A common recipe, developed in the Middle Ages, is to first powder the brazilwood, turning it into sawdust. Then, the powder can be soaked in lye (which produces a deep, purplish red) or a hot solution of alum (which produces an orange-red color), either of which extracts the color better than plain water alone. To the lye extract, alum is added (or to the alum extract, lye) in order to fix the color, which will precipitate from the solution. The precipitate can be dried and powdered, and is a type of lake pigment.

Like many lake pigments, the exact colors produced depends on the pH of the mixture and the fixative used. Aluminum mordants used with brazilin produce the standard red colors, while the use of a tin mordant, in the form of SnCl2 or SnCl4 added to the extract is capable of yielding a pink color.

An alternative preparation which produces a transparent red color involves soaking the brazilwood powder in glair or a solution of gum arabic. Alum is added to help develop and fix the color, which can then be used as a transparent ink or paint.

As with haematoxylin, brazilin can be used for staining cell nuclei in histological preparations when combined with aluminum. The nuclei are then colored red instead of blue.

References

  • The Merck Index, 12th Edition. 1392
  • Armstrong, Wayne P. (1994). "Natural Dyes". HerbalGram 32: 30. 
  • Thompson, Daniel V. The Materials and Techniques of Medieval Painting, Dover Publications, Inc. New York, NY. 1956.

External links


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Look at other dictionaries:

  • Brazilin — Braz i*lin, n. [Cf. F. br[ e]siline. See {Brazil}.] (Chem.) A substance contained in both Brazil wood and Sapan wood, from which it is extracted as a yellow crystalline substance which is white when pure. It is colored intensely red by alkalies.… …   The Collaborative International Dictionary of English

  • brazilin — brazìlīn m <G brazilína> DEFINICIJA 1. bot., v. sezalpinija 2. kem. C16H14O5, biljna boja, žućkasti kristali koji na zraku postaju narančasti, upotrebljava se za bojenje tekstila, drva i mikroskopskih preparata ETIMOLOGIJA prema brazilskom… …   Hrvatski jezični portal

  • brazilin — [braz′ə lin΄, brə zil′in] n. [ BRAZIL + IN1] a bright yellow compound, C16H14O5, obtained from brazilwood as a crystalline powder and used as a dye and indicator …   English World dictionary

  • brazilin — /braz euh lin, breuh zil in/, n. Chem. a yellow, water soluble, needlelike, crystalline solid, C16H14O5, obtained from brazil and sappanwood: used as a dye and an indicator. Also, brasilin. [1860 65; BRAZIL + IN2] * * * …   Universalium

  • brazilin — noun A red pigment obtained from brazilwood …   Wiktionary

  • brazilin — A red natural dye, C16H14O5, obtained from the bark of several species of tropical trees and oxidized to the active red dye brazilein; resembles hematoxylin in origin, chemistry, and usage; used as a nuclear stain and as an indicator (red in… …   Medical dictionary

  • brazilin — braz·i·lin …   English syllables

  • brazilin — /ˈbræzələn/ (say brazuhluhn) noun a yellow substance, C16H14O5, from brazil, used as a dye and indicator. Also, brasilin …  

  • brazilin — …   Useful english dictionary

  • brezilin — Brazilin Braz i*lin, n. [Cf. F. br[ e]siline. See {Brazil}.] (Chem.) A substance contained in both Brazil wood and Sapan wood, from which it is extracted as a yellow crystalline substance which is white when pure. It is colored intensely red by… …   The Collaborative International Dictionary of English

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