Orcein
Encyclopedia
Orcein, also archil, orchil, lacmus, Citrus Red 2, and C.I. Natural Red 28, are names for dye
s extracted from several species of lichen
, commonly known as "orchella weeds", found in various parts of the world. A major source is the archil lichen, Roccella tinctoria
. Orcinol
is extracted from such lichens. It is then converted to orcein by ammonia
and air. In traditional dye-making methods, urine
was used as the ammonia source. If the conversion is carried out in the presence of potassium carbonate
, calcium hydroxide
, and calcium sulfate
(in the form of potash
, lime
, and gypsum
in traditional dye-making methods), the result is litmus
, a more complex molecule. The manufacture was described by Cocq in 1812 and in the UK in 1874 . Commercial archil is either a powder (called cudbear) or a paste. It is red in acidic pH
and blue in alkaline pH.
Orcein is approved as a food dye, with E number
E121. Its CAS number is . Its chemical formula is C28H24N2O7. It forms dark brown crystals. The chemical components of orcein were elucidated only in the 1950s by Hans Musso . The structures are shown below. A single alternative structure, possibly incorrect, is given by the National Library of Medicine http://chem.sis.nlm.nih.gov/chemidplus/jsp/common/ChemInfo.jsp?calledFrom=lite&type=formulas and Emolecules http://www.emolecules.com/cgi-bin/search?t=ss&q=1400-62-0&c=1&v=.
Orcein is a reddish-brown dye, orchil is a purple-blue dye. Orcein is also used as a stain
in microscopy to visualize elastic fibers
, Hepatitis B surface antigens, and copper
-associated proteins. It is a mixture of phenoxazone derivates - hydroxyorceins, aminoorceins, and aminoorceinimines.
extracted from orchil lichens that produces colours in the purple
range. It can be used to dye wool
and silk
, without the use of mordant
.
Cudbear was developed by Dr Cuthbert Gordon of Scotland
: production began in 1758, and it was patent
ed in 1758, British patent 727 http://www.chriscooksey.demon.co.uk/lichen/bp727.html. The lichen is first boiled in a solution of ammonium carbonate
. The mixture is then cooled and ammonia
is added and the mixture is kept damp for 3-4 weeks. Then the lichen is dried and ground to powder. The manufacture details were carefully protected, with a ten-feet high wall being built around the manufacturing facility, and staff consisting of Highlanders sworn to secrecy. The lichen consumption soon reached 250 tons per year and import from Norway and Sweden had to be arranged.http://gdl.cdlr.strath.ac.uk/stecit/stecit05.htm
Cudbear was the first dye to be invented in modern times, and one of the few dyes to be credited to a named individual.
Similar process was invented in France. The lichen is extracted by urine or ammonia. Then the extract is acidified, the dissolved dye precipitates and is washed. Then it is dissolved in ammonia again, the solution is heated in air until it becomes purple, then it is precipitated with calcium chloride
; the resulting insoluble purple solid is known as French purple, a fast lichen dye that did not fade in light like the other lichen dyes.
Dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....
s extracted from several species of lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
, commonly known as "orchella weeds", found in various parts of the world. A major source is the archil lichen, Roccella tinctoria
Roccella tinctoria
Roccella tinctoria is a species of fungus in the genus Roccella, homotypic synonym of Lecanora tinctoria Czerwiak., 1849. It was first described by Augustin Pyramus de Candolle in 1805. It has the following varieties:...
. Orcinol
Orcinol
Orcinol is a natural phenolic organic compound that occurs in many species of lichens including Rocella tinctoria and Lecanora. It can be formed by fusing extract of aloes with potash....
is extracted from such lichens. It is then converted to orcein by ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
and air. In traditional dye-making methods, urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
was used as the ammonia source. If the conversion is carried out in the presence of potassium carbonate
Potassium carbonate
Potassium carbonate is a white salt, soluble in water , which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid...
, calcium hydroxide
Calcium hydroxide
Calcium hydroxide, traditionally called slaked lime, is an inorganic compound with the chemical formula Ca2. It is a colourless crystal or white powder and is obtained when calcium oxide is mixed, or "slaked" with water. It has many names including hydrated lime, builders lime, slack lime, cal, or...
, and calcium sulfate
Calcium sulfate
Calcium sulfate is a common laboratory and industrial chemical. In the form of γ-anhydrite , it is used as a desiccant. It is also used as a coagulant in products like tofu. In the natural state, unrefined calcium sulfate is a translucent, crystalline white rock...
(in the form of potash
Potash
Potash is the common name for various mined and manufactured salts that contain potassium in water-soluble form. In some rare cases, potash can be formed with traces of organic materials such as plant remains, and this was the major historical source for it before the industrial era...
, lime
Agricultural lime
Agricultural lime, also called aglime, agricultural limestone, garden lime or liming, is a soil additive made from pulverized limestone or chalk. The primary active component is calcium carbonate...
, and gypsum
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
in traditional dye-making methods), the result is litmus
Litmus
Litmus or litmus test may refer to:* Litmus test, a common pH test* Litmus , a test case management tool maintained by Mozilla* "Litmus" , an episode in the first season of the television series...
, a more complex molecule. The manufacture was described by Cocq in 1812 and in the UK in 1874 . Commercial archil is either a powder (called cudbear) or a paste. It is red in acidic pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
and blue in alkaline pH.
Orcein is approved as a food dye, with E number
E number
E numbers are number codes for food additives that have been assessed for use within the European Union . They are commonly found on food labels throughout the European Union. Safety assessment and approval are the responsibility of the European Food Safety Authority...
E121. Its CAS number is . Its chemical formula is C28H24N2O7. It forms dark brown crystals. The chemical components of orcein were elucidated only in the 1950s by Hans Musso . The structures are shown below. A single alternative structure, possibly incorrect, is given by the National Library of Medicine http://chem.sis.nlm.nih.gov/chemidplus/jsp/common/ChemInfo.jsp?calledFrom=lite&type=formulas and Emolecules http://www.emolecules.com/cgi-bin/search?t=ss&q=1400-62-0&c=1&v=.
Orcein is a reddish-brown dye, orchil is a purple-blue dye. Orcein is also used as a stain
Staining (biology)
Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image. Stains and dyes are frequently used in biology and medicine to highlight structures in biological tissues for viewing, often with the aid of different microscopes...
in microscopy to visualize elastic fibers
Elastic fibers
Elastic fibres are bundles of proteins found in extracellular matrix of connective tissue and produced by fibroblasts and smooth muscle cells in arteries. These fibers can stretch up to 1.5 times their length, and snap back to their original length when relaxed...
, Hepatitis B surface antigens, and copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
-associated proteins. It is a mixture of phenoxazone derivates - hydroxyorceins, aminoorceins, and aminoorceinimines.
Cudbear
Cudbear is a dyeDye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....
extracted from orchil lichens that produces colours in the purple
Purple
Purple is a range of hues of color occurring between red and blue, and is classified as a secondary color as the colors are required to create the shade....
range. It can be used to dye wool
Wool
Wool is the textile fiber obtained from sheep and certain other animals, including cashmere from goats, mohair from goats, qiviut from muskoxen, vicuña, alpaca, camel from animals in the camel family, and angora from rabbits....
and silk
Silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...
, without the use of mordant
Mordant
A mordant is a substance used to set dyes on fabrics or tissue sections by forming a coordination complex with the dye which then attaches to the fabric or tissue. It may be used for dyeing fabrics, or for intensifying stains in cell or tissue preparations. The term mordant comes from the Latin...
.
Cudbear was developed by Dr Cuthbert Gordon of Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
: production began in 1758, and it was patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
ed in 1758, British patent 727 http://www.chriscooksey.demon.co.uk/lichen/bp727.html. The lichen is first boiled in a solution of ammonium carbonate
Ammonium carbonate
Ammonium carbonate is a commercial salt with the chemical formula 2CO3. It is used when crushed as a smelling salt. It can be crushed when needed in order to revive someone who has fainted...
. The mixture is then cooled and ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
is added and the mixture is kept damp for 3-4 weeks. Then the lichen is dried and ground to powder. The manufacture details were carefully protected, with a ten-feet high wall being built around the manufacturing facility, and staff consisting of Highlanders sworn to secrecy. The lichen consumption soon reached 250 tons per year and import from Norway and Sweden had to be arranged.http://gdl.cdlr.strath.ac.uk/stecit/stecit05.htm
Cudbear was the first dye to be invented in modern times, and one of the few dyes to be credited to a named individual.
Similar process was invented in France. The lichen is extracted by urine or ammonia. Then the extract is acidified, the dissolved dye precipitates and is washed. Then it is dissolved in ammonia again, the solution is heated in air until it becomes purple, then it is precipitated with calcium chloride
Calcium chloride
Calcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation...
; the resulting insoluble purple solid is known as French purple, a fast lichen dye that did not fade in light like the other lichen dyes.