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Topic: Azo dye


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In the News (Mon 28 May 12)

  
  Azo Metal Dye On GlobalSpec
Colorants, pigments and dyes are dispersed in paints and caulk to provide characteristics such as color, hiding power, bulk, durability and corrosion resistance.
Dye lasers use a dye solution as an active medium.
Azo metal dyes and optical data carrier containing one such azo metal dye as a...
www.globalspec.com /Industrial-Directory/azo_metal_dye   (1330 words)

  
  Food-Info.net : Azo dyes
Azo dyes are stable in the whole pH range of foods, are heat stable and do not fade when exposed to light or oxygen.
The azo linkage is the most labile portion of an azo dye molecule and may easily undergo enzymatic breakdown in mammals, including man. The azo linkage may be reduced and cleaved, resulting in the splitting of the molecule in two parts.
Azo dyes are too small to have a direct effect on the immune system and thus do not cause a direct allergic reaction.
www.food-info.net /uk/colour/azo.htm   (1153 words)

  
 Non azo disperse dye mixtures - Patent 7118604
The dye mixture according to claim 1, wherein the ratio by weight of dye (I): dye (II) is from 5 to 95:95 to 5.
The dye mixture according to claim 1, wherein the ratio by weight of dye (I): dye (II) is from 75 to 90:25 to 10.
The dye mixture as claimed in claim 1, wherein R.sup.1 or R.sup.2 is H. The dye mixture as claimed in claim 1, wherein R.sup.1 or R.sup.2 is H and the R.sup.1 or R.sup.2 that is not H is a -O(CH.sub.2).sub.n R.sup.4.
www.freepatentsonline.com /7118604.html   (2301 words)

  
 Dye Summary
Dyes from plants included blue dye from the indigo plant; blue dye from woad; red and brown dyes from the madder plant; yellow, orange, brown, and fl dyes from various trees; orange or red dye from henna; and yellow from safflower and weld.
Dyes were dissolved and applied to the cloth and the color change would take place either because the dye molecules became bonded to the fiber molecules or because the dye was unable to pass out of the fibers' fine capillaries once it is inside of them.
The dye is usually used as an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber.
www.bookrags.com /Dye   (1806 words)

  
 Azo compound Summary
In chemistry, azo compounds generally have a molecular formula of the form R-N=N-R', in which R and R' can be either aromatic or aliphatic.
Their colour originates from absorbance in the visible region of the spectrum due to the delocalization of electrons in the benzene and azo groups forming a conjugated system, whereby the N=N group is the chromophore.
Because of their instability, especially for aliphatic ones, care should be taken with the handling of azo compounds or an explosion may occur.
www.bookrags.com /Azo_compound   (660 words)

  
 SingaporeMoms - Parenting Encyclopedia - Dye
The dye is usually used as an aqueous solution and may require a mordant to improve the fastness of the dye on the fibre.
Water soluble anionic dyes that are applied to fibres such as silk, wool, nylon and modified acrylic fibres from neutral to acid dyebaths.
Many are azo dyes but anthraquinone and triphenylmethane compounds are used for colours such as green and blue.
www.singaporemoms.com /parenting/Dye   (757 words)

  
 Azo compound - Wikipedia, the free encyclopedia
In chemistry, azo compounds generally have a molecular formula of the form R-N=N-R', in which R and R' can be either aromatic or aliphatic.
The name azo comes from azote, an old name of nitrogen that originates in French and is derived from the Greek a (not) + zoe (to live).
Their colour originates from absorbance in the visible region of the spectrum due to the delocalization of electrons in the benzene and azo groups forming a conjugated system, whereby the N=N group is the chromophore.
en.wikipedia.org /wiki/Azo_dye   (402 words)

  
 FD&C Red Dye #40 Information, Education and Discussion
Azo dyes come in all colors, though the only azo dyes used in food are in the red-yellow range.
Sudan 1 is a red dye and has a very close structure to the certified azo dyes.
There are many, many other azo dyes similar to the three mentioned here but they are not certified for use in foods.
www.red40.org /pages/chemistry.html   (633 words)

  
 Azo Dyes
One of the most important structural types of synthetic dyes are azo compounds.
The typical azo dye consists of two aromatic units joined by a dinitrogen bridge.
Of course to be useful, the dye must adhere to the fabric to which it is applied.
www.chem.pacificu.edu /Projects2004/Pages/AzoDye.htm   (474 words)

  
 MFA - CAMEO - Material Description
Azo chromophores were first discovered in 1863 when Martius and Lightfoot coupled diazonium ions and amines.
The simplest azo dyes are yellow, but changing the number of chromophores or the backbone structure can produce red, violet, blue and even fl dyes.
Azo dyes are used as textile colorants, and well as in industrial paints, printing inks, varnishes, plastics, crayons and other products.
mfa.org /_cameo/frontend/material_description.asp?name=azo+dye&...   (242 words)

  
 COLL 323 - Spectroscopic characterization of azo dye aggregation on catanionic vesicle surfaces   (Site not responding. Last check: )
Spectroscopic characterization of azo dye aggregation on catanionic vesicle surfaces
We use the spectral properties of azo dye aggregates to characterize the self-assembly of oppositely-charged surfactants in aqueous solution to generate unilamellar "catanionic" vesicles.
In particular, surfactant spacing on the outer vesicle surface dictates the proximity of attached azo dyes and the ability of intermolecular forces between dyes to operate to yield H- and J-aggregates.
membership.acs.org /c/coll/neworleans/P615672.HTM   (193 words)

  
 Research on Food Dye and Flavorings   (Site not responding. Last check: )
The reduction of azo dyes by the intestinal microflora.
Thus, significant brain uptake of intravascular dye is normally prevented by its binding to plasma protein (greater than 99% bound) and by the blood-brain barrier impermeability to the dye-protein complex.
We report a patient with chronic cutaneous LCV in whom the presumed cause was an excipient (a dye) used in the capsule form of lithium carbonate.
www.diet-studies.com /dye.html   (8147 words)

  
 Acid dye - Wikipedia, the free encyclopedia
Acid dye is a member of a class of dye that is applied from an acidic solution.
The structure of azo dyes is based on azobenzene, Ph-N=N-Ph (see right showing cis/ trans isomers) Although Azo dyes are a separate class of dyesuff mainly used in the dyeing of cotton (cellulose) fibers many acid dyes have a similar structure, most are red in color.
Any dyes including acid dyes have the ability to induce senstisation in humans due to their complex molecular structure and the way in which they are metabolised in the body.
en.wikipedia.org /wiki/Acid_dye   (725 words)

  
 DIRECTONS
Naphtol dyes are not sold in the form of a "finished dye" but in form of their components (insoluble azo base and fast colour coupling compound) which combine on the fibre to produce a water insoluble azo dye of outstanding fastness properties.
NOTE: After all dyeing is completed, immerse the fabric in soapy boiling water for a couple of minutes to eliminate excess dye and to stabilize the colour.
Vat dyes are insuluble in water, and to be able to be applied to the cloth must be first "reduced" to leuko form with the aid of Caustic Soda and Sodium Hydrosulphite.
www.dyeman.com /directions2.html   (2278 words)

  
 azo dye definition - Dictionary - MSN Encarta
azo dye definition - Dictionary - MSN Encarta
Search for "azo dye" in all of MSN Encarta
dye containing azo group: an artificial dye, usually orange, yellow, or brown, containing an azo group.
encarta.msn.com /dictionary_1861685689/azo_dye.html   (79 words)

  
 Colours   (Site not responding. Last check: )
Similar behavior is responsible for the change in color of morning glories as the bright blue of morning becomes purple or pink in the evening as the flower dies and becomes acidic.
Formation of Dye on the Fiber: This most often involves the preparation of an azo dye by soaking the fabric in one component and then immersing it in a solution of the second.
One or two chlorides are replaced by dye molecules, and then the third is used to bind to the fiber.
instruct.uwo.ca /chemistry/223b-98/colours.htm   (2110 words)

  
 Synthesis of Azo dyes from the f
The synthesis of an azo dye by coupling the water extract of the fruit husk of Parkia clappertoniana, a polyphenolic compound with diazonium salt was attempted.
The dye was characterized using spectroscopic methods (infrared and ultraviolet) and chromatographic analysis.
Results obtained showed the synthesized dye to have similar properties, which are characteristic of conventional azo dyes.
www.rmrdc.gov.ng /NEWS/synthesisofazo.htm   (165 words)

  
 Azo Dye Formation   (Site not responding. Last check: )
Azo dyes are toxic and may cause genetic mutations.
Coupling reaction: The diazotized sulfanilic acid reacts with 2-naphthol and 1-naphthylamine to produce an acidic and basic azo dye alternatively (2).
In azo compounds the -N=N- group is part of an extended delocalized electron system involving the aromatic rings, called a chromophore.
www.uni-regensburg.de /Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/D-Azo-Dyes-e.htm   (304 words)

  
 Degradation of Azo Dyes by Trametes villosa Laccase over Long Periods of Oxidative Conditions -- Zille et al. 71 (11): ...
dye I indicates that the degradation of the molecule was not
the degradation pathways of dye I (8, 14).
Phenolic azo dye oxidation by laccase from Pyricularia oryzae.
aem.asm.org /cgi/content/full/71/11/6711   (3088 words)

  
 Polymerizable dichroic azo dyes patent invention
The present invention is directed towards polymerizable dichroic azo dyes comprising azo-chromophores having at least one standard mesogenic ring system attached to said chromophores and at least one polymerizable group leading to dyes having sufficient solubilty and a very high order parameter.
[0003] Dichroism is the property whereby an oriented assembly of dye molecules exhibits relatively low absorption of a given wavelength of light in one state of orientation and a relatively high absorption of the same wavelength in another state of orientation with respect to the polarization direction of the light source.
are the optical densities of a dichroic dye in a liquid crystal measured for light polarizations parallel and perpendicular to the liquid crystal director.
www.freshpatents.com /Polymerizable-dichroic-azo-dyes-dt20060824ptan20060188663.php   (1008 words)

  
 SEI - Bangladesh Dye Network - FAQ
Azo dyes are a group of organic compounds which contain the N=N functional group, known as the azo group.
Under aerobic conditions (in the presence of oxygen) azo dyes are resistant to degradation but under anaerobic (in the absence of oxygen) conditions, they can be reduced to certain aromatic amines called arylamine.
The optimum dyeing temperatures and dyeing conditions for reactive dyes differ according to the type of reactive group involved, so the first thing that must be decided is the type of dye that will be used.
www.sei.se /asia/dyenetwork/qa.html   (2644 words)

  
 Azo-dye-doped photorefractive polymer composites for holographic testing and image processing - Patent 5744267   (Site not responding. Last check: )
The method of claim 26 wherein said dye is present in a concentration within a range of about 30 to 60 wt %, and said photosensitizer is present within a range of about 1 wt % or less.
The second-order, non-linear chromophore is preferably an azo dye, having a wavelength of maximum absorption that is about 250 nm less than the operating wavelength.
All the azo dyes employed in the practice of the invention were synthesized in the following manner: 10 g p-nitrobenzenediazonium tetrafluoroborate (0.042 moles) were dissolved in 150 ml acetonitrile.
www.freepatentsonline.com /5744267.html   (6128 words)

  
 chemistry of dyes
The relationship between the colour of an azo dye has been more fully discussed in The Basis of Colour.
Azo dyes give bright, high intensity colours, much more so than the next most common dye class (anthraquinones).
As other dye classes become less viable from either an environmental or economic reasons, azo dyes become ever more attractive options.
www.chm.bris.ac.uk /webprojects2002/price/azo.htm   (519 words)

  
 azo dye on GlobalSpec
Industrial Dyes (121 companies) Industrial dyes are colorants consisting of single molecules that are able to absorb certain parts of the spectrum of visible light and reflect others.
The dye is transferred imagewise to an image-receiving layer where it is contacted with metal ions to form a metal-complexed azo dye transfer image of...
This azo dye is used particularly for colouring wool and polyamide fibres and has been found to cause pollution risks in respect of the environment.
industrial-lasers.globalspec.com /Industrial-Directory/azo_dye   (1549 words)

  
 azo dye
These new azo dyes are synthesized from benzotriazoles using a novel ring opening reaction.
Our azo dyes contain a lipophilic o-nonafluorsulfonamido group in one aromatic ring and one o-hydroxyl group in the other aromatic ring.
This "lipophilic ortho effect" is even increased for azo dyes (3) and (4), respectively which are completely insoluble in water even in form of their potassium salts.
www.uni-tuebingen.de /Ziegler/azo_dye.html   (194 words)

  
 azo dye
Synthetic dye containing the azo group of two nitrogen atoms (N
Azo dyes are usually red, brown, or yellow, and make up about half the dyes produced.
Helicon Publishing is a division of Research Machines plc.
www.tiscali.co.uk /reference/encyclopaedia/hutchinson/m0024365.html   (118 words)

  
 some reactions of diazonium ions
These strongly coloured azo compounds are frequently used as dyes known as azo dyes.
Azo compounds account for more than half of modern dyes.
Azo compounds contain a highly delocalised system of electrons which takes in both benzene rings and the two nitrogen atoms bridging the rings.
www.chemguide.co.uk /organicprops/aniline/propsdiazo.html   (1257 words)

  
 azo dye - Search Results - MSN Encarta
- dye containing azo group: an artificial dye, usually orange, yellow, or brown, containing an azo group.
Azo Compound, any synthetic organic compound that contains two organic molecules linked by an azo group.
Dyestuffs, any of a large group of chemicals almost exclusively organic in nature, used for the coloring of textiles, inks, food products, and other...
ca.encarta.msn.com /azo+dye.html   (74 words)

  
 Benzene Diazonium Salts - Azo Dyes
These particular dyes are of little practical value owing to their only slight solubility in water.
In azo compounds the -N=N- group is part of an extended delocalised electron system involving the aromatic rings, called a chromophore.
Because intermolecular bonding is much weaker than covalent bonding, the dye molecules must be long and straight so that they can align closely with the cellulose fibres of cotton giving more opportunities for intermolecular attractions.
www.avogadro.co.uk /organic/azodyes/azodyes.htm   (686 words)

  
 AZO Dyes - AZO Dyes Manufacturers,AZO Dyes Suppliers & Exporters
Leading supplier and exporter of azo dye, azo dyestuff, azo dye powder and azo dye liquid.
Leading exporter and supplier of AZO dyes and color additives, modified dyes, natural dyes, blended dyes.
Exporters of AZO dyes, fast dyes, disperse dyes, acid dyes, acid chrome dyes, basic dyes, cationic dyes, direct dyes, neuter dyes, reactive dyes, sulphur dyes and vat dyes.
catalogs.indiamart.com /products/azo-dyes.html   (333 words)

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