Chem Chp 9

what structural characteristics gives beta-carotene and crocetin the ability to be visibly colored?

a chain of 7 alternating double bonds

what is a mordant?

a dye where another chemical (metal ion) is needed to fix color to a fabric

name the compound from the madder plant that produced the red dye with which alexander the great used to trick the persian army

alizarin

define dye

an organic molecule that absorbs some wavelengths of light preferentially and reflects all the other wavelengths

what source does juglone, lawsone, echinochrome, and carminic acid come from?

animals

what is the formation of the blue indigo from the molecule?

1-fermentation in a base (under alkaline conditions) and 2-oxidation in air

what three german dye companies were reorganized after WW I into the chemical powerhouse company IG Farben?

Badische Anilin und Soda Fabrik (BASF), Hoechst, and Bayer and Company

what other functional group allows alizarin, juglone, lawsone, echinochrome, and carminic acid to be colored instead of colorless like the parent compounds anthraquinone and naphthaquinone?

OH groups

what functional disadvantages exist for the use of picric acid as a dye?

because it is nitrogen containing it had explosive potentials

where does the visible spectrum appear in the EM spectrum?

between ultraviolet waves and infrared waves

if all wavelengths of color are absorbed, what color is seen?

black

what is the relationship between molecular conjugation in a dye molecule and visible light absorption/reflection?

conjugation can be extended and the wavelength of light absorbed is changed

perkin's accidental creation of mauveine led to the development of many aniline-based dyes. what is aniline?

dyes made from the coal tar residues from the coal gas industry

what is the electromagnetic spectrum (EM)?

entity responsible for all radiation in the universe

what limitations were associated with early dyes?

extraction process was complicated (from plants), most substances did not adhere permanently to untreated fibers, colors were not strong and faded quickly, bled out at every wash

what country developed the largest chemical 'empire' out of the dye trade revolutionized by perkin?

germany

what functional group identifies many basic materials? what effect does the fermentation step have on the molecule? what chemical transformation occurs with the oxidation step?

glucose identifies with many basic materials, the fermentation allows for the indigo color to appear in the leaves which then splits off the flucose unit to produce the indoxol molecule. this reacts with oxygen to create the blue-colored indigo

what reasons encouraged william henry perkin to try and synthesize the malaria drug quinine?

his professor had convinced him that quinine could be synthesized from materials found in coal tar

both indigo and tyrian purple are blue dyes. compare and contrast these dyes, including source, preparation technique, value, and chemical structure

indigo is extracted from a plant, has a two step process to produce the color, was a valuable substance because of the demand, does not have a bromine atom. tyrian is obtained from the Murex (marine mollusk or snail), obtained from the animals secretions, was the most expensive dye, in some cultures it implied an aristocratic pedigree, and includes 2 bromine atoms

what plants are sources of natural indigo dyes?

indigofera tinctoria and isatis tinctoria

what advantages did perkins' mauveine have over natural purple dyes?

it was colorfast, and did not fade after washing

what is pH? what pH values are associated with acidic materials? what pH values are associated with basic or alkaline materials?

pH describes the acid-alkaline balance in a substance. p for potential and h for hydrogen. acidic materials are associated with lower numbers and basic materials are associated with higher (0-14)

what is the difference between a dye and a pigment?

pigments are made from finely ground minerals and other organic compounds

what source does alizarin come from?

plants

what factors enabled germany to do so well in its growth of the dye and chemical industries?

the collaborative effort between their industry and universities

what defines a color seen by the eye?

the color seen by the eye depends on the light that is reflected back to the eye rather than absorbed

why did perkin's experiment fail to produce quinine? what was not yet understood?

unknown knowledge about the actual structures of allyltoluidine and quinine, it isnt possible to devise the chemical steps necessary to transform one molecule into another

if all wavelengths of color are reflected, what color is seen?

white