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Copper chromite - Sciencemadness Wiki

. Historically, magnesium is most important as magnesium euxanthate, commonly called or indian yellow. It was probably introduced into India in the 15th century from Persia (modern Iran), and is prominent in Indian paintings of the Mughal period (late 16th to 19th centuries). The pigment was known in Europe as early as 1780, and used infrequently throughout the 19th century, mostly in watermedia paints. In daylight the fresh color fluoresces in "yellow green" wavelengths; this combines with a deep yellow pigment color to produce a unique luminescent, duotoned golden yellow hue. This synthetic inorganic pigment was made from the urine of cows fed on mango leaves; crystals of the concentrated dried urine were formed into balls and covered with mud for shipment to England, where some still reside in the Winsor & Newton pigment archives. The manufacturing process was not accurately described until 1886, after laws against cruelty to animals had been passed by the British regime in India (the mango leaf diet is inadequate nutrition for the cows). It's commonly reported that this process was banned entirely in 1908, but no modern source has actually found a copy of this edict; instead the pigment likely disappeared due to enforcement of statutes against animal cruelty passed in 1890. More to the point, demand for the pigment had by then largely disappeared, displaced by the new , (which often inherited the name "indian yellow") and . Winsor & Newton discontinued the pigment in watercolor paints in the 1920's, but their substitute (listed under ) provides a close color match. Modern tests show that original indian yellow has good lightfastness in a gum arabic vehicle, though the fluorescing yellow color fades after moderate exposure to light. In modern pigments magnesium is important primarily in the formation of (magnesium aluminum oxide, MgAl2O4), an octahedral crystal lattice in which the atoms of magnesium or aluminum (or both) can be replaced by other metal ions (chiefly , iron, zinc, manganese, copper, cobalt, nickel or chromium) to produce a wide range of whitish, highly durable turquoise, green, yellow or red pigments.

Cladingboel, D. E. 2001. Copper Chromite. e-EROS Encyclopedia of Reagents for Organic Synthesis. .

Copper is also the metallic atom in the green azomethine pigments ( and ), and the green and blue phthalocyanines, all described in the section on pigments. A couple of black pigments are known, made of the spinel crystal of copper chromite (PBk22 and PBk28), but these are not currently used in artists' paints.

(copper chromite) water, hydrogen

Copper is also the metallic atom in the green azomethine pigments ( and ), and the green and blue phthalocyanines, all described in the section on pigments. A couple of black pigments are known, made of the spinel crystal of copper chromite (PBk22 and PBk28), but these are not currently used in artists' paints.

A more exotic iron pigment is iron blue ( sometimes with sodium or potassium ions substituted for the ammonia ion) known to 18th and 19th century artists as Prussian blue, Berlin blue, Paris blue, Milori blue or Chinese blue (). This is the first modern synthetic inorganic pigment, discovered by chance in Berlin (hence the name "Prussian" or "Berlin" blue) in 1704 when the colormaker Heinrich Diesbach attempted to make a crimson pigment called Florentine lake from cochineal, alum, ferrous sulfate and some borrowed potash that was contaminated with animal blood. Diesbach communicated the recipe to his pupil de Pierre, who began to manufacture it in Paris. (Hence "Paris" blue. The label "Chinese" derives from the use of iron blue in the blue patterns on Meissen china, manufactured near Dresden.) Held secret for two decades, the manufacturing process was published in England by John Woodward in 1724, but by then alternative methods of production had been devised and the pigment was being manufactured throughout Europe and in America. It has been used in watercolors since around 1730 and is still sold today, although most watercolor artists now seem to prefer the more intense pigments. PB27 is a dark, unsaturated, staining, semitransparent and completely nontoxic middle blue; the color is sometimes adjusted by mixing with barium sulfate or alumina (which makes antwerp blue, a lighter, greener and less lightfast pigment). Iron blue is very reliable in pure form (both the ASTM reports and my own tests give it "excellent (I)" lightfastness), but it loses permanency if mixed with impurities such as potassium ferrocyanide or with other pigments such as titanium dioxide; my lightfastness tests demonstrated significant lightfastness variations across different watercolor paint manufacturers. Some descriptions of its quirks (for example, that it fades in masstone when exposed to strong light, but returns to its original color in darkness) have been uncritically handed down from the 19th century and are, as far as I can determine, myth. PB27 is currently manufactured as a precipitate from the reaction in solution of iron salts with sodium or potassium ferrocyanide, which is aged and oxidized to create the blue color. The pigment tends to agglomerate into rather stringy clumps that resist milling, but a special manufacturing method developed by BASF in 1982 (using the anodic oxidation of iron particles in hydrogen cyanide acid) produces very fine, pure and easily dispersable pigment particles with an atypically intense reddish color, valuable in printing inks. The pigment prussian green is a fused matrix of iron blue and lead chromate; cyanine blue is a mixture of iron blue and cobalt blue.

Copper Chromite Catalyst Preparation ..

The amazing story of these early industrial pigments is well told in Nearly all synthetic inorganic pigments were discovered or identified in the grand European flowering of inorganic chemistry that occurred in the century after 1750, when European industries sponsored intensive minerological and metallurgical research, and early chemists isolated and identified many new metallic elements — cadmium, cobalt, chromium, zinc, manganese, magnesium, and so on. (These new puzzle pieces helped John Dalton to formulate modern atomic theory in around 1805.) Several synthetic inorganic pigments still used today, including , , and , were discovered prior to 1800.

The amazing story of these early industrial pigments is well told in Nearly all synthetic inorganic pigments were discovered or identified in the grand European flowering of inorganic chemistry that occurred in the century after 1750, when European industries sponsored intensive minerological and metallurgical research, and early chemists isolated and identified many new metallic elements — cadmium, cobalt, chromium, zinc, manganese, magnesium, and so on. (These new puzzle pieces helped John Dalton to formulate modern atomic theory in around 1805.) Several synthetic inorganic pigments still used today, including , , and , were discovered prior to 1800.

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Copper Chromite - Copper Chromite, Manufacturer, …

An efficient synthesis of cyclopropanecarboxylic acids using copper chromite spinel nanoparticles and basic ionic liquid is described. In this study, a relatively simple method starting with trans-cinnamic acid for the synthesis of (±)-trans-2-phenylcyclopropanecarboxylic acid, a key intermediate in the synthesis of tranylcypromine sulfate as an active pharmaceutical ingredient, was employed. Using a combination of basic ionic liquid [Bmim]OH and copper chromite spinel nanoparticles as a catalytic system, the best results were obtained in THF as a polar solvent. This method is a useful alternative to other approaches described in the literature. The use of commercially available chemicals, decreased environmental hazards, with no need for the separation of stereoisomers, and consequently a reduced number of overall steps, are the advantages of this approach that make it an appropriate choice at an increased scale.

Solution Combustion Synthesis of Nanosized Copper Chromite …

. Historically copper is a major source of blue or green pigments, which only recently have been available as lightfast compounds. The natural mineral forms (hydrated copper silicate), and were known and used since antiquity. Cyan blue copper carbonate, called blue verditer or bice, is the synthetic form of azurite. It played a minor role in artists' colors in the 18th and 19th centuries (it has a relatively low tinting strength, and was more commonly used as a housepaint). Copper is more important as a constituent of several impermanent, synthetic inorganic green pigments. Verdigris (copper acetate, PG20) is an ancient pigment manufactured by exposing copper strips to acetic acid (vinegar); it fell out of use by the 19th century (not least because it was impermanent and would eat through cellulose). Scheele's green (PG22), the first modern synthetic green pigment, was discovered around 1775 by the Swedish chemist Carl Wilhelm Scheele; the hue ranged from pale yellow green to deep middle green. Schweinfurt green (copper acetoarsenite, PG21) is an intense, light valued, blue green compound of arsenic and verdigris; it was discovered independently in 1814 by the paint manufacturer Wilhelm Sattler and the chemist Ignaz von Mitis, and commercially manufactured from public recipes after 1822 under a variety of names — Vienna green, King's green, Paris green, Mitis green, Parrot green, and (in English speaking countries) emerald green. All these synthetic copper compounds fell out of use by the mid 20th century because they have very poor permanency (they turn black through the formation of copper oxide, PBk15, especially when used with sulfur pigments), and because those containing arsenic are extremely toxic (Schweinfurt green was also sold as a pesticide — "the only sure exterminator of the potato bug and cotton worm" reads one 19th century ad — and was possibly the poison used to kill Napoleon).

Pechini synthesis and microstructure of nickel-doped copper …

. Historically copper is a major source of blue or green pigments, which only recently have been available as lightfast compounds. The natural mineral forms (hydrated copper silicate), and were known and used since antiquity. Cyan blue copper carbonate, called blue verditer or bice, is the synthetic form of azurite. It played a minor role in artists' colors in the 18th and 19th centuries (it has a relatively low tinting strength, and was more commonly used as a housepaint). Copper is more important as a constituent of several impermanent, synthetic inorganic green pigments. Verdigris (copper acetate, PG20) is an ancient pigment manufactured by exposing copper strips to acetic acid (vinegar); it fell out of use by the 19th century (not least because it was impermanent and would eat through cellulose). Scheele's green (PG22), the first modern synthetic green pigment, was discovered around 1775 by the Swedish chemist Carl Wilhelm Scheele; the hue ranged from pale yellow green to deep middle green. Schweinfurt green (copper acetoarsenite, PG21) is an intense, light valued, blue green compound of arsenic and verdigris; it was discovered independently in 1814 by the paint manufacturer Wilhelm Sattler and the chemist Ignaz von Mitis, and commercially manufactured from public recipes after 1822 under a variety of names — Vienna green, King's green, Paris green, Mitis green, Parrot green, and (in English speaking countries) emerald green. All these synthetic copper compounds fell out of use by the mid 20th century because they have very poor permanency (they turn black through the formation of copper oxide, PBk15, especially when used with sulfur pigments), and because those containing arsenic are extremely toxic (Schweinfurt green was also sold as a pesticide — "the only sure exterminator of the potato bug and cotton worm" reads one 19th century ad — and was possibly the poison used to kill Napoleon).

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