Blue prussia is the dark blue pigment produced by the oxidation of iron ferrocyanide salts. It has the ideal chemical formula Fe
7 (CN)
18 . Another name for the color is Berlin blue or, in the painting, Parisian or Paris blue . Turnbull Blue is the same substance, but is made up of different reagents, and slightly different colors come from different impurities.
Blue prussia is the first modern synthetic pigment. It is prepared as a very fine colloidal dispersion, because the compound is insoluble in water. It contains a number of other ionic variables and its appearance is highly dependent on the size of colloidal particles. The pigment is used in paint, and it is the traditional "blue" in the blueprint and aizuri-e Japanese woodblock prints.
In the treatment, given orally Prussian blue is used as an antidote for certain types of heavy metal poisoning, for example, by thallium and the radioactive isotope of cesium. In particular, it is used to absorb 137 Cs of those poisoned in GoiÃÆ'Â ¢ nia accident. This therapy utilizes the properties of ion exchange compounds and high affinity for certain "soft" metal cations.
It's in the List of Essential Medicines of the World Health Organization, the most important drugs needed in basic health systems. Prussian blue lends its name to prussic acid (hydrogen cyanide) derived from it. In Germany, hydrogen cyanide is called BlausÃÆ'¤ure ("blue acid"). The French chemist Joseph Louis Gay-Lussac gave cyanide his name, from the Greek word ?????? ( Kyanos , "blue"), because of the Prussian blue color.
Video Prussian blue
History
The Prussian blue pigment is important because the first stable and relatively lightfast blue pigment is widely used after the loss of knowledge about the Egyptian blue synthesis. The previous European painter used a number of pigments such as indigo, smalt, and purple Tyrian dyes, which tend to fade, and very expensive ultramarine made of lapis lazuli. Japanese painters and woodblock printing artists, too, do not have access to long lasting blue pigments until they start importing Prussian blue from Europe.
Prussian blue Fe
7 (CN)
18 (also ( Fe
4 [Fe (CN)
6 ]
3 ) Ã, Â · x H
2 ) may be synthesized for the first time by the Diesbach paint maker in Berlin around 1706. Partly great source of history does not mention the first name of Diesbach. Only Berger calls it Johann Jacob Diesbach. These pigments are believed to have been inadvertently made when Diesbach used blooded potash with blood to make some red cochineal dye. The original dyes require potassium, iron sulfate, and dry cochineal. In contrast, blood, potassium, and iron sulphate react to create a compound known as iron ferrocyanide, which, unlike the desired red pigment, has a very different blue color. It was named PreuÃÆ'Ÿisch blau and Berlinisch Blau in 1709 by its first trader. Pigments replaced the expensive lapis lazuli and were an important topic in the letter exchanged between Johann Leonhard Frisch and the president of the Royal Academy of Sciences, Gottfried Wilhelm Leibniz, between 1708 and 1716. This was first mentioned in a letter written by Frisch to Leibniz, March 1708. Not more than 1708, Frisch began to promote and sell pigments throughout Europe. In August 1709, the pigment was called Preussisch blau ; in November 1709, the German name Berlinisch Blau has been used for the first time by Frisch. Frisch himself was the first known publishing author of the blue Prussia on Notepia Coerulei Berolinensis nuper inventi paper in 1710, as can be inferred from his letters. Diesbach has been working for Frisch since around 1701.
Until now, the Entombment of Christ, in 1709 by Pieter van der Werff (Picture Gallery, Sanssouci, Potsdam) is the oldest known painting in which the Prussian blue is used. Around 1710, painters in the Prussian palace were already using pigments. At about the same time, Prussia's blue arrived in Paris, where Antoine Watteau and later his successors Nicolas Lancret and Jean-Baptiste Father used it in their paintings.
In 1731, Georg Ernst Stahl published a report on the first synthesis of Prussian blue. This story not only involves Diesbach, but also Johann Konrad Dippel. Diesbach attempts to create red lake pigments from cochineal, but obtains a blue color as a result of the contaminated potion he uses. He borrowed a potash from Dippel, who had used it to produce his "animal oil". No other historical source is known to mention Dippel in this context. Therefore, it is difficult to assess the reliability of this story today. In 1724, the recipe was finally published by John Woodward.
In 1752, the French chemist Pierre J. Macquer made an important step to show the Prussian blue can be reduced to a new iron salt and acid, which can be used to rearrange the dye. The new acid, hydrogen cyanide, was first isolated from Prussian blue in pure form and characterized in 1782 by Swedish chemist Carl Wilhelm Scheele, finally named BlausÃÆ'¤ure (literally "blue acid") because derivatives of Prussian blue, and in English popularly known as Prussic acid. Cyanide, a colorless anion formed in the Prussian blue making process, takes its name from the Greek word for dark blue.
From the early 18th century, the prussian blue color was the dominant uniform color worn by the infantry and artillery troops of the Prussian Army. Like Dunkelblau (dark blue), this shadow reached a symbolic interest and continued to be worn by German soldiers for ceremonial and non-task ceremonies until the outbreak of World War I, when it was replaced by greenery gray field gray (< i> Feldgrau ).
Maps Prussian blue
Production
Prussia blue is produced by the oxidation of iron ferrocyanide salts. This white solid has the formula M
2 Fe [ Fe (CN)
6 ] where M = Na or K . Iron in this material is all iron, hence the absence of deep color is associated with mixed valence. The oxidation of these white solids with hydrogen peroxide or sodium chlorate produces ferricyanide and gives the Prussian blue color.
The form of "soluble", K [Fe III Fe II (CN)
6 ] , which is really colloid, can be made from potassium ferrocyanide and iron (III):
- K Fe 3 < span> [Fe II (CN)
6 ] 4 - -> KFe III [Fe II (CN)
6 ]
A similar reaction of potassium ferricyanide and iron (II) produces the same colloidal solution, because [Fe III (CN)
6 ] 3 -
changed to ferrocyanide.
"Insoluble" Prussia blue is produced when, in the above reaction, excess Fe 3
or Fe 2 < br> , respectively, added. In the first case:
- 4 Fe 3
3 [Fe II (CN)
6 ] 4 - -> Fe III Fe II (CN)
6 ]
Despite the fact that it is made from cyanide salts, Prussia's blue is not poisonous because the cyanide group is tightly bound to iron. Other polymeric cyanometalates are also stable with low toxicity.
Turnbull Turnbull blue
In the past, the addition of iron salt (II) to a ferricyanide solution was considered capable of purchasing different materials from Prussia blue. This product has traditionally been given the blue name of Turnbull (TB). X-ray diffraction and electron diffraction methods have shown, that the structure of PB and TB is identical. The color differences for TB and PB reflect subtle differences in precipitation methods, which greatly affect particle size and impurity content.
Properties
Prussian blue is a microcrystalline blue powder. Insoluble, but crystallites tend to form colloids. Such colloids can pass through fine filters. Although it is one of the oldest known synthetic compounds, the Prussian blue composition remains uncertain for years. Its precise identification is complicated by three factors:
- Prussian blue is very insoluble, but also tends to form colloids.
- Traditional synthesis tends to produce impure compositions.
- Even Prussia blue is purely structurally complex, opposing routine crystallographic analysis.
Crystal Structure
The insoluble formula of Prussia blue chemistry is Fe
7 (CN)
18 Ã, Â · Ã, x H
2 O , where x Ã, = Ã, 14-16. Structures were determined using IR spectroscopy, MÃÆ'¶ssbauer spectroscopy, X-ray crystallography, and neutron crystallography. Because X-ray diffraction can not distinguish carbon from nitrogen, the locations of these light elements are deduced by means of spectroscopy, and by observing the distance from the iron atom centers.
The NT has a cubic lattice structure. PB soluble crystal contains interstitial K ion; Insoluble PBs have interstitial water, instead In an ideal insoluble PB crystal, a cubic frame is constructed from Fe (II) -CN-Fe (III) sequences, with a Fe (II) -carbon spacing of 1.92 Æ'... and Fe (III) -nitrogen distance of 2 , 03 ÃÆ'.... A quarter of the site Fe (CN)
6 empty subunit (empty), leaving the three groups. An empty nitrogen site is filled with water molecules, instead, which are coordinated with Fe (III).
The Fe (II) center, which is a low spin, is surrounded by six carbon ligands in an octahedral configuration. The Fe (III) center, which is a high spin, is octahedral surrounded by an average of 4.5 nitrogen atoms and 1.5 oxygen atoms (oxygen from six coordinated water molecules). An additional eight water molecules (interstitials) are present in unit cells, either as isolated molecules or hydrogen bonded to water.
This composition varies greatly because of a lattice defect, which allows it to be hydrated to various levels when water molecules are inserted into the structure to occupy the cation void. The variability of the Prussian blue composition is due to its low solubility, which causes rapid settling without time to achieve full equilibrium between solid and liquid.
Color
Prussian blue is highly colored and tends toward dark black and blue when mixed into oil paint. The exact color depends on the preparation method, which determines the particle size. The intense blue blue of Prussia is associated with the energy transfer of electrons from Fe (II) to Fe (III). Many such mixed-valence compounds absorb certain wavelengths of visible light resulting from the charge transfer intervalence. In this case, an orange-red light of about 680 nanometers in wavelength is absorbed, and reflected light appears blue as a result.
Like most high chroma pigments, Prussia's blue color can not be displayed accurately on a computer screen. PB is electrochromic - changing from blue to colorless after reduction. This change is caused by the reduction of Fe (III) to Fe (II), eliminating the transfer of the interval cost that causes the Prussia blue color.
Use
Pigment
Because it is easy to make, inexpensive, non-toxic, and highly colored, Prussia's blue has attracted many applications. It was adopted as pigment soon after discovery and was almost immediately widely used in oil, watercolor, and dyeing. The dominant use is for pigments: about 12,000 tonnes of blue Prussia is produced annually for use in black and bluish ink. Other pigments also contain ingredients. Blue colors and pigment engineers are formed on cyanotypes - giving them a common name blueprint. Certain crayons were once stained with Prussian blue (later labeled midnight blue). It is also a popular pigment in paints. Similarly, Prussian blue is the basis for washing clothes.
Medicine
The ability of Prussian blue to combine monocations makes it useful as an alienating agent for certain heavy metal toxins. Pharmaceutical-Prussia blue classes are especially used for people who have swallowed thallium or radioactive cesium. According to the International Atomic Energy Agency, an adult male can eat at least 10 g Prussia Blue per day without serious harm. The US Food and Drug Administration has established "Prussian 500 mg capsules, when manufactured under conditions of approved New Drug Application, that safe and effective therapies can be found" in certain cases of poisoning. Radiogardase (Prussian blue in soluble capsules) is a commercial product for the removal of cesium-137 from the intestine, so indirectly from the bloodstream by interfering with the cesium-137 enterohepatic circulation, reduces the internal residual time (and exposure) by about two-thirds.
Stain for iron
Prussian blue is a common histopathological stain used by pathologists to detect the presence of iron in biopsy specimens, as in bone marrow samples. The original dye formulation, known historically (1867) as "Perls' Prussian blue" after its discoverer, German pathologist Max Perls (1843-1881), used a separate solution of potassium ferrocyanide and acid to the stain tissue (this is now used in combination, just before staining). The iron deposits in the tissue then form the purple Prussia blue dye in place, and are visualized as a blue or purple deposit. This formula is also known as Perls Prussian blue and (false) as the blue blue Perl.
By machine experts and tool builders
Blue engineer, Prussian blue at oily base, is a traditional material used to find metal surfaces such as surface plates and pads to scratch the hand. A thin layer of nondrying paste is applied to the reference surface and transfer to the high points of the workpiece. Tool makers then scratch, stone, or remove marked high points. Prussian blue is preferred because it will not erode the reference surface very precisely because a lot of ground pigment can.
In analytical chemistry
Prussian blue is formed in the Prussian blue test for total phenol. Samples and phenolic standards were given ferric chloride and ferricyanide acids, which were reduced to ferrocyanide by phenol. Iron chloride and ferrocyanide reacts to form Prussian blue. Comparing absorbances in the 700 nm sample with the standard allows the total determination of phenol or polyphenols.
See also
- Blue billy
- Purple crystal
- Fluorescein
- Han purple and Han blue
- Midnight blue
- List of inorganic pigments
References
External links
- FDA page on blue prussia
- The CDC page in blue prussia
- National Pollutant Inventory - Fact Sheet Cyanide Compound
- Heyltex Corporation Distributor from Radiogardase (a capsule insoluble in Prussian blue)
- Sarah Lowengard, "Prussian Blue" in Color Creation in Eighteenth Century Europe Columbia University Press, 2006
- Prussian blue, ColourLex
- Kraft, Alexander (2008). "About Prussian blue discoveries and history" (PDF) . Bull. Hist. Chem. 33 (2): 61-67. Ã,
Source of the article : Wikipedia
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