Cyanide pigments

Alkali or alkaline-earth salts of both complexes are soluble in water (except for Ba2[Fe(CN)g]) but are insoluble in alcohol. The salts of hexakiscyanoferrate(4—) are yellow and those of hexakiscyanoferrate(3—) are mby red. A large variety of complexes arise when one or more cations of the alkah or alkaline-earth salts is replaced by a complex cation, a representative metal, or a transition metal. Many salts have commercial appHcations, although the majority of industrial production of iron cyanide complexes is of iron blues such as Pmssian Blue, used as pigments (see Pigments, inorganic). Many transition-metal salts of [Fe(CN)g] have characteristic colors. Addition of [Fe(CN)g] to an unknown metal salt solution has been used as a quaUtative test for those transition metals. 

Other salts include lead arsenates and lead arsenites (see Insect control technology), lead chromates and lead sihcochromates (see Pigments), lead cyanide (see Cyanides), lead 2-ethyIhexanoate (see Driers and metallic soaps), and lead fluoroborate (see Fluorine compounds, inorganic). 

Cyanide Iron Blues. Cyanide iron blue, also known as Pmssian blue, is one of the oldest industrially produced, inorganic pigments. Chemically, cyanide iron blues are based on the [Fe " Fe (CN) ] anion. The charge is balanced by sodium, potassium, or ammonium cations. Modem... 

Two blue pigments can be prepared in transparent form cyanide iron blue and cobalt aluminum blue. These pigments are used in achieving a blue shade of the metal effect pigments in metallic paints. Transparent cyanide iron blue is prepared by a precipitation reaction similar to the one used for the preparation of the opaque pigment, but considerably lower concentrations of solutions are used. It is produced by Degussa (Germany), Manox (U.K), and Dainichiseika (Japan). 

Aero Agro Chemical hidustries Ltd., 168 AERO , calcium cyanide, 9 Aerojet Fine Chemicals, 215, 229 AEROPHINE , phosphine, 9 AEROTHENE MM , methylene chloride, 9 AFFLAIR , luster pigments, 9 Aflatoxins, 9... 

The formation of a DPP molecule was first reported in 1974 as a minor product in low yield from the reaction of benzonitrile with ethyl bro-moacetate and zinc. A fascinating study by research chemists at Ciba Geigy into the mechanistic pathways involved in the formation of the molecules led to the development of an efficient one-pot synthetic procedure to yield DPP pigments from readily available starting materials, as illustrated in Scheme 4.10. The reaction involves the treatment of diethyl succinate (1 mol) with an aromatic cyanide (2 mol) in the presence of a strong base. The reaction proceeds through the intermediate 88, which may be isolated and used to synthesise unsymmetrical derivatives. 

As a result of variation shown in toxicity, the evaluation of technologies applicable for discharge control, and treatment by some compounds within the industrial chemicals, the SIC 281 groups are further subdivided into 11 subcategories.23 They are aluminum fluoride, chlor-alkali, chrome pigments, copper sulfate, hydrofluoric acid, hydrogen cyanide, nickel sulfate, sodium bisulfate, sodium... 

The synthetic pigment CuPc was obtained by serendipity in 1927 but not identified as such by the authors probably due to analytical limitations and/or because attention was focused on other compounds (de Diesbach von der Weid, 1927). Upon reaction of o-C6H4Br2 with cuprous cyanide and C5H5N a blue insoluble compound was obtained, which undoubtedly was CuPc. Basically there are two commercially important processes to produce CuPc. One is based on phthaloni-trile and the other one uses phthalic anhydride. The phthalonitrile process often yields a product with fewer impurities and using metallic copper gives CuPc by cyclotetramerization. 

Iron Blue, Cl Pigment Blue 27, which has been known by various names over the years, perhaps the best known being Prassian Blue, is ferric ammonium ferricyanide, FeNH Fe(CN)g(xH20. The hrst step in its preparation involves the precipitation of complex iron(ii) cyanides, e.g. potassium hexacyanoferrates(ii) with iron(i) salts, e.g. the sulfate or chloride, in an aqueous solution in the presence of ammonium... 

Iron blue pigments are produced by the precipitation of complex iron(II) cyanides by iron(II) salts in aqueous solution. The product is a whitish precipitate of iron(II) hexacyanoferrate(II) M 2Fe1I[Fe1I(CN)6] or M11Fe11[Fe11(CN)6], (Berlin white), which is aged and then oxidized to the blue pigment [3.180]. 

Even prior to Pasteur, alcohol content determination was important as a basis for local, import, and export taxes. Other important applications of accurate wine analysis have been to detect and to accurately determine food additives now there are legal reasons for analyzing wines for sulfur dioxide, organic chloride or bromide, sodium, cyanide, diglucoside pigments, various insecticides, fungicides, etc. Winery control calls for analytical determination of iron, copper, protein, total acidity, pH, tartaric, malic and lactic acids, etc. Finally, quality control... 

Another oxygen-containing pigment is confusingly named hetnocyania, which contains neither the heme group nor the cyanide ion the name simply means "blue... 

Zinc chromate is a useful yellow pigment widely used in metal priming paints zinc cyanide is used in electropating the fluoride, ZnF2, is used in the fluorination of organics, in the manufacture of phosphors for fluorescent electric lights, in glazes and enamels for porcelain and in wool preservation. 

Copper Carbonate (Basic), CuCOi CutOH j. dark-green monoclinic crystals, insoluble in cold HiO decomposes in hot H 0, soluble in potassium cyanide. Malachite, a copper ore. is of this composition. Refined compound is used as a pigment. 

Bone black which has been recently prepared and not washed contains small quantities of calcium cyanide, which may be detected by extracting about 200 grams of the pigment with cold water and evaporating the filtrate to very small volume with a few drops of ammonium sulphide this procedure yields calcium thiocyanate, which is recognisable by its reaction with ferric chloride. 

History. Braun and Tschemak [23] obtained phthalocyanine for the first time in 1907 as a byproduct of the preparation of o-cyanobenzamide from phthalimide and acetic anhydride. However, this discovery was of no special interest at the time. In 1927, de Diesbach and von der Weid prepared CuPc in 23 % yield by treating o-dibromobenzene with copper cyanide in pyridine [24], Instead of the colorless dinitriles, they obtained deep blue CuPc and observed the exceptional stability of their product to sulfuric acid, alkalis, and heat. The third observation of a phthalocyanine was made at Scottish Dyes, in 1929 [25], During the preparation of phthalimide from phthalic anhydride and ammonia in an enamel vessel, a greenish blue impurity appeared. Dunsworth and Drescher carried out a preliminary examination of the compound, which was analyzed as an iron complex. It was formed in a chipped region of the enamel with iron from the vessel. Further experiments yielded FePc, CuPc, and NiPc. It was soon realized that these products could be used as pigments or textile colorants. Linstead et al. at the University of London discovered the structure of phthalocyanines and developed improved synthetic methods for several metal phthalocyanines from 1929 to 1934 [1-11]. The important CuPc could not be protected by a patent, because it had been described earlier in the literature [23], Based on Linstead s work the structure of phthalocyanines was confirmed by several physicochemical measurements [26-32], Methods such as X-ray diffraction or electron microscopy verified the planarity of this macrocyclic system. Properties such as polymorphism, absorption spectra, magnetic and catalytic characteristics, oxidation and reduc-... 

Reports of blue pigmentation of walls resulting from fumigation with hydrogen cyanide for the destruction of vermin in areas with... 

The iron cyanides have long been known for their extraordinary stability, one of them having achieved particular fame as one of the most commonly used blue pigments during the last three centuries ... 

Iron Blue is the ISO designation (ISO 2495) for iron cyanide blue pigments of various composition, which are also known as Berlin Blue, Turnbull s Blue, Prussian Blue, Vossen Blue , Milori Blue, Paris Blue, French Blue, China Blue, Bronze Blue, Steel Blue, Ink Blue, among others. 

---