Manufacture of Chromium Compounds

In 1997, the major manufacturers of chromium compounds were (1) chromic(VI) acid, including chromic(VI) anhydride and chromic(VI) trioxide (total capacity 76,000 metric tons) American Chrome Chemicals Inc., Corpus Christi, Texas Occidental Chemical Corporation Specialty Business Group, Castle Hayne, North Carolina (2) chromium(III) sulfate Blue Grass Chemical Specialties, L.P., New Albany, Indiana Johnson Matthey, Inc., Ward Hill, Massachusetts Wayne Chemical Corp., Amarillo, Texas, Dakota City, Nebraska, and Milwaukee, Wisconsin (3) chromium(III) acetate Blue Grass Chemical Specialties, L.P., McGean-Rohco, Inc., Cleveland, Ohio The Shepard Chemical Company, Cincinnati, Ohio (4) chromium acetylacetonate MacKenzie Corporation, Bush, Louisiana The Shepard Chemical Company, Cincinnati, Ohio (5) chromium boride Cerac Incorporated, Milwaukee,... 

Satoh K, Fukuda Y, Torrii K, et al. 1981. Epidemiological study of workers engaged in the manufacture of chromium compounds. J Occup Med 23(12) 835-838. 

Shmitova LA. 1980. [Content of hexavalent chromium in the biological substrates of pregnant women and women in the immediate post-natal period engaged in the manufacture of chromium compounds]. 

Use Corrosion inhibitor, catalyst, manufacture of chromium compounds. 

Ca.ta.lysts, A more important minor use of chromium compounds is ia the manufacture of catalysts (Table 14). Chromium catalysts are used ia a great variety of reactions, including hydrogenations, oxidations, and polymerizations (229—231). Most of the details are proprietary and many patents are available. 

Chromium Manufacture of Cr compounds, paint pigments Lung cancer... 

Hepatic Effects. Chromium(VI) has been reported to cause severe liver effects in four of five workers exposed to chromium trioxide in the chrome plating industry. Derangement of the cells in the liver, necrosis, lymphocytic and histiocytic infiltration, and increases in Kupffer cells were reported. Abnormalities in tests for hepatic dysfunction included increases in sulfobromophthalein retention, gamma globulin, icterus, cephalin cholesterol flocculation, and thymol turbidity (Pascale et al. 1952). In a cohort of 4,227 workers involved in production of stainless steel from 1968 to 1984, excess deaths were observed from cirrhosis of the liver compared to expected deaths (0/E=55/31.6) based on national rates and matched for age, sex, and calender time having an SMR of 174 with confidence limits of 131-226 (Moulin et al. 1993). No measurements of exposure were provided. Based on limited information, however, the production of chromium compounds does not appear to be associated with liver effects. As part of a mortality and morbidity study of workers engaged in the manufacture of chromium(VI) compounds (84%) and chromium(III) compounds (16%) derived from chromium(VI) in Japan, 94 workers who had been exposed for 1-28 years were given a complete series of liver function... 

Fourcroy and Hatiy suggested chromium as a suitable name for the element in recognition of the various colours shown by its derivatives, Greek khroma colour. The same year Vauquelin detected chromium in the spinel ruby while Taessert showed it to be an essential constituent of chrome iron ore or chromite, FeO.Cr2Os — now the main source of chromium compounds. The colour of the ruby is now usually attributed to its chromium content and artificial rubies are manufactured by fusing pure alumina with a little oxide of chromium, to colour it, in an... 

In 1799, Tassierf a German chemist active in France, discovered chromium in an iron mineral from the Var region of southeastern France. This interested Fourcroy, who anticipated that iron-chromium ores might be source materials for a diversified manufacture of chromium chemicals. Due to the richness of color of the metal s compounds the minerals could be used for painting and for manufacturing colored glass and china. 

Chromium Oxide-Based Catalysts. Chromium oxide-based catalysts were originally developed by Phillips Petroleum Company for the manufacture of HDPE resins subsequendy, they have been modified for ethylene—a-olefin copolymerisation reactions (10). These catalysts use a mixed sihca—titania support containing from 2 to 20 wt % of Ti. After the deposition of chromium species onto the support, the catalyst is first oxidised by an oxygen—air mixture and then reduced at increased temperatures with carbon monoxide. The catalyst systems used for ethylene copolymerisation consist of sohd catalysts and co-catalysts, ie, triaLkylboron or trialkyl aluminum compounds. Ethylene—a-olefin copolymers produced with these catalysts have very broad molecular weight distributions, characterised by M.Jin the 12—35 and MER in the 80—200 range. 

Sulfates of sodium are iadustriaUy important materials commonly sold ia three forms (Table 1). In the period from 1970 to 1981, > 1 million metric tons were consumed aimuaHy ia the United States. Siace then, demand has declined. In 1988 consumption dropped to 890,000 t, and ia 1994 to 610,000 t (1,2). Sodium sulfate is used principally (40%) ia the soap (qv) and detergent iadustries. Pulp and paper manufacturers consume 25%, textiles 19%, glass 5%, and miscellaneous iadustries consume 11% (3). About half of all sodium sulfate produced is a synthetic by-product of rayon, dichromate, phenol (qv), or potash (see Chromium compounds Fibers, regenerated cellulosics Potassium compounds). Sodium sulfate made as a by-product is referred to as synthetic. Sodium sulfate made from mirabilite, thenardite, or naturally occurring brine is called natural sodium sulfate. In 1994, about 300,000 t of sodium sulfate were produced as a by-product another 300,000 t were produced from natural sodium sulfate deposits (4). 

The starting materials of the aldehyde method may be sulfonated. For example. Cl Acid Blue 9 [2650-18-2] Cl Food Blue 2 (Cl 42090), is manufactured by condensing a-(A/-ethylanilino)-y -toluenesulfonic acid with o-sulfobenzaldehyde. The leuco base is oxidized with sodium dichromate to the dye, which is usually isolated as the ammonium salt. In this case, the removal of the excess amine is not necessary. However, this color caimot be used in the food sector because separation of the chromium compounds from the dye is difficult. An alternative method which gives food-grade Cl Acid Blue 9 (14) and dispenses with the use of sodium dichromate employs oxidative electrolysis of the leuco base (49). 

Around 1800, the attack of chromite [53293-42-8] ore by lime and alkaU carbonate oxidation was developed as an economic process for the production of chromate compounds, which were primarily used for the manufacture of pigments (qv). Other commercially developed uses were the development of mordant dyeing using chromates in 1820, chrome tanning in 1828 (2), and chromium plating in 1926 (3) (see Dyes and dye intermediates Electroplating Leather). In 1824, the first chromyl compounds were synthesized followed by the discovery of chromous compounds 20 years later. Organochromium compounds were produced in 1919, and chromium carbonyl was made in 1927 (1,2). 

Manufacture The primary iadustrial compounds of chromium made directly from chromite ore are sodium chromate, sodium dichromate, and chromic acid. Secondary chromium compounds produced ia quantity include potassium dichromate, potassium chromate, and ammonium dichromate. 

Water-Soluble Trivalent Chromium Compounds. Most water-soluble Cr(III) compounds are produced from the reduction of sodium dichromate or chromic acid solutions. This route is less expensive than dissolving pure chromium metal, it uses high quaHty raw materials that are readily available, and there is more processing fiexibiHty. Finished products from this manufacturing method are marketed as crystals, powders, and Hquid concentrates. 

The final consideration for the manufacture of Cr(III) compounds is the mole ratio of acid to Cr. This ratio determines the basicity value of the product. Basicity can also be stated as the amount of positive charge on chromium (ITT) neutralized by hydroxide. For example, is 0% basic,... 

Fourcroy predicted that this mineral would give chemists the opportunity to make a more thorough study of the properties of chromium and perhaps to discover compounds of it which, because of their rich and varied colors, would be useful in painting and in the manufacture of glass and enamel (90). He also encouraged study of the chromium alloys. The chrome-iron ore is now known as chromite. It is not a chromate, but has the spinel composition, Fe(Cr02)2-... 

Such reactions comprise practically all those in which hydrogen is linked to carbon to produce of necessity hydroxy compounds, which are of industrial importance, e.g., the manufacture of methanol and higher alcohols from carbon monoxide and hydrogen in presence of catalysts, such as zinc-chromium oxides. 

The fact that only one proton is lost from an o.o -diaminodiarylazo compound on metal complex formation is not only of theoretical interest but has important practical implications in the synthesis of unsymmetrical 2 1 chromium(III) and cobalt(III) complex dyestuffs for wool. The most important complexes of these types are those which are doubly negatively charged (Section 58.1) and are obtained from one molecule of a sulfonated tridentate azo compound and one molecule of an unsulfonated tridentate azo compound. In general the latter are insoluble in water and it is necessary to use organic solvents in the manufacture of complexes such as (10). This is very undesirable from the point of view of the dyestuffs manufacturer and any means of avoiding the use of solvents is attractive to him. The use of sulfonated o,u -diaminodiarylazo compounds in combination with, for example, sulfonated o,o -dihydroxydiarylazo compounds opened up one such possibility, e.g. (77), although this has not yet been exploited commercially. 

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