Iron compounds, manufacture

Most commercial liquid ammonia contains up to several ppm of colloidal iron compounds, possibly the iron oxide catalyst commonly used in manufacturing ammonia. Reduction converts these compounds to colloidal iron which strongly catalyzes the reaction between alcohols and sodium and potassium. The reaction of lithium with alcohols is also catalyzed by iron but to a markedly lesser degree. The data in Table 1-4 illustrate the magnitude of these catalytic effects. The data of Table 1-5 emphasize how less than 1 ppm... 

Mossbauer spectroscopy is a selective tool for the quantitative analysis and spe-ciation of a very limited number of elements. It has been mainly used to study iron compounds—e.g., ceramics, as it gives valuable information about iron-bearing oxide and silicate minerals. This technique has been applied to the identification of the provenance of clay and used raw materials—the manufacturing method employed in pottery and, to a lesser extent, to the characterization of pigments and weathering crusts formed on stone monuments [23]. 

Tt is well known that iron is a common constituent of works of art and of artifacts of archaeological interest. This is undoubtedly because of its occurrence in most rocks of the earths crust and in a variety of colored compounds. The chemistry of iron compounds is fairly complex, and the form in which it is eventually found in an object can provide information on the source and the technique of manufacture of that object. Mossbauer effect spectroscopy (MES) is particularly suitable for studying iron and its compounds. Already there are two published reports 1,2) of MES applied to the study of ancient pottery. However, those studies, like most MES work, required sample taking and preparation. We have explored the possibility of nondestructive MES and now report on practicality of this method. Since there are many good descrip-... 

If the linters are to be used for the manufacture of particularly pure, white collodion cotton intended for production of varnishes or celluloid, it is necessary to remove any iron compounds from the cellulose. This can be carried out by washing the cotton with an oxalic add solution, followed by a water rinse. 

Several iron compounds, some of which are FeC03, FeCl2, and FeS04, have industrial uses. The last of these is used in the manufacture of inks and dyes. Two interesting reactions involving iron compounds can be shown as follows ... 

Iron delivery to cells in culture needs careful consideration transferrin has been used successfully for many years, human transferrin being more effective than bovine [65]. However, this is stiU an animal-derived raw material and thus undesirable for biopharmaceutical manufacturing. Some cells do not need an iron carrier and can be supplied with soluble iron compounds such as ferric ammonic citrate [66]. In other cases an iron carrier may be required such as the synthetic lipophiUc iron carrier tropolone [67, 68]. 

Direct use of chlorine is in pulp and paper manufacturing and water treatment operations. Chlorine is used in the pulp and paper industiy to bleach the pulp to produce a high-quality whitened material, devoid of dark lignin and any other undesirable residuals. Chlorine has been the most common disinfectant and is still used by municipalities and others to treat potable, process, and waste water streams. Because of this specific use of chlorine, waterborne diseases such as typhoid and cholera have been eradicated in the industrialized world. Chlorine also removes hydrogen sulfide, iron compounds, and organic species that are responsible for objectionable tastes or odor associated with water. 

In regard to surfactants used in emulsion polymerizations, the presence of small quantities of iron salts or complexes is usually desirable particularly in redox-initiated systems. At least one manufacturer of surfactants furnishes a grade specifically designed for use in emulsion polymerizations. This material probably contains controlled amounts of iron compounds. 

According to the manufacturer, SulfaTreat is a substantially dry, free-flowing material, composed of a unique, proprietary iron compound mixed with supplemental chemicals, which has been granulated to facilitate ease of handling. The insoluble particles range in size between 4 and 30 mesh, and have a bulk density of 70 Ib/cu ft (Gas Sweetener Associates. Inc., 1991). 

The o- and p-isomers are manufactured by the direct chlorination of benzene in the presence of iron as a catalyst, the resulting mixture being separated by fractional distillation. The w-isomer may be obtained by isomerization of the 0- or p-compound in the presence of a catalyst. 

In 1990, appioximately 66,000 metric tons of alumina trihydiate [12252-70-9] AI2O2 3H20, the most widely used flame retardant, was used to inhibit the flammabihty of plastics processed at low temperatures. Alumina trihydrate is manufactured from either bauxite ore or recovered aluminum by either the Bayer or sinter processes (25). In the Bayer process, the bauxite ore is digested in a caustic solution, then filtered to remove siUcate, titanate, and iron impurities. The alumina trihydrate is recovered from the filtered solution by precipitation. In the sinter process the aluminum is leached from the ore using a solution of soda and lime from which pure alumina trihydrate is recovered (see Aluminum compounds). 

In the Bnchamp process, nitro compounds are reduced to amines in the presence of iron and an acid. This is the oldest commercial process for preparing amines, but in more recent years it has been largely replaced by catalytic hydrogenation. Nevertheless, the Bnchamp reduction is still used in the dyestuff industry for the production of small volume amines and for the manufacture of iron oxide pigments aniline is produced as a by-product. The Bnchamp reduction is generally mn as a batch process however, it can also be mn as a continuous (48) or semicontinuous process (49). 

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

Dichlorophenols. Among all the dichlorophenols, C H Cl O, it is 2,4-dichlorophenol that is produced in greatest quantity. 2,4-Dichlorophenol is used in manufacturing 2,4-dichlorophenoxyacetic acid [94-75-7] (2,4-D) and 2-(2,4-dichlorophenoxy)propionic acid [720-36-5] (2,4-DP). Industrially, 2,4-dichlorophenol can be obtained by chlorinating phenol, -chlorophenol, o-chlorophenol, or a mixture of these compounds in cast-iron reactors. The chlorinating agent may be chlorine or sulfuryl chloride in combination with a Lewis acid. For example ... 

Rock Paintings in the Field. The manufacturing and composition of paints from prehistoric periods are of great archaeological interest because it is possible to deduce aspects of the ancient cultures based on their abilities to produce works of arts. Many pigments used in ancient paintings are iron-based compounds. In most... 

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