Iron sources

As can be seen in Figure 8, the proportion of world pig iron produced in the United States has decreased dramatically since 1950. Also notable is the widening gap between pig iron and steel production, indicating the increasing use of recycled iron or scrap (see Recycling, ferrous metals) and alternative iron sources such as DRI and HBI. The increased demand for scrap is reflected in scrap iron prices (Fig. 9), which in turn have spurred growth in direct reduction processes. 

Pig iron and iron and steel scrap are the sources of iron for steelmaking in basic-oxygen furnaces. Electric furnaces have rehed on iron and steel scrap, although newer iron sources such as direct-reduced iron (DRI), iron carbide, and even pig iron are becoming both desirable and available (see Iron bydirectreduction). In basic-oxygen furnaces, the pig iron is used in the molten state as obtained from the blast furnace in this form, pig iron is referred to as hot metal. 

Williams, S. M., Ainsworth, R. G., and Elvidge, A. F., A method of assessing the corrosivity of water towards iron , Source document 3, Water Mains Rehabilitation Manual, Water Research Centre/Water Authorities Association (1986)... 

An iron complex-catalyzed asymmetric hydrosilylation of ketones was achieved by using chiral phosphoms ligands [68]. Among various ligands, the best enantios-electivities (up to 99% ee) were obtained using a combination of Fe(OAc)2/(5,5)-Me-Duphos in THF. This hydrosilylation works smoothly in other solvents (diethylether, n-hexane, dichloromethane, and toluene), but other iron sources are not effective. Surprisingly, this Fe catalyst (45% ee) was more efficient in the asymmetric hydrosilylation of cyclohexylmethylketone, a substrate that proved to be problematic in hydrosilylations using Ru [69] or Ti [70] catalysts (43 and 23% ee, respectively). 

Iron-catalyzed C(sp )-C(sp ) bond-forming cross-coupling reactions of alcohols with alkenes has been reported by Tu and coworkers in 2009 [109]. Reactions of primary alcohols with various alkenes in the presence of a catalytic amount of FeCls in 1,2-dichloroethane afford the desired secondary alcohols as the crosscoupling products in moderate to good yields (Scheme 33). Iron sources such as... 

Beller and coworkers found in 2009 that alkynes react with amines under the CO pressure (20 bar) in the presence of catalytic amounts of [Fe3(CO)i2] to the corresponding succinimide in moderate to excellent yields (Scheme 35) [110]. Various terminal and internal alkynes and ammonia or primary amines are adaptable for this transformation. Furthermore, [Fe(CO)s] as an iron source showed high activity. The catalytic activity, however, decreased considerably when a phosphine ligand such as PPh3 and ( Bu)2P("Bu) was employed. 

In 2009, Beller (Scheme 45) [147] and Nagashima (Scheme 46) [148] independently reported an iron-catalyzed hydrosilane reduction of carboxamides to amines. Although inexpensive PMHS and TMDS as an H-Si source are usable, the yield of product considerably decreased when hydrosilane containing only one H-Si moiety or iron sources such as Fe(acac)2 and FeX2 (X = F, Cl) was used. In both thermal and photoassisted conditions, almost the same reactivities were observed upon using a combination of Fe catalyst with TMDS (Scheme 46). 

Wandersman C, P Delepelaire (2004) Bacterial iron sources from siderophores to hemophores. Annu Rev Microbiol 58 611-647. 

The use of microbial siderophores by dicotyledonous plants appears to involve uptake of the entire metallated chelate (42-44), or an indirect process in which the siderophore undergoes degradation to release iron (45). As demonstrated in initial studies examining this question, there was concern that iron uptake from microbial siderophores may be an artifact of microbial iron uptake in which radiolabeled iron is accumulated by root-colonizing microorganisms (46). Consequently, evidence for direct uptake of iron from microbial siderophores has required the use of axenic plants. In experiments with cucumber, it was shown that the microbial siderophore ferrioxamine B could be used as an iron source at concentrations as low as 5 pM and that the siderophore itself entered the plant (42). 

Several studies have shown that ferrated pyoverdine-type siderophores can be used as iron sources for plants when added to soils (79,80). However, to date almost all attempts to supply iron to plants by inoculation of hydroponic solutions with siderophore-producing bacteria or by inoculating soils with pseudomonads have been unsuccessful (58,63,81). In experiments with cucumber, inoculation of a hydroponic medium with P. putida or with soil microorganisms and amend-... 

E. Jurkevitch, Y. Hadar, Y. Chen, M. Chino, and S. Mori, Indirect utilization of the phytosiderophore mugineic acid as an iron source to rhizosphere fluorescent Pseudomonas. BioMetals 6 119 (1993). 

E. Bar-Ness, Y. Chen, Y. Hadar, H. Marschner, and V. Romheld, Siderophores of Pseudomonas puiida as an iron source for dicot and monocot plants. Iron Nutrition and Interactions in Plants (Y. Chen and Y. Hadar, eds.), Kluwer Academic Publishers, Boston, 1992, pp. 271-281. 

FhuA and FepA will prove to be the reference structures for a large group of bacterial outer-membrane transporters that take up bacterial Fe3+-siderophores, Fe3+ released from host transferrin and lactoferrin, haem, and haem released from haemoglobin and haemopexin. It is assumed that all iron sources are transported... 

Uptake by FeoB is inhibited by the energy poisons 1 111 FCCP, DCCD, and vanadate. Both Fe3+ and Fe2+ serve equally well as iron sources, but Fe3+ provided as a citrate salt is immediately reduced to Fe2+, as demonstrated by the formation of the magenta-coloured Fe2+-ferrocine complex. 

Changes in transporter proteins by high-frequency genetic mutation mechanisms, while maintaining transport activity, helps to evade the host s immune response, and in cases where the substrate specificity is changed, helps the microorganism to adapt to new iron sources. 

Figure 6. Predicted and experimental Mossbauer spectra for a magnetized Co in a-iron source at room temperature and a single crystal of Ca2lFe ](Fe)Os. Crystallographic b axis of Ca2lFeVFe)Og and magnetization direction of source are parallel ana perpendicular to the y-ray propagation direction, respectively.

Daniels, R.B. Gamble, E.E. Buol, S.W. Bailey, H.H. (1975) Free iron sources in a aquult-udult sequence from North Carolina. Soil Sci. Soc. Am. Proc. 39 335-340 Danielsson, L.-G. Dyrssen, D. Graneli, A. (1980) Chemical investigations of Atlantis II and discovery brines in the Red Sea. Geo-chim. Cosmochim. Acta 44 2051-2065 Dao, K. Bee, A. Treiner, C. (1998) Adsorption isotherm of sodium octylbenzenesulfonate on iron oxide particles in aqueous solutions. 

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