Solid reducing agents

However, the reduction reactions in which a solid reducing agent is used usually give impure products. In this case, the product contains 80% to 95% boron that also contains magnesium and boron oxide as impurities. The boron produced in this way is a brownish-black form having a density of 2.37 g/cm3. 

Main uses for K alloys. Intercalation compounds with graphite are powerful solid reducing agents. See Na for Na-K alloys. 

Reduction of solids with solid reducing agents, solid-solid reactions (see tungsten, p. 1622). 

Other solid reducing agents include metal hydrides (forexample, CaHg) [2] and caibon. However, reduction with caibon does not yield solid oxidation products and introduces the danger of caibide formation. 

The first method is that the ilmenite is mildly reduced with a solid reducing agent, iron is removed by a magnetic separation, furthermore the remaining iron was completely percolated with sulfuric acid, filtrated, dried, fractionated and calcined to give a synthetic rutile (Ti02, 95 %). 

Chromium(IJ) chloride, chromous chloride, CrCl2- White solid (Cr plus HCl gas) dissolving to give a blue solution. Forms hydrates, widely used as a reducing agent. 

NH4)2Fe(S04)2,6H20. Pale green crystalline solid used as a standard reducing agent (e.g. for KMn04). More stable than FeS04. 

Tiianium(III) chloride, TiClj. Violet or brown solid (TiCU plus H3 at 700°C TiCU plus AIR3 (brown form)). Forms violet 6 hydrate. Used as a reducing agent. The fibrous brown form is an active agent in the Ziegler-Natta siereoregular polymerization of olefines. 

The first step in designing a precursor synthesis is to pick precursor molecules that, when combined in organic solvents, yield the bulk crystalline solid. For metals, a usual approach is to react metal salts with reducing agents to produce bulk metals. The main challenge is to find appropriate metal salts that are soluble in an organic phase. 

These closely resemble the corresponding sulphides. The alkali metal selenides and tellurides are colourless solids, and are powerful reducing agents in aqueous solution, being oxidised by air to the elements selenium and tellurium respeetively (cf. the reducing power of the hydrides). 

The metal is slowly oxidised by air at its boiling point, to give red mercury(II) oxide it is attacked by the halogens (which cannoi therefore be collected over mercury) and by nitric acid. (The reactivity of mercury towards acids is further considered on pp. 436, 438.) It forms amalgams—liquid or solid—with many other metals these find uses as reducing agents (for example with sodium, zinc) and as dental fillings (for example with silver, tin or copper). 

At reduction temperatures below about 1000°C, the reducing agents usually ate restricted to CO and Above about 1000°C, solid carbon can... 

After evaporation of the solvent, the solid residue consists of 5-(2-chlorobenzyl)-thieno[3,2-cl -pyridinium chloride which melts at 166°C (derivative n°30). This compound is taken up into a solution comprising ethanol (300 ml) and water (100 ml). Sodium borohydride (NaBH4) (20 g) is added portionwise to the solution maintained at room temperature. The reaction medium is maintained under constant stirring during 1 2 hours and is then evaporated. The residue is taken up into water and made acidic with concentrated hydrochloric acid to destroy the excess reducing agent. The mixture is then made alkaline with ammonia and extracted with ether. The ether solution is washed with water, dried and evaporated. The oily residue is dissolved in isopropanol (50 ml) and hydrochloric acid in ethanol solution is then added thereto. 

Let us apply these ideas to the third-row elements. On the left side of the table we have the metallic reducing agents sodium and magnesium, which we already know have small affinity for electrons, since they have low ionization energies and are readily oxidized. It is not surprising, then, that the hydroxides of these elements, NaOH and Mg(OH)z, are solid ionic compounds made up of hydroxide ions and metal ions. Sodium hydroxide is very soluble in water and its solutions are alkaline due to the presence of the OH- ion. Sodium hydroxide is a strong base. Magnesium hydroxide, Mg(OH)2, is not very soluble in water, but it does dissolve in acid solutions because of the reaction... 

Alpha carbon atoms, 348 Alpha decay, 417, 443 Alpha particle, 417 scattering, 245 Aluminum boiling point, 365 compounds, 102 heat of vaporization, 365 hydration energy, 368 hydroxide, 371 ionization energies, 269, 374 metallic solid, 365 occurrence, 373 properties, 101 preparation, 238. 373 reducing agent, 367 Alums, 403 Americium... 

K Salt. A yellow cryst solid, prepd by the action of basic K salts on TeNMe in the presence of reducing agents (see also above under TNMe). Some which have been used are K methoxide in me ale (this proc is subject to dangerous expins) (Ref 8) K cyanide in me ale (Ref 23) a satd aq soln of K ferrocyanide (Ref 9) or K nitrite in w, yield 80% (Ref 38). It has also been prepd by the action of K nitrite on dibromodinitromethane (Ref 13). Its expln temp is 97-98° (Ref 3) and its impactg sensy, using a noisemeter to detect explns, was found to... 

In propellants (see Propellants, Solid in this Vol), some of the work reported by Dunkle (Ref 6) examined the addn of flash reducing agents versus smoke evolved in propint compns for the cal. 50 rifle. The oxides examined included aluminum oxide, stannic oxide, silicon dioxide, ferric oxide and, after proplnt ignition, nickel... 

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