Antimony compounds reduction

Two methods are used to measure pH electrometric and chemical indicator (1 7). The most common is electrometric and uses the commercial pH meter with a glass electrode. This procedure is based on the measurement of the difference between the pH of an unknown or test solution and that of a standard solution. The instmment measures the emf developed between the glass electrode and a reference electrode of constant potential. The difference in emf when the electrodes are removed from the standard solution and placed in the test solution is converted to a difference in pH. Electrodes based on metal—metal oxides, eg, antimony—antimony oxide (see Antimony AND ANTIMONY ALLOYS Antimony COMPOUNDS), have also found use as pH sensors (8), especially for industrial appHcations where superior mechanical stabiUty is needed (see Sensors). However, because of the presence of the metallic element, these electrodes suffer from interferences by oxidation—reduction systems in the test solution. 

Semiconductor and Solar Cells. High purity (up to 99.9%) antimony has a limited but important appHcation in the manufacture of semiconductor devices (see Semiconductors). It may be obtained by reduction of a chemically purified antimony compound with a high purity gaseous or soHd reductant, or by thermal decomposition of stibine. The reduced metal may be further purified by pyrometaHurgical and zone melting techniques. 

Stibiae may be prepared by the treatment of metal antimonides with acid, chemical reduction of antimony compounds, and the electrolysis of acid or alkaline solutions usiag a metallic antimony cathode ... 

In situations such as the acid pickling of steel or the use of steel pipes to handle sour oil streams, the use of suitable inhibitors can give a significant reduction in hydrogen entry. In this context it is important to emphasise that the efficiency of an inhibitor in reducing hydrogen entry is not the same as its efficiency in reducing corrosion. Thus arsenic and antimony compounds... 

Stibine. Sbl h, is formed by hydrolysis of some metal antimonides or reduction (with hydrogen produced by addition of zinc and HC1) of antimony compounds, as in the Gutzeit test. It is decomposed by aqueous bases, in contrast with arsine. It reacts with metals at higher temperatures to give the antimonides. The antimonides of elements of group la. 2a, and 3a usually are stoichiometric, with antimony trivalent. With other metals, the binary compounds are essentially intermetallic. with such exceptions as the nickel series, Ni. Sb.. NiSb, Ni5Sb2 and Ni4Sb. 

Stibogluconate [stib o GLOO koe nate] is not effective in vitro therefore it has been proposed that reduction to the trivalent antimony compound is essential for activity. The exact mechanism of action has not been determined. Evidence for inhibition of glycolysis in the parasite at the phosphofructokinase reaction5 has been found. 

Derivation Action of hydrogen chloride on antimony-metal compounds such as Zn3Sb2 also released by reduction of antimony compounds in hydrochloric acid solutions with zinc or other reducing metal. 

An unusual example where an oxirane ring is actually formed under FVP conditions involves the X -antimony compound 3 which undergoes reductive ehmination upon FVP at 500 °C to give the bis(trifluoromethyl)oxirane... 

Although distibenes, the antimony analogues of azo compounds, have never been isolated as free, monomeric molecules (130), a tungsten complex, tritungsten pentadecacarbonyl[p.2-Tj -diphenyldistibene] [82579-41-7] C2yH2Q025Sb2W2, has been prepared by the reductive dehalogenation of phenyldichlorostibine (131) ... 

For many years, cat cracker operators have used additive compounds for enhancing cat cracker performance. The main benefits of these additives (catalyst and feed additives) are to alter the FCC yields and reduce the amount of pollutants emitted from the regenerator. The additives discussed in this section are CO promoter, SO reduction, ZSM-5, and antimony. 

The equilibrium levels of the reaction products are very small, but both can dissolve in liquid sodium, and sodium oxide can form compounds with silica. As a consequence, the reaction moves to the right, leading to further reduction of silica. Nevertheless, vitreous silica crucibles have been used sucessfully for containing molten antimony (850°C), copper (1 210°C), gallium (1 100°C), germanium (1 100°C), lead (500°C) and tin (900 C). 

Solutions containing compounds of copper, tin, arsenic, antimony, and other reducible metals must never be used. These must be removed before the reduction by treatment with hydrogen sulphide. 

The addition of finely dispersed solid particles improves the IR absorption of the polymer and positively influences blowing of the preforms. Such solid particles can be obtained by the reduction of Sb3+ to metallic antimony during polycondensation by the addition of trivalent phosphorous compounds such as phosphonic acid or its esters (phosphites). However, only a slight improvement in properties could be achieved by this approach [35],... 

Antimony(III) trichloride can be used as a catalytic mediator in the electroreduction of carbonyl compounds. The advantage of the procedure is illustrated by the selective reduction of acetophenones (497), leading to the corresponding benzylic alcohols (498) (Scheme 173) [575]. The electroreduction is performed in an EtOH/BuOH(l/1.5)-aq.HCl-(Pt/Pb) system in the presence... 

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