Electro zinc compounds

The anodic processes with zinc compounds are similar to those suggested for electro-Grignard reactions ... 

Table 4.1-149 Electro-optical constants of zinc compounds. Under the influence of an electric field, the refractive index changes in accordance to the nonlinearity of the dielectric polarization (Pockels effect). Crystals with hexagonal symmetry have three electro-optical constants rsi, 733, 751 crystals with cubic symmetry have only one electro-optical constant 741...

Since the first synthesis of mesoporous materials MCM-41 at Mobile Coporation,1 most work carried out in this area has focused on the preparation, characterization and applications of silica-based compounds. Recently, the synthesis of metal oxide-based mesostructured materials has attracted research attention due to their catalytic, electric, magnetic and optical properties.2 5 Although metal sulfides have found widespread applications as semiconductors, electro-optical materials and catalysts, to just name a few, only a few attempts have been reported on the synthesis of metal sulfide-based mesostructured materials. Thus far, mesostructured tin sulfides have proven to be most synthetically accessible in aqueous solution at ambient temperatures.6-7 Physical property studies showed that such materials may have potential to be used as semiconducting liquid crystals in electro-optical displays and chemical sensing applications. In addition, mesostructured thiogermanates8-10 and zinc sulfide with textured mesoporosity after surfactant removal11 have been prepared under hydrothermal conditions. 

When azo benzene is reduced or when the reduction of nitro benzene is continued beyond the stage of the azo compound we obtain hydrazo benzene, a colorless crystalline solid, m.p. 126°. The reduction may be accomplished (i) by using zinc and alcoholic sodium hydroxide, (2) by means of an alcoholic solution of ammonium sulphide or (3) electro-lytically in the presence of an alkali. 

By reduction, it is possible to pass from nitrobenzene to aniline through the intermediate compounds nitrosobenzene and phenyl-hydroxylamine, and by oxidation in the reverse direction. It has been shown that nitrosobenzene and phenylhydroxylamine are formed in the electro-reduction of nitrobenzene, but it is impossible, at present, to effect some of the transformations indicated above in such a way that the reactions can be used as preparative methods. Some, however, can be used for this purpose. Phenylhydroxylamine, for example, is oxidized in the cold by potassium bichromate and sulphuric acid to nitrosobenzene, and is converted by reducng agents into aniline. In certain cases it is possible, by selecting the proper reagent, to effect the change indicated by two of the steps noted above. Phenylhydroxylamine is best prepared by treating with zinc dust a solution of nitrobenzene in dilute alcohol which contains a small amount of calcium chloride. 

Zinc calcium strontium polyphosphate silicate. In this pigment, the electro-chemicaUy active compounds are also fixed on the surface of wollastonite. 

To avoid the cost and disposal problems of once-through processes employing alkali metal compounds, a considerable amount of research and development effort has been expended on techniques for regenerating this type of absorbent. Processes used employ precipitation of insoluble compounds (double alkali), and thermal decomposition (Wellman-Lord and Elsorb). Processes under development or which have been investigated include precipitation of insoluble compounds (zinc oxide), low-temperature reduction of sulfite (citrate and potassium formate processes), high-temperature reduction (aqueous carbonate process), electro-dialysis (SOXAL), and electrolytic (Stone Webster/Ionics Process). Descriptions of some of these processes are provided in subsequent sections. 

Ring substituted phthalocyanines are mixtures of geometrical isomers [68], unless they are structurally made to be symmetrical, such as octa-substituted phthalocyanines [69,70. The synthesis of pure, un-symmetrical phthalocyanines have been reported. For example, Konami and Hatano [71] reported the isolation of mono-t-butyl zinc phthalocyanine, which is soluble in organic solvents, by a chromatographic technique. Leznoflf and Hall [72] showed that unsym-metrical phthalocyanines can be synthesized by a polymer support method. Numerous investigators showed that mono substituted phthalocyanines can be synthesized by reacting a substituted 1,3-diiminoisoin-dolenine with a chlorosubphthalocyanine [73]. The synthesis of these compounds is usually quite elaborate and these compounds are primarily targeted to molecular electro-optical applications. 

---