Nickel 248 Inorganic Syntheses

Natural gas contains both organic and inorganic sulfur compounds that must be removed to protect both the reforming and downstream methanol synthesis catalysts. Hydrodesulfurization across a cobalt or nickel molybdenum—zinc oxide fixed-bed sequence is the basis for an effective purification system. For high levels of sulfur, bulk removal in a Hquid absorption—stripping system followed by fixed-bed residual clean-up is more practical (see Sulfur REMOVAL AND RECOVERY). Chlorides and mercury may also be found in natural gas, particularly from offshore reservoirs. These poisons can be removed by activated alumina or carbon beds. 

The most important applications of hydrogen sulfide involve the production of sodium sulfide and other inorganic sulfides. Hydrogen sulfide obtained as a by-product often is converted into sulfuric acid. It also is used in organic synthesis to make thiols or mercaptans. Other applications are in metallurgy for extracting nickel, copper, and cobalt as sulfides from their minerals and in classical qualitative analytical methods for precipitation of many metals (see Reactions). It also is used in producing heavy water for nuclear reactors. 

Historically, the first chemical synthesis of urea by Wohler, from ammonium cyanate in 1828, was a milestone that established a bridge between inorganic and organic chemistry. Urease was the first enzyme ever to be crystallized (6), and it was the first protein shown to contain nickel ions in the active site (7). The first X-ray crystal structure of urease became known in 1995 (8). Significant progress was made since then toward an understanding of its catalytic mechanism, as well as toward the structural and functional emulation of its active site by synthetic model complexes (5, 9). 

Scheme 5.2. Structures of Ni-azacyclams complexes obtained by template synthesis. Reprinted from Scheme 5.1 R Abba, G. De Santis, L. Fabrizzi, M. Licchelli, A.M. Manotti Lanfredi, R Pallavicini, A. Poggi and F. Ugozzoh, Nickel (II) complexes of azacyclams Oxidation and reduction behavior and catalytic effects in the elctroreduction of carbon dioxide. Inorganic Chemistry 33 (1994) 1366-1375. Copyright 1994, with permission of American Chemical Society.

Behera, J. N., Gopalkrishnan, K. V. and Rao, C. N. R. (2004). Synthesis, structure, and magnetic properties of amine-templated open-framework nickel(ii) sulfates, Inorganic Chemistry 43, 8, pp. 2636-2642. 

Synthesis and Modes of Coordination of Energetic Nitramines Ligands in Copper (II), Nickel (II) and Palladium (II) Complexes Inorganic Chemistry 27, 2963-2971. 

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