Other Inorganic Starting Materials

Silicon carlnde is prepared from quartz sand and coke in the presence of sawdust and salt at 2500 °C in an electrical resistance furnace. The iron, aluminium and other metal impurities may be removed with salt as volatile metal chlorides. 

Gaseous (b.p. 8.3 °C) dichlorosilane H2SiCl2 is produced from trichlorosilane, aluminium and hydrogen [42]. (Eq. 2.3)  

Gaseous tetrafluorosilane reacts with elemental silicon to form polymeric silicon(II) fluoride (Eq. 2.4) and with hydrofluoric acid to form hydrofluorosilicic acid (Eq. 2.5). 

Tetrachlorosilane produces monosilane SiH4 (Eq. 2.6) when reacted with lithium aluminium hydride, and when reacted with various alcohols, it produces tetraalkoxy-silanes (Eq. 2.7). 

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Other scientists took up Oparin s ideas, used them for their own concepts, and tried to form organic molecules from inorganic starting materials. The Mexican scientist A. L. Herrera reported in 1942 in an article entitled A New Theory of the Origin and Nature of Life on his investigations with sulphobes (Herrera, 1942). These are morphological units ( lifelike forms ) which he obtained from reactions between thiocyanates and formalin. Sulphobes are spherical in form, with a diameter between 1 and 100 pm, and can interact with their surroundings thus they can adsorb dyestuffs. In some ways, they resemble the coacervates studied by Oparin and his school (Sect. 10.2.2). 

Some experiments attempting to simulate the origin of life by chemical synthesis from inorganic starting materials have yielded mixtures of amino acids (and other molecules) similar to those found in biology. However, the solutions do not show any circular dichroism. Why is this ... 

Alkyl halides are such useful starting materials for preparing other functional group types that chemists have developed several different methods for converting alcohols to alkyl halides Two methods based on the inorganic reagents thionyl chloride and phosphorus tnbromide bear special mention... 

Most chemicals used in the procedure will appear in the index. Thus, there will generally be entries for all starting materials, reagents, intermediates, important by-products, and final products. Most products shown in the Tables in the discus.sion sections of this volume are included unless the compounds are quite similar in which case a general descriptive name was entered. Chemicals generally nut indexed included coiimion solvents, standard inorganic acids and bases, reactants shown in the Tables, and compounds cited in the discussion section in connection with other methods of preparation. 

The compound HCN occupies a position at the border between inorganic and organic chemistry. It is paradoxical that hydrogen cyanide is on the one hand an important starting material for prebiotic syntheses of biomolecules and on the other a deadly poison for living organisms. 

There are several methods of producing gas-phase inorganic ions, the starting materials in mass spectrometric studies. The properties of the source of the ions required for study are important in the choice of ionization method. The production of bare metal ions from an involatile nonmolecular source requires a large amount of energy deposited on the surface of the material. The processes that occur after the initial ionization process may also affect the ions finally observed (e.g., clustering). At the other end of the ionization energy spectrum, gas-phase ions of a complexity similar to those observed in the condensed phases require a soft ionization process. A brief description of some of the ionization methods follows. 

Describe how you would prepare each of the following compounds from the indicated starting materials. Assume that any other necessary inorganic or organic reagents are available. Specify the reagents and reaction conditions as closely as possible. 

Exercise 13-17 Show how each of the following compounds could be synthesized from the indicated starting material and other appropriate organic or inorganic reagents. Specify the reaction conditions, mention important side reactions, and justify the practicality of any isomer separations. 

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