Systems Chemistry carbon, hydrogen, nitrogen

In addition to the successful reductive carbonylation systems utilizing the rhodium or palladium catalysts described above, a nonnoble metal system has been developed (27). When methyl acetate or dimethyl ether was treated with carbon monoxide and hydrogen in the presence of an iodide compound, a trivalent phosphorous or nitrogen promoter, and a nickel-molybdenum or nickel-tungsten catalyst, EDA was formed. The catalytst is generated in the reaction mixture by addition of appropriate metallic complexes, such as 5 1 combination of bis(triphenylphosphine)-nickel dicarbonyl to molybdenum carbonyl. These same catalyst systems have proven effective as a rhodium replacement in methyl acetate carbonylations (28). Though the rates of EDA formation are slower than with the noble metals, the major advantage is the relative inexpense of catalytic materials. Chemistry virtually identical to noble-metal catalysis probably occurs since reaction profiles are very similar by products include acetic anhydride, acetaldehyde, and methane, with ethanol in trace quantities. 

Many of the non metals such as hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, chlorine, and iodine are essential elements, and most are used in quantities for beyond the trace levels. Nevertheless, most of the chemistry of these elements in biological systems is more closely associated with organic chemistry than with inorganic chemistry. 

In a departure from the first edition we include here a brief account of selected non-metals and their multiple and various activities in biological systems. We pointed out in Chapter 1 that organic chemistry is the chemistry of hydrocarbons, but that if we restricted ourselves to just hydrogen and carbon, it would be impossible to construct the molecules we know to be essential for life as we know it. To construct proteins, nucleic acids, carbohydrates, and lipids, we also need oxygen, nitrogen, phosphorus, and sulfur. Indeed, we also require, as we saw in Chapter 1, a number of other elements, notably a not-inconsiderable number of metals. 

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