Ammonia, formation from methane

Figure 2.5a. Reactor for high-throughput testing of catalytic materials at temperatures up to about 1,200 °C (e.g. for HCN formation from methane and ammonia using capillaries to compensate for equal pressure drop in all reactor channels (Moehmel et al, 2008).

Yuasa S, Ishigami M. High frequency discharge experiment. I formation of organic compounds from methane and ammonia. Orig. Life. 1975 6 75-81. 

The amino group comes from ammonia. All of the carbon atoms are derived from methane. The hydrogen atoms bonded to the carbon atoms remain with the methane during bond formation or they may come from hydrogen gas. The oxygen atoms of the carboxyl group are from water. 

Irradiation of ethyleneimine (341,342) with light of short wavelength ia the gas phase has been carried out direcdy and with sensitization (343—349). Photolysis products found were hydrogen, nitrogen, ethylene, ammonium, saturated hydrocarbons (methane, ethane, propane, / -butane), and the dimer of the ethyleneimino radical. The nature and the amount of the reaction products is highly dependent on the conditions used. For example, the photoproducts identified ia a fast flow photoreactor iacluded hydrocyanic acid and acetonitrile (345), ia addition to those found ia a steady state system. The reaction of hydrogen radicals with ethyleneimine results ia the formation of hydrocyanic acid ia addition to methane (350). Important processes ia the photolysis of ethyleneimine are nitrene extmsion and homolysis of the N—H bond, as suggested and simulated by ab initio SCF calculations (351). The occurrence of ethyleneimine as an iatermediate ia the photolytic formation of hydrocyanic acid from acetylene and ammonia ia the atmosphere of the planet Jupiter has been postulated (352), but is disputed (353). 

Production of ammonia requires large quantities of hydrogen, most of which comes from the partial oxidation of hydrocarbons with water or oxygen. A simple and important example is the so-called methane-steam gas reaction, which is favorable only at very high temperatures because of the entropy effect in the formation of H2 (see Section 4-4B) ... 

The possibility of the incorporation of oxygen into the particle is particularly relevant for the carbides and nitrides of molybdenum and tungsten which possess a high affinity for this element.13,23 The oxygen may come from the carbonyl precursor, and result in oxycarbide or oxynitride formation in the core of the nanoparticle itself.16 Exposure to the ambient can also result in the formation of surface oxycarbides and oxynitrides with catalytic properties different from those of the pure nitride or carbide phase.15,24-26 However, heat treatment of these nanoparticles with a mixture of methane/hydrogen or ammonia/hydrogen should convert the surface to a pure nitride or carbide form. 

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