Dihydrogen combustion

Table 12.1. Rate constants of elementary steps of dihydrogen combustion...

Works on the inhibition of dihydrogen combustion by additives of various substances play an important role in studies of this reaction. Among active species formed in this system atomic hydrogen is formed in the greatest amount and provides chain branching (see Table 12.1). Atomic hydrogen rapidly enters into such reactions as H abstraction... 

Commercial dihydrogen hexachloroplatinate(lV) of high purity is now readily available (for a platinum assay of 40.0%, x is 2.32 in the above equation). The acid, 10 g, is spread into a thin layer less than 5-mm thick in a combustion boat and a steady air purge is maintained (200 mL/min) through a combustion tube of approximately 1 L in volume. The temperature of the furnace is raised from 25 to 350° in 50° steps over a period of 3 hours. The temperature is held at 350° for 0.5 hours. The sample can then be removed from the furnace and stored in a desiccator. The yield is quantitative based on the Pt assay of the dihydrogen hexachloroplatinate(IV) used (>98% ). 

Long-chain potassium polyphosphate, (KP03) , can be prepared simply by heating potassium dihydrogen orthophosphate when repeated condensation takes place to give a continuous chain of tetrahe-dra (5.142). Potassium polyphosphate can also be prepared by reaction (5.143) in which the heat of combustion of white phosphorus is used to assist the condensation of the PO4 tetrahedra as they are formed in embryo. 

Dihydrogen has the potential to act as a clean alternative to fossil fuels [1]. The oxidation of dihydrogen, either electrochemically or via combustion, leads only to the production of water. One of the major drawbacks of solar, hydroelectric and wind power is that periods of peak energy production do not necessarily coincide with periods of peak energy consumption. Solar, hydroelectric and wind power, however, could be used to electrochemically generate H2 that can be stored and later burned to produce thermal power or converted back to H and e to produce electrical power [2]. 

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