Process parameters methanol formation selectivity

The works [158,185—188] investigated the effect of various parameters on the reaction onset temperature and the yield of the products. At pressures of 1 and 5 atm, the increase of the initial concentration of NO to 1% significantly, by 100 °C, decreased the temperature of the process, although the maximum obtainable conversion of methane was almost the same. However, the increase of the NO concentrations to 1.5% produced practically no effect. At these pressures, the selectivity of formation of oxygenates (methanol, formaldehyde, and nitromethane) reached a maximum at an NO concentration of 0.5%, so this concentration was adopted as optimal. The ethane formation selectivity decreased rapidly with increasing NO concentration, nearly to zero. Diluting the mixture with helium, at least up to 60%, had a moderate effect on the process. Even the CH4/O2 ratio, a key parameter of the... 

However, with increasing duration of the process, accompanied by the growth of the conversion of reactants and the concentration of the products in the reactor, the methanol selectivity dropped to 22%, i.e., a value typical for this pressure range ( 40 atm). After decreasing the pressure from 40 to 5 atm, the selectivity of methanol formation in this initiated radical—chain reaction decreases sharply to 2%, thereby confirming the importance of this parameter for the formation of methanol. Thus, reducing the process temperature by more than 200 °C due to its initiation does not show any advantage in terms of selectivity of methanol. 

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