HCN synthesis from CH4, NH3, and O2 on clean Pt*1
1987; Elsevier BV; Volume: 104; Issue: 2 Linguagem: Inglês
10.1016/0021-9517(87)90376-9
ISSN1090-2694
Autores Tópico(s)Advanced Chemical Physics Studies
ResumoRates of reactions in HCN synthesis were measured between 0.01 and 10 Torr on clean Pt foils between 600 and 1500 K in a steady state flow reactor attached to an analysis system equipped with AES for surface analysis. Addition of O2 to a 1:1 CH4:NH3 mixture at foil temperatures between 1000 and 1400 K caused the HCN production to fall while NO rose to become the dominant product. The CO production rate was lower than that of NO, and very small amounts of CO2 were formed. AES showed that addition of O2 produces a reduction of surface carbon from approximately a monolayer to a small coverage. Oxygen appears to react with NH3 to form NO faster than with CH4 to form CO. However, NO is capable of reacting with CH4 to produce HCN so that NH3 does not oxidize totally to N2. The rates of CH4 oxidation and the rate of formation of HCN from CH4 and NO were also examined. Individual rates are fit to Langmuir-Hinshelwood models, and the rates and selectivities predicted by the rate equations agree well with experiments. These results indicate that under the conditions of industrial HCN synthesis HCN is produced mostly by the NH3 + CH4 and CH4 + NO reactions.
Referência(s)