Kostyniuk A. Preparation of iron-molybdenum oxide catalyst for conversion of methanol to formaldehyde by precipitation technique

The dissertation is devoted to the determination of the regularity of precipitation and thermal treatment processes of iron(III) molybdate and molybdenum(VI) oxide mixtures and the development on the basis of their technological parameters of producing of iron-molybdenum oxide catalyst for the conversion of methanol into formaldehyde. This paper deals with the physical and chemical processes of precipitation of iron(III) molybdate with an excess of molybdenum oxide(VI), their thermal treatment, grinding, granulation and broiling of the catalyst. The regularity of the iron(III) molybdate precipitation prosess is studied theoretically and experimentally and the optimal conditions for its precipitation with a minimal content of admixtures are determined. On the basis of thermodynamical studies of equilibrium systems and Fe2(MoO4)3-MoO3-NH4NO3 in terms of its thermal treatment in different gaseous environments an upper temperature limit of the annealing process of the catalytic mass is determined. The values of entropy, enthalpy and Gibbs energy in the investigated temperatures range are calculated. The time characteristics of the processes of dehydration, decomposition and phase formation in the system Fe2O3 MoO3 NH4NO3 in nonisothermal and isothermal conditions are ascertained and the mechanisms and kinetic parameters of these processes are determined. The phase composition of the catalyst is studied. The kinetic equations that accurately describe the experimental data are selected. The influence of synthesis conditions and composition of the iron-molybdenum catalyst on its catalytic activity in the reaction of partial oxidation of methanol to formaldehyde is investigated. The principal scheme of the catalytic agent production is elaborated, the optimal process parameters are established and the producing cost of iron-molybdenum oxide catalyst is evaluated.