Obtaining low-molecular oxidized organic compounds by partial oxidation of propane on a modified zeolite catalyst

On an industrial scale, low-molecular-weight oxidized organic compounds are produced by the heterogeneous catalytic oxidation of aliphatic alcohols. Catalysts used in these processes include metals (Cu, Ag, Au, Fe, and Mo), transition metal oxides (CuO+Cu₂O, V₂O₅, Cr₂O₃, MoO₃, etc.), mixed oxides, and salts of transition metals (vanadates, tungstates, stannates, and molybdates of zinc, cobalt, and bismuth). These reactions typically occur at temperatures between 350–450°C and exhibit relatively low selectivity toward the desired products.

Natural clinoptilolite, when modified with metal cations via ion exchange, demonstrates high catalytic activity and selectivity for the partial oxidation of propane to low-molecular-weight oxidized organic compounds (formaldehyde, acetaldehyde, methyl alcohol and acetic acid) under the action of oxygen at comparatively mild temperatures (320–370°C).

Catalyst samples were synthesized from natural clinoptilolite with different silica modules by ion-exchange treatment with Ca²⁺, Sn²⁺, and Li⁺ cations. According to the data, natural clinoptilolite with silica modules λ = 8.68 and 9.8 exhibits low catalytic activity.

Catalytic activity tests were performed for natural clinoptilolite with silica modules λ = 8.68, 9.8, and 10.8, as well as their modified forms containing Ca²⁺, Sn²⁺, and Li⁺, during the partial oxidation of propane to low-molecular-weight oxidized organic compounds at T = 350°C, a volumetric flow rate of 1000 h⁻¹, and various molar ratios of propane:O₂:N₂. The best performance was observed for λ = 10.8 with 7% Ca²⁺, 7% Sn²⁺, and 8% Li⁺, achieving a propane conversion of 46.3%. The content of metal cations introduced into the zeolite was determined using mass spectrometry with an Agilent 7700 ICP-MS instrument.

The catalyst exhibits a service life of 72 hours, after which it can be regenerated and reused. These results indicate high thermal stability and reusability, which are particularly important for industrial applications.