Polyampholite–Metal Complexes for Catalytic Processes

Abstract

Polyampholyte–metal complexes based on polyacrylic acid; the aliphatic diamines ethylenediamine, 1,3-diaminopropane, and 1,4-diaminobutane; and Cu²⁺ was obtained by reacting aqueous solutions of polyampholytes and CuSO₄. Using the method of simultaneous thermal analysis, it was found that the thermal degradation of the complexes occurs in three steps. The activation energy of thermal degradation of the polyampholyte–metal complexes is 22–99 kJ/mol. It was established by X-ray diffraction analysis that the products of thermal degradation of polyampholyte–metal complexes are heterogeneous systems composed of CuO and Cu₂O phases, while catalysts based on them are heterogeneous systems consisting of Al₂O₃ and CuO phases. The size distribution of catalyst pores showed that the volume of pores with a diameter of less than 773 nm was 0.80–0.83 cm³/g, the specific surface area was 349–351 m²/g, and the predominant equivalent pore diameter was 6.2–6.3 nm. The mechanical crushing strength of catalyst pellets was found to be 7.1–7.3 MPa. In the process of CO oxidation to CO₂, the catalyst began to exhibit its activity at 180–187°C; the complete conversion of CO in the oxidation reaction was achieved at 280–286°C. The performance of the obtained catalysts was 2.7–2.8 times higher than that of a reference sample.