The application of composite ion track membranes with embedded gold nanotubes in the reaction of aminomethylation of acetophenone

The interaction of acetophenone, benzaldehyde and aniline in the one-pot-three-component Mannich reaction in the presence of composite membrane catalysts based on gold nanotubes (NTs) and NTs with mixed composition of Ag/Au was studied. NTs were synthesized by the electroless template approach in the pores of ion track membranes based on polyethylene terephthalate (density of pores was 4 ⋅ 107 ion cm−2 and the pores diameter −410 8 nm). The wall thickness of Au and Ag/Au NTs was determined to be of 35.8 9.0 and 77.8 6.1 nm respectively. The crystal structure of the samples before and after the tests in the Mannich reaction was comprehensively characterized by scanning electron microscopy and x-ray diffraction analysis methods. The catalytic activity was investigated for five successive test cycles. It is shown that the decrease in the yield of the final ß-aminocarbonyl compound after the second test cycle is due in the case of monocomponent gold NT to the leaching of active particles from the membrane surface, and in the case of Ag/Au NT to the formation of the inert phase of silver oxide.