Nano Pt/TiO(2) photocatalyst for ultrafast production of sulfamic acid derivatives using 4-nitroacetanilides as nitrogen precursor in continuous flow reactors

The design of reactors based on high performance photocatalysts is an important research in catalytic hydrogenation. In this work, modification of titanium dioxide nanoparticles (TiO(2) NPs) was achieved by preparation of Pt/TiO(2) nanocomposites (NCs) through photo-deposition method. Both nanocatalysts were used for the photocatalytic removal of SOx from the flue gas at room temperature in the presence of hydrogen peroxide, water, and nitroacetanilide derivatives under visible light irradiation. In this approach, chemical deSOx was achieved along with protection of the nanocatalyst from sulfur poising through the interaction of the released SOx from SOx-Pt/TiO(2) surface with p-nitroacetanilide derivatives to produce simultaneous aromatic sulfonic acids. Pt/TiO(2) NCs have a bandgap of 2.64 eV in visible light range, which is lower than the bandgap of TiO(2) NPs, whereas TiO(2) NPs have a mean size of 4 nm and a high specific surface area of 226 m(2)/g. Pt/TiO(2) NCs showed high photocatalytic sulfonation of some phenolic compounds using SO(2) as a sulfonating agent along with the existence of p-nitroactanilide derivatives. The conversion of p-nitroacetanilide followed the combination processes of adsorption and catalytic oxidation–reduction reactions. Construction of an online continuous flow reactor–high-resolution time-of-flight mass spectrometry system had been investigated, realizing real-time and automatic monitoring of completion the reaction. 4-nitroacetanilide derivatives (1a-1e) was converted to its corresponding sulfamic acid derivatives (2a–2e) in 93–99% isolated yields of within 60 s. It is expected to offer a great opportunity for ultrafast detection of pharmacophores. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11356-023-25968-9.