Narrow Results

Movement of different strains in Drosophila melanogaster was continuously observed by using computer interfacing techniques and was analyzed by permutation entropy (PE) after exposure to toxic chemicals, toluene (0.1 mg/m³) and formaldehyde (0.01 mg/m³). The PE values based on one-dimensional time series position (vertical) data were variable according to internal constraint (i.e. strains) and accordingly increased in response to external constraint (i.e. chemicals) by reflecting diversity in movement patterns from both normal and intoxicated states. Cross-correlation function revealed temporal associations between the PE values and between the component movement patterns in different chemicals and strains through the period of intoxication. The entropy based on the order of position data could be a useful means for complexity measure in behavioral changes and for monitoring the impact of stressors in environment.

Nanosized Cu–Mn composite oxide catalysts were prepared from potassium permanganate, copper nitrate, n-butanol, and cetyltrimethylammonium bromide as a manganese source, copper source, reducing agent, and surfactant, respectively. The Cu${}_{0.2}$–Mn sample possessed a small particle size (10–40nm) and a relatively high specific surface area ($46.24{\mathrm{\text{m}}}^2\cdot {\mathrm{\text{g}}}^{-1}$); its main components were Cu${}_{1.5}$Mn${}_{1.5}$O₄ and Mn₃O₄. As a consequence, the Cu${}_{0.2}$–Mn catalyst exhibited good catalytic activity in the oxidation of toluene. At a toluene concentration of 1000ppm and a space velocity of $60,000\mathrm{\text{mL}}\cdot {\mathrm{\text{g}}}^{-1}\cdot {\mathrm{\text{h}}}^{-1}$, the $T_{50}$ and $T_{90}$ of the Cu${}_{0.2}$–Mn catalyst toward toluene were 239${}^{\circ }$C and 250${}^{\circ }$C, respectively. Furthermore, even after 30h of operation at 275${}^{\circ }$C, the conversion of toluene was 99% (at the space velocity of $60,000\mathrm{\text{mL}}\cdot {\mathrm{\text{g}}}^{-1}\cdot {\mathrm{\text{h}}}^{-1}$).

This chapter aims to illustrate the research that was conducted in Portugal or in collaboration with Portuguese research groups in the 2011–2022 period on the oxidative conversion of volatile organic compounds (VOCs) to useful building blocks. It concerns the selective oxidation under mild catalytic oxidations of some VOCs (toluene, xylene, ethylbenzene, styrene and n-hexane), which are hazardous to human health and the environment. Both homogeneous and heterogeneous catalysts are discussed.