Chimie ParisTech

The encapsulation of hydrophobic bioactive molecules, such as essential oil compounds (EOCs), in aqueous nanodispersions is critical for enhancing their solubility, stability, and applicability across diverse industries. This study examines the formulation of oleic acid nanodroplets stabilized by a biobased alkylpolyglucoside (APG), without the need for auxiliary cosurfactants. In this system, oleic acid simultaneously provides the oil core and contributes to interfacial charging, enabling the nanodroplets to act as efficient carriers for thymol and carvacrol. In contrast to conventional formulations requiring cosurfactants, this work presents a simplified and greener approach. A pseudoternary phase diagram defined the regions of stable dispersion formation, confirming the feasibility of a one-surfactant-only system. Dynamic light scattering confirmed a monomodal size distribution (10–15 nm), whereas fluorescence spectroscopy revealed up to three distinct chemical environments for the EOCs within the droplets. Crucially, the system’s stability is governed by the pH-dependent dissociation of oleic acid at the interface, as elucidated by conductivity and pH measurements. The results demonstrate that increasing EOC concentration leads to droplet growth, which may destabilize dispersions, highlighting the need for compositional optimization. This APG/oleic acid platform provides a scalable, eco-friendly alternative for delivering poorly soluble bioactives, aligning with the principles of sustainable chemistry and reducing the environmental footprint of essential oil formulations.

• Oxygenate quantification methods strongly affect conclusions on catalytic performance. • Indirect subtraction method overestimates oxygenate selectivity by up to 10 × . • Cold bath recovers only 50% alcohols and 10% ketones, underestimating selectivity. • Direct oxygenate quantification with a heated transfer line is more reliable. • Oxygenate selectivity remains low (< 3 %) and barely depends on the catalyst. The direct conversion of CO 2 and CH 4 into oxygenated products via plasma catalysis offers a promising route for biogas valorization, generating molecules usable as fuels or fuel additives, or convertible into energy carriers. However, many studies lack rigor in the quantification of oxygenate selectivity, often leading to overestimations and misleading conclusions regarding catalyst performance and energy efficiency. Typically, gaseous products are analyzed online, while liquid products are collected and analyzed offline. Oxygenate selectivity is often estimated indirectly by subtracting selectivities of other carbon products from 100%, a method that lacks accuracy and tends to overestimate performance. This work highlights the need for accurate and reliable analytical approaches to provide a realistic assessment of plasma-assisted CO 2 and CH 4 conversion and guide future research. An improved experimental setup is proposed, keeping all products in the gas phase using a heated transfer line and enabling direct online quantification by gas chromatography directly after the reactor. This approach minimizes errors from incomplete condensation and indirect calculations, achieving a carbon balance close to 95%. Beyond analytical considerations, the conversion of CO 2 and CH 4 into oxygenated products by plasma catalysis remains a challenge. Results indicate that while catalysts enhance overall conversion, their effect on oxygenate selectivity is limited. These findings suggest that future work should focus on tailoring plasma conditions rather than solely on catalyst optimization. Overall, this study emphasizes the importance of robust analytical methods as a foundation for better understanding reaction mechanisms and for guiding future research on energy conversion by plasma catalysis.

In this article, we report the electro-induced C–H functionalization of aromatic compounds by isocyanides and water, to produce arylcarboxamides. This controlled oxidation of electron-rich aromatic compounds leads to an eco-efficient synthesis of secondary benzocarboxamides, along with cyanide group formation. The optimization process was guided by a Bayesian optimization-based model, and good yields were quickly obtained.

Abstract A precise methodology for determining the growth mode of oxide layers on metallic materials at high temperatures is proposed. The approach combines sequential isotopic oxidation tests (using 16 O and 18 O isotopes) with secondary ion mass spectrometry (SIMS and nanoSIMS) analyses. NanoSIMS provides high-resolution localisation of oxygen diffusion pathways and oxide growth zones. However, its limited accessibility and specialised instrumentation can pose practical constraints. In contrast, dynamic SIMS offers broader accessibility and the ability to directly quantify oxygen isotope ratios across depth profiles. The detection of both conventional atomic (O − ) and diatomic (O 2 − ) oxygen signals in dynamic SIMS analysis proved highly effective in offering insights on oxide growth mode, closely replicating nanoSIMS results. The diatomic signal analysis complements the atomic signal data by improving the understanding of oxidant transport within the oxide layer. The methodology was validated through its application to a Co-10Cr alloy oxidised at 900 °C in O 2 , under sequential exposures to 16 O and 18 O isotopes. Both SIMS and nanoSIMS revealed the formation of a duplex oxide layer, consisting of an outer layer formed by outward Co cation diffusion and an inner layer growing by inward oxygen penetration, particularly in the grain-boundary regions of the outer oxide layer. The alloy is proposed to oxidise according to the Available Space Model.