Search Results (3)

This paper studies the cooperative effect of Au nanoparticles deposited on vanadyl pyrophosphate oxide (VPO) in the liquid phase oxidation of benzyl alcohol. VPO was prepared using the classical method by thermally treating VOHPO₄·0.5H₂O precursor in reacting atmosphere at 420 °C for a period of 72 h. Au nanoparticles were deposited by incipient wetness method. The catalysts were characterized by means of XRD, TEM, XPS and Raman. The bulk VPO catalyst contains vanadyl pyrophosphate phase ((VO)₂P₂O₇), and a small amount of VOPO₄. The catalytic system exhibits a high activity in the base-free liquid phase oxidation of alcohols compared to Au on activated carbon, classic catalyst used for this type of reaction. Au/VPO showed a high peculiar selectivity to benzyl benzoate (76%), an important product used in the pharmaceutical and perfume industries. This behavior might be ascribed to the presence of strong acid sites of VPO, as determined by liquid phase titration. Stability tests performed on Au/VPO showed a deactivation of 10% after the first run, but a constant conversion along the following five cycles. This phenomenon can be attributed to the increase of mean Au particle size (from 19.1 to 23.4 nm) after recycling tests as well as the partial leaching of Au and V in the reaction media. Moreover, XRD evidenced a modification in the VPO structure with the partial formation of VOHPO₄·0.5H₂O phase. Full article

The application of nanoemulsions as a novel delivery system for lipophilic materials, such as essential oils, flavors, and fragrances is one of the growing technologies used in cosmetic, pharmaceutical, and food industries. Their characteristic properties, like small droplet size with high interfacial area, transparent or semi-transparent appearance, low viscosity, and high kinetic stability, make them a perfect vehicle for fragrances, in the perfume industry. They could be a great alternative to water-based perfumes, without alcohol, and solve problems related to the oxidation and low bioavailability of fragrances with other non-alcoholic vehicles of perfumes like pomades or gels. The aim of our study was to develop stable Oil-in-Water (O/W) nanoemulsions that are compatible with selected fragrance compositions, without ethanol, polyols, and ionic surfactants, and to study their physicochemical, microbiological, and dermatological properties. The nano-perfume systems were obtained with a low-energy (Phase Inversion Composition; PIC) and with a high-energy (ultrasound, US) method, taking into account the possibility of moving from the laboratory scale to an industrial scale. The optimized nano-perfume formulations, prepared with different methods, yielded the same physicochemical properties (stability, medium droplet size of the inner phase, polydispersity, viscosity, surface tension, pH, density). Stable systems were obtained with a fragrance composition concentration within 6–15% range. These formulations had a low viscosity and a pH suitable for the skin. Moreover, the obtained results confirmed the protective role of nanoemulsions. The peroxide number measurement (POV) showed that the tested fragrance compositions had a high chemical stability. The results of the microbiological tests confirmed that the obtained products were free of microbiological contamination and were appropriately preserved. The dermatological test results confirmed the safety of the developed preparations. Full article

Alcohol-based perfumes, e.g., eau de parfum, eau de toilette, eau de cologne or au fraiche, are the most common type of fragrance products available on the market. There are also alcohol-free fragrance products, mainly in the form of solid or oil perfume. From the consumers’ point of view, such perfumery products are of interest; therefore, looking for new solutions is still interesting. Nanoemulsions are liquid, kinetically stable colloidal dispersions, consisting of an aqueous phase, an oil phase and a surfactant, with or without a co-surfactant. They are transparent, not greasy, easy to spray and spread. Additionally, they show capacity to protect fragrances from oxidation. The development of a water-based perfumes in the form of stable nanoemulsions containing fragrance compositions (in the range of 5–15%), stabilized by nonionic surfactants, allows to create safe products for a wider group of consumers, including children, adolescents and people with sensitive skin. In this article, an application of nanoemulsions as a potential form of perfumery products were described. Full article