No abstract

Oleic acid (OA) is a renewable monounsaturated fatty acid obtained from high oleic sunflower oil. This work was focused on the oxidative scission of OA, which yields a mono‐acid (pelargonic acid, PA) and a di‐acid (azelaic acid, AA) through an emulsifying system. The conventional method for producing AA and PA consists of the ozonolysis of oleic acid, a process which presents numerous drawbacks. Therefore, we proposed to study a new alternative process using a green oxidant and a solvent‐free system. OA was oxidized in a batch reactor with a biphasic organic‐aqueous system consisting of hydrogen peroxide (H2O2, 30 %) as an oxidant and a peroxo–tungsten complex Q3{PO4[WO(O2)2]4} as a phase‐transfer catalyst/co‐oxidant. Several phase‐transfer catalysts were prepared in situ from tungstophosphoric acid, H2O2 and different quaternary ammonium salts (Q+, Cl–). The catalyst [C5H5N(n‐C16H33)]3{PO4[WO(O2)2]4} was found to give the best results and was chosen for the optimization of the other parameters of the process. This optimization led to a complete conversion of OA into AA and PA with high yields (>80 %) using the system OA/H2O2/[C5H5N(n‐C16H33)]3{PO4[WO(O2)2]4} (1/5/0.02 molar ratio) at 85 °C for 5 h. In addition, a new treatment was developed in order to recover the catalyst.

The state of the art on the glycerol carbonate (GC) synthesis has been updated since the last published reviews in 2012, 2013, and 2016. Three types of reactions continue to be studied: glycerolysis of urea, transcarbonation of DMC, DEC, or cyclic carbonates with glycerol and reaction using CO 2 . Among these different routes, DMC and glycerol were selected as the raw materials for the GC synthesis in this work since the transcarbonation from these green reagents leads to high yields and selectivities, using mild conditions including a less energy consuming GC separation process. Catalytic conditions using Na 2 CO 3 seem to be a good compromise to achieve a high yield of GC, leading to an easier purification step without GC distillation. Mild temperatures for the reaction (73–78°C) as well as a low waste amount confirmed by the E-factor calculation, are in favor of controlled costs. Plasticizing properties of synthesized GC were compared to the behaviors of a commercial plasticizer and natural dialkyl carbonates, for a colorless nail polish formulation. The resulting films subjected to mechanical and thermal stresses (DMA and Persoz pendulum) showed the high plasticizing effect of GC toward nitrocellulose based films, probably due to hydrogen bond interactions between GC and nitrocellulose. The GC efficiency gives the possibility to decrease the content of the plasticizer in the formulation. Glycerol carbonate can be thus considered as a biobased ingredient abiding by the green chemistry concepts, and safe enough to be used in an ecodesigned nail polish formulation.

Hansen and COSMO-RS approaches show that glycerol ketals and acetals can be effective alternatives to certain harmful petro-sourced solvents.

No abstract

We present a unified description of the imaginary part of the dynamical magnetic susceptibility χ (ω, T ) and measurements of the static susceptibility χ(T ) and electrical resistivity ρ(T ) in the uranium intermetallics UCu5−xPdx (x = 1, 1.5). For temperatures T and excitation energies ω in the range 12 K < ω, T < 150 K, our analysis demonstrates that the dynamics of isolated uranium ions are responsible for the observed temperature and frequency scaling, although interion interactions may become important at lower temperatures and frequencies. We derive a strict criterion for single-ion scaling in the form of a universal scaling function, providing a model-independent description of the compiled experimental data.

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible.

(BEDT-TTF)2I3 nanoparticles of 2–6 nm have been isolated, and they exhibit a superconducting behaviour and encouraging thermoelectric properties.