A potential novel rapid screening NMR approach to boundary film formation at solid interfaces in contact with ionic liquids

The boundary films generated oil a series of inorganic compounds, typical of native films oil metal and ceramic surfaces, when exposed to various ionic liquids (ILs) based oil the trihexyl(teti-adecyl)phosphonium cation have been characterized using multinuclear solid-state NMR. The NMR results indicate that SiO2 and Mg(OH)(2) interact strongly with the anion and cation of each IL through a mechanism of adsorption of the anion and subsequent close proximity of the cation in a surface double layer as observed through H-1-Si-29 cross polarization experiments). In contrast, Al2O3, MgO, ZnO, and ZrO2 appear less active, strongly suggesting the necessity of hydroxylated surface groups ill order to enhance the generation of these interfacial films. Using solid-state NMR to characterize Such interfaces not only has the potential to elucidate mechanisms of wear resistance and corrosion protection via iLs, but is also likely to allow their rapid screening for such durability applications

O lugar dos sujeitos brancos na luta antirracista: provocações e pautas para conversas

- Artigo publicado em três idiomas: português, espanhol e inglês.- Título em espanhol: El lugar de los sujetos blancos en la lucha antirracista: provocaciones y pautas para conversaciones- Título em inglês: The role of white people in the fight against racismo: provocations and topics for conversatio

Halide-Free Synthesis and Tribological Performance of Oil-Miscible Ammonium and Phosphonium-Based Ionic Liquids

Due to their low vapor pressures, nonflammability, high thermal stabilities, and excellent tribological properties ionic liquids (ILs) are highly attractive lubricant base oils and additives. However, for practical applications of ILs in lubrication, two requirements are often limiting, the required miscibility with standard mineral oils (≥5 wt %) and the complete absence of corrosive halide ions in the ionic liquid. Moreover, the need for full compatibility with standard oil additives reduces the number of potential IL-based lubricant additives even further. In this contribution, an economic halide-free synthesis route to oil-miscible ionic liquids is presented, and very promising tribological properties of such ILs as base oil or additive are demonstrated. Therefore, sliding tests on bearing steel and XPS analysis of the formed surface films are shown. Corrosion test results of different bearing metals in contact with our halide-free ILs and (salt) water prove their applicability as real life lubricants. In the sustainable chemistry and engineering context, we present a halide-free design approach for ionic performance chemicals that may contribute to significant energy savings due to their enhanced lubrication properties