Subacute toxicity assessment of biobased ionic liquids in rats

Ionic liquids (ILs) derived from compounds obtained from natural sources, such as fatty acids (FAs) have attracted the interest of the scientific and industrial communities because of their sustainable appeal and possible low toxic effects or nontoxicity. These aspects open new perspective of applications in other fields, which demands a better comprehension of their toxicity. This work evaluated the subacute toxicity of bis(2-hydroxyethyl)ammonium carboxylates in Wistar rats, considering the alkyl chain length of FAs (capric and oleic acids), and the concentration (0.16%, 1.6% or 3.2%, w_IL/w_Oil) of ILs added in diets. The blood serum of the rats was evaluated in relation to total cholesterol, triglycerides, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and γ-glutamyl transferase. Lipid peroxidation was determined in plasma, liver and kidney tissues by determining the level of thiobarbituric acid reactive substances. Histological analyses of the liver and kidney tissues were performed in order to evaluate morphological changes. No signal of toxicity was observed according to lipid peroxidation. Triglycerides increased with the increasing of the concentration and alkyl chain length of the IL, but no difference in serum level of lipid peroxidation was observed. This behavior may be attributed to the amphiphilic nature of FAs based ILs, which might facilitate lipid digestion. However, more studies are necessary in order to understand such behavior. Therefore, the synthesis of ILs from FAs, has been evaluated as a strategy to produce compounds with low or without toxicity for the agro-food, pharmaceutical or cosmetic industries.

Fatty Acid-Derived Ionic Liquid Lubricant. Protic Ionic Liquid Crystals as Protic Ionic Liquid Additives

Fatty acids are natural products which have been studied as green lubricants. Ionic liquids are considered efficient friction reducing and wear preventing lubricants and lubricant additives. Fatty acid-derived ionic liquids have shown potential as neat lubricant and additives. Protic ionic liquid crystals (PILCs) are protic ionic liquids (PILs) where cations and anions form ordered mesophases that show liquid crystalline behavior. The adsorption of carboxylate units on sliding surfaces can enhance the lubricant performance. Ionic liquid crystal lubricants with longer alkyl chains can separate sliding surfaces more efficiently. However, they are usually solid at room temperature and, when used as additives in water, transitions to high friction coefficients and wear rates, with tribocorrosion processes occur when water evaporation takes place at the interface. In order to avoid these inconveniences, in the present work, a protic ammonium palmitate (DPA) ionic liquid crystal has been added in 1 wt.% proportion to a short chain citrate ionic liquid (DCi) with the same protic ammonium cation. A spin coated layer of (DCi + DPA) was deposited on AISI316L steel surface before the sliding test against sapphire ball. Synergy between DCi PIL and DPA PILC additive reduces friction coefficient and wear rate, without tribocorrosion processes, as shown by scanning electron microscopy (SEM)/energy dispersive X-ray microanalysis (EDX) and X-ray photoelectron spectroscopy (XPS) results.

Ammonium bio-ionic liquids based on camelina oil as potential novel agrochemicals

Third generation bio-ionic liquids (bio-ILs) were synthesized based on cheap and increasingly available camelina oil.