Toxicity ionic liquids

Petkovic M, Ferguson JL, Nimal Gunaratne HQ, Ferreira R, Leitao MC, Seddon KS, Rebelo LPN, Pereira CS (2010) Novel biocompatible cholinium-based ionic liquids - toxicity and biodegradability. Green Chem 12 643-649... 

TABLE 3.18A Spectral Structure Activity Relationships (SPECTRAL-SAR) of the Ionic Liquids Toxicity of Table 3.17 Against the Daphnia magna Species, and the Associated Computed Spectral Norms, Computed Upon Eq. (3.62), With the Observed/ Recorded Result YEXP> =9.59481, Statistic and Algebraic Correlation Factors, Computed Upon Eqs. (3.87) (3.86) (Putz Lacrtoia, 2007 Putz, 2012b), Throughout the Possible Correlation Models Considered From the Anionic, Cationic, and Ionic Liquid 0+> and l+> States, see Eqs. (3.84) and (3.85), Respectively (Lacrama et al., 2007 Putz et al., 2007 Putz Putz, 2013a)... 

Couhng, D. J., Bemot, A. R., Docherty, K. M., Dixon, J. K., Maginn, E. J. (2006). assessing the factors responsible for ionic liquid toxicity to aquatic organisms via quantitative structure- property relationship modehng. Green Chem. 8, 82-90. 

The correlation coefficients (R2) demonstrated that the structural parameters and the ECso values were well-correlated. The models showed that toxicity clearly increases with the length of the substituent chains, as seen in previous studies. In this case, the toxicity of the anion is not taking into account in the estimative of the ionic liquid toxicity. [1] Later, a similar equation (to equation 16) was obtained in an independent study with [MIM]-based... 

In the meantime, we believe that the best prediction of the toxicity of an ionic liquid of type [cation] [anion] can be derived from the often well known toxicity data for the salts [cation]Cl and Na[anion]. Since almost all chemistry in nature takes place in aqueous media, the ions of the ionic liquid can be assumed to be present in dissociated form. Therefore, a reliable prediction of ionic liquids HSE data should be possible from a combination of the loiown effects of the alkali metal and chloride salts. Already from these, very preliminary, studies, it is clear that HSE considerations will be an important criterion in selection and exclusion of specific ionic liquid candidates for future large-scale, technical applications. 

Without a doubt, tetrafluoroborate and hexafluorophosphate ionic liquids have shortcomings for larger-scale technical application. The relatively high cost of their anions, their insufficient stability to hydrolysis for long-term application in contact with water (formation of corrosive and toxic HF during hydrolysis ), and problems related to their disposal have to be mentioned here. New families of ionic liquid that should meet industrial requirements in a much better way are therefore being developed. FFowever, these new systems will probably be protected by state of matter patents. 

As new compounds, very limited research has been done to evaluate the biological effects of ionic liquids. The topical effect of [EMIM]C1/A1C13 melts and [EMIMjCl on the integument of laboratory rat has been investigated. The study reports that [EMIMjCl is not in itself responsible for tissue damage. However, the chloroaluminate salt can induce tissue irritation, inflammation, and necrosis, due to the presence of aluminium chloride. However, treatments for aluminium chloride and hydrochloric acid are well documented. This study needs to be expanded to the other ionic liquids, and their toxicity need to be investigated [46]. 

Ionic liquid solvents are non-volatile and non-toxic and are liquids at ambient temperature. Originally, work was concerned with battery electrolytes. These ionic liquids (IL) show excellent extraction capabilities and allow catalysts to be used in a biphasic system for convenient recycling (Holbrey and Seddon, 1999). IFP France has commercialized a dimerization process for butenes using (LNiCH2R ) (AlCU) (where L is PRj) as an IL and here the products of the reaction are not soluble in IL and hence separate out. The catalyst is very active and gives high selectivity for the dimers. 

Rhodium catalyzed carbonylations of olefins and methanol can be operated in the absence of an alkyl iodide or hydrogen iodide if the carbonylation is operated in the presence of iodide-based ionic liquids. In this chapter, we will describe the historical development of these non-alkyl halide containing processes beginning with the carbonylation of ethylene to propionic acid in which the omission of alkyl hahde led to an improvement in the selectivity. We will further describe extension of the nonalkyl halide based carbonylation to the carbonylation of MeOH (producing acetic acid) in both a batch and continuous mode of operation. In the continuous mode, the best ionic liquids for carbonylation of MeOH were based on pyridinium and polyalkylated pyridinium iodide derivatives. Removing the highly toxic alkyl halide represents safer, potentially lower cost, process with less complex product purification. 

In the Eastman process for 2,5-dihydrofuran production, the situation is different and the problem of heavy products has been tackled in a highly original manner. [31] The oligomers formed in the process are highly polar and insoluble in alkanes. The ionic liquid, [P(oct)3C18H37]I and the Lewis acid catalyst, [Sn(oct)3]I, which are non toxic (LD50 > 2 g kg"1 for each), non-flammable (flammability 1) and non-corrosive (340 stainless steel is used for the reactor), have been designed to be soluble in... 

While very tittle toxicity data are available it would appear that many ionic liquids are nontoxic. 

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