In order to evaluate the impact of the alkyl side chain length and symmetry of the cation on the thermophysical properties of water saturated ionic liquids (ILs), densities and viscosities as a function of temperature were measured at atmospheric pressure and in the (298.15 363.15) K temperature range, for systems containing two series of bis(trifluoromethylsulfonyl)imide based compounds: the symmetric [CnCnim][NTf2] (with n 1 8 and 10) and asymmetric [CnC1im][NTf2] (with n 2 5, 7, 9 and 11) ILs. For water saturated ILs, the density decreases with the increase of the alkyl side chain length while the viscosity increases with the size of the aliphatic tails. The saturation water solubility in each IL was further estimated with a reasonable agreement based on the densities of water saturated ILs, further confirming that, for the ILs investigated, the volumetric mixing properties of ILs and water follow a near ideal behavior. The water saturated symmetric ILs generally present lower densities and viscosities than their asymmetric counterparts. From the experimental data, the isobaric thermal expansion coefficient and energy barrier were also estimated. A close correlation between the difference in the energy barrier values between the water saturated and pure ILs and the water content in each IL was found, supporting that the decrease in the viscosity of ILs in presence of water is directly related with the decrease of the energy barrier.

The increasing interest on the application of ionic liquids (ILs) to a wide range of processes and products has been hampered by a lack of toxicological data, mainly in what concerns novel cations, such as guanidinium, phosphonium, and functionalized and non-functionalized imidazolium-based ILs. The present study reports the toxicity of five guanidinium-, six phosphonium, and six imidazolium-based ILs, towards the luminescent marine bacteria Vibrio fischeri. These new results clearly show that guanidinium-, unlike the imidazolium- and phosphonium-based ILs, do not follow the trend of increasing toxicity with the increase in the alkyl chain length. Moreover, the introduction of oxygenated groups on the alkyl chains, such as ether and ester, leads to a decrease of the toxicity of guanidinium and also imidazolium compounds. In what respects the effect of the different cations, it is possible to recognize that the phosphonium-based ILs seem to be more toxic when compared to the analog imidazolium-based ILs (with the same anion and alkyl chains).

In order to evaluate the impact of the alkyl side chain length and symmetry of the cation on the thermophysical properties of water-saturated ionic liquids (ILs), densities and viscosities as a function of temperature were measured at atmospheric pressure and in the (298.15 to 363.15) K temperature range, for systems containing two series of bis(trifluoromethylsulfonyl)imide-based compounds: the symmetric [C n C n im][NTf2] (with n = 1-8 and 10) and asymmetric [C n C1im][NTf2] (with n = 2-5, 7, 9 and 11) ILs. For water-saturated ILs, the density decreases with the increase of the alkyl side chain length while the viscosity increases with the size of the aliphatic tails. The saturation water solubility in each IL was further estimated with a reasonable agreement based on the densities of water-saturated ILs, further confirming that for the ILs investigated the volumetric mixing properties of ILs and water follow a near ideal behaviour. The water-saturated symmetric ILs generally present lower densities and viscosities than their asymmetric counterparts. From the experimental data, the isobaric thermal expansion coefficient and energy barrier were also estimated. A close correlation between the difference in the energy barrier values between the water-saturated and pure ILs and the water content in each IL was found, supporting that the decrease in the viscosity of ILs in presence of water is directly related with the decrease of the energy barrier.

Biodiesel production is performed in the industry by alkaline transesterification of oils with a low amount of free fatty acids. Aiming to minimize its production costs, low quality, or waste oils have been investigated as an alternative source of triacylglycerols. In order to reduce the disposal of conventional catalysts used industrially, ionic liquids (ILs) have been studied to be applied as catalysts in transesterification, since they can be recovered and reused in next reaction cycles. The main objective of this work was to investigate the application of alkaline type ionic liquids in the catalysis of transesterification reactions of mixtures of triacylglycerols. In the present work, the ionic liquid bis-(3-methyl-1-imidazole)-ethylene dihydroxide (IMC2OH) synthesis was carried out. The use of the IL choline hydroxide (ChOH) as a catalyst was evaluated in the production of biodiesel through a kinetic modelling study under the specific conditions of 2 wt.% catalyst dosage, 1:10 oil/methanol molar ratio, for the periods of 0, 10, 20, 30, 45, 60, 120, 240, 360, and 480 minutes at 65 ℃. A possible way to recover this IL from liquid-liquid extraction with water/butanol and water/ethyl acetate has been evaluated. Due to some challenges occurred in IMC2OH synthesis, the conversion obtained in the second step of synthesis was lower than expected. Transesterification with choline hydroxide presented 85.21% of conversion in FAME content in 30 minutes of reaction, and the results of the kinetic study which was carried out demonstrated that the second-order model was the best fit for the reaction with a rate constant (k) estimated as 0.2930 L.mol-1.min-1. From the recovery of the IL, it was possible to conclude that although there was some separation of it from the glycerol by the extraction with butanol and water, an amount of ChOH remained in glycerol phase. In conclusion, ChOH revealed an excellent capacity for fast transesterification. Thus, based on a more detailed study of the optimal reaction parameters for ChOH and subsequent application of the recovered amount of this ionic liquid in new reaction cycles, there is a strong indication that its reuse as a catalyst is technically feasible for the conversion of triacylglycerols, which enables its possible industrial application.

Cholinium-based ionic liquids are quaternary ammonium salts with a wide range of potential industrial applications. Based on the fact that the cholinium is a complex B vitamin and widely used as food additive, the cholinium-based ionic liquids are generically regarded as environmentally \"harmless\" and thus, accepted as \"non-toxic\", although their ecotoxicological profile is poorly known. This work provides new ecotoxicological data for ten cholinium-based salts and ionic liquids, aiming to extend the surprisingly restricted body of knowledge about the ecotoxicity of this particular family and to gain insight on the toxicity mechanism of these compounds. The results reported here show that not all the cholinium tested can be considered harmless towards the test organism adopted. Moreover, the results suggest that the cholinium family exhibits a different mechanism of toxicity as compared to the imidazolium ionic liquids previously described in the literature. (C) 2014 Elsevier Inc. All rights reserved.

In this work, a study was developed for the detection of Nicotine (NIC) and Ciproflixacin (CPX), applying modified carbon paste electrodes with reduced graphene oxide (OGr) and the ionic liquids (LIs) 1-octyl-3-methylimidazolium hexafluorophosphate (OMIMPF6) and 1-butyl-3-methylimidazolium acetate (BMIMAc). All electrodes used are electroactive in relation to redox couple [Fe(CN)6] 3-/4- and also resulted in electrochemical responses for a CPX and a NIC. Modification percentages were evaluated, varying the proportions of OGr and LIs for the development of the modified electrode. The use of 10.0% OGr and 2.5% BMIMAc resulted in higher intensities of anode peak current for CPX, while the unmodified carbon paste electrode (EPC) showed better performance for a NIC. After that, studies were carried out to optimize the cell parameters (electrolyte, pH and preconcentration time) and technique parameters (scan rate, pulse amplitude and pulse time) for the detection of CPX. From the parameters optimized for CPX detection, an analytical curve was used from standard CPX solution, resulting in two dynamic linear concentration ranges. A range of interest corresponds to the detection of CPX with a concentration range of 6.99 x 10-9 to 6.95 x 10-7 mol L-1 (R2 = 0.9984), with a detection limit calculated at 4.21 x 10-9 mol L-1 and limit of quantification calculated at 1.28 x 10-8 mol L-1 . The application of the method in a commercial pharmaceutical sample shows a linear range with a concentration range of 4.99 x 10-8 to 1.57 x 10-7 mol L -1 (R2 = 0.9953). The reproducibility and repeatability calculated for EPCM/OGr-BMIMAc resulted in relative standard deviation values equal to 5.7% and 5.3%, respectively, ensuring the applicability of the developed analytical method.

Three imidazolium cations based on the imidazolium ring, 1,2,3-triethylimidazolium (123TEI), 1,2,3- triethyl-4-methylimidazolium (123TE4MI), and 2-ethyl-1,3-dimethylimidazolium (2E13DMI), were employed as structure directing agents (SDA) in the synthesis of pure silica zeolites, and led the crystallization of the STF zeolite. The three cations showed a different specificity for this phase, following the order 123TE4MI 4 123TEI 4 2E13DMI. Nevertheless, the 123TEI cation was also able to produce zeolite MFI when considerably high H2O/SiO2 ratios were employed. In order to understand the selectivity of these imidazolium-based SDAs and explain the experimental results, a computational study was performed, showing a perfect agreement with the experimental observations. In the case of the MFI framework, the order of interaction energies found for this framework was 123TEI 4 123TE4MI 4 2E13DMI, providing an explanation to the experimental results. Hence, the 123TEI cation presents a certain template effect in terms of a spatial relationship between the shape of the organic cation and the topology of the MFI structure. A higher degree of motion of the 123TEI cation is observed when occluded within the cavities of the STF framework compared to when hosted in the channel intersections of the MFI framework, explaining the different widths of the 13C NMR bands in the two materials

Agradecimentos: Ariel A. C. Toledo Hijo thanks the São Paulo Research Foundation (FAPESP) (Grant # 2016/24461-5) for the scholarship and financial support. The authors thank the national funding agencies of the São Paulo Research Foundation (FAPESP) (2014/21252-0, 2016/24461-5, 2016/08566-1, 2014/03992-7, 2012/05027-1, and 2004/08517-3), the National Council for Scientific and Technological Development (CNPq) (406963/2016-9, 406918/2016-3, 406856/2013-3, 133152/2014-6, 483340/2012-0, 305870/2014-9, 309780/2014-4, and 143050/2009-5), CAPES and UNICAMP/FAEPEX (PAPDIC 0125/16) for the financial support and scholarships. J. F. B. P. acknowledges financial support by FAPESP (2014/16424-7)

Agradecimentos: JPVD, MS, CMM, and LPC are indebted to CNPq and CAPES for fellowships. IOM, FAS and YG are indebted to CNPq and FAPESP for financial support and to Prof. C. H. Collins (IQ-UNICAMP, Brazil) for English revision. Contributions from LNNano (Brazilian Nanotechnology National Laboratory) for TEM imagens and the Multiuser Laboratory of Advanced Optical Spectroscopy (LMEOA/IQ-UNICAMP) for use of its equipment are also gratefully acknowledged. This work is a contribution from the National Institute of Science and Innovation in Complex Functional Materials (INOMAT)