76,282 research outputs found
Publisher Correction: Fe-functionalized paramagnetic sporopollenin from pollen grains: one-pot synthesis using ionic liquids (Scientific Reports, (2020), 10, 1, (12005), 10.1038/s41598-020-68875-6)
No full textIn the original version of this Article, F. Rossella was incorrectly listed as a corresponding author. The correct corresponding author for this Article is C.S. Pomelli. Correspondence and request for materials should be addressed to [email protected]. This error has now been corrected in the HTML and PDF versions of the Article
Combined Use of Scanning Electron Microscopy-Energy-Dispersive X-ray Spectroscopy and Fourier Transform Infrared Imaging Coupled with Principal Component Analysis in the Study of Ancient Egyptian Papyri
No full textThis paper reports the results of a spectroscopic study on the chemistry of some small papyrus fragments arising from three Egyptian excavation sites. The aim of this investigation was to verify the possibility to identify significant differences in ancient Egyptian papyri using noninvasive analytical methods, that is, ATR (attenuated total reflection)-FTIR (Fourier transform infrared) spectroscopic imaging and scanning electron microscopy-energy-dispersive X-ray spectroscopy. Differences in both lignin and cellulose compositions, which are difficult to detect with traditional FTIR and FTIR imaging spectral analysis, were revealed by the multivariate approach, and the second derivative spectroscopy was applied to enhance the spectrum resolution. Thus, it has been possible to recognize a fragment characterized by the presence of lead and of long chain aliphatic organic compound, which are not present in the other fragments, in the ink region. These data show not only that the combination of these techniques can provide important chemical information, such as to evidence the different compositions and manufacture of each papyrus, but also that metal inks were probably used also in ancient Egyptian papyri
Ab initio study of the SN@ reaction CH3Cl+CL- -> Cl- + CH3Cl in supercritical water with the PCM model
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Reply to the comment on ?Computational studies on organic reactivity in ionic liquids? by C. Chiappe and C. S. Pomelli, Phys. Chem. Chem. Phys., 2013, 15, 412
No full textAn improved iterative solution to solve the electrostatic problem in the polarizable continuum model
No full textAn improved iterative solution to solve the electrostatic problem in the polarizable continuum model
No full textSynthesis, thermal behavior and kinetic study of N-morpholinium dicationic ionic liquids by thermogravimetry
No full textSix N-morpholinium dicationic ionic liquids (DILs) with the following general formula [C4H8NO]2(CH2)n[X]2, being n = 4, 6 and 8 and X = Br, NTf2 (where NTf2 = bis(trifluoromethane)sulfonimide) have been synthesized. Their thermal behavior was studied by thermogravimetry (TG) using five different heating rates (2, 4, 8, 10 and 12 K min−1) aiming at assessing their relative thermal stability. All the DILs investigated undergo a single step of mass loss in the temperature range between 200 and 520 °C, except in the case of both the C4 DILs (with bromide and NTf2 imide anion), where two partially overlapping steps occur. NTf2 DILs are more stable than bromide ones according to the thermal stability scale based on the onset decomposition temperature. Taking into account the kinetic analysis of the thermal decomposition, the estimated decomposition time at given degree of conversion for the same temperature (250 °C) was evaluated as an alternative stability parameter. A substantial agreement between the stability trends assessed with the two different approaches was found, and the effect of the length of the linker between the two morpholinium rings of the dicationic structures was also considered. The reaction mechanism beneath the decomposition of the shortest member (C4) of the bromide series was investigated by DFT. A double retro-SN2 pathway was found to be the reasonable two-step mechanism for the first thermal degradation event. This hypothesis was further corroborated by analyzing the samples obtained from TG after heating the bromide and NTf2 C4 DILs up to the first degradation temperatures as well as the thermal behavior of the assumed spiro intermediate ILs
Effective generation of molecular cavities in the polarizable continuum model by the DefPol procedure
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