Density and viscosity were determined for the binary mixtures containing the ionic liquid 1-butyl-3-methylimidazolium thiocyanate
([BMIM][SCN]) and 1-alcohols (1-butanol, 1-pentanol and 1-hexanol) at six temperatures (298.15, 308.15, 318.15, 328.15, 338.15
and 348.15) K and ambient pressure. The density and viscosity correlation for these systems was tested by an empirical second-order
polynomial and by the Vogel-Fucher-Tammann equation in wide ranges of temperatures. Excess molar volumes were described by
the Redlich-Kister polynomial expansions. The density and viscosity variations with composition were described by polynomials.
A qualitative analysis of the trend of the properties with solvent and temperature was performed. The obtained results indicate
that ionic liquid interactions with 1-alcohols are strongly dependent on the special trend of packing of this ionic liquid
into hydroxylic solvents. As previously observed, an increase of the 1-alcohol carbon-chain length leads to lower interactions
on mixing.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
Hydrogen electrosorption into Pd-rich (>80 at.% Pd in the bulk) Pd–Rh alloys has been studied in acidic solutions (0.5 M H2SO4) using cyclic voltammetry and chronoamperometry. The influence of temperature (in the range between 283 and 328 K), electrode potential and alloy bulk composition on hydrogen electrosorption properties of Pd–Rh alloys is presented. It has been found that the additive of Rh to Pd–Rh alloys increases the maximum hydrogen solubility (for Rh bulk content below 10 at.%), decreases the potential of absorbed hydrogen oxidation peak and decreases the potential of the α → β phase transition. Increasing temperature decreases the potential of absorbed hydrogen oxidation peak, the maximum hydrogen solubility, and the potential of the α → β phase transition. The amounts of electrosorbed hydrogen for α- and β-phase boundaries, i.e., αmax and βmin, have been determined from the integration of the initial parts of current–time responses in hydrogen absorption and desorption processes. The H/M ratio corresponding to αmax increases with increasing Rh content, while for βmin a maximum of H/M ratio is observed for the alloys containing ca. 95% Rh.
(Liquid + liquid) phase equilibria (LLE) of binary mixtures containing hyperbranched polymer Boltorn® H2004 and n-alkanes (n-hexane, n-heptane, n-octane, and n-decane) were studied over the temperature range from about (260 up to 360) K. The polymer is partially miscible with n-alkanes and the solubility decreases with an increase of the chain length of the solvent. Corresponding LLE phase diagrams including spinodal and binodal (liquid + liquid) coexistence curves were calculated in terms of the statistical mechanics – based on the lattice-cluster theory, based only on the upper critical solution temperature, and the polymer chain architecture. The results show semi-qualitative agreement of predicted and experimental equilibrium compositions and temperatures. Boltorn® H2004 reveals complete miscibility in the liquid phase with alcohols (C1–C8), aromatic hydrocarbons (benzene, toluene, and thiophene), and ethers (methyl tetra-butyl ether, ethyl tetra-butyl ether, and tetrahydrofurane). 相似文献
Using bioconversion and simultaneous value-added product generation requires purification of the gaseous and the liquid streams before, during, and after the bioconversion process. The effect of diversified process parameters on the efficiency of biohydrogen generation via biological processes is a broad object of research. Biomass-based raw materials are often applied in investigations regarding biohydrogen generation using dark fermentation and photo fermentation microorganisms. The literature lacks information regarding model mixtures of lignocellulose and starch-based biomass, while the research is carried out based on a single type of raw material. The utilization of lignocellulosic and starch biomasses as the substrates for bioconversion processes requires the decomposition of lignocellulosic polymers into hexoses and pentoses. Among the components of lignocelluloses, mainly lignin is responsible for biomass recalcitrance. The natural carbohydrate-lignin shields must be disrupted to enable lignin removal before biomass hydrolysis and fermentation. The matrix of chemical compounds resulting from this kind of pretreatment may significantly affect the efficiency of biotransformation processes. Therefore, the actual state of knowledge on the factors affecting the culture of dark fermentation and photo fermentation microorganisms and their adaptation to fermentation of hydrolysates obtained from biomass requires to be monitored and a state of the art regarding this topic shall become a contribution to the field of bioconversion processes and the management of liquid streams after fermentation. The future research direction should be recognized as striving to simplification of the procedure, applying the assumptions of the circular economy and the responsible generation of liquid and gas streams that can be used and purified without large energy expenditure. The optimization of pre-treatment steps is crucial for the latter stages of the procedure. 相似文献
The purpose of the study was to evaluate the impact of the Saccharomyces cerevisiae and S. kudriavzevii mixed culture on the fermentation, chemical and aromatic composition of semi-sweet white wines. The variables tested in the experiment were the initial ratio of yeast in mixed cultures and the time of inoculation of the S. kudriavzevii co-culture. The addition of S. kudriavzevii to the inoculum did not significantly change the chemical composition of the wines obtained. No reduction in ethanol yield was found in mixed culture fermented wines; however, in some variants of the experiment, the ethanol content was higher. The mixed cultures of S. cerevisiae and S. kudriavzevii increased the level of volatile compounds in white grape wines. Wines fermented with the co-culture of S. kudriavzevii were characterized by a more diversified ester profile. The mixed cultures of S. cerevisiae and S. kudriavzevii raised the levels of terpenes in white wines. The most promising results were obtained for mixed culture variants, in which S. kudriavzevii was sequentially inoculated on the sixth day of fermentation. 相似文献
Reversed-phase HPLC was optimised for simultaneous determination of several derivatives of benzoic and hydroxycinnamic acids (so-called phenolic acids) in plums using a commercially available monolithic column. Mobile phase pH and concentration of organic modifier (methanol and acetonitrile) were tested in order to obtain the best resolution. Satisfactory separation was achieved in gradient mode with a mobile phase consisting of 50 mM phosphate buffer at pH 2.2 (solvent A) and acetonitrile (solvent B). The limits of detection for a UV detector ranged between 0.098 and 2.04 microg/mL for vanillic acid and p-hydroxyphenylacetic acid, respectively. The developed method was used for monitoring the content of polyphenolic acids in plums during their ripening process. The presence of these constituents was confirmed by checking their MS spectra. 相似文献
A spectroscopic study combining IR absorption and Raman scattering is presented for methylcyanodiacetylene (CH3C5N). Gas‐phase, cryogenic matrix‐isolated, and pure solid‐phase substance was analyzed. Out of 16 normal vibrational modes, 14 were directly observed. The analysis of the spectra was assisted by quantum chemical calculations of vibrational frequencies, IR absorption intensities, and Raman scattering activities at density functional theory and ab initio levels. Previous assignments of gas‐phase IR absorption bands were revisited and extended. 相似文献
Instead of cyclopentanol, 2-cyclopentylidene-cyclopentanone is the main product of liquid phase hydrogen transfer from secondary
alcohols to cyclopentanone in the presence of pure MgO [1]. In the present work it has been shown that a significant increase
in the selectivity towards cyclopentanol has been observed for MgO treated with I2 or alkyl iodides. 相似文献
The newly established structures of sesquiterpene lactones from Laser trilobum showed that these lactones belong among the stereostructural types of germacranolides, guaianolides, eudesmanolides and elemanolides. 相似文献