2 research outputs found
Screening Monoethanolamine As Solvent to Extract Phenols from Alkane
Coal tar is a byproduct of low temperature
coal carbonization. The separation of the compounds has great significance
since its main component is the mixture of phenols and hydrocarbons.
In this paper, the separation of specific phenolic compounds from
model coal tar (phenols + hexane) was studied. The solvent was screened
by empirical analysis, the universal quasichemical functional group
activity coefficient (UNIFAC), and conductor-like screening model
COSMO-SAC (segment activity coefficient). COSMO-SAC was used to calculate
the capacity, selectivity, and performance index of solvents. Finally,
the monoethanolamine (MEA) was selected as the solvent to extract
the phenols. The liquid–liquid equilibrium for the ternary
mixture of phenols + hexane + MEA was measured at 303.15 K and 323.15
K under atmospheric pressure, and the results showed that MEA provided
a high distribution coefficient, efficiency, and selectivity for phenols.
Meanwhile, the extraction process of phenols was simulated based on
the nonrandom two-liquid (NRTL) model, for which binary interaction
parameters were obtained through calculations of phase equilibrium.
The results showed that the purity of phenols can achieve more than
99.5 wt % using MEA as a solvent
Preparation and mesomorphic properties of 1-methyl-<i>1H</i>-benzimidazole-based compounds
<p>A series of 1-methyl-<i>1H</i>-benzimidazole-based compounds, 2-(4ʹ-alkoxy-1,1ʹ-biphenyl-4-yl)-1-methyl- <i>1H</i>-1,3-benzimidazole derivatives (nPPMx-M) with terminal hydrogen, methyl and nitro moieties (coded as nPPMH-M, nPPMM-M and nPPMN-M, respectively), were prepared and their structures were characterised. The compounds display enantiotropic smectic mesophases for hydrogen and methyl terminated compounds (nPPMH-M and nPPMM-M), and enantiotropic nematic mesophases for nitro terminated compounds (nPPMN-M) with short alkoxy chain below than 10 carbon atoms, where the mesophase ranges are 24–72°C and 74–104°C on heating and cooling processes for nPPMH-M, 90–119°C and 110–135°C for nPPMM-M, and 102–129°C and 113–207°C for nPPMN-M, respectively. It is noted that the compounds nPPMx-M exhibit much lower melting points and much wider mesophase range both in heating and cooling than non-1-methyl substituted analogs, which are ascribed to the disruption of hydrogen bonding among the molecules caused by methyl substitution at 1-position of benzimidazole. Meanwhile, among the compounds nPPMx-M, much wider mesophase ranges are obtained for nPPMM-M and nPPMN-M, indicating a much high mesophase stability for the compounds bearing terminal moiety (CH<sub>3</sub> and NO<sub>2</sub>).</p