A new separation method for phenolic compounds from low-temperature coal tar with urea by complex formation

Jiao, Tiantian; Gong, Maoming; Zhuang, Xulei; Li, Chunshan; Zhang, Suojiang

doi:10.1016/j.jiec.2015.04.013

Cited by 56 publications

(33 citation statements)

References 16 publications

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“…Phenolic compounds are valuable chemical resources with a mass fraction between 20 and 30% in low-temperature coal tar (LTCT), 1 − 4 among which m -cresol is an important component that can be extensively used to produce organic chemicals. 5 , 6 Therefore, it is of significance to separate m -cresol from LTCT for further applications.…”

Section: Introductionmentioning

confidence: 99%

Separation of m-Cresol from Coal Tar Model Oil Using Propylamine-Based Ionic Liquids: Extraction and Interaction Mechanism Exploration

et al. 2020

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m -Cresol is an important chemical material, which is mainly derived from low-temperature coal tar. In this work, for separating m -cresol from coal tar model oil, two propylamine-based ionic liquids (ILs) propylamine formate ([PA][FA]) and propylamine acetate ([PA][Ac]) were selected as extractants. The selected ILs were synthesized and characterized by Fourier transform infrared (FT-IR) and 1 H nuclear magnetic resonance (NMR) spectroscopy. The effects of temperature, mass ratio of IL to model oil, and separation time on the separation efficiency of m -cresol were explored. The separation efficiency (SE) and distribution coefficient ( D ) were calculated from the experimental data to assess the separation performance of [PA][FA] and [PA][Ac]. The results showed that propylamine formate was a promising extractant with the separation efficiency of 97.8% and distribution coefficient of 27.59 at 298.15 K and m IL / m oil = 0.2. In the meantime, molecular dynamics (MD) simulations were employed to comprehend the interaction mechanism, from which the noncovalent interaction energy (IE), radial distribution function (RDF), spatial distribution function (SDF), and averaged noncovalent interaction (aNCI) were calculated. The results showed that both cation and anion formed hydrogen bonds with m -cresol and the anions played a leading role with electrostatic interaction energy in separating m -cresol. In addition, the regeneration and reuse of the ionic liquids were explored.

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Section: Introductionmentioning

confidence: 99%

Separation of m-Cresol from Coal Tar Model Oil Using Propylamine-Based Ionic Liquids: Extraction and Interaction Mechanism Exploration

et al. 2020

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“…1,2 The composition of coal tar is very complex with more than 500 components identified, consisting of mainly polyalkylene aromatic hydrocarbon, aliphatic chain alkane, alkene, and phenols. [3][4][5] The content of phenols is about 20%-30% (wt.) in the tar produced in Shaanxi Province, China, where the annual production of coal tar in this region is estimated to be over three million tonnes.…”

Section: Introductionmentioning

confidence: 99%

“…Although a range of separation methods have been examined, such as extraction crystallization, molecular sieve adsorption, complexation, and ion exchange resin, 12,21 they commonly involve complicated processes and additional agents resulting in low yield, high cost, and further waste treatment burdens. 3,4,11 The concept of xylenols separation through alkylationdistillation-dealkylation was proposed decades ago, 22,23 where isobutene was commonly used for alkylation reagent and concentrated sulfuric acid as catalyst. 24 However, these previous studies are limited to laboratory research.…”

Section: Introductionmentioning

confidence: 99%

“…Coal tar is one of the main by‐products of coal processing for the production of coke or coal gas through destructive distillation of coal at elevated temperatures (typically, 500°C–800°C) 1,2 . The composition of coal tar is very complex with more than 500 components identified, consisting of mainly polyalkylene aromatic hydrocarbon, aliphatic chain alkane, alkene, and phenols 3–5 . The content of phenols is about 20%–30% (wt.)…”

Section: Introductionmentioning

confidence: 99%

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Separation of close‐boiling 2,4‐/2,5‐xylenol isomers from coal tar

Wei

et al. 2020

Asia-Pacific J Chem Eng

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It is challenging to separate 2,4-/2,5-xylenol isomers with very close boiling points. In the present work, a multistep process for the separation of 2,4-/2,5-xylenol isomers from coal tar was investigated, involving alkylation, distillation, and dealkylation. Starting from the selection of suitable catalyst, the operating conditions for alkylation, distillation, and dealkylation were optimized by varying key parameters systematically. Among the four catalysts examined, p-toluenesulfonic acid (PTSA) showed best performance in terms of conversion and selectivity. Under the optimized alkylation conditions, the yields of 6-tert-butyl-2,4-xylenol and 4-tert-butyl-2,5-xylenol were 97.3% and 86.2%, respectively. Following pH adjusted to 7-8 with 10% sodium carbonate and water washing, the minimum reflux ratios during distillation for obtaining 6-tert-butyl-2,4-xylenol and 4-tert-butyl-2,5-xylenol were 4 and 12, with product purity of 99.8% and 99.5%, respectively. Under the optimized dealkylation conditions, both yields of 2,4-xylenol and 2,5-xylenol reached 99.9%. After recrystallization, the final product purity was over 99.5%. This lab-scale investigation provides key information for an ongoing pilot-scale process design.

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“…(Liquid + liquid) extraction technology are a desirable method in the abatement of phenolic compounds from wastewaters, which has a range of advantages over other kinds of organic wastewater treatment methods, such as high through put, ease of automatic operation and scale up [6], handling high concentration of phenolic wastewater effectively [5], and providing economic benefits by recovering cresols, for the reason that the isomers of cresols are very useful materials in the production of various kinds of chemicals, such as epoxy resins (by o-cresol), disinfectants (by m-cresol), light-resistant antioxidants (by p-cresol), etc. [7].…”

Section: Introductionmentioning

confidence: 99%

Measurement and thermodynamic modeling of ternary (liquid + liquid) equilibrium for extraction of o-cresol, m-cresol or p-cresol from aqueous solution with 2-pentanone

Chen

et al. 2017

The Journal of Chemical Thermodynamics

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The (liquid + liquid) equilibrium (LLE) data are vital for the liquid extraction of cresols from aqueous solution with 2-pentanone as an extraction agent. Therefore, the ternary LLE data for {2-pentanone + o-cresol, m-cresol or p-cresol + water} were determined at T = (298.15 and 323.15) K and p = 101.3 kPa. And the reliability of the LLE data was ascertained by using the Othmer-Tobias and Hand equations. The distribution coefficients and separation factors were calculated to evaluate the effectiveness of extracting cresols from water. The thermodynamic NRTL and UNIQUAC models were used to correlate the experimental LLE data of the studied systems, and the binary interaction parameter values were obtained from the data correlation.

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A new separation method for phenolic compounds from low-temperature coal tar with urea by complex formation

Cited by 56 publications

References 16 publications

Separation of m-Cresol from Coal Tar Model Oil Using Propylamine-Based Ionic Liquids: Extraction and Interaction Mechanism Exploration

Separation of m-Cresol from Coal Tar Model Oil Using Propylamine-Based Ionic Liquids: Extraction and Interaction Mechanism Exploration

Separation of close‐boiling 2,4‐/2,5‐xylenol isomers from coal tar

Measurement and thermodynamic modeling of ternary (liquid + liquid) equilibrium for extraction of o-cresol, m-cresol or p-cresol from aqueous solution with 2-pentanone

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