A New Two-Step Oxidative Degradation Method for Producing Valuable Chemicals from Low Rank Coals under Mild Conditions

Mae, Kazuhiro; Shindo, Hiroyuiki; Miura, Kouichi

doi:10.1021/ef000177e

Cited by 100 publications

(57 citation statements)

References 9 publications

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“…4,5 Lignite is unsuitable for direct burning, but suitable for developing as a feedstock for value-added chemicals due to the high content of organic oxygen. [6][7][8] It is reasonable to utilize lignite for non-fuel purposes and important to understand the molecular composition of the organic species present in lignite.…”

Section: Introductionmentioning

confidence: 99%

Characterization of humic acids extracted from a lignite and interpretation for the mass spectra

et al. 2017

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Humic acids obtained from a Chinese lignite via alkali treatment were analyzed using Fourier transform infrared spectroscopy and Orbitrap mass spectrometry coupled with an electrospray ion source (ESIOrbitrap-MS). Raw coal and the corresponding residue were characterized via scanning electron microscopy and energy dispersive spectrometry. Over 4700 heteroatom-containing compounds with wide distributions of molecular mass and unsaturation degree were detected via the ESI-Orbitrap-MS, and around 60 percent of the detected species were found to be oxygen-containing compounds. In addition, van Krevelen diagram and double-bond equivalent (DBE) plot were introduced to provide more structural details of the compounds. For the species only containing C, H, and O (HA CHO ), condensed aromatic compounds with a DBE value over 20 only contained 1 or 2 oxygen atoms. Carboxyl-and hydroxylcontaining aliphatic compounds (CHCACs) were predominant in HA CHO with 5 or 6 oxygen atoms. Both the CHCACs and aromatic carboxylic acids or phenols were grouped into clusters in the van Krevelen diagram to be recognized. The introduction of a nitrogen atom to the HA CHO species was based on the structures of the HA CHO species, which is also indicated by the van Krevelen diagram.

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Section: Introductionmentioning

confidence: 99%

Characterization of humic acids extracted from a lignite and interpretation for the mass spectra

et al. 2017

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“…The time period and temperature for the treatment were 24 h and 60°C, respectively, according to literature. 20,21) The oxidized lignite was isolated from the solution by filtration and subsequent washing with deionized water. The conversion of HPO was determined by quantifying HPO in the spent solution.…”

Section: Oxidative Leaching With Hydrogen Peroxidementioning

confidence: 99%

“…This work also investigated treatments of the lignite in aqueous solution of hydrogen peroxide (H2O2), which oxidatively depolymerized the lignite in-situ forming lower organic acids that played roles of leaching agents. 20,21) …”

Section: Introductionmentioning

confidence: 99%

Modification of Reactivity and Strength of Formed Coke from Victorian Lignite by Leaching of Metallic Species

et al. 2015

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Binderless briquetting of lignite at 100-200°C and subsequent carbonization produces formed coke with tensile strength (ST) of 5-40 MPa, while the briquetting often requires mechanical pressure over 100 MPa. High reactivity is another feature of the lignite-derived coke, and this arises from highly dispersed metallic species such as alkali/alkaline-earth metallic species and ferrous/ferric ones that catalyze CO2 gasification. This work investigated effects of leaching of those metallic species in aqueous solution of hydrochloric acid, acetic acid or oxalic acid on the reactivity and ST of resulting coke from a lignite. The leaching at pH ≤ 1 removed catalytic metallic species near completely, reducing the coke reactivity by a factor of 8-15. The reduced reactivity was similar to the reactivity of coke from a typical coking coal. The leaching at pH ≤ 2.2 increased ST from 6 to 13 MPa for briquetting at 200°C and 32 MPa. The performance of leaching with oxalic acid, of that solution had pH of 0.75 at 1 mol/L, was much better than that with acetic acid. This work also examined another type of leaching, oxidation of the lignite in aqueous solution of hydrogen peroxide, which produced organic mono-/di-acids in-situ from the oxidation of aromatic carbons of the lignite. The degree of reduction of the coke reactivity was between that for leaching at pH of 1 and 2. The degradation of macromolecules enhanced plasticizability of the lignite under briquetting and increased ST of the resulting coke to 22 MPa.

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“…Among the chemicals derived from LRCs, the organic acids, including the small-molecule fatty acids (SMFAs) and benzene carboxylic acids (BCAs), are important industrial blocks with wide applications (Wang et al 2013a, b;Hu et al 2016;Lv et al 2016). Various oxidation approaches, including ruthenium ion-catalyzed oxidation (RICO), (Huang et al 2008;Liu et al 2016) oxidation with different oxidizing agents such as H 2 O 2 , ozone, oxygen (Mae et al 2001;Yu et al 2014), and alkalioxygen oxidation (Wang et al 2012(Wang et al , 2013aYang et al 2015), were developed to produce organic acids from LRCs. High yields of the organic acids, including 18.4%-21.5% of BCAs and 39.8%-23.2% of SMFAs, have been achieved via alkali-oxygen oxidation (Wang et al 2013a, b).…”

Section: Introductionmentioning

confidence: 99%

Using benzene carboxylic acids to prepare zirconium-based catalysts for the conversion of biomass-derived furfural

Zhou

Sha

Xiao

et al. 2017

Int J Coal Sci Technol

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Benzene carboxylic acid (BCAs) are common and useful chemical blocks, which can be derived from the abundant low rank coals (LRCs) via oxidative degradation. In this work, we proposed a novel strategy to utilize BCAs as raw materials to prepare catalysts with transition metal zirconium, and the prepared catalysts were applied into the conversion of the renewable biomass resources. Typical model BCAs in the oxidative products of LRCs, including pyromellitic acid, trimesic acid (TMSA), trimellitic acid, and benzoic acid, were used as the block to construct the ZrBCAs catalysts. The chemoselective conversion of furfural into furfuryl alcohol (FAL), an important reaction in the biomass conversion chain, is chosen to evaluate the activity of the catalysts. The preparation conditions of the catalysts and experiment factors during the reaction were systematically investigated. The prepared catalysts were characterized by SEM, TEM, XRD and TG-DTG. The results showed that the prepared catalysts were efficient for the conversion of furfural into FAL, among which Zr-TMSA gave the highest activity. Zr-TMSA could be recycled for ten times without obvious deactivation, indicating an excellent stability. The strategy proposed in this work may be beneficial for the value-added utilization of both LRCs and biomass resources.Graphical Abstract Zr-BCAs catalysts prepared using benzene carboxylic acids and Zr are very efficient and stable for hydrogenation of biomass-derived furfural to furfuryl alcohol at mild conditions.

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A New Two-Step Oxidative Degradation Method for Producing Valuable Chemicals from Low Rank Coals under Mild Conditions

Cited by 100 publications

References 9 publications

Characterization of humic acids extracted from a lignite and interpretation for the mass spectra

Characterization of humic acids extracted from a lignite and interpretation for the mass spectra

Modification of Reactivity and Strength of Formed Coke from Victorian Lignite by Leaching of Metallic Species

Using benzene carboxylic acids to prepare zirconium-based catalysts for the conversion of biomass-derived furfural

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