Supercritical Ethanolysis of Wheat Stalk Powder over CaO/Al2O3and CaO/Al2O3/Fe3O4†

Xu, Wenjuan; Zhao, Wei; Sheng, Chunhong; Zhong, S.; Wu, Xiaona; Yan, Cai-Hui; Bai, Sha; Zong, Zhi‐Min; Wei, Xian‐Yong

doi:10.1021/ef900535y

Cited by 12 publications

(7 citation statements)

References 13 publications

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“…Liquefaction reactions are typically catalyzed by acid and base catalysts. 17,18 In this paper, the activities of different catalysts were investigated. Fig.…”

Section: Effect Of Reaction Parameters On the Liquefaction Reactionmentioning

confidence: 99%

Renewable chemical feedstocks from integrated liquefaction processing of lignocellulosic materials using microwave energy

Jiang

Hse

et al. 2012

Green Chem.

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The objective of this investigation was to find a simple method for the production of phenolic rich products and sugar derivatives (biopolyols) via separation of liquefied lingocellulosic materials. Liquefaction of lignocellulosic materials was conducted in methanol at 180°C for 15 min with the conversion of raw materials at about 75%. After liquefaction, the liquefied products were separated by addition of a sufficient amount of water. It was found that the hydrophobic phenolics could be largely separated from aqueous solutions. The phenolic products that precipitated from the aqueous phase were mainly composed of phenolic derivatives such as 2-methoxy-4-propyl-phenol and 4-hydroxy-3-methoxybenzoic acid methyl ester. Afterwards, the aqueous solution was distilled under vacuum to remove water and formed a viscous liquid product henceforth termed biopolyol. As evidenced by GC-MS analysis, the biopolyols contained methyl sugar derivatives, including methyl β-D-mannofuranoside, methyl α-D-galactopyranoside, methyl α-D-glucopyranoside, and methyl β-D-glucopyranoside. The effect of glycerol on promotion of the liquefaction reaction was also studied. The yield of residue was significantly decreased from approximately 25 to 12% when a glycerol-methanol mixture was used as solvent rather than methanol. According to the GC-MS analysis, the total content of phenolics and poly-hydroxy compounds (including glycerol and sugar derivatives) in phenolic products and biopolyols was 65.9 and 84.9%, respectively. Therefore, a new method for fractionation of liquefied products was proposed according to the molecular structure of the biomass.

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“…Liquefaction reactions are typically catalyzed by acid and base catalysts. 17,18 In this paper, the activities of different catalysts were investigated. Fig.…”

Section: Effect Of Reaction Parameters On the Liquefaction Reactionmentioning

confidence: 99%

Renewable chemical feedstocks from integrated liquefaction processing of lignocellulosic materials using microwave energy

Jiang

Hse

et al. 2012

Green Chem.

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“…In contrast to LA, the low boiling point, acid-free and easilyseparable EL, produced by the ethanolysis of various carbohydrates such as glucose, fructose, sucrose, or cellulose, is a better alternative for the synthesis of GVL. 31 Recently, Zhao et al 32 demonstrated a high-pressure direct liquefaction process through supercritical ethanolysis over metal oxides, GVL was detected in the mixture after reaction. Dumesic et al reported the catalytic transfer hydrogenation (CTH) of LA and its esters into GVL through the Meerwein-Ponndorf-Verley (MPV) reaction over metal oxide catalysts using alcohols as the hydrogen donors in the presence of an alkylphenol.…”

Section: Introductionmentioning

confidence: 99%

Conversion of biomass-derived ethyl levulinate into γ-valerolactone via hydrogen transfer from supercritical ethanol over a ZrO2 catalyst

et al. 2013

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A green and efficient process was developed for the conversion of biomass-derived ethyl levulinate (EL) into c-valerolactone (GVL) using supercritical ethanol as the hydrogen donor and the reaction medium over low-cost and eco-friendly ZrO 2 catalysts, which were prepared by the precipitation method and characterized by BET, SEM, XRD, FT-IR, TGA-DTA, TPD-NH 3 and TPD-CO 2 . The results indicated that amorphous ZrO 2 with a high specific surface area and a large number of acid-base sites exhibited the highest catalytic activity, an excellent GVL yield of 81.5% with 95.5% EL conversion was achieved at 523 K over 3 h. In addition, combined with the results of poisoning experiments, a plausible mechanism of catalytic transfer hydrogenation (CTH) via a six-membered ring transition state was also presented.

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“…CAs were also detected from non-catalytically degraded corn stalk in supercritical alkanols and from catalytically degraded WS in supercritical ethanol . Reported CAs detected in degraded biomass are usually indene, naphthalene, acenaphthene, fluorene, anthracene, pyrene, and their alkyl derivatives. ,− , Similar kinds of CAs were detected in F 1–1 , but the detection of BQs, BNs, PDs, BNFs, and AFs, which were enriched in F 4–1 and F 4–2 , from either non-degraded or degraded biomass were seldom reported, if any.…”

mentioning

confidence: 92%

“…17 CAs were also detected from non-catalytically degraded corn stalk in supercritical alkanols 24 and from catalytically degraded WS in supercritical ethanol. 25 Great attention should be paid to their toxicities, including teratogenicity, carcinogenicity, and mutagenicity. On the other hand, most CAs, especially HCAs, are value-added chemicals.…”

mentioning

confidence: 99%

Enrichment and Identification of Condensed Aromatics in a Bio-oil from Degraded Wheat Stalk in Supercritical Ethanol

et al. 2012

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Crop stalks (CSs) are common agricultural wastes in China. The annual yield of CSs in China is ca. 0.7 billion tons, 1 but only 1 / 3 of CSs is used. The problem of dealing with tons of CSs needs to be solved urgently. Part of CSs is piled up along roads, ditches, and even beside houses, which occupies a lot of space and hinders the traffic. During harvest seasons, most of the CSs in China are burned to ensure normal farming. 2 CS combustion in the field degrades air quality by emitting soot, carbon monoxide, methane, and other volatile organic compounds and forming aerosol. 2−9 Condensed aromatics (CAs) are important parts of aerosol and ubiquitous in the environment. 10−12 They are primarily generated from anthropogenic pollution, such as incomplete combustion of oil and biomass in boiler, heating installation, commercial installation, and engine. 8,13 CAs associate with inhalable particles, resulting in harm to human health as a result of the teratogenicity, carcinogenicity, and mutagenicity. 13−16 They tend to accumulate in aquatic organisms and plants or form more virulent products under effects of photoinduction, bioaccumulation, or biological processes in rivers, lakes, oceans, and soil. Quite a few studies, including volatilization, photo-and chemical oxidation, adsorption to soil particles, leaching, and biodegradation, were focused on seeking solutions to the pollution from CAs. 10,13 However, the methods are considered as treatments after CAs enter the environment. It is urgent and necessary to find a clean way to use CSs and avoid CAs emitting to the environment. In the present investigation, we tried to understand the modes of CA occurrences in wheat stalk (WS) by degradation of the WS in supercritical ethanol, column chromatography of degraded WS, and subsequent analysis of the eluted fractions with gas chromatography/mass spectrometry (GC/MS).The WS was collected from a Xuzhou suburb, Jiangsu province, China. It was pulverized to pass through an 80-mesh sieve and dried in a vacuum oven at 105 °C for 3.5 h. Table 1 shows proximate, ultimate, and chemical analyses of the sample. All of the solvents used in the experiment, including petroleum ether (PE), methyl acetate (MA), and ethanol, are analytical reagents and distilled prior to use. Silica gel (SG, 100−200 mesh) was activated in a vacuum oven at 145 °C for 6 h before use. As Figure 1 shows, 10 g of WS and 300 mL of ethanol were put into a 500 mL stainless-steel, magnetically stirred autoclave. The autoclave was heated to 300 °C within 1 h, kept at that temperature for 0.5 h, and then immediately cooled to room temperature in an ice−water bath. The reaction mixture was

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Supercritical Ethanolysis of Wheat Stalk Powder over CaO/Al₂O₃and CaO/Al₂O₃/Fe₃O₄^†

Cited by 12 publications

References 13 publications

Renewable chemical feedstocks from integrated liquefaction processing of lignocellulosic materials using microwave energy

Renewable chemical feedstocks from integrated liquefaction processing of lignocellulosic materials using microwave energy

Conversion of biomass-derived ethyl levulinate into γ-valerolactone via hydrogen transfer from supercritical ethanol over a ZrO2 catalyst

Enrichment and Identification of Condensed Aromatics in a Bio-oil from Degraded Wheat Stalk in Supercritical Ethanol

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