Rapid Liquefaction of Wood in Polyhydric Alcohols Under Microwave Heating and its Liquefied Products for Preparation of Rigid Polyurethane Foam

Wang, Dechao

doi:10.2174/1874088x01105010001

Cited by 30 publications

(21 citation statements)

References 7 publications

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“…This behavior could be associated with the increase of organic acid generated from decomposed spent coffee grounds components, such as hemicelluloses . The acid numbers (11–18 mg KOH /g polyol ) were almost in the same range as those reported in the literature …”

Section: Resultssupporting

confidence: 79%

“…10,43 The acid numbers (11-18 mg KOH / g polyol ) were almost in the same range as those reported in the literature. 9,13,15,19,20 Viscosity Figure 6 shows the effect of reaction time on the viscosity of the liquefied spent coffee grounds obtained under optimal liquefaction conditions (160 ∘ C and 4 wt% of sulfuric acid concentration). The viscosity values varied between 356 and 434 cP at 25 ∘ C throughout the reaction time.…”

Section: Acid Numbermentioning

confidence: 99%

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Spent coffee grounds as a renewable source for ecopolyols production

Soares

Gama

Freire

et al. 2014

J. Chem. Technol. Biotechnol.

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BACKGROUND Based on the biorefinery concept, the main focus of this work was the increase in value of spent coffee grounds via an acid liquefaction process using polyhydric solvents in the presence of sulfuric acid, at moderate temperature. For that purpose the effect of temperature, sulfuric acid concentration and time on biomass conversion was studied using design of experiments combined with statistical analysis. RESULTS The ANOVA results (95% confidence level) showed that temperature is the factor with most influence on biomass conversion, within the studied range, while reaction times above 40 min don't seem to bring significant advantages. The maximum conversion obtained in this study was 70 wt% which was achieved at 160°C, 4 wt % of catalyst and 80 min. The polyol obtained using these conditions presented a hydroxyl number value of 199 mg KOH/g polyol and a viscosity of 390 cP, at 25°C. CONCLUSION This work showed that it is possible to convert spent coffee grounds into liquid polyols via an acid liquefaction process at moderate temperature and autogeneous pressure. These polyols have similar properties to those of petroleum‐based polyols typically used in the polyurethane foam industry. © 2014 Society of Chemical Industry

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Section: Resultssupporting

confidence: 79%

Section: Acid Numbermentioning

confidence: 99%

Spent coffee grounds as a renewable source for ecopolyols production

Soares

Gama

Freire

et al. 2014

J. Chem. Technol. Biotechnol.

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“…The absorbance at 1150 cm -1 was due to the ether bond in cellulose (Salehian et al 2013), which was weakened with prolonging reaction times and increasing liquefaction temperatures, suggesting that the cellulose participated in recondensation. The intensity peak at 1088 cm -1 corresponding to the stretching vibration of C-O from polysaccharide gradually decreased as liquefaction proceeded (Zheng et al 2011). This result was confirmed by the GC-MS analysis of bio-oils as discussed below.…”

Section: Energy Efficiency Evaluationsupporting

confidence: 61%

“…The intensified peak at 1409 cm -1 from 140 °C/15 min to 180 °C/15 min, which arose from the plane deviational vibration of hydroxyl group in carboxylic groups, further evidenced the oxidation reactions during liquefaction (Zhang et al 2007). The characteristic peaks of aromatic ring at 1650 and 1450 cm -1 and benzene ring at 1363 cm -1 and 1210 cm -1 tended to be weaker with extended liquefaction, indicating that the decomposed lignin at the initial liquefaction stage underwent recondensation Zheng et al 2011). The intensity of 1210 cm -1 decreased as the liquefaction proceeded, demonstrating that the lignin derivatives participated in a cross-link reaction.…”

Section: Energy Efficiency Evaluationmentioning

confidence: 89%

Microwave-assisted Liquefaction of Rape Straw for the Production of Bio-oils

et al. 2017

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The acid-catalyzed liquefaction of rape straw in methanol using microwave energy was examined. Conversion yield and energy consumption were evaluated to profile the microwave-assisted liquefaction process. Chemical components of the bio-oils from various liquefaction conditions were identified. A higher reaction temperature was found to be beneficial to obtain higher energy consumption efficiency as heated by microwaves. Fourier transform infrared spectroscopy of the bio-oils indicated that hydroxyl groups underwent oxidation with increasing liquefaction temperature and/or prolonged reaction time; methanol esterification of oxidation products was also observed during the liquefaction process. The GC-MS chromatograms indicated that the further decomposition of C5 and C6 sugars resulted in a remarkable reduction of hydroxyl group products and an apparent increase in levulinic ester; furan derivatives and succinic acid derivatives were increased as well. The chemical reactions in liquefaction for the production of bio-oils mainly included decomposition of hemicelluloses, cellulose, and lignin; the oxidation reactions of the hydroxyl groups and methanol esterification were also presented. Comprehensively, a high content of hydroxyl group products was obtained at a moderate liquefaction condition (140 °C/15 min), and a high yield of levulinic ester products was acquired in severe reaction conditions (180 °C/15 min), regardless of energy consumption efficiency.

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“…However, at 15% of lignin, 3% of catalyst and at 100 min, the OH groups were diminished considerably (where acid groups were also reduced). In this sample the low OH groups could be due to the dehydration reaction [12]. The viscosity of the polyols is shown in Tab.…”

Section: Resultsmentioning

confidence: 78%

Liquefaction o Kraft Lignin at Atmospheric Pressure

Silva¹,

Santos²,

Gatto³

et al. 2019

Journal of Renewable Materials

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Kraft lignin was liquefied using polyethylene glycol #400 (PEG) and glycerol (G) in a weight ratio of 80/20 (w/w) and sulphuric acid (SA) as catalyst under atmospheric pressure at 160ºC. The three independent variables: reaction time (60, 80 and 100 min), percentage of lignin (15, 20 and 25%, w/w), and catalyst concentration (0, 3 and 6%, w/w), were varied resulting in 27 experimental runs. The effect of these reaction conditions on the properties of the polyols was evaluated. The statistical analysis showed that only "the percentage of lignin" did not influence the properties of the liquefied products, however, reaction time and catalyst load were important parameters. The resulting liquefied products were characterized by FTIR analysis.

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Rapid Liquefaction of Wood in Polyhydric Alcohols Under Microwave Heating and its Liquefied Products for Preparation of Rigid Polyurethane Foam

Cited by 30 publications

References 7 publications

Spent coffee grounds as a renewable source for ecopolyols production

Spent coffee grounds as a renewable source for ecopolyols production

Microwave-assisted Liquefaction of Rape Straw for the Production of Bio-oils

Liquefaction o Kraft Lignin at Atmospheric Pressure

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