Characterization of lignin residues derived from the alkaline hydrolysis of glycol lignin

Thring, Ronald W.; Chornet, E.; Bouchard, Jean; Vidal, P. F.; Overend, R. P.

doi:10.1139/v90-017

Cited by 38 publications

(15 citation statements)

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“…It can be observed that the prominent difference was 3407 cm −1 (O-H stretching in hydroxyl group), 2917 cm −1 (C-H stretching in methyl and methyene groups), 1645 cm −1 (C O stretching in conjugated aryl ketone), 1247-1519 cm −1 (guaiacyl and syringyl lignin characteristic peaks), and 1031 cm −1 (aromatic C-H in-plane deformation). 21,22 All these bands disappeared or decreased after alkali pretreatment assisted by photocatalysis. These results again highlight the delignification effect of this pretreatment process.…”

Section: Physical Properties and Microstructure Of Pretreated Rice Strawmentioning

confidence: 97%

Enhanced enzymatic hydrolysis of rice straw pretreated by alkali assisted with photocatalysis technology

Niu

Chen

Zhang

et al. 2009

J of Chemical Tech & Biotech

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Section: Physical Properties and Microstructure Of Pretreated Rice Strawmentioning

confidence: 97%

Enhanced enzymatic hydrolysis of rice straw pretreated by alkali assisted with photocatalysis technology

Niu

Chen

Zhang

et al. 2009

J of Chemical Tech & Biotech

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“…The methyl acetate may be one of the impurities in the ethylene glycol, while the various 1,3 dioxolane derivatives are produced from the ethylene glycol. The other identified compounds derive from glucose pyrolysis as shown by Niemela (1988a and1988b).…”

Section: The S Fraction (Condenser Trap At 0°c)mentioning

confidence: 99%

The behavior of ethylene glycol during the thermal solvolysis of cellulose

et al. 1992

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The composition of the ethylene glycol solution resulting from cellulose thermal solvolysis, to produce microcrystal‐line cellulose, has been studied. Liquid and gas chromatographic analyses showed, a) little degradation of the ethylene glycol up to 280°C, and b) an acceleration of the degradation at higher temperatures in the presence of cellulose and glucose. Solubilized compounds resulting from the cellulose depolymerization although numerous were present in too low concentrations to warrant their recovery.

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Production of phenol compounds by alkaline treatment of poplar wood bark

2010

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It is well known that, as a result of thermo-chemical treatment in a water-alkaline medium, lignin is destroyed and low-molecular-weight phenol compounds are obtained [1][2][3][4]. Low-molecular-weight phenol compounds (LMPC) 2-methoxyphenol, 2,6-dimethoxyphenol, vanillin, etc. were previously obtained from the alkaline destruction of technical hydrolysis lignin (THL), wood biomass, and poplar wood bark [5]. The optimal conditions for obtaining LMPC were lignin-5% NaOH ratio 1:10 and process duration 6 hours. The experiment has been carried out at 180qC [6].Technical hydrolysis lignin is not as common a residue as wood bark. Moreover, treatment of the poplar wood bark leads to a considerably higher yield of low-molecular-weight compounds in comparison with those from THL treatment [5]. This statement is due to the more condensed THL structure. The aim of the present investigation is to carry out alkaline treatment of poplar wood bark under different conditions.The lignin content in poplar wood bark is 37.40 mass % of initial bark. It was found that with increasing process duration and concentration of NaOH (6 h, 7% NaOH) the highest quality of LMPC was obtained (Table 1). Moreover, at these conditions the influence of hydromodule on LMPC yield was studied. It was established that at h.m. 1:8 and 1:10 a similar yield of LMPC was obtained (Table 2). Table 3 presents low-molecular-weight phenol compounds obtained from poplar wood bark under different conditions. The possibility for obtaining low-molecular-weight phenol compounds through alkaline treatment of poplar wood bark was investigated. It was found out that alkaline treatment is an effective process, in which the main part of the lignin is destroyed, and as a result of this, low-molecular-weight phenol compounds are obtained. Using extraction with toluene from the liquid phase, the following compounds were isolated: 2-methoxyphenol, 2,6-dimethoxyphenol, 4-hydroxy-3-methoxybenzaldehyde, 4-hydroxy-3,5-dimethoxybenzaldehyde, 1-(4-hydroxy-3-methoxyphenyl) ethanone, etc.For the purpose of this investigation, poplar wood bark was previously powdered. The process and extraction conditions were determined based on the results of our previous investigations [5,6]. The alkaline treatment of bark was carried out in stirring autoclaves made of stainless steel, heated in a bath of polyethyleneglycol at 180qC for 2, 4, and 6 hours. A water solution of NaOH (3, 5, and 7%) was used at different bark/water solution of NaOH ratios (hydromodule) -1:6, 1:8, and 1:10.The amounts of obtained extracts, insoluble residue, and precipitated and nonprecipitated lignin were determined. The LMPC were identified by GC-MS analysis [5,6].

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Characterization of lignin residues derived from the alkaline hydrolysis of glycol lignin

Cited by 38 publications

References 11 publications

Enhanced enzymatic hydrolysis of rice straw pretreated by alkali assisted with photocatalysis technology

Enhanced enzymatic hydrolysis of rice straw pretreated by alkali assisted with photocatalysis technology

The behavior of ethylene glycol during the thermal solvolysis of cellulose

Production of phenol compounds by alkaline treatment of poplar wood bark

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