Infrared spectroscopic characteristics of bagasse cresol lignin

Nada, A. M. A.; El‐Saied, Houssni; Fadl, Mohamed H.; Nassar, Mona A.

doi:10.1016/0141-3910(94)90225-9

Cited by 9 publications

(2 citation statements)

References 5 publications

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“…A typical GC/MS chromatogram for the bagasse reaction products is shown in Figure ,and peaks for the major dimers are identified on it. Nada et al , analyzed bagasse lignin recovered from the black liquors of organosolv, soda, SAQ, and kraft pulping and found that their methoxyl contents consistently fell in the range of 0.98–1.05 OCH 3 /C 9 . Chen et al performed alkaline nitrobenzene oxidation on bagasse meal and obtained a high total yield of substituted benzaldehyde + benzoic acids.…”

Section: Resultsmentioning

confidence: 99%

Trapping of p-Coumaryl and Coniferyl Alcohol during Soda–Anthraquinone Treatment: A Means of Estimating Uncondensed β-O-4 Structures in Native Lignin

Alves

Bose

Francis

et al. 2012

J. Agric. Food Chem.

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In most native lignins, at least 50% of the phenylpropane (C(9)) units are involved in β-O-4 linkages. It was recently observed that ethylguaiacol (EG) was efficient at trapping coniferyl alcohol generated from the cleavage of uncondensed β-O-4 dimeric structures during soda-anthraquinone (AQ) or SAQ delignification of sugar maple wood meal. Some of the coniferyl alcohol was transformed to vinylguaiacol and isoeugenol, and the α-carbon atom in all three monomers formed C-C bonds with the C-5 position of EG. In the present research, eucalyptus and sugar cane bagasse meals were also investigated, and the yields of uncondensed β-O-4 structures in the nonsyringyl fraction were quantitated. The estimates of the uncondensed fraction of the lignin in the three samples (assuming S units are 90-95% uncondensed) were in close agreement with results from traditional but more tedious methods such as permanganate oxidation or spectroscopic methods requiring a sample representative of native lignin.

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Section: Resultsmentioning

confidence: 99%

Trapping of p-Coumaryl and Coniferyl Alcohol during Soda–Anthraquinone Treatment: A Means of Estimating Uncondensed β-O-4 Structures in Native Lignin

Alves

Bose

Francis

et al. 2012

J. Agric. Food Chem.

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“…It is a renewable and nontoxic resource, which has potential application as polymer-based products such as lignin-phenol formaldehyde resin, lignin-isocyanate polyurethane adhesives, foam insulation, etc. [2][3][4]. But at present time, lignin is mainly separated from the black liquor of the pulping process, in which the original structure of lignin is destroyed.…”

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confidence: 98%

Separation and characteristic analysis of steam-exploded lignin from cornstalk residue

Chen

Cheng

2009

Chem Nat Compd

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UDC 547.992Steam-exploded lignin (SEL) was separated from cornstalk residue, which came from steam-exploded cornstalk after enzymatic hydrolysis. There are two methods to acquire SEL, the alkali solution and the organic solvent method. SEL was analyzed with respect to the elementary composition, molecular weight, IR spectrum, and 13 C NMR spectra. The C 9 -formula of SEL was calculated from the experiment data. According to 13 C NMR, SEL can be classified as a "GSH" type of lignin, and it is composed mainly of β-O-4 ether bonds together with β-5 and β-1 carbon-carbon linkages between the lignin structural units.Key words: enzymatic hydrolysis of cornstalks, steam-exploded lignin (SEL), structure of SEL, separation.Many researchers use cornstalks as raw material for making bioalcohol by transforming the saccharide components through steam explosion to enzymatic hydrolysis [1]. This is an important application for renewable natural resources. There is about 30-35% lignin in cornstalk residue [2]. Steam-exploded lignin (SEL) from cornstalk residue can be obtained by two methods, the aqueous alkali solution and the organic solvent method.Lignin is an amorphous aromatic network polymer made up of phenylpropane (C 6 -C 3 ) units by carbon-carbon bonds and ether linkages, in which the β-aryl ether linkage (48% and 60% in spruce and birch lignin, respectively) is the most dominant [3]. It is a renewable and nontoxic resource, which has potential application as polymer-based products such as lignin-phenol formaldehyde resin, lignin-isocyanate polyurethane adhesives, foam insulation, etc. [2][3][4]. But at present time, lignin is mainly separated from the black liquor of the pulping process, in which the original structure of lignin is destroyed. In spite of many years of development effort, industrial lignin products are limited in number. SEL is used in polymer modification because it preserves the original chemical activity perfectly. Chemical analysis as well as NMR and infrared spectroscopy were used to analyze the structure of lignin, and also to give information on the actual chemical group altered, removed, and/ or added to lignin during the separation process [5]. In this paper, the structural and physical and chemical characterization of SEL was investigated by chemical analysis and infrared and NMR spectroscopy.There are two methods for extracting SEL. An aqueous alkali solution easily reacts with lignin. Sodium hydroxide or ammonia was selected as the alkali solution. According to orthogonal analysis, the reaction temperature is set at 65-70°C. If the pH value is adjusted by H 2 SO 4 , lignin will be precipitated [6]. The second method of separating lignin is by organic solvent extraction. Some solvents such as 1,4-butanediol, glycol, tetrahydrofuran, or dimethyl sulfoxide can be chosen to dissolve the lignin, but the boiling point of tetrahydrofuran or dimethyl sulfoxide is very low, and its toxicity is unfavorable to work with. So 1,4-butanediol and glycol were chosen to dissolve the lignin. The extraction yi...

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Preparation and characteristic analysis of rice husk high boiling solvent lignin

Chen

Cheng

2008

Journal of Forestry Research

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Rice husk high boiling solvent lignin (RHL) was prepared by high boiling solvent method, and its characteristics was analyzed by using chemical composition analysis, infrared spectroscopy, and 1 H-NMR and 13 C-NMR spectroscopy. The optimum prepared condition was that the rice husk with 70%-90% aqueous solution of 1, 4-butanediol was mixed with autoclave, under a certain weight ratio of solid raw material and solvent, heated to 200-220°C for 1.0-3.0 h, then water-insoluble RHL was separated from the liquor reaction mixture by water precipitation. Results suggested that the lower digestion temperature and concentration of 1,4-butanediol were both unfavorable for extracting lignin. Chemical weight-average molecular weight of RHL was 1939 g⋅mol -1 , and the residual polysaccharide content was 5.12%. The 1 H-NMR spectra of RHL showed the relative intensity ratio, aliphatic over aromatic methoxyl groups, situated at 3.5-3.8 and 3.8-4.0 ppm, respectively. The results from 13 C-NMR spectra showed that β-O-4 bond and β-5 carbon-carbon linkage were the major linkages between RHL units. The C 9 -formula of RHL was calculated by the experiment data.

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Infrared spectroscopic characteristics of bagasse cresol lignin

Cited by 9 publications

References 5 publications

Trapping of p-Coumaryl and Coniferyl Alcohol during Soda–Anthraquinone Treatment: A Means of Estimating Uncondensed β-O-4 Structures in Native Lignin

Trapping of p-Coumaryl and Coniferyl Alcohol during Soda–Anthraquinone Treatment: A Means of Estimating Uncondensed β-O-4 Structures in Native Lignin

Separation and characteristic analysis of steam-exploded lignin from cornstalk residue

Preparation and characteristic analysis of rice husk high boiling solvent lignin

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