Nucleus Exchange Reaction

Funaoka, Masamitsu; Abe, Isao; Chiang, Vincent L.

doi:10.1007/978-3-642-74065-7_25

Cited by 14 publications

(7 citation statements)

References 17 publications

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“…The so called nucleus exchange method gives similar results (Funaoka et al 1992). As judged from a recent reassessment of the nucleus exchange method, however, the number of condensed units determined by this method can be expected to be too low (Chan et al 1995).…”

Section: The Bonding Of the Phenylpropane Unitssupporting

confidence: 54%

Lignin Chemistry and its Role in Biomass Conversion

Brunow¹

2005

Biorefineries‐Industrial Processes and Products

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Section: The Bonding Of the Phenylpropane Unitssupporting

confidence: 54%

Lignin Chemistry and its Role in Biomass Conversion

Brunow¹

2005

Biorefineries‐Industrial Processes and Products

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“…Lignocresol was characterized by the phenyl nucleus exchange technique (Funaoka and Abe 1987;Funaoka et al 1992), nitrobenzene oxidation, and a combination of periodate oxidation with them Funaoka 1993 a, 1993 b). The phenyl nucleus exchange reaction involves selective and quantitative cleavage of alkyl-aryl carbon-carbon linkages in diphenylmethane type structural units.…”

Section: Degradative Analysismentioning

confidence: 99%

Characteristics of Lignin Structural Conversion in a Phase-Separative Reaction System Composed of Cresol and Sulfuric Acid

Funaoka¹,

Fukatsu²

1996

HFSG

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The chemical structures of lignocresols derived from native lignins by the phase-separative treatment with cresol and sulfuric acid were characterized by spectral analyses and chemical degradations. The changes in the structure of lignin during the conversion process were discussed. Lignocresol had few conjugated systems, being pinkish white, its brightness comparable to milled wood lignin. Spruce lignocresol included 0.64mol/C9 of cresolic nuclei in the molecule (0.9mol/C9 in birch lignocresol), 77% of which were linked to lignin Cα-positions through carbon-carbon linkages, 16% possibly to Cy-positions, and the remaining 7% etherified to lignin side chains through its phenolic hydroxyl groups. The molecular weight (Mw) of lignocresol was ca. 3500 in spruce, lower in birch. Most of the β-and γ-positions in the side chains of Cg units remained intact, except the coniferyi alcohol and aldehyde units. These structural features were constant during the reaction time up to 60min. It is concluded that the fragmentation of lignin in the phase-separative reaction system was principally due to the cleavage of benzyl aryl ethers, and the skeleton of lignocresol represents those of lignin subblocks formed by the dehydrogenative polymerization of monolignols.

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“…We have conducted studies (Lai et al 1994 aimed at understanding the nature and reactivity of those suspected diphenylmethane (DPM) or equivalent type structures formed in alkaline pulping (Chiang and Funaoka 1988;Funaoka et al 1992). Recent findings indicated that phenolic DPM model dimers were rather reactive in alkalioxygen solution and under nitrobenzene oxidation conditions (Chan et al 1995;Xu et al 1997), giving a significant formation of monomeric products.…”

Section: Introductionmentioning

confidence: 96%

Reactivity of Lignin Diphenylmethane Model Dimers. 2. Permanganate Oxidation

Meguro¹,

Hong²,

Lai³

1998

Holzforschung

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Major products obtained from the permanganate oxidation of unsubstituted guaiacyl oc-diphenylmethane-model dimers were the diguaiacylketone compounds (35-45%) and veratric acid (3-14%). Also, small amounts of isohemipinic (4%) and metahemipinic (1 %) acids were produced from the oc-5 and ct-6 dimers, respectively. The results indicate that the oc-methylene groups were rather reactive under permanganate oxidation conditions.

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Nucleus Exchange Reaction

Cited by 14 publications

References 17 publications

Lignin Chemistry and its Role in Biomass Conversion

Lignin Chemistry and its Role in Biomass Conversion

Characteristics of Lignin Structural Conversion in a Phase-Separative Reaction System Composed of Cresol and Sulfuric Acid

Reactivity of Lignin Diphenylmethane Model Dimers. 2. Permanganate Oxidation

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