Kinetic Evaluation and Modeling of Lignin Catalytic Wet Oxidation to Selective Production of Aromatic Aldehydes

Sales, Fernando G.; Maranhão, Laísse C.A.; Filho, Nelson M. Lima; Abreu, César Augusto Moraes de

doi:10.1021/ie0601697

Cited by 66 publications

(70 citation statements)

References 12 publications

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“…To explore the influence of the lignin concentration on the yield of products, experiments were conducted at four different lignin concentrations (4,10,20, and 40 g L -1 ). The reaction temperature and oxygen partial pressure were kept constant at 225°C and 10 bar, respectively.…”

Section: Effect Of the Lignin Concentrationmentioning

confidence: 99%

“…Various types of catalysts from expensive noble metals [20][21][22] to inexpensive metal ions such as iron, copper, and cobalt have been extensively studied [23][24][25][26][27] for a lignin catalytic wet oxidation process. In general, the lignin conversion rate and the yield of aromatic aldehydes are enhanced significantly in catalytic processes compared with non-catalytic processes [28].…”

Section: Introductionmentioning

confidence: 99%

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Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

et al. 2015

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The production of carboxylic acids by partial wet oxidation of alkali lignin was studied experimentally. The factors influencing the different types of products, their yields and concentrations were investigated. Formic, acetic, succinic, oxalic, and glutaconic acid were the main identified products. Both the temperature and oxygen partial pressure are shown to have direct effects on the product yields whereas the lignin concentration has an indirect effect. At low lignin concentrations, the yield of products was relatively high. However, at higher concentrations, the yield decreased. By measuring the lignin molecular weight distributions, it is shown that this decrease is linked to repolymerization/condensation reactions of lignin fragments which compete with oxidative lignin depolymerization.

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Section: Effect Of the Lignin Concentrationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

et al. 2015

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“…[10][11][12][13] There are two reports of lignin being oxidized by the Co/Mn/Br catalyst in acetic acid. Organosolv lignins have been oxidized using a Co/Mn/Br catalyst in acetic acid at 210 8C to give vanillin and vanillic acid in 1.9 and 3.0 wt% yield, respectively.…”

Section: Introductionmentioning

confidence: 99%

The Aerobic Oxidative Cleavage of Lignin to Produce Hydroxyaromatic Benzaldehydes and Carboxylic Acids via Metal/Bromide Catalysts in Acetic Acid/Water Mixtures

Partenheimer

2009

Adv Synth Catal

115

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Roughly 30% of all woody plants is composed of lignin. Five different lignin samples, from wood and bagasse, were oxidized in air with a cobalt/ manganese/zirconium/bromide (Co/Mn/Zr/Br) catalyst in acetic acid as a function of time, temperature, pressure, and lignin and catalyst concentrations. 18 products were identified via gas chromatographymass spectrometry (GC/MS). The most valuable products from lignin were 4-hydroxybenzaldehyde, 4-hydroxybenzoic acid, 4-hydroxy-3-methoxybenzaldehyde (vanillin), 4-hydroxy-3-methoxybenzoic acid (vanillic acid), 4-hydroxy-3,5-dimethoxybenzaldehyde (syringaldehyde) and 4-hydroxy-3,5-dimethoxybenzoic acid (syringic acid). 10.9 wt% of the lignin was converted to the aromatic products. By the use of model compounds we demonstrate that 1) the presence of the phenolic functionality on an aromatic ring does inhibit the rate of reaction but that the alkyl group on the ring still does oxidize to the carboxylic acid, 2) that the masking of phenol by acetylation occurs at a reasonable rate in acetic acid, 3) that the alkyl group of the masked phenol does very readily oxidize, 4) that an acetic anhydride/acetic acid mixture is a good oxidation solvent and 5) that a two-step acetylation/oxidation to the carboxylic acid is feasible.

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“…2 can be obtained from the wet aerobic oxidation (WAO) process of lignin. These aldehydes have wide applications such as flavoring, chemical intermediaries for pharmaceutical drugs and agricultural defensives [4,5].…”

Section: Introductionmentioning

confidence: 99%

Perovskite-type Oxide LaMnO3: An Efficient and Recyclable Heterogeneous Catalyst for the Wet Aerobic Oxidation of Lignin to Aromatic Aldehydes

et al. 2008

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The perovskite-type oxide catalyst LaMnO 3 prepared by the sol-gel method was found to be an efficient heterogeneous and recyclable catalyst for the wet aerobic oxidation of lignin to aromatic aldehydes. The lignin conversion rate and the yield of each aromatic aldehyde were enhanced significantly by the catalytic process as compared with the non-catalyzed process. Moreover, the activity, specific surface area and perovskite-type structure of the LaMnO 3 catalyst remained nearly unchanged after five successive recycles of catalytic reactions.

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Kinetic Evaluation and Modeling of Lignin Catalytic Wet Oxidation to Selective Production of Aromatic Aldehydes

Cited by 66 publications

References 12 publications

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

The Aerobic Oxidative Cleavage of Lignin to Produce Hydroxyaromatic Benzaldehydes and Carboxylic Acids via Metal/Bromide Catalysts in Acetic Acid/Water Mixtures

Perovskite-type Oxide LaMnO3: An Efficient and Recyclable Heterogeneous Catalyst for the Wet Aerobic Oxidation of Lignin to Aromatic Aldehydes

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