1,721,166 research outputs found
Biomimetic approach to lignin degradation: Metalloporphyrins catalyzed oxidation of lignin and lignin-model compounds
No full textAdvanced lignin oxidative strategies. Catalysis, biocatalysis and biomimetic systems
No full textAmong the fundamental aspects of lignin chemistry a special focus is toward the design and development of new selective oxidative degradation processes. Pulp and paper industry requires environmentally friendly lignin oxidation procedures that can give high yield pulps thus
preserving cellulose. This aim can be reached developing oxidative strategies that do not involve the formation of hydroxyl radical species mainly responsible for cellulose degradation. An example
of the design of deligninfication strategies is outlined
Methyltrioxorhenium: a new catalyst for the activation of hydrogen peroxide to the oxidation of lignin and lignin model compounds
No full textA New Efficient and Mild Synthesis of 2-Sxindoles by One-Pot Wolff-Kishner Like Reduction of Isatin Derivatives
No full textIndole-2-one derivatives were prepared from the corrisponding isatines
via one pot reduction in hydrazine hydrate
Oxidative functionalisation of lignin by layer-by-layer immobilised laccases and laccase microcapsules
No full textLayer-by-Layer coated tyrosinase: An efficient and selective synthesis of catechols
Full text linkAgaricus bisporous tyrosinase was immobilized on commercial available epoxy-resin Eupergit (R) C250L and then coated by the Layer-by-Layer method (LbL). The two novel heterogeneous biocatalysts were characterized for their morphology, pH and storage stability, kinetic properties (K-m, V-max, V-max/K-m) and reusability. These biocatalysts were used for the efficient and selective synthesis of bioactive catechols under mild and environmental friendly experimental conditions. Ascorbic acid was added in the reaction medium to inhibit the formation of ortho-quinones, thus avoiding the known enzyme suicide inactivation process. Catechols were obtained mostly in quantitative yields and conversion of substrate. Tyrosinase immobilized on Eupergit (R) C250L and coated by the LbL method showed better catalytic activities, higher pH and storage stability, and reusability with respect to immobilized uncoated tyrosinase. Since chemical procedures to synthesize catechols are often expensive and with high environmental impact, the use of immobilized tyrosinase represents an efficient alternative for the preparation of this family of bioactive compounds. (C) 2011 Elsevier Ltd. All rights reserved
TRATTAMENTI ENZIMATICI PER LA FUNZIONALIZZAZIONE DELLA LIGNINA E DELLE FIBRE LIGNOCELLULOSICHE
No full textPer sviluppare l’utilizzo delle biomasse è necessario ampliare gli utilizzi industriali della lignina. Le possibili strategie
per la valorizzazione della lignina passano attraverso due principali direzioni, definibili come una funzionalizzazione selettiva del polimero o una depolimerizzazione ossidativa, per sintetizzare dei composti monomerici opportunamente derivatizzati. Si riporta una breve rassegna di processi enzimatici che comportano l’attivazione dell’ossigeno per ottenere una funzionalizzazione ossidativa della lignina.Enzymatic Treatments for the Functionalization of Lignin and Lignocellulosic Fibers
Novel processing methods and product concepts are required to extend the role of lignin for future biomass and biofuel applications in emerging platforms such as the biorefinery. The possible strategies of lignin valorisation are focused into two main directions, namely the selective functionalisation of the lignin polymer or in its oxidative polymerization to get polyfunctional monomeric compounds. Here we report a short panel of enzymatic processes group for the activation of the environmental friendly oxidants oxygen in the oxidative functionalization of lignin
PROCEDIMENTO DI ANALISI DI TANNINI
No full textLa presente invenzione ha per oggetto un procedimento di analisi e caratteriz-
zazione di tannini del tipo precisato nel preambolo della prima rivendicazion
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